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Muscle Systems and Sensory Neurons Study Guide

by: Jasmine Guo

Muscle Systems and Sensory Neurons Study Guide Biology 2108

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Jasmine Guo

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Study Guides for Biology 2108K Information covering Muscular Systems, Immune System, and Sensory Neurons
Biology 2108k
Dr. Matthew Nusnbaum
Study Guide
Biology, GSU, Studyguide
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This 131 page Study Guide was uploaded by Jasmine Guo on Saturday June 25, 2016. The Study Guide belongs to Biology 2108 at Georgia State University taught by Dr. Matthew Nusnbaum in Winter 2016. Since its upload, it has received 80 views. For similar materials see Biology 2108k in Biology at Georgia State University.


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Date Created: 06/25/16
Immune System Study Guide ● What are the three phases of the defense response? o 1) recognition phase o 2) activation phase o 3) effector phase o What takes place in each? ▪ 1) recognition: particle binds to receptor ▪ 2) activation: mobilization of cells and molecules to fight invader ▪ 3) effector: mobilized cells and molecules destroy invader by digesting particle ● What are the differences between non-specific and specific defenses? o Non-specific (INNATE)-provides protection in a nonspecific manner against ALL kinds of infections; does not depend on exposure of pathogen o Specific (ADAPTIVE)-specific to A PARTICULAR a pathogen; it remembers past infections and subsequent encounters with the same pathogen, which ultimately generates a stronger response o What are the players in the non-specific defenses? What is another name for the non-specific defense system? ▪ Mast cells- releases histamine (an important contributor to allergic reactions and inflammations) ▪ Granulocytes- a white blood cell with secretory granules ● Basophil ● Eosinophil ● Neutrophil ▪ Phagocytes- immune cells that engulf and destroy foreign cells; travel freely in the lymph and circulatory systems ● Neutrophil ● Macrophages ● Dendritic Cells ▪ Natural Killer- does not recognize foreign cells, but they recognize and kill host cells that are affected by a virus or have become cancerous o What cell types are involved in specific defenses? What is another name for the specific defense system? ▪ INNATE= another name ▪ B cells ● Memory cells ● Plasma cells ▪ T cells ● Cytoxic t cells ● Helper t cells ● Where does lymph come from? o Lymph= fluid derived from blood and other tissues; from the tissues, lymph moves into lymph system vessels ● What do the lymph system vessels do? o It transports material through lymph nodes throughout the body. They join and eventually form the thoracic duct, which joins the circulatory system at a major vein near the heart! o What is the role of the lymphatic system in the function of the immune system? ▪ Protects us against disease ▪ The cells of the lymphatic system respond to environmental pathogens, toxins, abnormal body cells (such as cancer) ● What are the roles of the complement protein system in aiding the immune system? o They’re inactive proteins in the blood activated by bacterial infection to disrupt bacterial invaders and to recruit phagocytes o It supplements other parts of the immune system o How do these proteins carry out their functions? ▪ 1) Lysis- breaking open of cells; complement proteins form a membrane attack complex (MAC) that makes holes in bacteria cells ▪ 2) phagocytosis- coating of bacteria with a protein that phagocytes recognize, causing it to engulf the bacteria and destroy it ● Phagocytes play very important roles in the immune system- there are a number of different varieties, but in general what do they all do? o Foreign cells, viruses, and fragments become attached to the phagocyte membrane and become engulfed- ultimately they destroy the pathogen o What specializations do phagocytes have to carry out their roles? ● What is inflammation and what does it do for the body? o A physiological response of the body to injury that removes the inciting agent if present and begins the healing process o Causes the following… ▪ Redness ▪ Warmth ▪ Swelling ▪ Pain o Why do we have inflammation? ▪ Triggered by histamine release ▪ Allows wounds to heal ● What is another name for an antibody? o Immunoglobulins o What do antibodies do in the body? ▪ They bind directly to antigens, effectively coating the surface of the invader, in order to prevent pathogens from entering or damaging healthy body cells. ▪ Antibodies can also stimulate other parts of the immune system (e.g. complement proteins) to destroy the pathogens. ▪ Antibodies can mark pathogens through a process called opsonization so that the pathogens can be identified and neutralized by other immune cells. ● What are the parts of an antibody/how can the body produce such a wide variety of antibodies? (Look at the slide on Antibody diversity, and read about the process in your text) o Parts Include: ▪ H (heavy) Chains ▪ L (light) Chains ▪ V (variable region),D (diversity region),J (joining region), and C (constant region) gene segments o Genomic Rearrangement= key to diversity o The association of different L and H chains