Physiology Midterm 1 Study Guide
Physiology Midterm 1 Study Guide 108
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Physiology Midterm 1 Study Guide Based off of the potential exam questions Professor Doohan gave us 1 Name the 4 primary tissues of the body and provide a function for each Epithelial Tissue forms membranes and lie on internal and external surfaces of organs stratified squamous protects underlying tissue simple squamous is good for diffusion across membranes simple cuboidalsimple columnar form glands 9 they are good for secretion columnar cells are in small intestine 9 good for absorption Connective Tissue protects supports and interconnects other tissues it is bone cartilage tendons ligaments fat and blood it is mostly made up of a matrix material with some fibroblast cells Nervous Tissue is specialized for rapid communication it detects stimuli processes info and develops responses Muscle Tissue is specialized for contraction there are three types skeletal smooth and cardiac muscle tissue 2 Define cellular differentiation The process by which less specialized cells become different more specialized cells 3 What39s the difference between simple and stratified epithelium Simple epithelial tissue is made up of only one layer Stratified epithelial tissue is made up of more than one layer 4 Define intracellular uid ICF The uid within cells 5 Define extracellular uid ECF What 2 types of body uids make up extracellular uid The uid surrounding cells it is made up of plasma the uid portion of blood and interstitial uid the uid that surrounds all cells the ECF gives nutrients and collects waste from all cells 6 Define homeostasis The tendency of a system to maintain a relatively constant internal environment due to coordinated responses within the organ systems o ex respiratory and circulatory systems work to keep 02 and CO2 levels constant 7 How is homeostasis maintained Sensors and neurons detect deviations from set points optimum values for certain conditions and they send signals to the brain where the brain responds by increasing or decreasing activity of effectors musclesglands which restores the body to a condition of homeostasis 0 Negative feedback regulates most homeostatic conditions via sensors integration centers ie the brain and effectors which feeds info to the brain to shut off certain pathways 8 Using temperature as an example explain how a sensor integrating center and effector work together to maintain constant body temperature The temperature drops below its set point 379C 9 sensors detect a change from the set point 9 they send info to the integration center brain 9 brain sends command to skeletal muscles to shiver 9 heat is produced 9 set point is restored 9 sensors send new info to integration center 9 brain ends the command to shiver 9 Do negative feedback loops tend to stabilize a system or disrupt a system Negative feedback loops tend to stabilize a system 10 What is the cytoplasm of a cell Everything inside the cell except the nucleus it contains cystol uid and organelles little organs within the cell 11 What is the function of the nucleus of the cell The nucleus is a membrane bound compartment that holds DNA the genetic material for our bodies it stores and protects the DNA and it controls expression of genes 12 Explain the process of gene expression DNA is copied via transcription into mRNA 9 it is transported outside of the nucleus into the cytoplasm where it is bound to and read by ribosomes via translation creating a long chain of amino acids a protein 13 What is the function of Smooth Endoplasmic Reticulum Smooth ER is the site of lipid biosynthesis production 0 ex phospholipids present in cell membranes cholesterol a steroid involved in production of estrogen and testosterone It also detoxifies drugs and makes drugs more soluble 9 excretion of drugs via kidneys 14 What is the function of Rough Endoplasmic Reticulum Rough ER packages proteins and delivers them often to the Golgi complex 15 Describe the process by which proteins are secreted outside the cell Include in your answer the roles of ribosomes endoplasmic reticulum and the Golgi Ribosomes read and translate mRNA into a chain of amino acids which is sent to the ER for modification The Endoplasmic Reticulum has ribosomes which read mRNA and make proteins 9 get threaded into the ER 9 membrane pinches off and it becomes a vesicle it is only partially chemically modified in the rough ER 9 send to Golgi The Golgi chemically modifies proteins from the rough ER further into their final state 9 proteins ie insulin pinches off from Golgi and travels to membrane where it waits until the body needs insulin or whatever is in the vesicle 9 when your body needs it the vesicle will fuse with the membrane and release the proteins EXOCYTOSIS 0 Every protein that will be secreted will go through the Golgi to be matured before it is released 16 What is the function of lysosomes What types of molecules are digested by lysosome enzymes Lysosomes contain hydrolytic enzymes that catalyze the degradation of macromolecules into smaller components lysosomes usually target old dysfunctional organelles and food ingested via phagocytosis o Immune system cells macrophages eat bacteria and bacteria is digested by lysosomal enzymes via phagocytosis 17 What is the function of mitochondria The mitochondria makes ATP through cellular respiration it uses 02 to metabolize fuel molecules ie carbs fats and proteins it39s the powerhouse of the cell 18 What is the function of ATP ATP is used by the body to maintain all cellular processes ATP 9ADP Pi energy 19 Does the conversion of ATP to ADP Pi release energy or require energy It releases energy 20 The production of ATP requires energy Where does the energy come from The energy comes from fuel molecules such as carbs proteins and fats that you consume from food in your diet 21 What39s the relationship between a solvent a solute and a solution A solvent is usually a liquid and it is much more prominent than the solute Solutes are molecules ions that are dissolved in the solvent A solution is the combination of a solvent and a solute all uids within the human body are solutions 22 Describe the charge distribution on a water molecule Water is a polar molecule that has slightly positive hydrogens attached to a slightly negative oxygen molecule 23 What does it mean that water molecules are polar This means that one end of the molecule is positively charged and the other end is negatively charged 24 Describe how water molecules hydrogen bond with each other 0 slightly H slightly o Slightly positive H will orient themselves towards slightly negative 0 that attraction is a Hydrogen bond Hydrogen bonds are individually weak but collectively strong 25 What does it mean that water molecules are cohesive It means that water is attracted to itself in this case via hydrogen bonds water forms H bonds with other H20 molecules 26 Why are electrically charged atoms like Na and Cl attracted to water Like dissolves like so polar or charged atoms will be attracted to polar charged solvents like water Charged atoms are hydrophilic water loving 27 What does it mean that a substance is hydrophilic or hydrophobic Hydrophilic means water loving those molecules ions will be attracted to the water Hydrophobic means water hating those molecules ions will try to get away from water like the hydrophobic tails of the plasma membrane which orient themselves away from water towards the middle of the bilayer 28 Define Molarity Molarity is the number of moles of solute per liter of solution Molarity is specific to a certain kind of solution ex 05 Molar HCl solution 29 Define Osmolarity Osmolarity is the number of total moles of ionsmolecules in solution per liter of solution o Ex 05 Molar HCl solution 07 Molar NaCl solution 12 Osmolar solution 30 What is the Osmolarity of a 1liter solution that contains 1 mole of glucose and 1 mole of sucrose and 1 mole of fructose 3 Osmolar 31 Describe the basic structure of a phospholipid A phospholipid is a type of lipid that has a polar hydrophilic head and a non polar hydrophobic tail They spontaneously form bilayers in liquid solutions 32 What is the function of phospholipids in the cell membrane It separates the ICF from the ECF 33 How does the presence of cholesterol affect the uidity of the plasma membrane Cholesterol increases the uidity of the plasma membrane 34 Define Diffusion Molecules spontaneously move from areas of high concentration to areas of low concentration 35 What is a concentration gradient A concentration gradient is a difference in