Muscles Flashcards

1
Q

what are the 3 types of muscle and their percent of body weight

A
  1. Cardiac (cardiac + smooth = 10%)
  2. Smooth
  3. skeletal (30-40%)
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2
Q

What are the 4 properties of muscle and what they do?

A
  1. Contractibility: can shorten and thicken to produce force
  2. Excitability: able to conduct a electrical signal
  3. Elasticity: returns to its original shape
  4. Extensibility: able to stretch without damage
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3
Q

What is myogenisis?

A

The creation of new muscle tissue

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4
Q

What do myoblasts do?

A

multiple myoblasts form together to create a new muscle fibre (called fusion)

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5
Q

Another word for myocytes?

A

myotubuals

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6
Q

What is a satellite cell?

A

stem cells in skeletal muscle that helps with repair and growth

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7
Q

Name the structure of a muscle starting from largest to smallest units. Include the facia layers covering them.

A
  1. Muscle - covered by epimysium
  2. Fasicles - surrounded by perimysium
  3. muscle fibers - surrounded by endomysium
  4. Myofibrils
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8
Q

Where are the sarcomeres located?

A

the myofibrils

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9
Q

what is the roll of the sarcoplasmic reticulum and where is it located?

A

It encases the myofibrils and is used as a transport system for calcium

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10
Q

Superficial facia vs deep facia

A

Deep: surrounding muscles and bones
Superficial: just below the skin

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11
Q

What is apponeurosis?

A

large sheet of connective tissue that connects bone to muscle. eg. at top of skull

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12
Q

Define muscle contraction

A

Tension in the muscle (Does not need to change length)

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13
Q

What are the 3 types of muscle contraction

A

Isotonic: Muscle changes in length (concentric and eccentric)
Isometric: Muscle length does not change but theirs tension in muscle
Isokinetic: Muscle changes length at a constant velocity

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14
Q

Describe all the steps of the sliding filament theory

A

look at page in binder

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15
Q

What needs to happen in order for cross bridges to form and a power stroke to occur?

A

Calcium must bind to troponin, which removes tropomyosin from the active sites on the actin. Myosin heads must be in an energized state. When ADP and Pi de attach it causes a power stroke.

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16
Q

What causes the cross bridge to de attach?

A

ATP binds to the myosin head causing it to de attach. ATP is then hydrolyzed

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17
Q

Explain why theirs still tension is isometric contractions

A

Myosin heads get stretched out causing tension. Myosin heads don’t attach to new active sites causing the muscle to not change lengths

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18
Q

Eccentric contract

A

the load is more than the tension and the muscle can’t hold up the weight. Myosin heads get forcefully ripped of the actin. This means that no ATP is used but more damage is done

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19
Q

Name the contractile proteins

A
  1. Actin
  2. Myosin
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20
Q

Name the regulatory proteins

A
  1. Troponin
  2. Tropomyosin
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21
Q

Name the structural support proteins and what they do

A
  1. Titin: connects the thick filaments to the Z-line
  2. Actinin: protein that makes the Z-line
  3. Dystrophin: Protein that helps make the costameres
  4. Nebulin: Part of the thin filament that helps hold the actin together
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22
Q

What are costameres and where are they found?

A

Links actin to the sarcolemma and transfers the force produced at the sarcomeres to the muscle. (eg. drive shaft in a car)

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23
Q

What’s a disease called where the costameres aren’t working properly?

A

Muscular dystrophy

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24
Q

What are the sections of the sarcomere

A

A band: Length of the thick filaments
H- zone: Zone where theirs only thick filament
I- zone: Zone with only thin filament
Z-line: Connects the thin filaments together
M- line: Midline. Connects the thick filaments together
Zone of overlap: Zone where their is both thick and thin filament