to make a functional antibody contributes to antibody diversity ● What is opsonization? o This is a means of identifying the invading particle to the phagocyte. ● What are the differences between T cells and B cells? o B-cells can connect to antigens right on the surface of the invading virus or bacteria. This is different from T-cells, which can only connect to virus antigens on the outside of infected cells. o What does each do? ▪ B cells- provide antibody-mediated immunity; they defend against antigens and pathogens in body fluids ▪ T cells- provide cell- mediated immunity; they defend against abnormal cells and pathogen inside the cell ● Why do B cells need to be “selected for” and how does that selection work? o What is a Plasma cell? ▪ A short-lived antibody-producing cell derived from a B cell. ● B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell. ● Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction. ● What are TC​ells (as opposed to H​ells)? o T​= Cytoxic T cells -> kill other cells, activated by cytokines released from helper T c ​ cells o TH ​Helper T cells -> help other cells of the immune system by secreting cytokines o What is the difference between a memory T cell and an effector T cell? o What are Natural Killer (NK) cells? ▪ does not recognize foreign cells, but they recognize and kill host cells that are affected by a virus or have become cancerous ● What is Immunological Memory and what cell types are involved? o Immunological Memory allows the adaptive immune system to rapidly clear infection due to the fact that the infections have been encountered before ● How do cellular and humoral immune responses differ? o How do they become activated? ▪ Humoral Immune- this involves the use of antibodies produced by the b cells to attack any invading foreign bodies like bacteria, viruses etc. Production of memory cells also takes place for a faster response in case of a second infection. ▪ Cellular Immune- this involves the destruction of self-cells damaged by mutations or infected by viruses. This form of immunity includes cells like cytotoxic t cells and nk cells. What is a vaccination and what is its purpose? o Why bother getting one? ▪ Purpose of vaccination is to produce immunity. Immunity means the presence in a person's body of cells and substances known as antibodies that can produce a protective immune response. ● How do immune cells recognize “self” vs foreign? o What are MHCs? What is the difference between type I and type II? ▪ Composed of many genes with high rate of polymorphism (meaning there’s a lot of variety in gene sequences) ▪ Class I- genes are expressed on surface of nucleated cells ▪ Class II- genes are expressed on surface of dendrite, macrophages, and B-cells Muscular System Review Sheet­ Questions to be able to answer  ● What are the functions of the muscular system?  ­generates force and produces movement      ● What are 2 characteristics of all muscles?  ­they all use muscle proteins actin and myosin, these proteins are used to contract and  generate force  ­organized in thin(actin) and thick (myosin) filaments     ● What are the 3 types of muscle? Where is each located? How does each appear? How does  each contract and are contractions rhythmic?  ­smooth: non­striated, contract slowly, functions to force fluid through internal channels;  regulates blood flow, control air flow  ­cardiac: striated, functions to power the heart; conracts to pump the heart   ­skeletal: striated, function to move libs and torso  ● What covers each individual muscle fiber?  o Elongated cells that are embedded in surrounding connecting tissues   ▪ Endomysium​  is the name of the fine connective tissue sheath that  surrounds/covers each single/individual muscle fibre  ● What wraps around fascicles?  o Fasciles are bundles of muscle fibers   o Fasciles are wrapped by perimysium     ● What binds many fascicles into an entire muscle?  o Since the perimysium wraps many fascicles (muscle fibers), together they are  binded by the epimysium     ● How are muscles attached to bones?  o Muscles attach to the bones by many connective tissues and specialized tendons  made of collagen     ● What are the 4 distinguishable regions (bands, zones) of myofibrils­ what is a sarcomere?   o The sarcomere is the basic contractile unit of muscle arranged along the muscle  fiber; largely determines a muscle’s ability to contract and generate force   ● Diagram a relaxed muscle showing these 4 regions.  o   ● Diagram a contracted muscle showing the major regions. Which disappears? Which  shortens?  ● What composes thick myofilaments?  o Myosin     ● What composes thin myofilaments?  o Actin w/ tropomyosin coiled around it; also with an active site of troponin (where  calcium comes to bind to it)     ● What is a motor unit? Diagram one.    o A motor unit is the partnership between a motor neuron and muscle tissue; motor  neurons are what causes a muscle tissue to fire    ● What are the steps in contraction ?  What are the players?  