concentration between two regions ie unequal distribution of ions across the cell membrane 36 How will the rate of diffusion change if the concentration of the diffusing molecule is increased As concentration is increased the rate of diffusion will increase 37 How will the rate of diffusion change if the temperature of the local environment is increased As temperature increases the rate of diffusion increases 38 How does molecular weight of the diffusing molecule affect the rate of diffusion As molecular weightsize increases the rate of diffusion decreases 39 Define an ion anion and cation Ion a charged molecule 0 Anion a negatively charged molecule 0 Cation a positively charged molecule 40 What types of molecules can diffuse directly across the lipid bilayer of the cell membrane Non charged molecules can diffuse directly across the lipid bilayer 41 Can ions diffuse directly across the plasma membrane Explain No because they have a charge and the non charged tails of the phospholipids will repel the charged molecule 42 What is the function of ion channels in the plasma membrane Ion channels allow ions to freely passively pass through the cell membrane into the cell The regulation of channels is tightly regulated because movement of ions in and out of the cell can majorly affect the electricity of the cell 43 Define Osmosis Osmosis is the diffusion of water across a membrane toward a higher solute concentration 44 What is the function of aquaporins They let water in they are water channels in the membrane water follows the solutes 45 The Osmolarity of the intracellular uid of a red blood cell is 03 osmolar The red blood cell is placed in a solution that has an Osmolarity of 04 osmolar The cell membrane is permeable to water but not to solutes will osmosis occur Explain Osmosis will occur because the membrane is permeable to water and the red blood cell is hypotonic compared to the solution Water will leave the cell via osmosis and enter the solution outside of the cell 46 Define the terms hypotonic isotonic and hypertonic Hypotonic the total molar concentration of all dissolved solute particles is less that that of another solution when a cell is exposed to a hypotonic solution there is a net water movement into the cell 9 cell expands Isotonic total molar concentration of dissolved solutes is the same in both environments Hypertonic the total molar concentration of all dissolved solute particles is greater than that of another solution when a cell is exposed to a hypertonic solution there is a net water movement out of the cell 9 cell shrinks 47 A cell is placed in a hypotonic environment The cell membrane is permeable to water but not to solutes Will osmosis occur Explain Osmosis will occur Water will rush into the cell because in a hypotonic solution there is a greater concentration of water outside of the cell than inside the cell 48 The CF of a cell is isotonic with the ECF surround it Now the cell begins to rapidly transport Ca2 out of the cell Will this action affect the Osmolarity of the CF and the ECF Will it affect osmosis Explain The transportation of Ca2 out of the cell will decrease the Osmolarity inside the cell and increase the Osmolarity outside of the cell making the cell hypotonic compared to the surrounding solution Osmosis will occur as water leaves the cell and follows the Ca2 into the surrounding solution 49 Define ligand A ligand is just an ion or molecule that can be recognized by and transported into the cell it is what neurotransmitters are made out of 50 What is the function of carrier proteins in the plasma membrane Carrier proteins have binding sites that recognize and bind the ion molecule ligand to be transported aka Carrier Mediated Transport 51 Carrier proteins display specificity What is meant by specificity in this case Each carrier only transports one type of molecule it has specific binding sites that are designed to only fit one type of molecule 52 Carrier proteins display saturation Explain Saturation occurs because each carrier has a maximum rate of transportation transport maximum o After the transport maximum is reached the ligand concentration cannot increase because the protein pumps cannot pump any faster Rate of ligand transport into cell Trasport Maximum 35 25 1 15 1 110lX3 JO 93123 05 Ligand concentration 1 U L L J U 0 02 04 06 08 1 12 14 16 53 Define Transport Maximum Tm in the context of carrier proteins and their ligands A transport maximum is the maximum rate that a carrier protein can transport ligands into the cell 54 Explain the process of facilitated diffusion With Facilitated diffusion the channel will bind to a ligand and bring it down its concentration gradient always 9 does not require any energy input because it s spontaneous but it can become saturated reach their transport maximum because proteins can only move so fast with regard to moving molecules in out 55 Does facilitated diffusion transport ligands into the cell or out of the cell Explain Facilitated diffusion transports ligands in either direction into and out of the cell it just depends on the concentration gradient of that ligand and the direction it naturally wants to diffuse 56 Does facilitated diffusion require an input of ATP energy to occur No because it follows the concentration gradient of the ligands it transports so it s spontaneous 57 During facilitated diffusion are ligands transported down their concentration gradient or against their concentration gradient Ligands are transported down their concentration gradient 58 Explain the process of primary active transport An intracellular molecule ion binds to its carrier 9 ATP is hydrolyzed into ADP Pi energy 9 the phosphate is bonded to the protein carrier 9 phosphorylation of the carrier causes a change that makes it open to the ECF 9 molecule ion is released 59 Does primary active transport require ATP energy to occur Yes 60 During primary active transport are ligands transported down their concentration gradient or against their concentration gradient Against their concentration gradient that39s why ATP is needed 61 What is the role of ATP in primary active transport ATP gives the protein the energy that it needs to change shape and transport the ligand against its concentration gradient 62 What is the function of the sodiumpotassium pump found in the plasma membrane The NaK pump uses ATP to pump 3Na ions out for every 2K ions pumped in This causes a very steep concentration gradient for both Na and K which is used in secondary active transport as ligands get pumped into the cell against their concentration gradient with Na that is going down its stronger concentration gradient 63 Describe the concentration gradients established by the NaK pump The NaK pump creates a very steep concentration gradient inside the cell because it pumps Na and K against their gradient with the use of ATP The increase of the steepness of concentration gradient acts as a form of potential energy that is later used to pump ligands into the cell against their concentration gradient without the use of ATP 64 Explain the process of secondary active transport 0 The steeper Na concentration gradient is a source of energy that can power the transport of other molecules Na and a ligand bind to the carrier 9 ligand induces the carrier to open to the ICF 9 Na molecule is released 9 carrier ips back to the ECF 65 What is the energy source for secondary active transport The energy source is the steep Na concentration gradient Na wants to get back into the cell badly because there is so much of it outside of the cell and so little in enabling it to power the secondary active transport mechanism 66 Compare and contrast primary active transport secondary active transport and facilitated diffusion Both primary and secondary active transport move ligands against their concentration gradients Primary active transport is powered by ATP Secondary active transport is powered by the steep concentration gradient of Na generated by NaK pumps Facilitated diffusion transports ligands down their concentration gradients spontaneously without the use of ATP or Na gradients either the carrier is open or it39s closed 67 Explain the process of endocytosis Endocytosis is used to move large molecules ie proteins into the cell via bulk transport Contractile elements within the cell cause a region of the cell membrane to invaginate 9 molecules to be transported are pulled into the pocket 9 edges of cell membrane touch and fuse together in the ICF 68 Explain the process of exocytosis Exocytosis is the reverse of endocytosis Proteins molecules to