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25
Explain the structure of the sarcoplasmic reticulum
1. Terminal cisternae: Enlarged region at each end of the sarcoplasmic reticulum that stores calcium 2. Tubes connect the terminal cisternae
26
What are T-Tubuals and where are they located
They are part of the sarcolemma (membrane of the muscle fibre) that dip down and are part of the process that releases calcium
27
One neuron can connect to multiple muscle fibres true or false?
True.
28
explain the neuromuscular junction process
look at sheet in binder
29
Explain the structure of the motor end plate
1. Has acetylcholine receptors that are ligand gated channels that allow for the entrance of sodium 2. Has a folded structure in order to increase surface area
30
What is the enzyme that breaks down acetylcholine
Acetylcholinesterase
31
What is depolarization?
Making the inside of the membrane more positive compared to its resting state
32
How is the calcium retrieved and put back into the sarcoplasmic reticulum?
A protein called calsequestrin brings the calcium back
33
Explain the process of the neuromuscular junction from the action potential coming down the motor neuron until the release of calcium from the terminal al cisternae
look at page in binder
34
What is the series of events starting from the action potential ending with muscle contraction called?
Excitation contraction coupling
35
What is tension, what is load?
Tension: The force placed on a load, coming from the muscle Load: The force placed on the muscle coming from the load
36
Changes in muscle length depend on...
1. Amount of load 2. Amount of tension
37
What is the load velocity relationship?
How fast a muscle can change lengths in relation to the load
38
When the load>tension what kind of contraction is it
Eccentric contraction (muscle lengthening)
39
When is the muscle shortening speed the fastest?
When the load = 0
40
What determines tension?
Amount of cross bridges formed. More cross bridges = more tension
41
What 2 types of tension add together to make total tension
Active tension: thick and thin filaments contracting passive tension: Tension is generated non activly and is produced by "hanging off of your joints"
42
explain the Length tension relationship
Active tension has an optimal length of contraction ion where it produced the most amount of tension. Muscle is too contracted: Thin filaments overlap onto of each other therefor myosin heads on the thick filament won't be able to bind to all off the active sites on the thin filament Muscle too stretched: Thin filaments are stretched out so much that not all of the myosin heads are in contact with actin therefor not as much cross bridges
43
Name the 3 different deep facia layers and what they surround
Epimysium: surround the muscle Perimysium: Surround the fascicles Endomysium: surrounds the muscle fibres
44
Explain what summation is
High frequency of action potentials reaching the muscle leads to continuous contractions. The muscle isn't allowed to fully relax before its contracted again leading to increased tension
45
Summation leads to tetinus. what is tetinus?
Frequent muscle twitches lead to a smooth muscle contraction
46
How far apart do the twitches have to be to not build up tension?
200ms
47
What are the 2 types of teninus and what are they?
Unfused: Some relaxation is allowed between contractions Fused: Action potential frequency so high no relation of the muscle between contractions
48
What are the 3 phases of a muscle twitch
1. Latent period: Time between the action potential reaching the motor end plate to when calcium is released from the terminal cisternae 2. Contraction phase: Time during cross bridge cycling 3. Relaxation phase: Time when tension decreases and calcium is being retuned to the sarcoplasmic reticulum
49
Explain what muscle recruitment is
Process where multiple motor units work together to produce force
50
Explain the difference in use between smaller motor units and larger motor units (what their used for)
Larger motor units: Nerve innervates more muscle fibres and can produce more power Smaller motor units: Nerve enervates less muscle fibres, but is more precise
51
Explain Heinemann size principal and explain why it happens
Theirs a specific order of muscle recruitment that happens. Smaller motor units gets recruited first then progresses to the bigger ones. Why: its easier for the brain
52
What is maximum muscle tension
All motor units are recruited
53
What is Muscle tone
Passive muscle contraction that is always present. (eg. holding our head up without thinking about it) due to a constant level of action potential always being produced
54
What is the first change seen when. beginning to workout?
Muscle tone increases leading to a more defined look of the muscles
55
What are the two types of muscle growth that occurs when doing resistamce training. explain what they are.
Transient hypertrophy: Increase in muscle size developed right after a workout due to fluids accumulating around the cells. (getting a pump) Chronic hypertrophy: Increase in muscle size as a result of long term exercise.
56
Explain the structure of ATP
Nitrogenous base + % carbon carb + 3 phosphates
57
What are the 4 ways ATP is generated?
1. Phosphocreatine system 2. Glycolysis (Anaerobic) 3. Glycolysis (aerobic) and oxidative phosphorlation 4. Oxidative phosphorylation of fat
58
Explain the Rate, location, production, oxygen requirement, and duration of... The Creatinephosphate system
Rate: immediate Location in the cytosol Production: very little Oxygen: No Duration: 3-15 seconds
59
Explain the Rate, location, production, oxygen requirement, duration and process of... anerobic glycolysis
Rate: fast Location in the cytosol Production: 2 net ATP Oxygen: No Duration: 30 seconds - 2 minutes process: -Start with glucose (6 carbon molecule) - Split into 2 molecules of pyruvate (3 carbon molecule) - Without oxygen pyruvate turns to lactate - produces 2 ATP
60
Explain the Rate, location, production, oxygen requirement, duration and process of... Aerobic glycolysis and oxidative phosphorlation
Rate: Slow Location in the mitochondria Production: 34 ATP Oxygen: Yes Duration: 40 minutes Process: - Glucose splits into 2 pyruvate molecules - Instead of turning into lactate, the presence of oxygen turns the pyruvate into acetyl co-A - Acetyl Co-A enters the Krebs cycle -Produces 34 ATP
61
Explain the Rate, location, production, oxygen requirement, and duration of... Oxidative phosphorylation of fat
Rate: Very slow Location in the mitochondria Production: >130 ATP Oxygen: Yes Duration: Energy lasts for hours
62
What are the 3 types of muscle fibres?
1. Slow oxidative fibers (type 1) 2. Fast oxidative glycolytic fibers (type 2a) 3. Fast glycolitic fibers (type 2b)
63
Explain slow fibres (type 1)
- Small diameter = least powerfull - Required the most oxygen therefore its structure produces the most oxygen by having... 1. High capillary density 2. High mitochondrial density 3. High myoglobin density - fatigue resistant - slow speed of contraction
64
Explain fast fibres (type 2a)
- medium diameter = medium power 1. medium capillary density 2. medium mitochondria density 3. medium myoglobin density - Relies on both glycolysis and oxidative phosphorylation - Medium resistance to fatigue - Fast speed of contraction
65
Explain fast fibres (type 2b)
- large diameter = most powerful 1. Low capillary density 2. low mitochondria density 3. low myoglobin density - Relies on anaerobic processes for ATP - very fatiguable - Fastest speed of contraction