phys chapter 12

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/48

encourage image

There's no tags or description

Looks like no tags are added yet.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

49 Terms

1
New cards

skeletal muscle

voluntary, striated

2
New cards

cardiac muscle

involuntary, striated

3
New cards

smooth muscle

involuntary, unstriated

4
New cards

functions of skeletal muscle

movement of body, posture, generation of body heat, movement of substances(ie.urinary tract), nutrient reserves, support soft tissues and organs

5
New cards

what is skeletal muscle linked to bones by

tendons

6
New cards

muscle cell is also called a

muscle fiber

7
New cards

components of muscle fiber

sarcoplasm, sarcolemma, and myofibril

8
New cards

what are myofibrils

contractile elements of the muscle fiber that are composed of myofilaments

9
New cards

thick filaments are composed of

myosin

10
New cards

thin filaments are composed of

actin

11
New cards

motor unit

single motor neuron and all the muscle fibers it innervates

12
New cards

motor end plate

area of sarcolemma where the motor neuron stimulates skeletal muscle

13
New cards

sarcomere

functional unit of contraction

14
New cards

what do myosin heads do

form cross bridges between thick and thin filaments

15
New cards

what is on myosin heads

actin binding sites, ATP binding site, ATPase

16
New cards

thin filaments regulatory proteins

troponin and tropomyosin

17
New cards

tropomyosin

resting, covers myosin binding sites blocking interaction

18
New cards

troponin

bind to tropomyosin, bind to actin, and bind to calcium

19
New cards

what do each actin have

special binding site for attachment with myosin cross bridges—> binding results in contraction of muscle fiber

20
New cards

Sliding FIlament Mechanism

contraction is accomplished by thin filaments from opposite sides of each sarcomere sliding closer together between thick filaments

21
New cards

Power Stroke

swiveling of myosin heads

22
New cards

sliding filament mechanism steps

  1. attachment of myosin cross bridge to a thin filament

  2. swiveling of myosin heads - power stroke

  3. detach of the cross bridge from thin filament

  4. reattach to a new actin binding site

  5. repeat cycle

23
New cards

Cross Bridge cycle steps

  1. resting fiber; CB is not attached to actin

  2. CB bind to actin

  3. P is released causing conformational change in myosin

  4. Power stroke causes filaments to slide; ADP is released

  5. a new ATP binds to myosin head allowing it to be released from actin

  6. ATP is hydrolyzed causing CB to return to normal orientation

24
New cards

Functions of ATP in contraction

  1. energizes CB providing energy for powerstroke

  2. binding of ATP disassociates CB from actin

25
New cards

do myosin and actin interact at rest

no

26
New cards

how does muscle excitation switch on CB cycling

Calcium

27
New cards

calcium is ___ at rest and is stored in the ____

low, sarcoplasmic reticulum

28
New cards

what happens to calcium for a contraction to happen

it is released from SR —→ increase in calcium —→ contraction

29
New cards

how is calcium released from the SR

AP propagated into interior by transverse tubules—> Ca2+ goes through voltage-gated channels in SR-—> release of calcium

30
New cards

tension

force exerted on an object by contracting muscle

31
New cards

load

force exerted on muscle by weight of an object

32
New cards

twitch

response of a single muscle fiber to a single AP

33
New cards

Muscle contraction phases

latent period, contraction time, relaxation time

34
New cards

force velocity curve

for muscle to contract they must generate force that is greater than opposing forces

the greater the force the slower the contraction

35
New cards

two types of muscle contraction

isotonic and isometric

36
New cards

isotonic

change in muscle length

37
New cards

two types of isotonic contractions

concentric and eccentric contractions

38
New cards

concentric contractions

muscle shortens

39
New cards

eccentric contractions

muscle lengthens

40
New cards

isometric contractions

muscles cant shorten because load is too great, can be voluntary

41
New cards

nervous system in muscle tension

frequency of stimulation and motor unit recruitment

42
New cards

frequency of stimulation

because muscle twitch is fairly slow compared to AP many AP arrive before twitch occurs, generation of force is greater than a single twitch , summation

43
New cards

muscle summation

muscle stimulated again before relaxation leads to summation

44
New cards

tetanus

contraction is usually 3-4 greater than a single twitch

45
New cards

motor unit recruitment

increasing the number of active motor units, increase tension and velocity

46
New cards

formation of ATP by muscle

phosphoralation of ADP by creatine phosphate

oxidative phosphoralation

glycolysis

47
New cards

creatine phosphate

48
New cards
49
New cards