be excreted are bundled into vesicles which are brought to the cell membrane 9 vesicle fuses with cell membrane 9 proteins molecules are excreted into the ECF 69 Describe how macrophages carry out phagocytosis Macrophages completely surround their targetcell with their plasma membrane and engulf it in a vesicle Lysosomes within the macrophage release digestive enzymes into the vesicle which breaks down the targetcell within and the products are absorbed by the macrophage 70 Draw a neuron label it parts dendrites axon terminal boutons axon hillock cell body myelin sheath and state the function of each part Dendrites receive information stimulus from surroundings E conducts the nerve impulse via action potentials Terminal boutons produce store secrete neurotransmitters which communicate with other neurons or muscle cells Axon hillock initiates action potentials its membrane has many voltage gaged Na and K channels Cell body Contains the nucleus and other cellular machinery Myelin sheath is an lipid insulator that prevents ions from leaking out 9 faster nerve signal conduction 71 Answer the following questions with regard to afferent neurons efferent neurons and interneurons Which have the cell bodies inside the CNS Which carry sensory information from organ systems to the CNS Which carry commands from the CNS to the organ systems Which are also called motor neurons Afferent neurons aka sensory neurons have cell bodies outside the CNS and terminal boutons inside the CNS they carry info from organ systems 9 CNS Efferent neurons aka motor neurons have cell bodies inside the CNS and terminal boutons outside the CNS carry nerve signals commands from CNS 9 organ systems Interneurons aka associate neurons are completely inside the CNS they store process info When you think interneurons are talking to each other they connect afferent neurons with efferent neurons T q KN 4 gt i J 1 E 139 c vs S D kl 3 C 4 s 3 l l l quot l 33 I 1 K 395 6 391 I O O lt I l I 1 gt 72 What is a membrane potential Electrical activity of neurons it is measured by differences in charge on either side of cell membrane ICF ECF 73 What is the value in mV of the resting membrane potential of a neuron 70mV 74 Describe the concentration gradients for Na and K across the plasma membrane Is Na more concentrated in the ICF or ECF What about K There is a steep concentration gradient for both Na and K across the plasma membrane Na is more concentrated outside the cell 0 K is more concentrated within the cell v J 39 39 J V f 39 1 r C 39 75 The membrane potential of a neuron changes from 70mV to 50mV Is that a depolarization or a hyperpolarization Depolarization 76 The membrane potential of a neuron changes from 70mV to 90mV Is that a depolarization or a hyperpolarization Hyperpolarization 77 Neuron experiences a change in membrane potential but then returns to resting membrane potential Is the return to resting called depolarization or repolarization Repolarization 78 What is an electrochemical gradient It is the combo of concentration gradient and electrical gradient two forces drive the movement of ions through channels in a membrane 79 If Na channels in the dendrites of a neuron open then Na will enter the cell What are the 2 forces that drive Na into the cell The concentration gradient and the electrical gradient 80 Does K ow into or out of the cell when K channels in the cell membrane open Explain why this happens K ows out of the cell when K channels in the cell membrane open because there is a steep electrochemical gradient for K that pushes it out of the cell 81 What is a graded potential It is a local change in the membrane potential caused by the opening of ion channels they happen around the open channels but not necessarily throughout the neuron 82 Is the magnitude strength of a graded potential always the same or do graded potentials vary in magnitude Explain Graded potentials vary in voltage magnitude magnitude depends on the number of ion channels that open and how long they stay open for graded potentials are decremental magnitude decreases with distance from origin 0 Grade potentials must occur to depolarize the neuron to threshold before an action potential can occur 83 Graded potentials are decremental What does that mean There is a progressive loss of voltage magnitude with distance 84 Provide an example of a graded potential A change from 70mV to 60mV is a 10mV graded potential the stimulus produces a depolarization which is not sufficient to reach threshold and trigger and action potential Ex Excitatory post synaptic potentials or Inhibitory post synaptic potentials the cell will either receive an EPSP or an IPSP which are examples of graded potentials 85 Where on the nerve are action potentials initiated The axon hillock initiates action potentials 86 What is the value in mV of the threshold potential of a neuron The threshold potential is 55mV for voltage gaged Na channels 87 What happens at the axon hillock when threshold potential is achieved Voltage gaged Na channels located in the membrane open and Na ions diffuse into the cell which cause the membrane to depolarize from 55mV to 30mV 88 Explain in detail the sequence of events in the action potential Your answer should include the nature of the stimulus that brought the neuron to threshold the site of the action potential initiation the activities of ion channels the movement of ions across the membrane and the changes in membrane potential over time Include a graph of mV versus time that shows the changes in membrane potential over the length of the action potential A stimulus received by the dendrites causes a graded potential depolarization that brings the axon hillock to threshold potential Voltage gaged Na channels located in the membrane open Na ions diffuse into cell down electrochemical gradient Increase of Na ions cause the membrane potential to depolarize from 55mV to 30mV Na channels close because they are timed K channels open when the membrane potential becomes positive 0 K ions diffuse out of cell down electrochemical gradient K channels are slow to close 9 membrane brie y hyperpolarizes below resting potential Membrane potential is repolarized and returned to its resting potential from 30mV to 70mV quot Send u39Le 1 393 39 0 L C o LC39 1v quotquot mm x Wt mm 39 N I 89 Explain the All or None Law of action potentials There are not small or large action potentials they are ALWAYS of the same magnitude They either happen or they don t if the axon hillock reaches the threshold potential then an action potential will happen 90 What is the molecular basis for the absolute refractory period of action potentials During the absolute refractory period Na channels in a neuron close and become inactive and they will not open regardless of the stimulus received The voltage gated Na channels close 9 they are insensitive to stimulus for a short period of time 91 After an action potential is initiated at the axon hillock how is it propagated down the axon The movement of the action potential is similar to the action of electricity in a wire cable Na ions rush into the neuron then follow the negative charge of the cytoplasm down the neuron towards the terminal boutons It travels via salutatory conduction leaping from one node to the next 92 Action potentials are nondecremental What does that mean That means that they do not lose strength over distance the action potential is just as strong when is finishes as when it started 93 What is the function of a myelin sheath on the axon of a neuron The myelin sheath acts as an insulator that prevents ions fro leaking out 9 faster nerve signal conduction 94 What type of cell forms the myelin sheath of peripheral neurons Schwann cells 95 What is a Node of Ranvier It is the unmyelinated area adjacent to the Schwann cells action potentials only occur at Nodes of Ranvier because they have a high density of voltage gaged ion channels 96 Explain the process of Saltatory Conduction Saltatory conduction is the leaping movement of an action potential from node of Ranvier to node of Ranvier Schwann cells are living cells that wrap themselves around the axon of peripheral nerves collectively it39s called a myelin sheath There are spaces in between the Schwann cells called nodes of Ranvier that have voltage gated channels so they are able to induce action potentials When Na enters a neuron it speeds towards the node of Ranvier where more Na in uxes and that Na zooms to the next node Action potentials jump to depolarize adjacent nodes of Ranvier 97 Does the presence of a myelin sheath increase or decrease the