o The player= Ca2+, ATP, Actin, Myosin, Troponin, Tropomyosin   o Step 1: Myosin binds to the ATP, which leads to the detachment of Actin   o Step 2: ATP then hydrolizes to ADP, which causes myosin head to cock back   o Step 3: Myosin binds actin, forming a cross bridge­ meaning the filaments are  sliding to create overlap   o Step 4: ADP are now released, producing a power stroke­ which causes thin  filaments to slide relative to thick filament     o Explain the sliding filament model of contraction  ▪ Thin filaments past the thick filaments so that actin and myosin overlap;  do not change length; myosin does not change position     o Explain the excitation­contraction coupling mechanism  ▪ Contraction occurs immediately following depolarization and the release  of Ca2+ from the sarcoplasmic reticulum   ▪ Ca2+ then binds to the troponin active site which releases actin to get  binded to the myosin head     ● What do the terms sarcolemma, sarcoplasmic reticulum, and sarcoplasm refer to in terms of  the muscle cell?  o Sarcolemma= the plasma membrane of a striated muscle   o Sarcoplasmic reticulum= a specialized type of smooth ER that regulates the  calcium ion concentration in the cytoplasm of striated muscle cells  ● How long does it take a muscle cell to contract?  o Smaller forces use higher amounts of velocity to contract  o Larger forces use lower amounts of velocity to contract     o What is meant by a muscle twitch?  ▪ The response of a muscle to a single, brief stimulus   ● What is an “all or none response?”  o The strength by which a muscle fiber responds to a stimulus is not dependent on  the strength of the stimulus. If the stimulus is any strength above threshold, the  nerve or muscle fiber will give a complete response or otherwise no response at  all.  ● What molecule is needed to provide energy for contraction? What are the 3 ways it can be  produced?  o ATP is the energy source   o 3 Ways are…  ▪ Creatine phosphate (no oxygen required)   ▪ Glycolysis  (no oxygen required)   ▪ Aerobic Cellular respiration (oxygen required)   ● What is muscle fatigue? How is it caused? Who is likely to get it?  o Decrease in a muscle’s capacity to generate force; results in a decline in tension  despite ongoing stimulation   o Causes include overwork of muscles, poor sleep   o Sprinter, weight lifters  ▪ Slow Twitch­ muscles that contract slowly and consumes less ATP   ▪ Fast Twitch­ fibers in muscles generate more quickly, creating rapid  movement, and utilizing more ATP     Excretory Systems Study Guide ● What does osmolarity refer to? o The osmotic concentration of an osmotically active substance in solution, expressed as osmoles of solute particles per liter of solution. ● What is the difference between an osmoregulator and an osmoconformer? o Osmoregulator- expand energy to control water uptake and loss in a hyperosmotic/hypoosmotic environment o Osmoconformer- match their body fluid osmolarity to that of the surrounding environment o What are the advantages of osmoregulation? Disadvantages? ▪ Advantage- cells exist in uniform/ionic environment ▪ Disadvantage- more energy required to complete ● What challenges do animals in hyperosmotic environments face? Hypoosmotic? o Hyper- less inside cell, more in environment o Hypo- more inside cell, less in environment o How do animals in each of these situations deal with the challenge? ▪ Osmoregulation and osmooconformation o What mechanisms are there to manipulate osmolarity? ▪ Increase/decrease in cell volume ▪ Increase/decrease in water and electrolytes ● How does salt excretion work? What improves the efficiency of the process? o Salt glands work by actively pumping ions from the blood into cells that make up the gland, followed by excretion of salt from the body through the gland and the nasal cavity. Their salt glands allow these animals to gain net water intake by drinking seawater. ● What are the main nitrogenous waste products and what are the differences between them? o Ammonia- generally release it across the whole body surface or through gills (MOST TOXIC, BUT IT’S EASILY RELEASED IN WATER) o Urea- carried to the kidney where it is excreted o Uric Acid- largely insoluble in water and can be secreted as a paste with very little water loss (LEAST TOXIC, BUT MORE ENERGETICALLY COSTLY TO PRODUCE) o Which animal groups utilize each of these products and why? ▪ Ammonia- most aquatic animals, mostly bony fish ▪ Urea- mammals, most amphibians, sharks ▪ Uric Acid- many reptiles, including fish; insects, land snails ● What processes take place in animal excretory systems? o Filtration- pressure- filtering of body fluids o Reabsorption- reclaiming valuable solutes o Secretion- adding toxins and other solutes and other solutes from the body fluids to the filtrate o Excretion- removing the filtrate from the system o What kinds of adaptations are necessary for these functions? ▪ Isolation of the waste into an extracellular space; waste compounds are isolated in a cellular compartment called a contractile vacuole ● Fusion of the contractile vacuole with the cell membrane eliminates the waste contents by exocytosis from the cell o What are the different animal systems described in the text? ▪ In flatworms, excretion involves isolating the fluid from the body cavity in excretory organs calledprotonephridia ▪ In segmented annelid worms such as earthworms, the body fluid is filtered through small capillaries into a pair of excretory organs cametanephridia ▪ In insects and other terrestrial arthropods, fluid passes from the main body