MCPHS Anatomy and Physiology
Exam 3 Actual legit|2025/2026 latest
Question and answers rated A+
Functions of the muscular system: - correct answer ✔Movement of the body
Maintenance of posture
Respiration
Production of body heat
Communication
Constriction of organs and vessels
Contraction of heart
Three Es and a C: Properties of muscle tissue - correct answer ✔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 - correct answer ✔Skeletal - voluntary
Smooth - controlled involuntarily by endocrine and autonomic nervous system
Cardiac - controlled involuntarily by endocrine and autonomic nervous system
Epimysium - correct answer ✔CT that surrounds whole muscle
Perimysium - correct answer ✔loose CT surrounding a group of muscle fibers; passage for blood vessels
and nerves
,Endomysium - correct answer ✔loose CT separating individual muscle fibers within each fasicle
Fiber anatomy - correct answer ✔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 - correct answer ✔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 - correct answer ✔Not striated, small fibers
Spindle-shaped, single, central nucleus
More actin than myosin, cross-bridging occurs
Ca2+ required to initiate contraction
Wavy
Sarcolemma - correct answer ✔plasma membrane, surround sarcoplasm (cytoplasm)
, Transverse tubules (T tubules) - correct answer ✔inward folds of sarcolemma; project into interior of
muscles
Sarcoplasmic reticulum - correct answer ✔specialized smooth ER; store calcium
terminal cisternae - correct answer ✔Enlarged portion od SR adjacent to T tubules
Myofibrils - correct answer ✔protein filament bundles; contain myofilaments that cause contraction
Myofilament - correct answer ✔actin and myosin
Actin - correct answer ✔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 - correct answer ✔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 - correct answer ✔basic functional unit of fiber - smallest part that can contract
Sarcomeres give striated appearance
Exam 3 Actual legit|2025/2026 latest
Question and answers rated A+
Functions of the muscular system: - correct answer ✔Movement of the body
Maintenance of posture
Respiration
Production of body heat
Communication
Constriction of organs and vessels
Contraction of heart
Three Es and a C: Properties of muscle tissue - correct answer ✔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 - correct answer ✔Skeletal - voluntary
Smooth - controlled involuntarily by endocrine and autonomic nervous system
Cardiac - controlled involuntarily by endocrine and autonomic nervous system
Epimysium - correct answer ✔CT that surrounds whole muscle
Perimysium - correct answer ✔loose CT surrounding a group of muscle fibers; passage for blood vessels
and nerves
,Endomysium - correct answer ✔loose CT separating individual muscle fibers within each fasicle
Fiber anatomy - correct answer ✔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 - correct answer ✔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 - correct answer ✔Not striated, small fibers
Spindle-shaped, single, central nucleus
More actin than myosin, cross-bridging occurs
Ca2+ required to initiate contraction
Wavy
Sarcolemma - correct answer ✔plasma membrane, surround sarcoplasm (cytoplasm)
, Transverse tubules (T tubules) - correct answer ✔inward folds of sarcolemma; project into interior of
muscles
Sarcoplasmic reticulum - correct answer ✔specialized smooth ER; store calcium
terminal cisternae - correct answer ✔Enlarged portion od SR adjacent to T tubules
Myofibrils - correct answer ✔protein filament bundles; contain myofilaments that cause contraction
Myofilament - correct answer ✔actin and myosin
Actin - correct answer ✔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 - correct answer ✔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 - correct answer ✔basic functional unit of fiber - smallest part that can contract
Sarcomeres give striated appearance