velocity of action potential propagation Increase 98 How does the diameter of a neuron s axon affect the velocity of action potential propagation An increase in the diameter of a neuron causes an increase in the velocity of action potential propagation 99 What is multiple sclerosis What causes it What are some common symptoms It is a chronic degenerative autoimmune disease The immune system attacks destroys the myelin sheath Demyelination of motor neurons causes muscle weakness and paralysis o Treatment is poor 100 What is a synapse A junction between a neuron and its target cell 101 Draw a synapse between two neurons and label the presynaptic cell and the postsynaptic cell P139cs39nupIic ccll quot 939 quot x quot PoltIs nuptic cell 102 Explain in detail the sequence of events at the synapse The presynaptic neuron has just experienced an action potential which depolarized the terminal bouton Explain what happens next Terminal bouton has many Vesicles that have neurotransmitters NTS NTs are released Via exocytosis only after appropriate stimulation Action potential 9 membrane portion of terminal bouton is depolarized This causes Voltage gated Ca2 channels to open 9 Ca2 diffuses into the neuron down its electrochemical gradient Ca2 binds to a protein complex 9 intracellular vesicles containing NTS fuse with membrane 9 exocytosis of neurotransmitter from pre synaptic cell into synaptic cleft NTs diffuse across the cleft and bind to ligand receptors on post synaptic cell Postsynaptic cell is stimulated to open ion channels that stay open as long as the NT is present Movement of ions through the channel changes the membrane potential of the postsynaptic cell o The change can be excitatory stimulate Na channels to open or inhibitory stimulate K channels to open Enzyme degradation of NTsactive transport of NTS back to presynaptic cell 9 end of stimulation in postsynaptic cell 103 How does Ca2 affect exocytosis of neurotransmitter at the terminal bouton Ca2 initiates the exocytosis of the neurotransmitter from the presynaptic cell to the postsynaptic cell 104 How is neurotransmitter removed from the synaptic cleft The neurotransmitter is removed from the synaptic cleft via reuptake of the NT by the presynaptic neuron or by enzyme degradation in which enzymes take apart the NT and remove it from the receptor site 105 Will the postsynaptic cell be stimulated or inhibited if neurotransmitter binding opens Na channels in the postsynaptic cell What if K channels open The postsynaptic cell will be stimulated if Na channels are opened 9 depolarization 9 excitement If K channels open the cell will be inhibited 9 hyperpolarization 9 inhibited 106 Will the postsynaptic cell experience depolarization or hyperpolarization if neurotransmitter binding causes K channels to open in the postsynaptic cell The postsynaptic cell will experience hyperpolarization if K channels open 107 Not a complete question 108 Neurotransmitter binding to receptors on the membrane of the postsynaptic cell causes Na channels to open Will the cell experience an excitatory postsynaptic potential EPSP or an inhibitory postsynaptic potential IPSP The cell will experience an excitatory postsynaptic potential EPSP 109 Are EPSPs and IPSPs considered action potentials or graded potentials They are considered graded potentials 110 Can EPSPs stimulate action potentials in the postsynaptic cell How Yes they can stimulate action potentials by depolarizing the cell to threshold at the axon hillock 111 Can IPSPs inhibit action potentials in the postsynaptic cell How Yes they can inhibit action potentials by hyperpolarizing the cell bringing it further away from its threshold 112 What is a temporal summation How does it result in an action potential A temporal summation occurs when the postsynaptic cell is brought to threshold by additive effects of many EPSPS originating from 1 presynaptic cell 0 Graded potentials fired in rapid succession 0 The sum of the EPSPS together can bring the axon hillock to threshold when one on its own may not 113 What is spatial summation How does it result in an action potential Spatial summation occurs when EPSPS originating from 21000 synapses sum together to bring the postsynaptic cell to threshold 0 Ex If neuron A and B fire at the same time then the size of depolarization produced may be enough to reach threshold 114 Refer to the figure on the right for the next few questions Repeated firing of presynaptic neuron A brings the postsynaptic Postsvnavlic cells to threshold Is Neuron A excitatory or Cequot inhibitory Is this spatial or temporal summation Simultaneous firing of presynaptic neurons A and B brings the postsynaptic cell to threshold Is Neuron B excitatory or inhibitory Is this spatial or temporal summation Simultaneous firing of presynaptic neurons A and C fails to bring the postsynaptic cell to threshold Is Neuron C excitatory or inhibitory Neuron A is excitatory This is temporal summation Neuron B is excitatory This is spatial summation Neuron C is inhibitory 115 What neurotransmitter is secreted by motor neurons that innervate skeletal muscles Acetylcholine ACh 116 How do skeletal muscles respond to acetylcholine ACh binds to receptors on the muscle which cause Na channels to open 9 depolarization of the muscle cell 9 action potential in the muscle cell 9 muscle contraction 117 How is ACh removed from the synaptic cleft of the neuromuscular junction ACh is removed by Acetylcholinesterase AChase an enzyme that removes ACh from the synaptic cleft AChase is embedded in muscle cell membranes and it catalyzes the degradation of ACh 9 choline acetyl group which is pumped back to the terminal bouton and reassembled 118 How does curare tubocurarine cause paralysis of skeletal muscles Curare binds to ACh receptors at the neuromuscular junctions 9 ACh cannot bind 9 muscle can39t move because Na cannot enter the muscle and induce an action potential in the muscle cell Curare acts as a competitive inhibitor when it binds it stays unlike ACh which is eeting 119 How does botulin toxin cause paralysis of skeletal muscles Botulin toxin aka Botox inhibits the exocytosis of ACh into the synaptic cleft 120 How does nerve gas serin cause spastic paralysis of skeletal muscles Nerve gas is an inhibitor of AChase 9 ACh builds up in the synaptic cleft and the muscle enters into sustained contraction spasm 9 fatigue and paralysis 121 What structure within skeletal muscles causes the striated look of muscles Sarcomeres smallest unit of muscle capable of contracting alternating dark and light bands of sarcomeres span the width of the muscle fiber 9 appears to be striated 122 What is the sarcolemma of the muscle fiber The sarcolemma is the muscle cell membrane 123 Arrange the following structures in order of size muscle fiber thin filaments myofibril sarcomere Muscle fiber gt myofibril gt sarcomere gt thin filaments 124 Draw a sarcomere and label its parts 2 3 Q 391 C 5 r39 39 l1f ex gg o T g 39 C a I C 125 Describe the structure of a thin filament Which proteins are structural and which are regulatory A thin filament is made of actin protein and it is attached to the z line and extends inward toward the center of the sarcomere Troponin and tropomyosin are regulatory proteins that act to prevent or allow the binding of myosin to actin troponin is bound to tropomyosin and when Ca2 binds to it it changes shape and moves tropomyosin out of the way of the myosin binding site 126 A thick filament is made from what kind of protein Myosin 127 Brie y describe the sliding filament model of muscle contraction Muscle contraction occurs when the thick and thin filaments slide past each other bringing the z lines closer together when a muscle fiber contracts all of the sarcomeres contract together 9 significant shortening of the muscle When muscles relax thick and thin filaments slide past each other in revers and 2 lines move further apart 128 What are the roles of troponin and tropomyosin in muscle contraction Troponin is bound to tropomyosin and when Ca2 binds to it it changes shape and moves tropomyosin out of the way of the actin binding site so the thick filament myosin can bind to actin and do a power stroke pulling the z lines together 129 How are cross bridges formed Cross bridges are formed when tropomyosin is moved out of the way of the actin binding site by troponin and the myosin head is able to bind to actin with the use of ATP 130 Explain how ATP powers cross bridge cycling The myosin head binds ATP then hydrolyses ATP 9 ADP Pi Energy which cocks the myosin head back and allows it to bind to an actin molecule