muscular system

Question 1

___________ msucle is essential for supporting the bosy and facilitating movement

Answer 1

skeletal

Question 2

the contraction of skeletal muscle also compresses ____________ structures and helps propel blood

Answer 2

venous

Question 3

_____________ muscle is responsible for involuntary movement

Answer 3

smooth

Question 4

_____________ muscle is able to maintain rhythmic contraction of the heart without nervous system input

Answer 4

cardiac

Question 5

skeltal muscle is responsible for ________ movement

Answer 5

involuntary

Question 6

skeletal muscle is innervated bu the ______________ nervous system

Answer 6

somatic

Question 7

why does skeletal muscle appear striped?

Answer 7

arrangement of actin ad myosin into repeatin units called sacromeres

Question 8

T / F - skeletal muscle is multinucleated

Answer 8

true

Question 9

give some characteristics of red fibers

Answer 9

slow twitch (marathons)
high mitochondria content
high myoglobin content = red
aerobic energy pathways

Question 10

give some characteristics of white fibers

Answer 10

fast twitch (sprints)
low mitochondria content
low myoglobin content = white

Question 11

identify:
muscles that contract slowly. but can sustain activity

Answer 11

mostly red fibers

Question 12

smooth muscle is innervated by the ___________ nervous system

Answer 12

autonomic

Question 13

T / F - smooth muscle is stiated and contains a single nucleus

Answer 13

false, smooth muscle is not striated, but it does only contain a single nucleus in each cell

Question 14

_____________ is the sustained contractions that is seen in blood vessels

Answer 14

tonus

Question 15

what is myogenic activity?

Answer 15

smooth muscle can contract witjpit mervpis susym input

*reflexes

Question 16

cardiac cells:
uni / multi nucleated?
involuntary / voluntary movement?
autonomic / somatic nervous system?
striated / nonstriated?

Answer 16

uninucleated
involuntary
autonomic
striated

Question 17

cardiac muscle cells ared conected by ______________, which contain may _________

Answer 17

intercalated dics
gap junctions

Question 18

what do gap junctions in cardiac cells allow for?

Answer 18

flow of ions directly between cells

allows for the rapid and coordinated depolarization of msucle cells and efficient contractio of cardiac muscle

Question 19

T / F - cardiac cells have myogenic activity

Answer 19

true

*they define and maintain their own rhythm

Question 20

starting at the ___________, depolarization spreads using conduction pathways to the ____________

Answer 20

sinoatrial (SA) node
atrioventricular (AV) node

Question 21

after depolarization of the SA node, then to the AV node, it spreads to the ___________ and finally to the _____________

Answer 21

bundle of his
purkinje fibers

Question 22

the vagus nerve provides parasympathetic outflow to the heart and (speeds / slows) the heart rate

Answer 22

slows

Question 23

_____________ or _______________ binds to adrenergic receptors in the heart, causing increased heart rate

Answer 23

epinephrine
norepinephrine

Question 24

epinephrine is made in the ______________
norepinephrine is made in the __________

Answer 24

epinephrine = sympathetic neurons
norepinephrine = adrenal medulla

Question 25

thick filaments are organized in bundles of ______________

Answer 25

myosin

Question 26

thin filaments are organized in bundles of __________

Answer 26

actin

Question 27

________ acts as a sprig and achors the actin and myosin filaments together, preventing excessive stretching of the muscle

Answer 27

titin

Question 28

__________ defines the boundaries of each sarcomere

Answer 28

Z line

Question 29

_________ runs down the center of the sarcomere, trhough the middle of the myosin filaments

Answer 29

M line

Question 30

_______ is the region containing exclusively thin filaments

Answer 30

I band

Question 31

_______ is the region containing only thick filaments

Answer 31

H zone

Question 32

______________ contains the thick filaments in their entirety, including any overlap with thin filaments

Answer 32

A band

Question 33

which of these areas becomes smaller during contraction? which ones remain the same? I band H zone M line Z line A band

Answer 33

decrease: H zone I band Z lines M lines same: A band

Question 34

sarcomeres are attached end to end to form ____________

Answer 34

myofibrils

Question 35

myofibrils are surrounded by a covering known as ______________

Answer 35

sarcoplasmic reticulum

Question 36

the sarcoplasmic reticulum contains a high concentration of ________ ions

Answer 36

Ca2+

Question 37

_____________ is a modified cytoplasm located hyst outside the sarcoplasmic reticulum

Answer 37

sarcoplasm

Question 38

what is the cell membrane of a myocyte called?

Answer 38

sarcolemma

Question 39

__________ is many myofibrils arranged in parallel

Answer 39

myocyte or muscle fiber

Question 40

many myocytes in parallel form a __________

Answer 40

muscle

Question 41

muscular contraction starts at the _______________

Answer 41

neuromuscular junction

Question 42

the nervous syste communicates with muscles via _______ neurons

Answer 42

efferent (motor)

Question 43

the signal travels down the neuron until it reaches the nerve terminal, where __________ is released into the synapse

Answer 43

acetylcholine

Question 44

acetylcholine binds to receptors on the sarcolemma, causing ____________

Answer 44

depolarization

Question 45

when the action potential reaches the sarcoplasmic reticulum, __________ is released

Answer 45

Ca2+

Question 46

calcium binds to a regulatory subunit in ______________, triggering a change in the confirmation of ____________

Answer 46

binds to = troponin reveals = tropomyosin

Question 47

explain the major steps fo the actin-myosin cross bridge cycle, starting with the resting stage

Answer 47

1. resting stage, ATP hydrolyzed (ADP + P) 2. Ca2+ binds to troponin, moves tropomyosin, myosin binds to actin 3. powerstroke occurs, sarcomere contracts, ADP and P dissociate from myosin 4. ATP binds to myosin which causes the detachment of myosin from actin, hydrolysis of ATP (ADP + P), recocks the myosin head

Question 48

without calcium, the myosin binding sites are covered by ____________ and contraction is prevented

Answer 48

tropomyosin

Question 49

_____________ is the response of a single muscle fiber to a brief stimulus at or above threshold

Answer 49

single twitch

Question 50

____________ is when contraction combine and become stronger and more prolonged

Answer 50

frequency summation

Question 51

_______________ is when contractions become so frequent that the muscle is unable to relax at all

Answer 51

tetanus

Question 52

what are the two supplemental energy reserves in muscle?

Answer 52

1. creatine phosphate 2. myoglobin

Question 53

T / F - myoglobin binds to O2 with high affinity

Answer 53

true

Question 54

fast twitch muscle fibers have (more / fewer) mitochondria and must rely on ____________ and ____________ to make ATP

Answer 54

fewer mitochondria glycolysis and fermentation

Question 55

what are some conditions that would shift the oxyhemoglobin dissociation curve to the right?

Answer 55

low pH (high H+) increased CO2 concentration increased temp

Question 56

____________ is the difference between the amount of O2 needed by the muscles and the actual amount present

Answer 56

oxygen debt

Question 57

most lactic acid is converted into ____________ which can enter the CAC

Answer 57

pyruvate