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Mcphs Anatomy and Physiology Exam 3 Questions and Answers

HEAL100 Health Care — exam and revision material · Other

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Health Care exam material, 8 pages. Originally published on StudyMerit.

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8
Academic year
2025/2026
Language
English

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MCPHS Anatomy and Physiology Exam 3 Students also studied Mcphs University BIO 110 Save MCPHS Anatomy and Physiology Ex ... 164 terms Arianna_Bacon48 Preview MCPHS A&P Exam 4 230 terms Arianna_Bacon48 Preview MCPHS A&P 1 - Exam 1 Teacher 560 terms S_Miles21 Preview McGraw 43 terms cou Practice questions for this set Learn 1 / 7 Study with Learn Flexion - muscles deep within the neck along the anterior margins of vertebral bodies Extension - posterior neck muscles attach to the occipital bone Rotation and abduction - lateral and posterior groups Functions of the muscular system: Movement of the body Maintenance of posture Respiration Production of body heat Communication Constriction of organs and vessels Contraction of heart Choose an answer 1 Head and neck muscles: 2 Functions of the muscular system: 3 terminal cisternae 4 Perimysium Don't know?

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Three Es and a C: Properties of muscle tissue Contractility - ability of a muscle to shorten with force Excitability - capacity of a muscle to respond to a stimulus Extensibility - muscle can stretch beyond normal resting length and be able to contract Elasticity - ability of muscle to recoil to original resting length after stretched 3 types of muscle Skeletal - voluntary Smooth - controlled involuntarily by endocrine and autonomic nervous system Cardiac - controlled involuntarily by endocrine and autonomic nervous system Epimysium CT that surrounds whole muscle Perimysium loose CT surrounding a group of muscle fibers; passage for blood vessels and nerves Endomysium loose CT separating individual muscle fibers within each fasicle Fiber anatomy Large, multinucleated 1-4 mm avg length Have striated appearance Number of fibers is relatively constant after birth - Get larger, but not more cardiac muscle Only in heart Striated Each cell has 1 nucleus Intercalated disks and gap junctions Autorhythmic Action potentials of longer curation and refractory period Ca2+ regulated contraction smooth. muscle Not striated, small fibers Spindle-shaped, single, central nucleus More actin than myosin, cross-bridging occurs Ca2+ required to initiate contraction Wavy Sarcolemma plasma membrane, surround sarcoplasm (cytoplasm) Transverse tubules (T tubules) inward folds of sarcolemma; project into interior of muscles Sarcoplasmic reticulum specialized smooth ER; store calcium terminal cisternae Enlarged portion od SR adjacent to T tubules Myofibrils protein filament bundles; contain myofilaments that cause contraction Myofilament actin and myosin

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Actin thin 2 strands of F actin form double helix extending length of myofilament; composed of G actin monomer that has active site, bind myosin during contraction Tropomyosin - elongated protein along the groove of F actin double helix - BLOCK binding site G actin Troponin - 3 subunits: bind actin, binds tropomyosin, bind calcium ions Troponin/tropomyosin complex regulates interaction between active sites on G actin and myosin myosin thick Shaped like golf clubs, consist of heave chains wound together to form rod portion lyin parallel to myosin microfilament and 2 myosin heads that extend laterally Heads: can bind active sites on actin to form cross-bridge, attach to rod portion bt hinged region that can bed during contraction, ATPase enzymes (break down ATP to release energy) sarcomeres basic functional unit of fiber - smallest part that can contract Sarcomeres give striated appearance Neuromuscular junction Motor neuron carry electrical signal that stimulate muscle fiber action potentials followed by muscle contraction NJ (or synapse) is point of contact between motor neuron and muscle fiber Presynaptic terminal (end of neuron) axon terminal w/ synaptic vesicles that contain AcH Synaptic cleft space Postsynaptic membrane (sarcolemma) muscle component function of neuromuscular junction Synaptic vesicles: AcH diffuses across the synaptic cleft and stimulates the production of an action potential in the postsynaptic membrane (AcH binds to ligand-gated channels) Acetylcholinesterase - degrades AcH in synaptic cleft, inhibit accumulation of AcH Sliding filament model Actin myofilaments slide over myosin to shorten sarcomeres During relaxation, sarcomeres lengthen because of external force (antagonistic muscles) Sarcomere shortening Relaxed: Actin and myosin slightly overlap, H zone is visible, sarcomere is normal length Muscle contraction initiated: actin myofilaments slide past myosin, z disks are brought closer, and sarcomere begins to shorten Contracted: A band do not narrow, ends of actin are pulled to and overlap the center of sarcomere, H zone disappears Skeletal muscle fiber physiology Nervous system controls muscle contract through action potentials Resting: membrane voltage difference across membrane (polarized) - inside is more negative, more K+ on outside, Na+/K+ pump maintains, must be in this condition for action potential to occur

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