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Anatomy > Chapter 10 Part 2 > Flashcards

Chapter 10 Part 2 Flashcards

1
Q

what does it mean when there is no zone of overlap?

A

something is broken or torn

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2
Q

what does the number of pivoting cross bridges depend on?

A

amount of overlap b/w thick and thin filaments

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3
Q

define optimal overlap

A

produces the most amount of tension

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4
Q

define a twitch

A

a single neural stimulation to a single muscle cell causes a single contraction/ twitch

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5
Q

what are 3 phases of a twitch

A
  1. latent period
  2. contraction period
  3. relaxation period
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6
Q

latent period

A

a few milliseconds b/w the arrival of the nerve signal & the generation; an action potential is generated, travels on t-tubules, Ca2+ release, etc.

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7
Q

contraction phase

A

sliding filaments model and tension builds to a peak

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8
Q

relaxation phase

A

active sites get covered; tension falls to resting levels

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9
Q

why is the tension increasing w/ each new signal that arrives?

A

building up Ca2+ w/ not enough time in between the signals. Ca2+ builds up because they can’t all go back into storage. More Ca2+building= more exposed- active sites = more pivoting cross bridge= more tension

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10
Q

Treppe

A

a star step increase in twitch tension

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11
Q

wave summation

A

repeated stimulations before the end of the relaxation period of the twitches
stimulation > 50 ksecond
even less time to pump ca2+ back into storage- tension rising faster

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12
Q

define complete tetanus

A

smooth, sustained movements; high stimulation= muscle never relaxes, continuous contraction

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13
Q

motor unit

A

consists of a motor neuron & all the skeletal muscle fibers that it contracts
- all the muscle cells in the motor unit contract at the same time

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14
Q

small motor unit

A

good for precise movements;
e.g. moving your eyeballs, moving fingertips for surgery

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15
Q

large motor unit

A

where movements don’t need to be as precise
e.g. calf and back

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16
Q

recruitment

A

activating additional motor units to make a muscle contraction

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17
Q

Muscle tone

A

the normal tension & firmness of a muscle cell at rest

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18
Q

effect on increasing muscle tone on metabolism during rest

A

increases it

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19
Q

Isotonic contraction

A

muscle length changes; usual muscle contraction

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20
Q

concentric contraction

A

muscle get shorter
tension in muscle> resistance

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21
Q

eccentric contraction

A

muscle get longer

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22
Q

describe eccentric contraction

A

myosin is attached & pivoting
generating tension even though muscle is lengthening
e.g. on the back down in a bicep curl
tension< resistance

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23
Q

define isometric

A

muscle develops tension but is prevented from changing length

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24
Q

define creatine phosphate

A

molecule that stores excess energy in resting skeletal muscle cells

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25
Q

Recharging ATP to CP

A

energy that stored in CP can be used to recharge ADP to ATP through creatine phosphokinase (CPK)

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26
Q

what are the 3 things that occur at peak exertion?

A
  1. lack O2 to support mitochondria
  2. muscles rely on glycolysis for ATP
  3. Lactic Acid builds up
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27
Q

what are 4 results of muscle fatigue

A
  1. depletion of energy reserves (ATP, CP, glycogen)
  2. low pH of lactic acid; cells w/ low pH–> sick, enzymes don’t work the way they should
  3. damage to organelles, SR, sarcolemma–> lactic acid
  4. muscle exhaustion and pain
28
Q

why does heavy breathing occur even after exercise?

A

repayment of oxygen debt - after exercise the body needs more O2 then usual to go back to normal levels

29
Q

How does the cells return back to normal?

A

restoring supplies of ATP, glycogen and CP
liver breaks down lactic acid
also, homeostasis of bp, blood flow, sweat glands, etc..

30
Q

define the cori cycle

A

removal of lactic acid from bloodstream carrying waste products to the liver to be recycled into glucose then it is released back into the blood stream to recharge muscle’s glycogen reserve

31
Q

how is heat produced or lost?

A

energy could be lost as heat when one molecule is converted into the other –> 70% is lost to raise body temperature

32
Q

define power

A

amount of tension a muscle can produce

33
Q

define endurance

A

the amount of time an activity can be sustained

34
Q

What does power and endurance both depend on?

