Lecture Exam 3
Lecture Exam 3 Bio243
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This 9 page Study Guide was uploaded by Naomi Chance on Sunday October 25, 2015. The Study Guide belongs to Bio243 at University of South Carolina Aiken taught by in Fall 2015. Since its upload, it has received 28 views. For similar materials see Anatomy and Physiology 1 in Biology at University of South Carolina Aiken.
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Date Created: 10/25/15
CH9 Difference between 3 types of muscles Skeletal muscle Skeletal muscle is striated muscle and it is voluntary it can be controlled consciously It can only be stimulated by the nervous system Multinucleated because very large cells Many mitochondria need lot of energy to contract Transverse tubules T tubules Smooth muscle It is involuntary no conscious control It can be stimulated or inhibited by either the nervous or the endocrine systems Cardiac muscle Striated and also involuntary It also can be stimulated or inhibited by either the nervous or endocrine function Connective tissue coverings of muscle Skeletal Muscle Covered in connective tissue epimysium Bundles of muscle fibers cells covered by perimysium Each muscle fiber myofiber Muscle cell covered by endomysium What is sarcolemma SR and sarcoplasm SarcolemmaPlasma membrane Sarcoplasm Cytoplasm Sarcoplasmic reticulum Smooth ER What are t tubules Importance of T tubules A T tubule or transverse tubule is a deep invagination of the sarcolemma which is the plasma membrane of skeletal muscle and cardiac muscle cells These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell Arrangement of myofibrils Structural organization of actin and myosin filaments Each myofibril composed of actin and myosin filaments Actin filaments thin or I band Myosin filaments thick or A band Sliding filaments mechanism All the definitions related to it The sliding filament theory eXplains muscle contraction based on muscle proteins the binding of myosin to actin that slide past each other to generate tension Z line Actin thin filaments radiate in either direction M line Myosin thick filaments are anchored to it I band On either side of Z line with only thin filaments A band Dark band composed of thick filaments and thin filaments H zone Lighter region within A band with no overlap of thick and thin filaments Neuromuscular junctions and related definitions fiber Neuromuscular Junction Interaction between a motor neuron and muscle Motor Neuron Neuron that stimulates muscle fiber Acetylcholine Chemical the motor neuron uses to talk to muscle fiber Synapse Space between motor neuron and muscle fiber that acetylcholine diffuses across Activation of Ca channels and release of neurotransmitters to stimulate a muscle 1 Motor neuron releases ACh it diffuses across the synapse and binds to receptors on the motor end plate 2 ACh opens Na channels near the T Tubules and Na ows into muscle cell via T Tubules 3 Na makes the SR release Ca Cross bridge cycle Understand each step of the process 1 Cross bridge binds to actin 2 Cross bridge moves 3 ATP binds to myosin causing cross bridge to detach 4 Hydrolysis of ATP energizes cross bridge O Crossbridge binds to actin Energized crossbridge Restin 9 muscle Thick filament myosin M M line 2 It AlMMADPF I me AM ADP PI 0 a H drol S39s Cross bridge ofyATlF39y I ADP Pi moves energizes crossbridge A M ATP A 39 Ml Fligor lmOFtiS Inn 3 r a No ATP ATP binds to myosini after death causing cross bridge to detach Rigor mortis Several hours after death all the muscles of the body go into a state of contracture called Rigor Mortis that is the muscles contract and become rigid even without action potentials This rigidity is caused by loss of the ATP which is required to cause separation of the cross bridges from the actin filaments during relaxation process Isometric and isotonic contractions Isometric contraction no shortening muscle tension is not enough to move the load Isotonic contraction muscle shortens because muscle tension is enough to move the load Difference between muscle twitch wave summation and trepe Muscle twitch Single contraction due to a single end plate potential single stimulus Three phases of muscle twitch Latent period Period of time between action potential and contraction No muscle tension seen Period of contraction cross bridge formation Tension increases Period of relaxation Time between peak tension and end of contraction Tension declines to zero Wave Summation Repeat stimulation before relaxation phase ends resulting in more tension production than treppe Muscle not allowed to fully relax Due to excess calcium available Tetnus Extreme wave summation due to very frequent or sustained stimulation Very little no relaxation between contractions Unfused tetnus Still have some uctuations between contractions Fused tetnus No peaks dips between contractions Treppe Stepping up of tension to max level with repeat stimulation of the same fiber following relaxation phase Repeated stimulations immediately after relaxation Causes a series of contractions with increasing tension 3 Processes that provide ATP for muscle contraction and when each of those is the main source ATP is regenerated quickly by three mechanisms Aerobic respiration Anaerobic pathway glycolysis and lactic acid formation Direct phosphorylation of ADP by creatine phosphate CP How is smooth muscle cell contraction different from skeletal and cardiac As in skeletal muscle cells contraction in a smooth muscle cell involves the forming of cross bridges and thin filaments sliding past thick filaments However because smooth muscle is not as organized as skeletal muscle shortening occurs in all directions During