cavity into a series of tubes cal​alpighian tubules ● Be able to describe the structures of the vertebrate kidney and how they are organized o Vertebrates filter their blood through specialized capillaries that have openings in their walls. o These porous capillaries form a tufted loop calledGLOMERULUS o There are thousands to millions of glomeruli in each kidney. Driven by circulatory pressure, nitrogenous wastes, electrolytes, other small solutes, and water move through small holes in the capillary walls into an extracellular space surrounded by a capsule. o The filtrate then moves through a series oRENAL TUBULES​ , which further process the filtrate by reabsorption and secretion before it enters COLLECTING DUCTS​ as urine. o The collecting ducts converge on a larger tube called tURETER​, which brings urine from the kidneys to a hollow organ called the bladder in mammals and fishes, or the cloaca in the case of amphibians, reptiles, and birds, for storage and elimination from the body. o What is a nephron? ▪ The glomerulus, capsule, renal tubules, and collecting ducts make up a nephron, the functional unit of the kidney. ▪ Perform the three basic steps of excretion and osmoregulation: filtration of blood passing through the glomerulus, reabsorption from the renal tubule back to the bloodstream of key electrolytes and solutes, and secretion of additional wastes by the renal tubules. o How are they organized in the kidney? ▪ The kidneys run along the length of the body, with nephrons arranged segmentally. ● What is special about the glomerulus and what is it for? o A network of capillaries tightly bound by another set of epithelial cells o What are podocytes? ▪ Epithelial cells ● How does the shape of the nephron allow the kidney to concentrate urine and what mechanisms are involved in this process? o Mammalian kidneys concentrate urine as an adaptation to living on land; the organization of the nephrons allows for efficient extraction of urea from the blood o What is the Loop of Henle? Who was Henle? (just kidding…) ▪ A curvature in the renal tubule that reverses the flow of the filtrate back pass the way it came o What solutes are brought into/out of the filtrate at each step in the process? ▪ What is active and what is passive transport? ● Water moves out through passive transport, making filtrate more concentrated ● Electrolytes are transported into the interstitial fluid through active transport o How does the osmolarity changes as the filtrate travels through the nephron? ▪ Increases going down through the proximal convoluted tubule ▪ Decreases going up towards distal convoluted tubule ▪ Then increase again going down to the filtrate to ureter ● How is the concentration of urine controlled in the body? o Through the Antidiuretic Hormone (ADH) o In the presence of ADH, the collecting duct walls become permeable to water. This change in permeability occurs because aquaporins insert in the membrane of cells of the collecting duct. The aquaporins allow water in the collecting duct to diffuse into the interstitial fluid, thus making the urine in the tubule more concentrated. o Absence of ADH cases the conducting duct to be less permeable to water, resulting in dilute urine o Why might you want to decrease or increase the concentration of the urine? ▪ Dehydration ▪ Having Alcohol in your system What are the major functions of the Vertebrate Skeletal System? The Vertebrate Endoskeleton •  Internal scaffoldings to which which they can pull.gainst •  Endoskeletons do not provide outer protection like the they can grow and enlarge, but inside the body as the animal grows •  Vertebrate skeletons are composed of cartilage, bone or both Anatomy of a long bone What are the differences between spongy and compact bone? Articular cartilage Compact bone Proximal epiphysis Spongy bone Epiphyseal line Periosteum Endosteum Compact bone Medullary cavity (lined by endosteum) Diaphysis Yellow bone marrow Compact bone Periosteum Perforating (Sharpey`s) Nutrient Distal arteries epiphysis Bone Tissue and Cells Spongy Bone Compact Bone Found where bones are not heavily Covers outside of all bones and found stressed or stresses arrive from many where stresses are high and unidirectional directions No osteons Concentric layers of osteons Lamellae form trabeculae Central canal (Haversian canal) Canaliculae connect lacunae (pockets for osteocytes) Osteogenic cell Osteoblast Osteocyte Osteoclast Stem cell Matrix-synthesizing Mature bone cell Bone-resorbing cell cell responsible that maintains the for bone growth bone matrix Osteoporosis •  Group of diseases in which bone resorption outpaces bone deposition •  Spongy bone of the spine is most vulnerable •  Occurs most often in postmenopausal women •  Bones become so fragile that sneezing or stepping off a curb can cause fractures 6- Formation of the Bony Skeleton •  Begins at week 8 of embryo development –  Prior to that the skeleton is all cartilage or fibrous structures –  Bone begins to develop and eventually replaces the cartilage •  Two types of ossification occur –  Intramembranous ossification •  bone develops from a fibrous membrane –  Endochondral ossification •  bone forms by replacing hyaline cartilage Bones are a type of connective tissue and develop from dense connective