Chapter 11 Notes for Anatomy & Physiology: The Unity of
Form and Function
What are the three types of muscular tissue? - (correct Answer) - 1. Skeletal
2. Cardiac
3. Smooth
Universal Characteristics of Muscles - (correct Answer) - excitability, conductivity, contractility,
extensibility, elasticity.
Excitability (responsiveness) - (correct Answer) - to chemical signals, stretch, and electrical changes
across the plasma membrane.
Conductivity - (correct Answer) - local electrical change triggers a wave of excitation that travels along
the muscle fiber.
Contractility - (correct Answer) - shortens when stimulated.
Extensibility - (correct Answer) - capable of being stretched between contractions.
Elasticity - (correct Answer) - returns to its original resting length after being stretched.
skeletal muscle - (correct Answer) - voluntary, striated muscle usually attached to bones.
striations of skeletal muscle - (correct Answer) - alternating dark and light transverse bands. Results from
arrangement of internal contractile proteins.
voluntary - (correct Answer) - usually subject to conscious control.
muscle cell is a... - (correct Answer) - ...muscle fiber (myofiber)-as long as 30 cm.
Endomysium - (correct Answer) - Connective tissue around a muscle cell.
Perimysium - (correct Answer) - connective tissue around muscle fascicle.
Epimysium - (correct Answer) - Connective tissue layer surrounding the entire muscle .
Tendons - (correct Answer) - attachments between muscle and bone matrix. Continuous with collagen
fibers of tendons. In turn, with connective tissue of bone matrix.
Collagen - (correct Answer) - somewhat extensible and elastic. Stretches slightly under tension and
recoils when released.
What can collagen of a skeletal muscle do? - (correct Answer) - Stretches slightly under tension and
recoils when released. Resists excessive stretching and protects muscle from injury. Returns muscle to its
resting length. Contributes to power output and muscle efficiency.
, Sarcolemma - (correct Answer) - plasma membrane of a muscle fiber.
sarcoplasm - (correct Answer) - cytoplasm of a muscle fiber.
Myofibrils - (correct Answer) - long protein cords occupying most of sarcoplasm.
Glycogen - (correct Answer) - carbohydrate stored to provide energy for exercise.
Myoglobin - (correct Answer) - red pigment; provides some oxygen needed for muscle activity.
multiple nuclei - (correct Answer) - flattened nuclei pressed against the inside of the sarcolemma.
Myoblasts - (correct Answer) - stem cells that fused to form each muscle fiber early in development.
satellite cells - (correct Answer) - unspecialized myoblasts remaining between the muscle fiber and
endomysium. Play a role in regeneration of damaged skeletal muscle tissue.
Mitochondria - (correct Answer) - Powerhouse of the cell. Packed into spaces between myofibrils.
sarcoplasmic reticulum (SR) - (correct Answer) - smooth ER that forms a network around each myofibril.
terminal cisternae - (correct Answer) - dilated end-sacs of SR which cross the muscle fiber from one side
to the other.
T tubules - (correct Answer) - tubular infoldings of the sarcolemma which penetrate through the cell and
emerge on the other side.
Triad - (correct Answer) - a T tubule and two terminal cisternae associated with it.
thick filaments - (correct Answer) - made of several hundred myosin molecules. Each molecule is shaped
like a golf club. Heads are directed outward in a helical array around the bundle.
fibrous (F) actin - (correct Answer) - Two intertwined strands of Thin Filaments.
tropomyosin molecules - (correct Answer) - Each blocking six or seven active sites on G actin subunits.
troponin molecule - (correct Answer) - small, calcium-binding protein on each tropomyosin molecule.
contractile proteins - (correct Answer) - actin and myosin do the work of contraction.
regulatory proteins - (correct Answer) - tropomyosin and troponin.
What can the regulatory proteins do/are associated with? - (correct Answer) - Act like a switch that
determines when fiber can (and cannot) contract. Contraction activated by release of calcium into
sarcoplasm and its binding to troponin. Troponin changes shape and moves tropomyosin off the active
sites on actin.
