CORRECT ANSWERS 2025
3 kinds of muscle tissue CORRECT ANSWER skeletal, cardiac, smooth
major purpose of muscle CORRECT ANSWER converting chemical energy in ATP --
> mechanical energy of motion
muscle functions CORRECT ANSWER -movement of: whole body, body parts, organ contents
-stability: maintain posture and prevent mvmt.
-communication: speech, facial expressions and writing
-control of openings and passageways: sphincters
-body heat production
characterizations of connective tissues of a muscle CORRECT ANSWER
fascia, epimysium, perimysium, endomysium
CT elements and how they merge with other tissues CORRECT
ANSWER Tendons = attachments between muscle and bone, dense-
regular CT made of collagen fibers, epimysium surrounding entire muscle is continuous with collagen fi
bers of tendons
role of collagen in connective tissues CORRECT
ANSWER stretches slightly under tension and recoils
when released
-resists excessive stretching and protects muscle from injury
-returns muscle to resting length
-contribute to power output and muscle efficiency
skeletal muscle shapes (with examples) CORRECT ANSWER Fusiform: biceps bracchi, gastrocnemius
Triangular (convergent): pec major, temporalis
Parallel: rectus abdominus, zygomaticus major
,Circular: orbicularis oculi, urethral and anal sphincters
Pennate: rectus femoris, deltoid
ways in which muscle attach to bone CORRECT ANSWER Indirect: tendons attach muscle to bone
Direct: fleshy attachment to bone
Some skeletal muscles do not insert on bone, but in dermis of the skin
how tendons attach muscle to bone CORRECT ANSWER collagen fibers fibers of endo-, peri-
, and epimysium continue into the tendon, the tendon merges into the periosteum of bone
-aponeurosis: tendon is a broad, flat sheet
origin and insertion definition CORRECT ANSWER
Origin: bony attachment at stationary end of muscle
Insertion: bony attachment to mobile end of muscle
functional groups of muscles with example CORRECT ANSWER for elbow flexion
Prime mover (agonist): brachialis
Synergist: biceps brachii
Antagonist: triceps brachii
Fixator: rhomboideus
intrinsic vs extrinsic muscles CORRECT ANSWER
Intrinsic: contained within a region (both origin and insertion there)
Extrinsic: act on a designated regions, but has origins elsewhere
characteristics of muscle CORRECT ANSWER
Responsiveness (excitability): to chemical signals, stretch and electrical changes across plasma membra
ne
Conductivity: local electrical change triggers a wave of excitation that travels along the muscle fiber
Contractility: shortens when stimulated
, Extensibility: capable of being stretched between contractions
Elasticity: returns to its original resting length after being stretched
properties of skeletal muscle CORRECT ANSWER
voluntary, straitaed muscle attached to one or more bones
myofiber CORRECT ANSWER muscle cell/muscle fiber, composed of myofibrils
myofibrils CORRECT ANSWER
long protein bundles that occupy the main portion of the interior of a muscle fiber, composed of myof
ilaments
myofilament CORRECT ANSWER
protein microfilament responsible for muscle cell contraction, composed of myosin or actin proteins
functions of each part of a muscle fiber CORRECT ANSWER
Sarcolemma: plasma membrane of a muscle fiber
Sarcoplasm: cytoplasm of a muscle fiber
Mitochondria: packed in spaces between myofibrils
Sarcoplasmic reticulum (SR): smooth ER that forms a network around each myofibril-calcium reservoir
Terminal cisternae: dilated end-sacs of SR which cross muscle fiber from one side to the other
T tubules: tubular infoldings of the sarcolemma which penetrate through the cell and emerge on the o
ther side
Triad: a T tubule and 2 terminal cisterns
Internal proteins: long protein bundles that occupy the main portion of the sarcoplasm
Multiple nuclei: flattened nuclei pressed against the inside of the sarcolemma
Glycogen and Myoglobin functions CORRECT ANSWER
Glycogen: stored in abundance to provide energy with heightened exercise
Myoglobin: red pigment that stores oxygen needed for muscle activity