tissue Intramembranous Ossification Endochondral Ossification The Vertebrate Endoskeleton • The human body has 206 bones that make up the axial and appendicular skeletons. Joints •  A joint is where two bones meet. The human skeleton has several types of joints. •  Movement around joints is accomplished by antagonistic muscle pairs—one contracting, the other relaxing. •  One muscle is the flexor (bends the joint) and the other is the extensor (straightens the joint). •  Ligaments stabilize the joint Joint  Categories   Func▯onal  Category   Structural  Category   Descrip▯on   Example   Synarthrosis   Fibrous   Suture   Fibrous  connec▯ons  and   Skull  Bones   interlocked  surfaces   Fibrous  connec▯ons  and   Gomphosis   inser▯on  in  bony  socket  th  in  Jaws   Car▯laginous   Synchondrosis   Interposi▯on  of  car▯lage Epiphyseal  car▯lages   Amphiarthrosis   Fibrous   Syndesmosis   Ligamentous  connec▯on   Tibia  and  Fibula   Car▯laginous   Symphysis   Connec▯on  by  fibrous  car▯Between  Vertebrae   pad   Diarthrosis   Synovial   Complex  joint  with  a  Shoulder,  ankle,   capsule  and  containing   synovial  fluid   knee,  etc.   Muscles Skeletal Cardiac Smooth Location Attach to the skeleton or skin Walls of the heart Walls of hollow visceral organs Appearance Obvious Striations (Stripes) Striations No striations Control Subject to Voluntary (conscious) Involuntary (unconscious) Involuntary (unconscious) control Activated by reflexes as well Function Move the skeleton Powers the heart Force fluids, etc. through internal channels Muscle Fiber Long, cylindrical shape Branching chains of cells Spindle shaped (cell) shape # of nuclei/ per Multinucleate One or two nuclei One nucleus cell Organization of Skeletal Muscles Epimysium Epimysium Bone Perimysium Tendon Endomysium Muscle fiber in middle of a fascicle Blood vessel Fascicle (wrapped by perimysium) Endomysium (between individual muscle fibers) Perimysium Fascicle Muscle fiber Muscle à Fascicle à Muscle Fiber à Myofibril àSarcomere Myofilaments Sarcomere SR and T-tubules •  Sarcoplasmic Reticulum –  Elaborate, smooth endoplasmic longitudinally and surrounds each myofibril •  Transverse tubules (T tubules) •  T tubules and SR provide tightly linked signals for muscle contraction –  sensitive and connected to theoltage 2+ –  on sarcoplasmic reticulum) channel Sliding Filament Model of Contraction •  Thin filaments slide past the thick ones so that the actin and myosin filaments overlap to a greater degree –  The filaments DO NOT change length –  Myosin does not change position •  In the relaxed state, thin and thick filaments overlap only slightly •  Upon stimulation, myosin heads bind to actin and sliding begins –  ANIMATION à 3/14 Sliding Filament Model of Muscle Contraction •  Involves 6 key players: 1. Myosin 2. Actin 3. Tropomyosin 4. Troponin Ca2+ 5. Ca 2+ 6. ATP ATP Figure 9.12 Sliding Filaments Skeletal Muscle Contraction •  In order to contract, a skeletal muscle must: –  Be stimulated by a nerve ending –  Propagate an electrical current, or action potential, along its sarcolemma 2+ –  Have a rise in intracellular Clevels, the final trigger for contraction •  Linking the electrical signal to the contraction is excitation-contraction coupling Neuromuscular Junction •  The neuromuscular junction is formed from: –  Axonal endings, which have small membranous sacs (synaptic vesicles) that contain the neurotransmitter acetylcholine (ACh) –  The motor end plate of a muscle, which is a specific part of the sarcolemma that contains ACh receptors and helps form the neuromuscular junction •  Though exceedingly close, axonal ends and muscle fibers are always separated by a space called the synaptic cleft Neuromuscular Junction The Neuromuscular Junction 1 Action potential arrives at axon terminal of motor neuron. 2+ 2+ Ca 2 Voltage-gated Ca Ca Synaptic vesicle channels open and Ca2+enters the axon containing Acetylcholine terminal. Mitochondrion Axon terminal of motor neuron Synaptic cleft 3 Ca2+entry causes some synaptic vesicles Fusing to release their synaptic contents vesicles (acetylcholine) by exocytosis. ACh 4 Acetylcholine, a Junctional neurotransmitter, diffuses folds of across the synaptic cleft sarcolemma and binds to receptors in the sarcolemma. Sarcoplasm of muscle fiber The Neuromuscular Junction 5 ACh binding opens ion channels that allow simultaneous passage of Na into the muscle fiber and K out of the muscle fiber. Na+ K + Postsynaptic mem- brane ion channel opens; ions pass. Coordination of Activity: Signal Propagation Axon terminal Open Na + Closed K + Channel Channel Na+ Synaptic cleft ACh– Na + + K+ ACh K Na K + 2 Generation and propagation of the action potential (AP) Closed Na+ Open K+ Channel Channel 1 Local depolarization: Na+ generation of the end plate potential on the sarcolemma K+ Sarcoplasm of muscle fiber 3 Repolarization Muscle Relaxation •  No active mechanism for muscle fiber elongation •  After a muscle contraction, a muscle fiber returns to its original length by: – Elastic forces – Opposing muscle contractions – Gravity 9- Motor Unit: The Nerve-Muscle Functional Unit Figure 9.13a Muscle Twitch •  A muscle twitch is the response of a muscle to a single, brief threshold stimulus •  Twitch measured in terms of tension, or force it generates. •  A single action potential generates a single twitch. Force generated depends on how many fibers are in the motor unit. •  There are three phases to a muscle twitch –  Latent period •  Excitation/Contraction (EC) coupling is occurring –  Period of contraction •  (mechanical force exerted by asion muscle) increases –  Period of relaxation •  Ca 2+ reabsorbed; muscle tension goes to zero Muscle Response to Varying Stimuli •Single twitc— if action potentials are close together in time, the twitches are summed, tension increases. 