Dystrophin - (correct Answer) - clinically important protein
Links actin in outermost myofilaments to membrane proteins that link to endomysium
Transfers forces of muscle contraction to connective tissue ultimately leading to tendon
Form and Function
What are the three types of muscular tissue? - (correct Answer) - 1. Skeletal
2. Cardiac
3. Smooth
Universal Characteristics of Muscles - (correct Answer) - excitability, conductivity, contractility,
extensibility, elasticity.
Excitability (responsiveness) - (correct Answer) - to chemical signals, stretch, and electrical changes
across the plasma membrane.
Conductivity - (correct Answer) - local electrical change triggers a wave of excitation that travels along
the muscle fiber.
Contractility - (correct Answer) - shortens when stimulated.
Extensibility - (correct Answer) - capable of being stretched between contractions.
Elasticity - (correct Answer) - returns to its original resting length after being stretched.
skeletal muscle - (correct Answer) - voluntary, striated muscle usually attached to bones.
striations of skeletal muscle - (correct Answer) - alternating dark and light transverse bands. Results from
arrangement of internal contractile proteins.
voluntary - (correct Answer) - usually subject to conscious control.
muscle cell is a... - (correct Answer) - ...muscle fiber (myofiber)-as long as 30 cm.
Endomysium - (correct Answer) - Connective tissue around a muscle cell.
Perimysium - (correct Answer) - connective tissue around muscle fascicle.
Epimysium - (correct Answer) - Connective tissue layer surrounding the entire muscle .
Tendons - (correct Answer) - attachments between muscle and bone matrix. Continuous with collagen
fibers of tendons. In turn, with connective tissue of bone matrix.
Collagen - (correct Answer) - somewhat extensible and elastic. Stretches slightly under tension and
recoils when released.
What can collagen of a skeletal muscle do? - (correct Answer) - Stretches slightly under tension and
recoils when released. Resists excessive stretching and protects muscle from injury. Returns muscle to its
resting length. Contributes to power output and muscle efficiency.
, Sarcolemma - (correct Answer) - plasma membrane of a muscle fiber.
sarcoplasm - (correct Answer) - cytoplasm of a muscle fiber.
Myofibrils - (correct Answer) - long protein cords occupying most of sarcoplasm.
Glycogen - (correct Answer) - carbohydrate stored to provide energy for exercise.
Myoglobin - (correct Answer) - red pigment; provides some oxygen needed for muscle activity.
multiple nuclei - (correct Answer) - flattened nuclei pressed against the inside of the sarcolemma.
Myoblasts - (correct Answer) - stem cells that fused to form each muscle fiber early in development.
satellite cells - (correct Answer) - unspecialized myoblasts remaining between the muscle fiber and
endomysium. Play a role in regeneration of damaged skeletal muscle tissue.
Mitochondria - (correct Answer) - Powerhouse of the cell. Packed into spaces between myofibrils.
sarcoplasmic reticulum (SR) - (correct Answer) - smooth ER that forms a network around each myofibril.
terminal cisternae - (correct Answer) - dilated end-sacs of SR which cross the muscle fiber from one side
to the other.
T tubules - (correct Answer) - tubular infoldings of the sarcolemma which penetrate through the cell and
emerge on the other side.
Triad - (correct Answer) - a T tubule and two terminal cisternae associated with it.
thick filaments - (correct Answer) - made of several hundred myosin molecules. Each molecule is shaped
like a golf club. Heads are directed outward in a helical array around the bundle.
fibrous (F) actin - (correct Answer) - Two intertwined strands of Thin Filaments.
tropomyosin molecules - (correct Answer) - Each blocking six or seven active sites on G actin subunits.
troponin molecule - (correct Answer) - small, calcium-binding protein on each tropomyosin molecule.
contractile proteins - (correct Answer) - actin and myosin do the work of contraction.
regulatory proteins - (correct Answer) - tropomyosin and troponin.
What can the regulatory proteins do/are associated with? - (correct Answer) - Act like a switch that
determines when fiber can (and cannot) contract. Contraction activated by release of calcium into
sarcoplasm and its binding to troponin. Troponin changes shape and moves tropomyosin off the active
sites on actin.
Dystrophin - (correct Answer) - clinically important protein
Links actin in outermost myofilaments to membrane proteins that link to endomysium
Transfers forces of muscle contraction to connective tissue ultimately leading to tendon
