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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
Recharging ATP to CP
energy that stored in CP can be used to recharge ADP to ATP through creatine phosphokinase (CPK)
26
what are the 3 things that occur at peak exertion?
1. lack O2 to support mitochondria 2. muscles rely on glycolysis for ATP 3. Lactic Acid builds up
27
what are 4 results of muscle fatigue
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
why does heavy breathing occur even after exercise?
repayment of oxygen debt - after exercise the body needs more O2 then usual to go back to normal levels
29
How does the cells return back to normal?
restoring supplies of ATP, glycogen and CP liver breaks down lactic acid also, homeostasis of bp, blood flow, sweat glands, etc..
30
define the cori cycle
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
how is heat produced or lost?
energy could be lost as heat when one molecule is converted into the other --> 70% is lost to raise body temperature
32
define power
amount of tension a muscle can produce
33
define endurance
the amount of time an activity can be sustained
34
What does power and endurance both depend on?
the type of muscle fiber involved physical conditioning
35
3 type of muscle fibers
1. fast fibers 2. slow fibers 3. intermmediate fibers
36
what are fast fibers
fibers that contract very quickly e.g. muscles in eyes
37
characteristics of fast fibers
strong contractions but fatigue quickly large diameter with large glycogen reserves; usually for anaerobic respiration
38
what are slow fibers
slower to contract
39
characteristics of slow fibers
slower to fatigue capillaries to supply blood, O2 and mitochondria and myoglobin
40
define myoglobin
red pigment that binds O2, similar to hemoglobin in RBCs; own supply of O2
41
what are intermmediate fibers
they are medium sized compared to fast fibers and slow fibers
42
characteristics of intermediate fibers
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
what type of fibers are in white muscle and give e.g.
fast fibers; chicken breast
44
what type of fibers are in red muscle
mostly slow fibers; e.g. chicken legs
45
what types of fibers do humans have?
mixed; appears pink
46
define muscle hypertrophy
muscles get larger from heavy training bc diameter of individual muscle fibers increases
47
Characteristics of muscle hypertrophy
# of mitochondria increa of myofibrils increase # of mitochondria increase # of glycogen reserves
48
Define muscle atrophy
lack of muscle activity reduces muscle size, tone and power
49
what does excercise improve
power and endurance
50
How is anaerobic endurance improved by
intense tiring sets one after the other
51
Define aerobic endurance
prolonged activities that elevate heart rate & breathing - muscle are not switching to glycogen & glycolysis- energy is from mitochondria
52
how is aerobic endurance improved by
cardiovascular training, doing aerobic activities for prolonged periods= growth of new capillaries to supply better flow to muscle cells
53
How are cardiocytes different from skeletal muscle fibers
-normal size for a cell - single nucleus - have intercolated discs - branched structure - aerobic (very high in myoglobin and mitochondria)
54
define intercolated discs
connects cardiocytes together; specialized contact points b/w cardiocytes ( the cell membrane)
55
functions of intercalated discs
- 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
define functional syncytium
term for the idea of cells functioning as one
57
4 functional characteristics of cardiac muscle tissue
1. Automaticity 2. variable heart rate and contraction tension 3. longer contractions than skeletal muscle contractions 4. prevention of summation and no tetanus
58
what is automaticity
heart contracts without neural stimulation; contractions conducted by pacemaker cells (generate impulses)
59
where does smooth muscle tissue form around
around other tissues
60
What are 4 e.g.s of what smooth muscle tissue does?
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
characteristics of smooth muscle tissue
- 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
what are dense bodies
anchor strongly into cell structure
63
how do contractions occur in smooth muscle cells?
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
other ways to stimulate contraction or relaxation of smooth muscles
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
Fast fibers eg.
sprinting, weightlifting anaerobic respiration

Anatomy (8 decks)

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