2+ 2+ •Twitches sum because Ca pumps can not clear Ca from sarcoplasm before next action potential arrives. 2+ •Tetanus — action potentials are so frequent there is always in the sarcoplasm. Figure 9.15 ATP is the energy source for muscle activity Direct phosphorylation Anaerobic pathway Aerobic pathway Coupled reaction of creatine Glycolysis and lactic acid formation Aerobic cellular respiration phosphate (CP) and ADP Energy source: CP Energy source: glucose Energy source: glucose; pyruvic acid; free fatty acids from adipose tissue; amino acids from protein catabolism Glucose (from Glucose (from CP ADP glycogen breakdown or glycogen breakdown or delivered from blood) delivered from blood) Creatine kinase O2 Glycolysis Pyruvic acid Creatine in cytosol Fatty ATP acids O2 O 2 ATP 2 Amino Aerobic respiration Pyruvic acid acids in mitochondria net gain O2 Released Lactic acid CO 2 32 ATP to blood H O 2 net gain per glucose Oxygen use: None Oxygen use: None Oxygen use: Required Products: 1 ATP per CP, creatine Products: 2 ATP per glucose, lactic aP cioducts: 32 ATP per glucose, CO , H2O 2 Duration of energy provision: Duration of energy provision: Duration of energy provision: Hours 15 seconds 60 seconds, or slightly more How is this information useful for exercise and athletics? Exercise & Muscle Fatigue •  Muscle fatigue –  Decrease in a muscle`s capacity to generate force –  Results in decline in tension despite ongoing stimulation •  Low intensity-long duration exercise makes muscles more resistant to fatigue by increasing blood supply and mitochondria •  Brief intense exercise causes actin and myosin synthesis which helps muscles exert more tension, but does not improve endurance Prolonged-duration Short-duration exercise exercise ATP stored in ATP is formed Glycogen stored in muscles is broken ATP is generated by muscles is from creatine down to glucose, which is oxidized to breakdown of several used first. Phosphate generate ATP. nutrient energy fuels by and ADP. aerobic pathway. This pathway uses oxygen released from myoglobin or delivered in the blood by hemoglobin. When it ends, the oxygen deficit is paid back. Muscle Performance •  Type of muscle fiber determines endurance and strength. •  Skeletal muscle fibers can express genes for different variants of myosin with different ATPase activity. •  Faster or slower ATPase activity determines different muscle characteristics: Fast Twitch and Slow Twitch Fibers •  Proportion of fast- and slow-twitch fibers in skeletal muscles is determined mostly by genetic heritage. Sensory Systems 1 Function • Sensory systems provide animals with information about the internal and external environment. • They allow organisms to interpret relevant stimuli and make appropriate behavioral decisions. 2 Sensory Neurons • Sensory Neurons transduce the energy of a specific stimulus into an electrical signal – This signal is called a receptor potential – Receptor potentials can generate action potentials in two ways: –Can generate action potentials in the receptor cell itself –Can trigger release of neurotransmitter so that an associated neuron generates an action potential Intensity of sensation can be coded as the frequency of action potentials. The connection between peripheral receptors and central processing is what allows for interpretation of sensory input and appropriate responses. Adaptation—diminishing response to repeated stimulation. Enables animals to ignore background conditions but remain sensitive to changing or new stimuli. Some sensory cells don`t adapt (e.g., mechanoreceptors for balance). Mechanoreceptors What might mechanoreceptors do? • Mechanoreceptors are located in tissues throughout body – Skin – Joints – Hollow organs of the digestive system – Inner Ear • Activated by physical distortion of the mechanoreceptor`s plasma membrane Mechanoreceptors •  In skin – The dendrites of some touch receptors are free nerve endings that produce sensations of itching, tickling, and touch – Some receptor endings connective tissue, including Pacinian corpuscles, which detect pressure •  What determines the sensitivity of an area of skin? Hearing • How Is Sound Sensed? –The Ear Converts Sound Waves into Electrical Signals –What is a sound wave? How can one signal be converted into another? The Outer Ear •  Captures sound waves and aids in sound source localization •  Consists of two parts: – External ear •and directs them intos the skull – Auditory canal •  carries sound waves to the middle ear The Middle Ear • Transmits sound waves to the inner ear • Consists of: –  tympanic membrane – middle ear bones • hammer (malleus) • anvil (incus) • stirrup (stapes) – auditory tube (Eustacian tube) The Inner Ear • Converts