Muscles - Exam 3

Question 1

functions of muscle

Answer 1

locomotion, respiration, digestion, parturition, blood/lymph circulation, swallowing, generation of body heat

Question 2

contractility

Answer 2

ability to contract or shorten

Question 3

excitability

Answer 3

capacity to receive & respond to a stimulus

Question 4

extensibility

Answer 4

ability to be stretched

Question 5

elasticity

Answer 5

ability to return to original shape after being stretched

Question 6

skeletal muscle is what % of the body

Answer 6

40%

Question 7

smooth muscle & cardiac muscle is what % of the body

Answer 7

10%

Question 8

visceral (smooth) muscle characteristics

Answer 8

slowly, viscera & blood vessels, involuntary

Question 9

skeletal (striated) muscle characteristics

Answer 9

rapidly, trunk, extremities, head & neck, voluntary

Question 10

cardiac muscle characteristics

Answer 10

rapidly, heart, involuntary

Question 11

skeletal muscle characteristics

Answer 11

body movement, attached to bones by tendons, stimulated by a motor nerve under voluntary control

Question 12

body movement is a result of

Answer 12

contraction of skeletal muscle across a movable joint, one or more muscles, increases or decreases its angle

Question 13

flexors function

Answer 13

side of the limb toward which the joint bends when decreasing the joint angle, contraction, biceps

Question 14

extensors function

Answer 14

side of the limb toward which the joint bends when increasing the joint angle, contraction, triceps

Question 15

adductors function

Answer 15

muscles that pull limb toward the median plane

Question 16

abductors function

Answer 16

muscles that pull limb away from the median plane

Question 17

sphincters function

Answer 17

circularly to constrict body opening i.e.: anal

Question 18

epimysium

Answer 18

sheath of connective tissue surrounding the muscle

Question 19

fascicle

Answer 19

small bundle or cluster of muscle fibers/cells

Question 20

perimysium

Answer 20

connective tissue extensions from the epimysium that surround each fascicle

Question 21

endomysium

Answer 21

connective tissue extensions from the perimysium that surround the muscle fibers and are attached to the sarcolemma

Question 22

sarcolemma function

Answer 22

thin cell membrane enclosing a skeletal muscle fiber/cell, fuses with tendon fibers, collect into bundles to form muscle tendons, connect the muscles to the bones

Question 23

muscle fiber characteristics

Answer 23

multinucleated, morphological syncytium, contractile unit, working together, pull transmitted by endo, peri, and epi to tendon or aponeurosis that is attached to the bone

Question 24

myofibrils composed by

Answer 24

linear series of repeating sarcomeres

Question 25

sarcomeres function & where found

Answer 25

basic contractile unit of striated muscle fibers, found between Z lines or disks, actin/myosin, striations

Question 26

myofilaments 2 components

Answer 26

thick & thin filaments

Question 27

t tubules function

Answer 27

arranged transversely to the myofibril, invaginations in the sarcolemma, contain ECF, carry the depolarization of the action potential to the interior of the fiber

Question 28

2 types of smooth muscle

Answer 28

multi unit smooth muscle & single unit visceral smooth muscle

Question 29

multi unit smooth muscle characteristics & function

Answer 29

separate, contract independently, inervated by a single nerve ending

Question 30

where can you find multi unit smooth muscles

Answer 30

ciliary muscles of the eyes, iris muscle of the eye, base of hair follicles, smaller airways to lungs, walls of large blood vessels

Question 31

single unit smooth muscle

Answer 31

visceral, arranged in sheets or bundles, adherent to one another, force generated in one muscle fiber can be transmitted to the next, contract together as a single unit, gap junctions

Question 32

purpose of gap junctions

Answer 32

allow ions to flow freely from one muscle cell to the next, fibers contract together

Question 33

where can you find single unit smooth muscle

Answer 33

GI tract, bile ducts, ureters, uterus, blood vessels

Question 34

dense bodies

Answer 34

large numbers of actin filaments attach here, some attached to cell membrane, some bond together by intracellular protein bridges, some dispersed inside the cell

Question 35

what kind of cross-bridges do myosin filaments have

Answer 35

side-polar

Question 36

side-polar cross-bridges

Answer 36

opposite direction

Question 37

smooth muscle can contract what % length

Answer 37

80%

Question 38

striated muscle can contract what % length

Answer 38

30%

Question 39

what is the major source of Ca for smooth muscle contraction

Answer 39

ECF

Question 40

caveolae

Answer 40

small invaginations of the cell membrane, surface of the SR (rudimentary t tubule & excite Ca release from the abutting SR

Question 41

the more extensive the SR in the smooth muscle fiber...

Answer 41

more rapidly it contracts

Question 42

cardiac muscle characteristics

Answer 42

fibers are striated, myofibrils are made up of actin & myosin filaments, contains SR and T tubules, contraction is involuntary, fibers are shorter/branched, uninucleated, interconnected by intercalated discs

Question 43

syn means

Answer 43

together

Question 44

kytos means

Answer 44

cell

Question 45

cardiac myocytes branch during

Answer 45

development & bind to other myocytes, fibers remain separated & electrically connect to each other

Question 46

intercalated discs

Answer 46

dark, dense cross-band in the end of each myocardial cell, continuous with the sarcolemma, contain important cell-cell junctions

Question 47

purpose of desmosomes

Answer 47

mechanical strength within myocardium