on the thin filament I I 39 3944l39 3939L 39 3 LKg 131 What is rigormortis and how does it happen Rigormortis is stiffness associated with the recently dead it lasts about 24 hrs 0 After death Ca2 leaks out of sarcoplasmic reticulum 9 muscles are stimulated to contract 9 ATP stores are depleted 23 hrs later 9 cross bridges equal locked in place 9 muscles can39t move 132 What is the role of Ca2 in skeletal muscle contraction Ca2 binds to troponin and changes its shape which allows troponin to move tropomyosin out of the way of the actin binding site so the myosin head can bind to actin power stroke and shorten the sarcomere 133 What structure within the skeletal muscle is a storage site for Ca2 The sarcoplasmic reticulum stores Ca2 134 How do motor neurons stimulate the release of Ca2 from the sarcoplasmic reticulum of skeletal muscle cells Explain in detail Muscle fibers are electrically excitable cells that are capable of initiating and conducting action potentials Secretion of ACh by a motor neuron 9 opening of Na ion channels in the sarcolemma 9 in ux of Na ions 9 depolarization 9 action potential in the muscle fiber moves in both directions down the muscle fiber and down into transverse tubules T tubules T tubules lie close to the sarcoplasmic reticulum so action potentials that travel through T tubules stimulate the opening of Ca2 channels within the sarcoplasmic reticulum 9 Ca2 diffuses into myofibrils 135 Describe the molecular events of contraction and relaxation of skeletal muscle Include in your description the roles of motor neurons actin myosin troponin tropomyosin calcium T tubules sarcoplasmic reticulum calcium pumps cross bridging sarcomeres and ATP Begin with contraction Finish with relaxation A motor neuron secretes ACh which stimulates the Na channels in the sarcolemma to open When Na rushes in the sarcolemma depolarizes and reaches threshold 9 and action potential travels down the sarcolemma in both directions and travels down the T tubules which lie close to the sarcoplasmic reticulum The action potential triggers the release of Ca2 from the sarcoplasmic reticulum and Ca2 diffuses into the myofibrils Ca2 binds to troponin 9 troponin moves tropomyosin out of the way of actinmyosin binding sites 9 cross bridge cycle occurs 9 sarcomeres shorten 9 muscle shortens and contracts When the action potential from the motor neuron stops Ca2 is pumped back into the sarcoplasmic reticulum via primary active transport In the absence of Ca2 troponin returns to its original shape and tropomyosin moves and covers myosin and the actin binding sites this stops cross bridging and thick and thin filaments slide back into their relaxed position 136 When calcium is transported out of the sarcoplasmic reticulum into the myofibril does it move down its concentration gradient or against it Ca2 moves down its concentration gradient when it is released from the sarcoplasmic reticulum 137 By what means is Ca2 transported back into the sarcoplasmic reticulum Ca2 is pumped back into the SR via primary active transport 138 Muscle contraction requires the hydrolysis of ATP to ADP In order for muscles to continue contracting ADP must be converted back to ATP What three processes are used by skeletal muscles to regenerate ATP Lactate fermentation anaerobic respiration Cellular respiration aerobic resp Phosphocreatine hydrolysis 139 Which process produces more ATP per glucose lactate fermentation or cellular respiration Cellular respiration 140 Which process requires oxygen lactate fermentation or cellular respiration Cellular respiration 141 What is the function of phosphocreatine in muscle fibers Phosphocreatine is a readily accessible store of high energy phosphate that can be used to regenerate ATP Phosphocreatine ADP ltgt Creatine ATP 0 It quickly regenerates ATP via hydrolysis of phosphocreatine 142 Define V02max Maximum amount of O2 consumed per minute per Kg body weight O2minkgwt a measure of fitness higher V02 max 9 indication of being in better shape 0 Ave 3040 Olympics 605705 143 What is the preferred fuel molecule during light exercise glucose or fat Fats 144 What is the preferred fuel molecule during heavy exercise glucose or fat Glucose 145 What is the Lactate Threshold It is the exercise intensity level at which significant amounts of lactate lactic acid appear in the blood during heavy exercise body relies on lactate fermentation 9 increase of lactate in blood 146 What causes muscle fatigue during short duration high intensity exercise Fatigue associated with sustained maximal contraction ie lifting weights is due to a build up of K in the ECF with in the transverse tubules of muscle fibers 9 degradation of K gradient required for new action potentials 147 What causes muscle fatigue during long duration low intensity exercise Glycogen stores in muscle tissue and liver become depleted and there is a decrease in the amount of Ca2 released from the sarcoplasmic reticulum 9 the body shifts to complete reliance of fat protein for fuel aka hitting the wall 148 Compare and contrast fasttwitch muscle fibers with slowtwitch muscle fibers Fast twitch fibers deliver an extreme amount of power for a short period of time a few seconds 1 min Slow twitch fibers provide endurance delivering prolonged strength of contraction over many minutes hours 149 Which fibers are more powerful fast twitch or slow twitch Fast twitch fibers are more powerful they are larger and they can contract faster 150 Which fibers are more resistant to fatigue fast twitch or slow twitch Slow twitch 151 Define the terms hypertrophy and atrophy as they apply to skeletal muscles Hypertrophy is when muscles grow and gain endurance this happens when they are used Atrophy occurs when muscles are not used and they shrink and become more susceptible to fatigue 152 What structural changes occur in muscle cells when they undergo hypertrophy There are an increased number of myofibrils in the muscle fiber that make the muscle swell muscle cells can39t divide 153 Sensor receptors are transducers Explain what that means Transducers convert energy of a stimulus into electrical stimulus an action potential 9 sensory receptors detect a stimuli and create an action potential to communicate with the CNS Sensory receptors are associated with sensory neurons 154 What is a receptor potential It is a grade potential that occurs in response to a stimulus if threshold is reached and action potential in the associated neuron will be made 155 Can receptor potentials induce action potentials Explain Yes receptor potentials can bring the sensory cell to threshold which will cause its associated sensory neuron to fire an action potential 156 How is the intensity of a stimulus coded by sensory receptors In other words how does the sensory receptor inform the brain that a stimulus is weak or strong As stimulus increases in strength receptor potential increases in magnitude 9 increased frequency of action potentials sent to the CNS 157 Define Sensory Adaptation as it applies to sensory receptors Receptors that undergo sensory adaptation are phasic receptors they fire action potentials when a stimulus is applied and removed they inform the CNS about changes in the environment and they can detect temperature odortouch 158 How do tonic and phasic receptors differ from one another Tonic receptors do not adapt to stimuli Phasic receptors do adapt to stimuli 159 Provide examples of phasic and tonic receptors Phasic ex receptors for touch temperature and odor Tonic ex receptors for deep pressure pain and proprioception sense of body39s position in space 160 What is the modality of a stimulus The modality refers to they type of stimulus lightheat pressure etc that the receptor responds to and the hardwiring of the brain how the brain perceives it 161 Explain the Law of Specific Nerve Energies Any given receptor responds preferentially to one type of stimulus its adequate stimulus Many stimuli may activate a receptor but the adequate stimulus requires the least amount of energy to do so 162 What are adequate stimuli for the following types of receptors mechanoreceptors thermoreceptors photoreceptors chemoreceptors nociceptors Mechanoreceptors pressure vibration stretch Thermoreceptors heatcold Photoreceptors light Chemoreceptors chemicals Nociceptors tissue damage 163 How does the brain know where on the body a stimulus originates In other words if you are touched on the leg how do you know it39s your leg and not your arm being touched Cutaneous sensations touchtemppressurepain are localized through specific wiring of the nervous system Each part of