A

the type of muscle fiber involved
physical conditioning

35
Q

3 type of muscle fibers

A
  1. fast fibers
  2. slow fibers
  3. intermmediate fibers
36
Q

what are fast fibers

A

fibers that contract very quickly
e.g. muscles in eyes

37
Q

characteristics of fast fibers

A

strong contractions but fatigue quickly
large diameter with large glycogen reserves; usually for anaerobic respiration

38
Q

what are slow fibers

A

slower to contract

39
Q

characteristics of slow fibers

A

slower to fatigue
capillaries to supply blood, O2 and mitochondria and myoglobin

40
Q

define myoglobin

A

red pigment that binds O2, similar to hemoglobin in RBCs; own supply of O2

41
Q

what are intermmediate fibers

A

they are medium sized compared to fast fibers and slow fibers

42
Q

characteristics of intermediate fibers

A

have some myoglobin; lower compared to slow fibers
better blood supply than fast fibers
slower to fatigue than fast fibers but faster to fatigue than slow fibers

43
Q

what type of fibers are in white muscle and give e.g.

A

fast fibers; chicken breast

44
Q

what type of fibers are in red muscle

A

mostly slow fibers; e.g. chicken legs

45
Q

what types of fibers do humans have?

A

mixed; appears pink

46
Q

define muscle hypertrophy

A

muscles get larger from heavy training bc diameter of individual muscle fibers increases

47
Q

Characteristics of muscle hypertrophy

A

of mitochondria increa

of myofibrils increase
# of mitochondria increase
# of glycogen reserves

48
Q

Define muscle atrophy

A

lack of muscle activity reduces muscle size, tone and power

49
Q

what does excercise improve

A

power and endurance

50
Q

How is anaerobic endurance improved by

A

intense tiring sets one after the other

51
Q

Define aerobic endurance

A

prolonged activities that elevate heart rate & breathing
- muscle are not switching to glycogen & glycolysis- energy is from mitochondria

52
Q

how is aerobic endurance improved by

A

cardiovascular training, doing aerobic activities for prolonged periods= growth of new capillaries to supply better flow to muscle cells

53
Q

How are cardiocytes different from skeletal muscle fibers

A

-normal size for a cell
- single nucleus
- have intercolated discs
- branched structure
- aerobic (very high in myoglobin and mitochondria)

54
Q

define intercolated discs

A

connects cardiocytes together; specialized contact points b/w cardiocytes ( the cell membrane)

55
Q

functions of intercalated discs

A
  • maintain the structure of the heart
  • enhance molecular & electrical connections b/w cardiocytes
  • conduct action potentials from cell to cell w/in the heart
56
Q

define functional syncytium

A

term for the idea of cells functioning as one

57
Q

4 functional characteristics of cardiac muscle tissue

A
  1. Automaticity
  2. variable heart rate and contraction tension
  3. longer contractions than skeletal muscle contractions
  4. prevention of summation and no tetanus
58
Q

what is automaticity

A

heart contracts without neural stimulation; contractions conducted by pacemaker cells (generate impulses)

59
Q

where does smooth muscle tissue form around

A

around other tissues

60
Q

What are 4 e.g.s of what smooth muscle tissue does?

A
  1. regulates bp & flow in muscle tissue
  2. moves secretions, egg and sperm in repro sustem
  3. causes peristalsis (rhythmic contractions in gastric systems)
  4. arrector pili muscles –> goosebumps
61
Q

characteristics of smooth muscle tissue

A
  • non-striated
  • thin with tapering ends (spindle shaped)
  • single, central nucleus
  • no t-tubules, no myofibrils or sarcomeres
  • no tendons or aponeuroses
  • scattered myosin fibers
  • thin filaments are attached to dense bodies
62
Q

what are dense bodies

A

anchor strongly into cell structure

63
Q

how do contractions occur in smooth muscle cells?

A

whe myosin pulls on the thin filaments, the dense bodies get dragged toward the middle of the cell and the cell scrunches up

dense bodies are also attached to adjacent cells so when one cell contracts, other cells contract as well

64
Q

other ways to stimulate contraction or relaxation of smooth muscles

A

hormones
local concentrations of O2 or Co2
stretching
irritation
signals from motor neurons
signals from pace setters
electrical impulses spread from smooth to smooth muscle through gap junctions

65
Q

Fast fibers eg.

A

sprinting, weightlifting
anaerobic respiration

Anatomy (8 decks)

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