Questions with Guaranteed Pass
Solutions.
3 kinds of muscle tissue - Answer skeletal, cardiac, smooth
major purpose of muscle - Answer converting chemical energy in ATP --> mechanical energy of
motion
muscle functions - 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 - Answer fascia, epimysium, perimysium,
endomysium
CT elements and how they merge with other tissues - Answer Tendons = attachments between
muscle and bone, dense-regular CT made of collagen fibers, epimysium surrounding entire
muscle is continuous with collagen fibers of tendons
role of collagen in connective tissues - 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) - 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 - 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 - 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 - Answer Origin: bony attachment at stationary end of muscle
Insertion: bony attachment to mobile end of muscle
functional groups of muscles with example - Answer for elbow flexion
Prime mover (agonist): brachialis
Synergist: biceps brachii
Antagonist: triceps brachii
Fixator: rhomboideus
intrinsic vs extrinsic muscles - Answer Intrinsic: contained within a region (both origin and
insertion there)
Extrinsic: act on a designated regions, but has origins elsewhere
characteristics of muscle - Answer Responsiveness (excitability): to chemical signals, stretch
and electrical changes across plasma membrane
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 - Answer voluntary, straitaed muscle attached to one or more
bones
myofiber - Answer muscle cell/muscle fiber, composed of myofibrils
myofibrils - Answer long protein bundles that occupy the main portion of the interior of a
muscle fiber, composed of myofilaments
myofilament - Answer protein microfilament responsible for muscle cell contraction,
composed of myosin or actin proteins
, functions of each part of a muscle fiber - 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 other 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 - Answer Glycogen: stored in abundance to provide energy
with heightened exercise
Myoglobin: red pigment that stores oxygen needed for muscle activity
Process of muscle growth and repair - Answer Repair by fibrosis rather than regeneration of
functional muscle
3 kinds of myofilaments found in a myofibril - Answer Thick filaments: myosin proteins
Thin filaments: primarily actin proteins
Elastic filaments: titin (connectin) proteins
Thick Myofilaments - Answer made of several hundred myosin molecules
-shaped like a golf club (2 chains make shaft-like tail, double globular head)
-heads directed outward in a helical array around the bundle
Thin Myofilaments - Answer Fibrous (F) actin: 2 intertwined strands, string of globular (G)
actin subunits each with an active site that can bind to head of myosin molecule
-Tropomyosin: each blocking 6 or 7 active sites on G actin subunits
-Troponin complex: small, calcium-binding protein on each tropomyosin molecule
Elastic Myofilaments - Answer Titin (connection): huge springy protein
-flank each thick filament and anchor it to the Z disc
-help the cell recoil to its resting length (elasticity)