the body sends sensory info to a specific region on the primary somatosensory cortex 164 How does the size of a receptor field affect the acuity of touch localization The density of receptors in one area are inversely proportional to the size of the receptor field Higher receptor density and smaller receptor fields are highly accurate there are many receptor cells in a small area ex a fingertip which allows them to be very accurate when detecting stimuli 165 Draw an ascending sensory pathway that originates at the skin and terminates at the somatosensory cortex of the brain Label the 15 2quot and 3 order neurons Show decussation in the spinal cord and label the spinal cord and thalamus 39vnxe xrv slt39 10 166 What type of receptor responds to pain A nociceptors 167 Damaged tissues release prostaglandin as part of the in ammatory response What effect does prostaglandin have on the intensity of pain Prostaglandin increases the intensity of pain 168 How does aspirin diminish the sensation of pain Aspirin inhibits the synthesis of prostaglandins 169 What is phantom limb pain Sensory neurons that have been severed with a limb may regenerate and fire 9 brain thinks the limb is still there and may be in pain 170 What is referred pain Explain how pain in the heart is felt in the left shoulder Internal organs have sensory nerves that are grouped with nerves coming from skin and muscles that39s why during a heart attack people have pain in their left shoulder arm the pain is referred 171 Define refraction as it applies to light Refraction is the bending of light as it is passed through the cornea and the lens in the eye 172 What structures of the eye refract light The cornea and the lens 173 Draw 2 convex lenses and make one of them more convex rounder and the other less convex atter Which lens would refract light more strongly The roundermore convex lens would refract light more strongly Focal Point 2 Focal Point 174 Explain in detail the process of accommodation in the eye Begin by drawing two eyes in cross section label the cornea ciliary muscle suspensory ligaments and retina Draw one eye accommodated for near vision and one accommodated for far vision Explain how and why the lens changes shape to focus on far and near objects Vin 1 quotCx Ner 39 3939O The ciliary muscle is attached to the lens by zonal fibers or suspensory ligaments The ciliary muscle is circular and when it contracts to View close up objects this lessens the tension on the suspensory ligaments This allows the lens to rebound to its fuller shape When the eye is focusing on a distant object it relaxes its ciliary muscles causing the suspensory ligaments to tighten This pulls the lens into a atter less convex shape Muscle Ligament Lens Distance Relaxed Taut Less convex atter Far Contracted Slack More convex Near rounder 175 What is the fundamental defect in myopia What causes it How is it corrected People with myopia cannot focus on far objects gt20ft but they can focus on near objects Myopic people are nearsighted and it is usually caused by having an abnormally long eyeball It can be corrected by wearing concave glasses lenses 176 What is the fundamental defect in hyperopia What causes it How is it corrected People with hyperopia cannot focus on near objects but they can focus on far objects They are farsighted Hyperopia is usually caused by having abnormally short eyeballs It can be corrected by wearing convex glasses lenses 177 What is the fundamental defect in presbyopia What causes it How is it corrected Presbyopia is age dependent farsightedness As we age the lens becomes less elastic It can be corrected by wearing convex glasses lenses 178 What is the fundamental defect in astigmatism What causes it Astigmatism is caused by uneven curvature of the cornea or lens The eye can39t focus all light onto one point An uneven convex lens of glasses corrects this 179 What is glaucoma What is the result of untreated glaucoma Glaucoma is a disease that occurs when aqueous humor secreted by the ciliary body and drained away by the canal of Schlemm is made faster than it can be drained 9 increased pressure 9 optic nerve damage 9 blindness if untreated 180 Compare and contrast rods and cones Rods and cones both allow us to see Rods are more sensitive to light than cones so we use them to see at night But they do not allow us to see in color and many rods are connected to one bipolar cell which feeds info to the ganglion cells that make up the optic nerve they form images that are less sharp than those from cones They are predominantly found in the peripheral region of the retina Cones are less sensitive to light but they can discriminate between different colors of visible lights They are focused in the fovea and create a very sharp image much sharper than rods There are many more rods than cones 301 181 Rods are very sensitive to light but provide less resolution than cones Conversely cones are less sensitive to light but provide higher resolution than cones What feature of the retina explains this difference The cones are concentrated in the fovea and the macula of the retina an indent in the retina where ganglion and bipolar cells are pulled aside to let light hit the photoreceptors directly Those cells usually cover rods which allows less light to pass through to them 182 What is rhodopsin Rhodopsin is a light sensitive photopigment in rods It is found in the inner membrane of a rod the membrane is a phospholipid bilayer and the opsin protein sits within the membrane with retinene 183 Describe the composition of photopigments found in the photoreceptors Rhodopsin is made of retinene absorbs light 9 chromophore and opsin a protein Retinene is made from Vitamin A and is capable of absorbing light 0 When retinene absorbs light it changes shape and dissociates from opsin 184 What is the role of opsin protein found in photopigments Opsin is a membrane bound protein that is also bound to trans retinene Opsin filters out light ie if it was a blue cone it would filter out red and green light so only blue light would hit the retinene There are different genes for different opsins they create red green and blue opsins In rhodopsin it only filters out far red 185 What is the role of the Cis retinene found in photopigments Cis retinene is light absorbing and when light hit it it changes shape to trans retinene light insensitiveand receptor potentials are created which cause action potentials in neurons that send visual information to the brain Cis retinene allows you to see well and the amount of cis retinene present affects your vision 186 How does light affect the structure of cisretinene Light changes the shape of cis retinene to trans retinene and causes cis retinene to dissociate from opsin 0 The transition from cis to trans retinene happens very quickly but the reverse process takes much more time which is why it takes us a while to adjust to a dark room when we come from outside 187 Describe the sequence of events in the photochemistry of vision When light hits cis retinene it changes its shape to trans retinene and dissociates from its opsin protein This causes a change in the ion permeability of the membrane of the cell 9 receptor potential 9 action potential in adjacent neuron 9 brain receives and interprets the stimulus 188 What happens to the ratio of cisretinenetransretinene as one moves from bright light to dim light How does this explain dark adaptation When a person moves from a brightly lit area to a dimly lit area he cannot see because there is too much trans retinene and not enough light absorbing cis retinene Over the period of a few minutes the trans retinene is slowly converted into cis retinene and your eyes become more light sensitive they undergo dark adaptation 189 Explain the trichromatic theory of color vision There are three types of cones red green and blue they all have unique photopsins and we mix the information received from those cones to produce other colors The brain receives and combines input from all three cones and perceives a certain color based on that information this allows us to see an infinite amount of colors 190 With regard to sound what is the relationship between frequency and pitch High frequency sounds 9 high pitch perception Low frequency sounds 9 low pitch perception 191 With regard to sound what is the relationship between amplitude and loudness Higher amplitude 9 loud Lower amplitude 9 quiet 192 State the three major structures of the outer ear and provide a function for each Auricle aka pinna collects sound and directs it to the external auditory meatus External