contraction the smooth muscle cells intermediate filaments help to draw the cell up like closing a drawstring purse Calcium ions regulate contraction in smooth muscle but they do it in a slightly different way than in skeletal muscle Calcium ions come from outside of the cell Calcium ions bind to an enzyme compleX on myosin called calmodulin myosin light chain kinase The enzyme complex breaks up ATP into ADP and transfers the Pi directly to myosin This Pi transfer activates myosin Myosin forms cross bridges with actin as occurs in skeletal muscle When calcium is pumped out of the cell the Pi gets removed from myosin by another enzyme The myosin becomes inactive and the muscle relaxes This process is called myosin regulated contraction CH 11 All the divisions and subdivision of nervous system I Structure l Function Difference between sympathetic and parasympathetic The sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight or ight response The parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions Structure of neuron Difference between nuclei and ganglia Neurons vary in size and shape but they all have A cell body or Soma Cluster in groups called nuclei in the CNS and ganglia in the PNS Dendrites Receive signals Axon Conducts impulses Axon hillock myelination and nodes of ranVier Region closest to cell body is the axon hillock where action potentials are generated Myelinated axons conduct impulses more rapidly Insulates the axon and keeps sodium owing smoothly down the length Nodes of RanVier allow more sodium to enter axon to carry on impulse Difference between sensory motor and intemeurons Sensory Neurons Conduct impulses from sensory receptors to the CNS Motor Neurons Conduct impulses from the CNS to target organs muscles or glands Interneurons Located completely within the CNS and integrate functions of the nervous system Different types of glial cells in CNS and PNS function of each Four main neuroglia support CNS neurons Astrocytes Most abundant and highly branched Microglial cells Migrate around neuronal tissue and eat foreign and dead material Ependymal cells Line the ventricles and secrete cerebro spinal uid Oligodendrocytes form myelin sheaths around axons in CNS Two major neuroglia seen in PNS Satellite cells Surround neuron cell bodies in PNS Function similar to astrocytes of CNS Schwann cells Form myelin sheaths around axons in PNS Similar function as oligodendrocytes Difference between uni multi and bipolar neurons with examples Multipolar three or more processes 1 axon others dendrites Most common and major neuron type in CNS Bipolar two processes 1 axon l dendrite Rare ex retina and olfactory mucosa Unipolar one T like process two axons Also called pseudounipolar Peripheral distal process associated with sensory receptor Proximal central process enters CNS Understand everything about synapses A Synapse is the functional connection between a neuron and the cell it is signaling In the CNS this second cell will be another neuron In the PNS the second cell may be in a muscle or gland The presynaptic neuron talks to the postsynaptic neuron by using a neurotransmitter which will result in changes to the membrane potential of the postsynaptic neuron Electrical Synapses Use Gap Junctions Occur in smooth muscle and cardiac muscle amp between some neurons of the brain Ions and action potentials pass through gap junctions Can produce more coordinated or stronger contraction of muscles Can synchronize the firing of neurons in brain Chemical Synapses Use Neurotransmitters Most synapses involve the release of a chemical called a neurotransmitter from the axons Terminal buttons Activation of Ca channels and release of neurotransmitters into synaptic cleft Resting membrane potential What is the voltage at this point Neurons have a resting potential of 70mV Established by Large negative molecules inside the cell Na K Pumps Permeability of the membrane to ions At rest there is a high concentration of K inside and Na as well as Ca and Cl outside of the cell What is action potential What is the threshold voltage of AP The action potential is an eXplosion of electrical activity that is created by a depolarizing current This means that some event a stimulus causes the resting potential to move toward 0 mV When the depolarization reaches about 55 mVa neuron will fire an action potential This is the threshold What is polarized depolarized repolarized and hyperpolarized Polarized Negatively Charged on the inside of the Cell Membrane and Positively Charged on the Outside The INSIDE of the membrane temporarily becomes MORE POSITIVE than the OUTSIDE THIS IS CALLED DEPOLARIZED REPOLARIZED the inside of the axon resumes a negative charge The DEPOLARIZATION and REPOLARIZATION of a Neuron Membrane is called an ACTION POTENTIAL Hyperpolarization is a change in a cell39s membrane potential that makes it more negative It is the opposite of a depolarization It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold Difference between gated channels Not gated always open sometimes called leaky K channels contribute to resting potential Ligand gated Open when a neurotransmitter Acetylcholine binds to it in the dendrites Voltage Gated Open when a particular membrane potential is reached in the axons Difference between EPSP and IPSP What type of stimulus will be excitatory or inhibitory EPSPs move the membrane potential closer to threshold May require EPSPs from several neurons to actually produce an action potential IPSPs move the membrane potential farther from threshold Can counter EPSPs from other neurons The summation of EPSPs and IPSPs determines whether an AP occurs
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