Skeletal Muscle Physio Flashcards Preview

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Flashcards in Skeletal Muscle Physio Deck (17):
1

Sliding Filament Mechanism

Actin and Myosin Filaments slide in between each other.

2

Ca2+ and ATP role in contraction

CA2+ for crossbridge cycle
ATP needed or rigor

3

Excitation Coupling Steps

Action Potentials
Depolarization T -Tubules
Inc Intracellular Ca2+
Ca2+ binds troponin C
-Cross bridge Cycle begins
Relaxation
Dec. Intracellular Ca2+
Ca2- Released

4

Types of Muscular Contractions

Isotonic - tension constant, length changes
Concentric - muscle shortens T>L
Isometric - muscle prevented from shortening T=L
Eccentric - lengthening to create action T

5

Effect of resting fiber length on muscular contraction

There are upper and lower limits on stretch and shortening. limited performance.

6

Mechanism by which skeletal muscle can vary the amount of tension

motor unit recruitment

7

Summation v Recruitement

Summation - another AP start before action ends
Recruitment - Size principle - choosing some motor units over others

8

ATP production in skeletal muscle - pthwy

.

9

Skeletal Muscle Fibers types + Characteristics

Type I - oxidative - Inc. myoglobin - least fatigueable
Type IIA - oxidative
Type IIB - glycoltic - Dec Myoglobin - easily fatigue

I before IIA before IIB

10

Skeletal Muscle Disorders

There are agents/disease that alter ACH release, reception and activation

11

Crossbridge Cycle - pthwy

ATP binds to myosin
Conf. Change = Myosin releases Actin
Myosin moves to + end actin and attaches (power stroke)
repeats cycle

LOW Ca2+ = no cross bridge cyles

12

NO ATP but calcium present = Rigor mortis

Myosin bound to actin permanently

13

Tetanus

Muscle doesn't complete relaxation

14

Constant Ca2+ - broken gate

Malignant hyperthermia

15

Myasthenia Gravis

Self-produces antibodies that inactivate Ach

16

Lamber-Eaton myasthenic syndrome

Self producing antibodies that Ca2+ channels - reduce Ca2+ influx into pre-synaptic terminal

17

Sources of Engery

1st - Creatine phosphate
2nd - Glycogen Glucose
3nd - Pyruvate