auditory meatus ear canal funnels the sound waves to the tympanic membrane Tympanic membrane ear drum vibrates with the same frequency as the sound wave that hits it it separates the outer ear from the middle ear 193 What is the relationship of the tympanic membrane to the ossicles The tympanic membrane vibrates against the ossicles which amplify the intensity of the sound waves because the tympanic membrane has a much greater diameter than the oval window the location that the ossicles attach to the inner ear 194 Name the three bones that make up the ossicles Malleus Incus Stapes 195 What is the function of the ossicles The ossicles transmit sound from the outer ear to the inner ear They are attached at the tympanic membrane and to the oval end of the cochlea Ossicles amplify intensity of sound waves because the tympanic membrane is much greater in diameter than the oval window small movements of the tympanic membrane generate much more movement of the stapes on the oval window The ossicles are bound by muscles that protect the ear from very loud sounds by contraction in response to loud sounds 9 restricted movement of the ossicles and decreased transmission of sound to the inner ear 196 What structure of the inner ear is attached to the stapes The oval window of the cochlea is attached to the stapes 197 What tubular structure connects the middle ear with the throat The Eustachian tube aka auditory tube connects the middle ear with the throat 198 Why do your ears feel funny when you change altitude Your ears feel funny when you change altitude because the pressure in your middle ear is not the same as the pressure outside When you gain altitude the pressure in your middle ear is greater than the pressure outside and it makes the tympanic membrane bulge outward uncomfortably When you pop your ears you replace the high pressured air in your ear with the low pressured air of your surroundings vice versa when you drop in altitude 199 What structures are the sensory receptors of the inner ear The basilar membrane within the cochlear duct contains hair cells that detect sound vibrations and convert them to actin potentials The vestibular apparatus informs the brain of the body39s orientation to gravity and whether or not you are accelerating 200 What is the function of the basilar membrane in hearing The basilar membrane contains hair cells that detect sound vibrations and convert them to action potentials Vibrations travel to the inner ear and hit the basilar membrane which vibrates and touches hair cells that send receptor potentials to associated neurons which create action potentials that get sent to the auditory cortex of the brain 201 How does the earbrain discriminate pitch In other words how can you tell the difference between a highpitched and a lowpitched sound Different regions of the basilar membrane are sensitive to different frequency of sounds The region next to the oval window is tighter and is more sensitive to high frequency sounds The furthest region of the basilar membrane is sensitive to low frequency sounds The brain knows the frequency of sounds based on where the basilar membrane is vibrating The number of hairs that vibrate determines loudness 202 Which region of the basilar membrane is sensitive to high pitched sounds Lowpitched sounds The region closest to the oval window is sensitive to high pitched sounds The region furthest from the oval window is sensitive to low pitched sounds 203 Explain the basic events in the process of hearing beginning with sound entering the ear canal The pinna picks up sound waves and funnels them through the ear canal where the sound waves hit and vibrate the eardrum aka the tympanic membrane The tympanic membrane is attached to the ossicles and the sound waves vibrate down the malleus incus and stapes which is attached to the oval window of the cochlea where the sound waves are amplified as they reach the oval window When sound waves reach the cochlea they vibrate down the basilar membrane which stimulates adjacent hair cells that create receptor potentials The receptor potentials created by the hair cells when stimulated cause action potentials to be created in the adjacent associated neurons 204 What is the difference between conduction deafness and nerve deafness Conduction deafness occurs when sound waves are not conducted from the outer ear to the inner ear 0 This is caused by ruptured tympanic membrane restricted movement of ossicles ear infections with associated swelling Nerve deafness aka sensorineural deafness occurs when sound waves are conducted to the inner ear but they aren39t translated into action potentials 0 This is caused by damage to hair cells damage to the cochlear nerve o Neural prebycusis is an age related disorder in which hair cells are worn out with use 205 What is the relationship between the cerebellum and balance The cerebellum maintains the body39s balance The primary motor cortex directs movement of skeletal muscles and informs the cerebellum of its intentions the cerebellum compares the intentions of the motor cortex to the actual movement of the body and modifies motor commands This makes movement smooth and balanced 206 What sensory inputs are sent to the cerebellum to help it maintain balance Visual cues proprioceptor signals and vestibular apparatus inputs inform the cerebellum of the body39s orientation and balance 207 What is the function of the vestibular apparatus The vestibular apparatus detects rotational acceleration 9with the semicircular canals and linear acceleration orientation to gravity with the otolith organs 208 Name the 3 major structures of the vestibular apparatus and provide a function for each Semicircular canals detect rotational acceleration Utricle has vertical hair cells that are associated with neurons and can detect when your body moves forward or backwards linear acceleration or when you move your head forwards or backwards nodding it is an otolith organ Saccule has horizontal hair cells that can detect head movements ie when your body goes from laying down to standing up it also gathers sensory info to orient the body in space it is an otolith organ 209 How does movement affect the frequency of action potentials generated by hair cells of the vestibular apparatus When the head rotates the endolymph uid in the cavities of the vestibular apparatus lags behind and pushes bends the hair cells This activates the hair cells and causes a change in the frequency of action potentials send to the brain Hair cells are mechanoreceptors they are stimulated by movement The brain knows if rotation is occurring based on increased and decreased rates of action potentials coming from the semicircular canals A similar concept occurs with otolith fibers they also have endolymph and hair cells that detect the movement of the head body due to a lag in the movement of the uid 210 Explain how the body detects rotation acceleration The body detects rotational acceleration via the semicircular canals because of the increase or decrease in action potentials received from the hair cells in the semicircular canals caused by a lag in the movement of the uid within those cells 211 Explain how otolith organs detect a change in a person39s orientation to gravity for example the change from standing up to lying down Otolith organs have hair cells embedded in a gelatinous layer that is covered with heavy crystals called otoliths The movement of the gelatinous layer bends the hair cells which causes a change in the frequency of action potentials sent to the brain If you lay down the gelatinous otolith membrane will be pushed downward by gravity which will bend the hair cells and cause depolarization or hyperpolarization of the hair cells The change in the baseline frequency of action potentials informs the brain about the position of your head relative to gravity 212 What types of organs are controlled by the autonomic nervous system The autonomic nervous system regulates the activities of visceral organs and blood vessels 213 Is the autonomic nervous system voluntary or involuntary Consciously controlled or unconsciously controlled The autonomic nervous system in involuntary and it is unconsciously controlled 214 Which subdivision of the autonomic nervous system dominates during physical activity During rest The sympathetic nervous system dominates during physical activity The parasympathetic nervous system dominates during rest 215 Are the sympathetic and parasympathetic divisions generally cooperative in their action or generally antagonistic The sympathetic and parasympathetic divisions