vibrations from sound waves into electrical signals • Consists of: –Cochlea: spiral, fluid- filled tubes; the middle ear bones transfer sound energy into it by vibrating the oval window membrane –Vestibular system: involved in balance Hair Cells •  Hair cells are the mechanoreceptor cells that detect stimuli in the auditory system and other systems as well The Cochlea •  Sound is converted into electrical signals in the cochlea •  The cochlea has three fluid-filled compartments containing – basilar membrane – tectorial membrane – Hair cells Hearing •  The basilar membrane varies in stiffness and width along its length – Different regions vibrate in response to different frequencies – Pitch is determined by location Chemoreceptors! •  Detect chemical stimuli in the environment and the body •  In vertebrates the chemical senses are generally organized into smell (olfaction) and taste (gustation) •  Olfactory receptors are neurons located in the upper nasal cavity – mucus layerlike dendrites that protrude into a –  Odorous molecules in air dissolve in nasal on olfactory dendritesto specific receptors • type of odorant receptor neuron generally expresses 1 –  Action potentials carry information to the brain •  Odor quality is perceived by the combination of receptors that are activated --> combinatorial code Olfactory Transduction Glomerulus in Olfactory Bulb + Extracellular + + + + + + + + + + Na / Ca+2 + + Cl- Receptor Channel Channel Olfactory Receptor Neuron cAMP Adenylate G Protein Cyclase - - ATP - - Intracellular cAMP Signaling Pathway ) m l t e o e n b Threshold Potential m Resting Potential M Time Taste Buds Dendrites wrap around gustatory cells Figure 15.23 Taste Receptors Ionotropic Metabotropic So,if we can only taste 5 basic categories;what is flavor? What does chocolate ltastez like? The Mammalian Eye • Mammalian eyes have three major tissue layers – Sclera: white outer layer; tough connective tissue – Choroid: dark middle layer that absorbs stray light; has rich blood supply – Retina: delicate inner layer; multilayered sheet of photoreceptors and neurons • Light encounters a series of eye structures before it can be transduced… The Adjustable Lens •  The adjustable lens allows focusing of distant and nearby objects •  Muscles attached to the lens can contract and change the shape of the lens – Allows images to be focused on the fovea of the retina when looking at objects at different distances The Retina •  Light striking the retina is captured by photoreceptors •  Cones – for color vision the fovea and allow –  Require relatively bright light to function –  Detect red, green, and blue light wavelengths •  Rods –  Concentrated in the periphery of the in dim lightre responsible for vision – grey)eive light intensities (shades of The Retina •  Rods and cones – the retinators at the rear of – forming receptor potentials •  Bipolar Cells – Connect Photoreceptors and Ganglion Cells •  Ganglion cells – At the front of the retina – Carry action potentials to brain along optic nerve •  Amacrine and Horizontal Cells – complex processing; contrast enhancement Phototransduction The blind spot and blood vessels of the eye Pain Withdrawal Reflex Central Nervous System: CNS • Brain and Spinal Cord compose the CNS • Signal Processing Center for sensory input and motor output The Brain • Composed of wrinkled, pinkish-gray tissue • Vertebrate anatomy includes cerebral hemispheres, cerebellum, and brain stem- plus spinal cord The Brain • All vertebrate brains develop anatomical and functional divisions –Hindbrain –Midbrain –Forebrain • These parts develop to different degrees in different species The Spinal Cord •  Neural cable that extends from the base of the brain to the lower back, and is protected by bones of the vertebral column •  Between vertebrae, nerves carrying axons of sensory neurons and motor neurons arise from the dorsal and peripheral nerves of the spinal cord erge to form the •  Anatomy of the spinal cord –  Contains a butterfly shaped area of gray matter that is composed of the cell bodies –  Gray matter is surrounded by white matter •  Composed of myelin wrapped axons •  In addition to relaying neural signals between brain and body, the spinal cord also contains the neural pathways for reflexive behaviors The Hindbrain •  Includes medulla, pons and cerebellum •  Medulla –  Like an enlarged extension of the spinal cord –  Has neuron cell bodies at its center, surrounded by a layer of myelin covered axons –  Controls several vital automatic functions •  Pons –  Above the medulla –  Influences transitions between sleep and wakefulness –  Also influences the rate and pattern of breathing along with the medulla •  Cerebellum –  Crucial for coordinating movements and position of the body –  Cerebellum is largest in animals whose activities require fine coordination –  Highly developed in birds that engage in the complex activity of flight The Forebrain • Includes the: • Diencephalon – Thalamus – Hypothalamus • Cerebrum – cerebral hemispheres that are connected by and communicate with one another through the corpus callosum Forebrain: Diencephalon • and includes the: in and the forebrain •  Thalamus – lGateway to the cerebral cortexz – Complex relay station that channels sensory information from