Skeletal, Smooth and Cardiac Muscle Structure and Contraction Flashcards

1
Q

Muscle fibre structures are…

A
  1. Striated
  2. Unbranched
  3. Multi-nucleated
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2
Q

The 3 different types of Muscle Fibres are…

A
  1. Type 1
  2. Type 11A
  3. Type 11
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3
Q

Contraction is….

A

Neurogenic

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4
Q

Type 1 Muscle Fibres are also called…

A

Slow Twitch

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5
Q

Slow Twitch (Type 1) features are….. (2)

A
  1. Very aerobic
  2. Low Fatigue (fibres can contract for a long period)
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6
Q

Slow Twitch (1) fibres are used in… (2)

A
  1. Postural Control
  2. Repetitive slow locomotion

e.g. Marathon Running

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7
Q

Type 11a Fibres are also called….

A

Fast Twitch (Oxidative) Fibres

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8
Q

Fast Twitch Fibres (11a) features are…. (3)

A
  1. Aerobic - somewhat resistant to fatigue
  2. Uses oxygen to convert glycogen to ATP (glycolysis)
  3. Oxidative
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9
Q

Fast Twitch fibres are used in….

A

Repetitive, fast locomotion

e.g. Sprinting

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10
Q

Type 11x Fibres are also called…

A

Fast-twitch (Glycolytic) Fibres

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11
Q

Fast-twitch (11x) Fibres features are… (2)

A
  1. Anaerobic - high power output, fatigue easily
  2. Rely on stored ATP to generate energy
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12
Q

Fast-twitch (11x) are used for…

A
  1. High output energy

e.g. Weightlifting

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13
Q

What are Slow twitch fibres microscopic features? (3)

A
  1. Smaller diameter
  2. Darker in colour (due to myoglobin)
  3. Numerous Mitochondria and capillaries (to produce ATP)
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14
Q

What are Fast twitch Fibres microscopic features? (3)

A
  1. Larger diameter
  2. Lighter in colour
  3. Less mitochondria (not needed as anaerobic)
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15
Q

Skeletal muscle are attached to bones by…

A

Tendons

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16
Q

What is the Skeletal Muscle Anatomy route from largest to smallest… : Myofibril, Fascicle, Muscle Fibre, Deep Fascia

A

Deep Fascia -> Fascicle -> Muscle Fibre -> Myofibril

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17
Q

Actin are _____ filaments

A

Thin

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18
Q

Myosin are ______ filaments

A

Thicker

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19
Q

3 Types of connective tissue in Skeletal Muscle

A
  1. Epimysium (around muscle)
  2. Perimysium (around fascicles)
  3. Endomysium (around myofibril)
20
Q

Muscle Myofibrils make up a _________

A

Sarcomere

21
Q

Sarcomeres are found between….

A

Two Z discs

22
Q

Sarcomeres contain the two proteins….

A

Actin and Myosin

23
Q

Muscle contraction occurs when ______ pulls ______ to shorten the sarcomere

A
  1. Myosin
  2. Actin
24
Q

Actin and Myosin are attached to ___ line by _____ _______

A
  1. Z
  2. Alpha Actin
25
Q

What is the role of Titin?

A

Keeps myosin straight

26
Q

Describe the Process leading up to Muscle Contraction in 7 Steps….

A
  1. AcH is released from an Axon terminal of a motor neurone
  2. AcH binds to receptors in the motor end plate
  3. This produces an end-plate potential which triggers AP in muscle cell
  4. AP travels along sarcolemma of muscle and down T tubules
  5. AP triggers Ca2+ release from Sarcoplasmic reticulum
  6. Ca2+ binds to troponin and activates power stroke
  7. After power stroke, Ca2+ is actively transported back into lumen on SR.
27
Q

Describe the Power stoke Theory in 4 Steps….

A
  1. Calcium from SR floods in and binds to the tropomyosin, moving the tropomyosin away from Actin binding sight.
  2. Myosin head binds with the Actin sights producing Actin-Myosin cross-bridges.
  3. ATP is converted to ADP + Pi, releasing energy to change Myosin head position (slanted)
  4. Actin is pulled past the myosin - Power stroke
  5. Actin-myosin cross bridge is broken when an ATP binds to the myosin head.
28
Q

During contraction the I (actin) band….

A

Gets smaller

29
Q

During contraction the Z band distance…

A

Gets smaller

30
Q

During contraction the H (myosin) band….

A

Gets smaller

31
Q

3 Functions of ATP in Skeletal Muscle Contraction….

A
  1. Hydrolysis of ATP for power stroke
  2. Allows cross-bridge to be formed between actin and myosin
  3. Movement of Ca2+ ions into the SR
31
Q

During contraction the A (actin and myosin) band….

A

Stays the same

32
Q

Smooth Muscle is….

A

Involuntary

33
Q

Smooth muscle cells are ______ in shape

A

Spindle

34
Q

Does smooth muscle contain actin and myosin?

A

Yes

35
Q

How is actin and myosin linked in smooth muscle?

A

Intermediate filaments

36
Q

What is the structure of Smooth Muscle?

  1. Striated
  2. Branched
  3. Not striated
A
  1. Not striated
37
Q

What connects adjacent cells….

A

Gap junctions

38
Q

What are the two types of Smooth Muscle?

A
  1. Single Unit
  2. Multi Unit
39
Q

What are examples of single unit SM?

A

Bronchi, Bladder, Uterus, GIT

40
Q

What are examples of multi unit SM?

A

Iris muscles, ciliary muscles

41
Q

What controls cross bridge activity?

A

Calcium Ions

  • Required to bind to Tropomyosin
42
Q

What is the structure of Cardiac muscle? (2)

  1. Striated
  2. Non-striated
  3. Branched
A
  1. Striated
  2. Branched
43
Q

Intercalated discs provide…

A

Stability

44
Q

What is the function of gap junctions?

A

Communication, spread of signals between cells

45
Q
A