are generally antagonistic but they can be cooperative on occasion 216 Sympathetic neurons originate from what part of the CNS Sympathetic neurons originate from the thoracic and lumber nerves 217 Parasympathetic neurons originate from what part of the CNS Parasympathetic neurons originate from the cranial and sacral nerves 218 Repeat of 217 219 What neurotransmitter is secreted by the preganglionic sympathetic fiber Acetylcholine Ach is secreted by preganglionic sympathetic fiber 220 What neurotransmitter is secreted by the postganglionic sympathetic fiber Norepinephrine is secreted by the postganglionic sympathetic fiber 221 What neurotransmitter is secreted by the preganglionic parasympathetic fiber ACh is secreted by the preganglionic parasympathetic fiber 222 What neurotransmitter is secreted by the postganglionic parasympathetic fiber ACh is also secreted by the postganglionic parasympathetic fiber 223 What feature of the sympathetic nervous system facilitates Mass Action The convergence and divergence of the sympathetic fibers Sympathetic fibers are a two chain system When you become startledscared the sympathetic nervous system fires all at once divergence and convergence of sympathetic fibers allows for a large amount of input to many organs all at once 9 fight or ight response 224 What is the relationship of the adrenal medulla to the sympathetic nervous system The adrenal medulla is an accessory organ to the sympathetic division It secretes epinephrine and norepinephrine into the blood stream in response to sympathetic input 225 What gland secretes epinephrine The adrenal gland 226 Epinephrine affects different tissues in different ways What accounts for this variable response to the same hormone Adrenalin is the same as epinephrine hormone which is similar to norepinephrine hormone neurotransmitter There are two major classes of norepinephrine receptors alpha receptors a1 and a2 and beta receptors b1 and b2 The type of receptor that a cell has depends on its response to the hormone 227 Explain in detail the Fight or Flight Response When you perceive danger mass activation of the sympathetic division prepares the body for intense physical action The sympathetic division anticipates the needs of the body and creates changes that will help 0 Glycogen is made into glucose to increase blood sugar levels provides a needed energy source 0 Dilation of airways allows for improved ventilation provides more 02 to blood 0 Increased heart rate moves glucose and O2 to tissue faster 0 Dilation of blood vessels in skeletal muscle brings the blood where it is needed most 0 Inessential activities are inhibited to conserve energy and blood for essential processes 0 Eyes change focus accommodate for far vision enhances visual assessment of the threat 228 What is the function of adrenergic receptors Adrenergic receptors bind epinephrine hormone and norepinephrine neurotransmitter adrenaline Adrenergic receptors allow one neurotransmitterhormone to have the opposite effects because of the receptor sites on receiving neurons 229 How do b1 adrenergic receptors in the heart respond to epinephrine B1 receptors are found in the heart and they increase heart rate in response to epinephrine A sympathetic neuron releases norepinephrine onto the SA node of the heart that has many b1 receptors which causes the heart to beat faster 230 How do b2 receptors in the bronchioles respond to epinephrine B2 receptors are found in smooth muscles and they dilate bronchioles airways in response to epinephrine 231 How do a1 adrenergic receptors on blood vessels respond to epinephrine A1 has the opposite effect of b2 it also affects smooth muscles A1 receptors on blood vessels constrict veins and decrease blood ow to visceral organs in response to epinephrine 0 In bronchioles there are not al receptors by design 232 What is the difference between an agonist and an antagonist An agonist mimics the normal neurotransmitter and fits into the receptor sites on the cell it is targeting An antagonist blocks the neurotransmitter from binding 233 What type of drug would stimulate a b1 adrenergic receptor a b1 agonist or a b1 antagonist A b1 agonist would stimulate a b1 adrenergic receptor 234 Atenolol is a b1 adrenergic receptor antagonist Is atenolol predicted to raise or lower heart rate Atenolol is predicted to lower heart rate 235 Name to 2 types of acetylcholine receptors Muscarinic receptors Nicotinic receptors 236 Describe paracrine signaling between cells Neighboring cells talk to each other local Paracrine signaling is a local interaction between adjacent cells within the same organ The signaling molecule is called a cytokine 0 A cytokine is secreted by one cell and diffuses to target cells 0 Neighboring cell has a receptor for that cytokine that can bind cytokine and cause the cell to respond 237 What is a cytokine A cytokine is a signaling molecule that communicates between adjacent cells of the same organ 238 Describe hormonal signaling Hormonal signaling aka endocrine signaling occurs through the circulatory system as hormones are secreted into the blood and travel all throughout the body Hormones always come from endocrine glands Endocrine gland secretes the hormone into the blood and it travels all throughout the body only cells that have receptors will respond do the hormone Target cells will have a receptor for the hormone and it will respond 0 Change activity of pre existing enzymes 0 Make new proteins 239 What is a hormone It is a chemical messenger produced by the body and transported throughout the body by the blood 240 What are the 2 major effects that hormones have on cells Hormones change the activity of a pre existing enzyme Hormones promote the synthesis of new proteins 241 blank 242 List the 3 classes of hormones Peptide hormones Steroid hormones Amine hormones 243 List the characteristics of peptide hormones They are structurally short chains of amino acids The bind to extracellular receptors Binding to receptor activates a 2nd messenger system that relays messages into the cell They have their affects by altering activity of pre existing enzymes within the cell o Ex Nutrients enter the body from GI tract 9 liver cells store extra glucose as glycogen when sugar is scarce liver cells are simulated by Glucagon to release glucose 9 increase in blood sugar 244 List the characteristics of steroid hormones They are all made from cholesterol They bind to intracellular receptor They induce synthesis of new proteins 245 State whether the following conditions apply to peptide or steroid hormones Derived from cholesterol 9 steroid Derived from amino acids 9 peptide Binds extracellular receptor 9 peptide Binds intracellular receptor 9 steroid Functions to change activities of pre existing enzymes 9 peptide Functions to stimulate synthesis of new proteins 9 steroid 246 Describe the process by which glucagon works with adenyl cyclase to stimulate glycogenolysis What is the second messenger produced by adenyl cyclase Know this in great detail Example of how a peptide hormone works Glucagon a peptide hormone regulates blood glucose Glucagon will bind to liver cells which will stimulate adenyl cyclase within the cell It will convert APT to cycline AMP PPi Cycline AMP is a second messenger a molecule that can rapidly increase inside the cell and cause the cell to respond it will activate a protein kinase which will turn enzymes on and off 9 make the cell do completely different things Protein kinase will stimulate the enzymes to break glycogen down to glucose 0 Glucagon basically tells the cell to take glycogen break it apart and turn it into glucose by binding with the liver cell 0 The opposite of glucagon is insulin Nutrients enter the body from GI tract 9 liver cells store extra glucose as glycogen when sugar is scarce liver cells are simulated by Glucagon to release glucose 9 increase in blood sugar 247 Describe the process by which aldosterone stimulates the production of sodium pumps Aldosterone stimulates reabsorption of Na at the distal tube and collecting ducts of nephron It diffuses directly through the plasma membrane of a nephron tubule cell and it binds to an intracellular receptor The receptor goes to the nucleus and turns on genes that direct the synthesis of Na carriers New Na carriers are made and inserted into the membrane of the tubule cell which increases its capacity for Na reabsorption 248 Amine hormones are derived from which amino acid They are derived from tyrosine and tryptophan They include epinephrine and norepinephrine
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