all parts of the body to the cerebral cortex •  Hypothalamus – Functions as a major coordinating center – Regulates Homeostasis (body temperature, fluid balance, blood pressure) – Releases hormones and is closely associated with the pituitary gland Telencephalon: Cerebral Hemispheres •  Dominant structures in the mammalian brain •  Cerebral cortex –  Sheet of gray matter about 4mm thick that covers each cerebral hemisphere –  Integrates and interprets sensory information and initiates voluntary movements –  Folded into ridges (gyri) and valleys (sulci) –  Cell bodies are organized into distinct layers and columns •  Under the cerebral cortex is white matter made up of the axons that connect the cell bodies in the cortex with one another and with other areas of the brain •  the body) ere acts contralaterally (controls the opposite side of –  Two hemispheres are not symmetrical with respect to all functions (eg.Language is predominantly in the left hemisphere) Anatomical Distinctions •  Deep sulci divide the cerebral hemispheres into five lobes: 1.Frontal 2.Parietal 3.Temporal 4.Occipital 5.Insula Functional Distinctions •  Different regions of the cerebral cortex have different functions •  The three types of functional areas are: – Motor areas • control voluntary movement – Sensory areas • conscious awareness of sensation – Association areas • integrate diverse information Functional andAnatomical Regions in Cerebral Cortex Where are the lobes in relation to this diagram? Motor areas Central sulcus Sensory areas and related association areas Primary motor cortex Primary somatosensory Premotor cortex cortex Frontal eye field Somatosensory Somatic association cortex sensation Broca`s area Gustatory cortex Speech Center (in insula) Taste Prefrontal cortex Working memory Wernicke `s area for spatial tasks General Interpretive Area Executive area for task management Working memory for Primary visual object-recall tasks cortex Visual Vision Solving complex, association multitask problems area Auditory association area Hearing Primary auditory cortex Lateral view, left cerebral hemisphere Primary motor cortex Motor association cortex Primary sensory cortex Sensory association cortex Multimodal association cortex Somatotopic Map of the body Posterior Motor Sensory Motor map in Anterior Sensory map in precentral gyrus postcentral gyrus Toes Genitals Jaw Primary motor Primary somato- Tongue cortex sensory cortex Intra- Swallowing (precentral gyrus) (postcentral gyrus) abdominal Multimodal Association Areas •  Anterior Association Area: Prefrontal Cortex – Anterior part of the frontal lobe – Most complicated cortical region – Involved with intellect, cognition personality ing abilities), recall, – reasoning, planning, production of abstract ideas Multimodal Association Areas Face Recognition Neuron in the Temporal Lobe • Posterior Association Area – Parts of temporal, parietal and occipital lobes – Recognizes patterns and faces, spatial awareness/ attention to body and location of body in space – Many parts of this area are Contralateral neglect syndrome from parietal lobe lesions important for understanding written and spoken language Functional Brain Systems • Networks of neurons working together and spanning wide areas of the brain • The two systems are: – Limbic system – Reticular formation Limbic System •  Important in emotions: –  Amygdala – deals with anger, danger, and fear responses •  The limbic system interacts with the prefrontal lobes, therefore: –  One can react emotionally to conscious understandings –  One is consciously aware of emotion in one`s life •  Hippocampus is important for memory; converts short term memories into long-term memories Reticular Formation •  Composed of three broad columns of nuclei along the length of the brain stem •  Has far-flung axonal connections with hypothalamus, thalamus, cerebellum, and spinal cord •  RAS – Reticular Activating System – Sends impulses to the cerebral cortex to keep it conscious and alert – Filters out repetitive and weak stimuli •  Some motor functions as well What does the nervous system do? •  •  •  •  •  •  •  •  Functions of the Nervous System 1. Sensory input •  Monitor internal and external stimuli 2. Integration •  Brain and spinal cord process sensory input and initiate responses 3. Controls of muscles and glands 4. Homeostasis •  Regulate and coordinate physiology 5. Mental activity •  Consciousness, thinking, memory, emotion 11- Nervous System •  Receives input from the periphery to inform it about the status of the body and the environment •  Processes these signals •  Sends output to the periphery to make appropriate changes to maintain homeostasis or accomplish various goals •  How does it send and receive signals? •  What adaptations would a cell need to participate in this process? Signal Transduction Input Output Nervous systems have two categories of cells: Neurons generate and propagate electrical signals, called action potentials. Glial cells provide support and maintain extracellular environment. Building Blocks of Nervous Systems: Neurons Types of Neurons •  Functional classification –  Sensory or afferent: action potentials toward CNS –  Motor or efferent: action potential


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