PHYSIO-s10_10 - 2/23/2010 BIOL 260: Human Physiology Human...

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Unformatted text preview: 2/23/2010 BIOL 260: Human Physiology Human Spring 2010 Spring W, Feb. 24, 2010 Feb. 1. Pre-Lab Writeups: Be sure to prepare before each Lab W riteups Be before each Monday or Wednesday labs (for WHOLE week!)!! Monday or Wednesday – (What? Why? How? are we doing in the lab??) 2. THIS Week: Expt. 7, EMG parts 1 & 2!!! • Nerves Report #2 Due THIS week in lab. • Expt. 4 Lab Data is POSTED under “Additional Materials”. Expt. 3. Midterm 1 study guide IS updated!! Midterm • Review sessions this week in lab ……. Review …… • Review also on WED. morning, 9:30 AM in 16-204 (Micro/Cell Lab). Review WED. • Work-out ALL short essays!! Know your terms!! 4. QUIZ #2 Due Tonight!!! REVIEW 1. Ch. 11: Describe several processes controlled by each branch of the efferent division of Describe the peripheral NS. (autonomic & somatic) the (autonomic 2. Distinguish the origins, anatomy, & preganglionic and postganglionic signaling Distinguish anatomy preganglionic and (neurotransmitters and receptors) of the sympathetic and parasympathetic branches of sympathetic of the autonomic efferent PNS. autonomic TODAY: Students should be able to…... 1. Describe several processes in which sympathetic and parasympathetic Describe sympathetic iinputs from the Autonomic EPNS exert antagonistic control. nputs antagonistic 2. Diagram the events that control skeletal muscles through neuromuscular Diagram junctions (somatic EPNS). Provide detailed cellular anatomy of the NMJ. junctions (somatic NMJ 3. Ch. 12: Diagram and compare the organ, tissue, and cellular organization on of muscles, from muscle, to fiber, to contractile unit (myofibril). muscle, 4. Diagram and describe 6 main steps in the Sliding Filament Theory of Diagram Sliding of muscle contraction, including all of the molecular players involved. muscle 1 2/23/2010 • Varicosities B. Synapses in Autonomic B. Nerves Nerves – swellings at swellings neuroeffector jxns. neuroeffector • NT released to ECF – Dilute, slow – may not reach may target target • No cleft • Impact: – Large area – Slow acting – Long duration Figure 11-8: Varicosities of autonomic neurons C. Mechanism: Norepinephrine C. Release and Recycling Release Figure 11-9: Norepinephrine release at a varicosity of a sympathetic neuron 9: varicosity MAO inhibitors = treat MAO depression, Parkinson’s depression, 2 2/23/2010 Review of Efferent Pathways: Review Motor & Autonomic Motor Figure 11-11: Summary of efferent pathways 11.4) Somatic Motor Division: 11.4) Somatic Controls Skeletal Muscles 1. 2. 3. 4. Body movement Appendages Locomotion Single neuron Single a) CNS origin a) b) Myelinated Figure 11-11: 11: Summary of efferent pathways 5. Terminus Terminus a) Branches a) b) Neuromuscular junction 3 2/23/2010 A. Neuromuscular Junction: A. Overview Overview 1. Terminal boutons Terminal boutons 2. Synaptic cleft a) b) c) a) b) – Matrix AChE Hold together On muscle High [nACh-R]’s Always excitatory!! 3. Motor End Plate Neuromuscular Junction (NMJ) Somatic motor neuron The neuromuscular junction Schwann cell sheath Axon terminal Mitochondria Muscle fiber Terminal bouton Motor end plate Synaptic v esicle ( ACh) Presynaptic membrane Synaptic cleft Figure 11-12: Anatomy of 12: the neuromuscular junction the Nicotinic ACh Receptors Postsynaptic Membrane = modified into MEP!! • NMJ = axon terminals, motor end plates on the muscle membrane, and Schwann cell sheaths. membrane, • The MOTOR END PLATE iis a region of muscle membrane s The MOTOR that contains high concentrations of ACh Receptors. that 4 2/23/2010 B. NMJ: Mechanism of Signal B. Conduction Conduction 1. Axon terminal a) AP signals b) ACh release 2. Motor end plate a) b) c) d) 2 ACh bind ACh opens cation channel opens cation Na+ influx Membrane Membrane depolarized depolarized content/chp44/4403s.swf 3. Stimulates fiber Stimulates contraction contraction NMJ: Mechanism of Signal Conduction Figure 11-13: Events at the neuromuscular junction • Acetylcholine (ACh) combines with nicotinic combines receptors, or is metabolized by acetylcholinesterase acetylcholinesterase (AChE). • The Nicotinic The Cholinergic Receptor Cholinergic binds two ACh binds ACh molecules, opening a molecules, nonspecific