Chapter 9: Muscles & Muscle Tissue

Question 1

muscle functions

Answer 1

produce movement
maintain posture & body position, and stabilize joints
support soft tissues
guard body entrances & exits
maintain body temperature

Question 2

types of muscle

Answer 2

skeletal muscles
cardiac muscles
smooth muscles

Question 3

skeletal muscles

Answer 3

attached to bones or (some facial muscles) to skin

Question 4

cardiac muscles

Answer 4

walls of the heart

Question 5

smooth muscles

Answer 5

unitary muscle in walls of hollow visceral organs; multi unit muscle in intrinsic eye muscles, airways, large arteries

Question 6

origin

Answer 6

attachment to immovable or less moveable bone

Question 7

insertion

Answer 7

attachment to moveable bone

Question 8

muscle fiber

Answer 8

skeletal muscle cell

Question 9

muscle fascicle

Answer 9

a bunch of muscle fibers

Question 10

epimysium

Answer 10

surrounds entire skeletal muscle, continuous with tendons
dense irregular connective tissue

Question 11

perimysium

Answer 11

separates adjacent muscle fascicles, vessels & nerves travel through
fibrous connective tissue

Question 12

endomysium

Answer 12

surrounds single muscle fiber
areolar connective tissue

Question 13

sarcolemma

Answer 13

cell membrane of muscle fibers

Question 14

sarcoplasm

Answer 14

cytoplasm of muscle fiber

Question 15

does a muscle fiber have more than one mitochondria or just one?

Answer 15

multiple mitochondria

Question 16

glycosomes

Answer 16

carry stored glycogen

Question 17

myoglobin

Answer 17

stores oxygen

Question 18

myofibrils

Answer 18

contain contractile elements

Question 19

sarcoplasmic reticulum & T tubules

Answer 19

stimulate and coordinate muscle contractions

Question 20

what are T Tubules?

Answer 20

tubular extension of sarcolemma that extend deep into sarcoplasm

Question 21

what does action potential in T tubules cause?

Answer 21

release of calcium by the sarcoplasmic reticulum

Question 22

what does the sarcoplasmic reticulum surround?

Answer 22

tubular network around each myofibril

Question 23

what does the sarcoplasmic reticulum do?

Answer 23

regulates levels of calcium & storage site of calcium

Question 24

myofibril

Answer 24

organized collection of myofilaments

Question 25

myofilaments

Answer 25

fine protein filaments

Question 26

how many myofibrils are in one muscle fiber?

Answer 26

100s-1000s

Question 27

how much of the cellular volume is myofibrils?

Answer 27

80%

Question 28

sarcomere

Answer 28

function unit of skeletal muscle

Question 29

characteristics of thick filaments

Answer 29

bundle of myosin club-shaped head head binds to active binding site of actin

Question 30

characteristics of thin filaments

Answer 30

twisted strand of actin active site on actin

Question 31

tropomyosin

Answer 31

binds to active site of actin at rest

Question 32

troponin

Answer 32

binds to tropomyosin and calcium

Question 33

elastic filaments

Answer 33

composed of protein titin

Question 34

dystrophin

Answer 34

links thin filaments to proteins of sarcolemma

Question 35

nebulin, myomesin, C proteins bind filaments, sarcomeres together

Answer 35

maintain alignment of sacromere

Question 36

what elicits/causes the contraction?

Answer 36

neurons stimulate the sarcolemma/T-tubules via neurotransmitter at the neuromuscular junction

Question 37

true or false: each muscle fiber is controlled by a motor neuron

Answer 37

true

Question 38

motor unit

Answer 38

motor neuron and all the muscle fibers it innervates

Question 39

what are the 4 steps that must occur for skeletal muscle to contract?

Answer 39

1.) events at the neuromuscular junction 2.) muscle fiber excitation 3.) excitation-contraction coupling 4.) cross bridge cycling

Question 40

steps in the neuromuscular junction:

Answer 40

1.) AP in prestnaptic neuron 2.) Ca+ voltage-gated channels open causing Acetycholine (ACh) to be released 3.) ACh diffuses across the cleft 4.) ACh binds to receptors on sarcolemma 5.) Binding of ACh causes an EPSP 6.) Excitatory graded potential travels along the sarcolemma 7.) AP is stimulated in the sarcolemma 8.) AP travels along sarcolemma to the T tubes

Question 41

excitation-contraction coupling steps:

Answer 41

1.) AP in T-tubules cause shape change in voltage-sensitive tubule protein 2.) Calcium is released into the sarcoplasm 3.) Calcium binds to troponin 4.)Tropomyosin moves away from actin active binding sights 5.) Myosdin can now bind to actin and form a cross bridge in the presence of ATP