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Flashcards in Physiology- Muscular Deck (39)
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1

What is the contractile until of muscle?

sarcomere

2

What is the name of the organelle in the muscle cell that is high in calcium?

sarcoplasmic reticulum

3

What is the neurotransmitter of the neuromuscular junction?

acetylcholine

4

What substance fluxes through open gated channels when the action potential reaches the terminal bouton?

calcium

5

The depolarization of the post-synaptic membrane is known as what?

The end plate potential

6

Why will the end plate potential always reach threshold every time?

because it is a suprathreshold

7

What stops the action of acetylcholine in the synaptic cleft?

acetyl choline esterase

8

Adrenergic synapses use what neurotransmitter?

norepinephrine

9

What are the 2 contractile proteins of muscle?

Actin and myosin

10

Which of the contractile proteins is found in the thin filament?

actin

11

Which of the contractile proteins is found in the thick filament?

myosin

12

What are the 2 regulatory proteins that are also found on the thin filament?

troponin, tropomyosin

13

Which is the regulatory protein that has an inhibitory action on the formation of actin-myosin complex?

tropomyosin

14

What substance causes the troponin-tropomyosin complex to fall away from the active site of the actin molecule?

calcium

15

to which of the regulatory proteins does calcium bind?

troponin

16

What substance is bound to the myosin head?

ATP

17

What two things do we need to get the muscle to relax?

1. Removal of calcium
2. ATP bound to the myosin head

18

Lifting and setting down contraction with muscle shortening and lengthening is known as what type of contraction?

Isotonic

19

Contraction with no external muscle shortening is what type of contraction?

Isometric

20

The force-velocity curve depicts what type of muscle contraction?

isotonic (velocity indicates movement)

21

The length-tension curve depicts what type of muscle contraction?

Isometric

22

Posture, heat generation, nerve nutrition of muscle and general circulation are all function of what?

muscle tone

23

What is it called when a series of action potentials reach a muscle such that it cannot relax and so force within a muscle is built to a maximum?

summation of twitches --> tetany

24

Accumulation of calcium in the cytoplasm is the mechanism for what?

summation of twitches

25

What are the 3 muscle types?

Fast oxidative glycolytic
Slow oxidative
Fast glycolytic

26

Marathon runners have more of what muscle fiber?

slow oxidative

27

Sprinter have more of what type of muscle fiber?

fast glycolytic

28

Where do you find smooth muscle in the body?

Hollow organs, blood vessels, lymphatics, skin (piloerection), eye

29

What are the 2 different types of smooth muscle?

1. Multi unit
2. visceral-contracts as a single unit

30

Piloerection and the ciliary muscles of the eyes are examples of what type of muscle?

multi unit smooth muscle

31

Gap junctions are found in which type of smooth muscle?

viscera (single unit)

32

What is the cytoplasmic binding protein found in smooth muscle?

Calmodulin

33

What are 2 possible sources of calcium for smooth muscle contraction?

1. mitochonrion
2. intracellular vescicles

34

How does relaxation of smooth muscle differ from relaxation of skeletal muscle?

It requires a light chain phosphates enzyme to remove phosphate from myosin. In skeletal muscle, relaxation is based on the repute of calcium and ATP binding to myosin head

35

What are the 2 types of action potentials in smooth muscle?

1. spike potential
2. Plateau potential

36

The gut, blood vessels experience what type of smooth muscle action potential?

spike

37

The uterus and bladder experience what type of smooth muscle action potential?

plateau potential

38

Smooth muscle contraction is regulated in what 2 ways?

1. Neurally i.e. via neurotransmitters
2. hormonally via blood borne agents (epic), local tissue factors (O2, CO2, H+)

39

What happens to smooth muscle when it is stretched?

It will often lead to a spike potential and a contraction