monovalent monovalent cation channel. • Binding to Ach Binding allows Na+ and K+ to pass. K+ 5 2/23/2010 Ch. 11: 1) 2) 3) 3) 4) 5) 6) Summary A. Autonomic branches: Autonomic Sympathetic and Parasympathetic Sympathetic and Parasympathetic Regulate glands, smooth & cardiac muscles Team with endocrine to regulate homeostasis Team Are regulated by hypothalamus, pons & medulla Are pons Have pathways with 2 neurons and a ganglion Use varicosities to release NTs Use NTs Have diverse receptors: tonic & antagonistic regulation B. Somatic: Efferent motor neurons control skeletal muscles Efferent motor control skeletal 1) Single long myelinated neuron from CNS Single 2) Neuromuscular junction structure & mechanism 2) Chapter 12 Muscles 6 2/23/2010 What Do Muscles Do? 1. Contract! 2. Generate motion Generate motion 3. Generate force Generate force 4. Generate heat Generate heat 5. Support Figure 12-2 12.1) Muscle Types 1. Cardiac – heart 2. Smooth – iinternal nternal organs organs 3. Skeletal – "voluntary" a) b) c) d) e) f) Attach to bone Move appendages Support body Antagonistic pairs Flexors Extensors Figure 12-1: Three types of muscles striated 7 2/23/2010 12.2) Skeletal Muscle Anatomy 1. About 40% body mass 2. Muscle fibers – cells; fused with multiple nuclei 3. Fascicle – bundle of fibers/cells 4. Motor unit = motor neuron + the groups of coordinated fibers it controls motor 5. Muscle 6. Sheath = connective tissues; collagen, elastin, nerves, blood vessels Sheath elastin 7. Attach to tendons (which attach to bone) Attach tendons Figure 12-3a-1: ANATOMY SUMMARY: Skeletal Muscle Skeletal Muscle Anatomy Figure 12-3a-2: ANATOMY SUMMARY: Skeletal Muscle 8 2/23/2010 A. Muscle Fiber Structure 1. Multiple nuclei – several 100 fused cells; largest in body! Multiple several cells; 2. Sarcolemma = muscle cell membrane 3. T-tubules (transverse) = bring AP to center of fiber 4. Sarcoplasmic reticulum – modified ER stores Ca++ reticulum – longitudinal 5. Sarcoplasm a) Mitochondria b) Glycogen & ions c) Myofibrils Muscle Fiber Structure Figure 12-3b: ANATOMY SUMMARY: Skeletal Muscle 9 2/23/2010 Muscle Fiber Structure Figure 12-4: T-tubules and the sarcoplasmic reticulum B. Myofibrils: Sites of B. Contraction Contraction 1. Actin – "thin fibers“; “action” cytoskeleton! 2. Tropomysin = blocks myosin binding to actin blocks actin 3. Troponin = Ca++-regulated control of Tropomyosin. regulated Tropomyosin 4. Myosin – "thick fibers“; motor proteins on actin motor actin 5. Titin – elastic anchor; largest known protein! 2.5 Mda !! elastic Mda • 25,000 amino acids!!! 25,000 • Restores sarcomere to relaxed state. Restores sarcomere 6. Nebulin – non-elastic; aligns actin double-filament elastic; actin 10 2/23/2010 Myofibrils: Sites of Contraction Figure 12-3c-f: ANATOMY SUMMARY: Skeletal Muscle C. Sarcomere: Organization of Fibers C. Sarcomere Organization 1. Z disks – Between sarcomeres; Between sarcomeres zigzags of proteins for microfilament attachment. microfilament 2. I band – Non-directional. 3. A band – Directional. 4. H zone – Clear. 5. M line – Middle/ myosin. 6. Titin 7. Nebulin Figure 12-5: The two- and three-dimensional organization of a sarcomere 11 2/23/2010 Sarcomere: Organization of Fibers Organization Figure 12-6: Titin and nebulin 12.3) Contraction Sequence: 12.3) Sliding Filament Theory Sliding Figure 12- 9 12 2/23/2010 Contraction Sequence: Contraction Figure 12-9 (steps 1-3): The Figure 3): molecular basis of contraction molecular ~45° • ATP head release, 45° ATP head 45 • ATP Hydrolysis ATP • Myosin binds actin, 90° Myosin actin 90 • Aided by Mg++ Aided Mg ~90° Contraction Sequence: Figure 12-9 (steps 4-5): The 5): molecular basis of contraction molecular 1. Pi Release Power stroke. Pi • Aided by Mg++ Aided Mg 2. ADP release Rigor State. ADP 13 2/23/2010 Sliding Filament Theory The Animation The Players SDSU: Based in part on Color Atlas of SDSU: Physiology, Agamemnon Despopoulos, Physiology Agamemnon Despopoulos Stefan Silbernagl Thieme Medical Publishers, Silbernagl Medical Inc. , 1991, New York Inc. 12.4) Skeletal Muscle Contraction: 12.4) Mechanism Mechanism • RyR = mechanically-gated gated Ca++ Release Ch. Ca • DHP = Voltage-sensing sensing receptor. receptor. Figure 12-11a: Excitation-contraction coupling 14 ...
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