Ch. 1 Flashcards
Epimysium
Outermost layer of fascia, surrounding the entire muscle
Perimysium
Middle layer of fascia, surrounds one bundle of muscle fibers
Endomysium
Innermost layer of fascia, surrounds one muscle fiber
Fascicle
A bundle of muscle fibers, grouped by fiber type
Motor Unit
One Nerve + Muscle Fibers it Innervates
Muscle Fiber
A Muscle Cell
Made of Myofibrils, contains sarcomeres
Sarcomere Structure:
- Z Disc
- A Band
- I Band
- H Zone
- Z Disc: The “Walls”
- A Band: Length of Myosin (always stays the same length)
- I Band: Actin, no myosin
- H Zone: Myosin, no actin
What happens to Z disc when muscles contract and relax?
contract = closer together
relax = farther apart
Action Potential
from CNS to nerve to neuromuscular junction, creating a muscular contraction
7 steps to activating muscle fiber
1 - Action potential
2 - Propagates down nerve to neuromuscular junction
3 - Aceylcholine crosses NMJ, exciting sarcolemma
4 - calcium is released from sarcoplasmic reticulum
5 - troponin binds to tropomyosin to pull out of way
6 - binding site opens
7 - myosin binds to actin forming cross bridge
Order of muscle fiber types
Type I = oxidative (slow twitch)
Type IIa = mixed
Type IIx = glycolytic (fastest twitch)
Muscle Spindle
Intrafusal/parallel, senses muscle stretch, reflex to contract muscle
Golgi Tendon Organ
myotendinous junctions/series, senses muscle contraction, reflex to relax muscle
Blood Flow Through Heart
Superior/Inferior Vena Cava
R Atrium
Tricuspid Valve
R Ventricle
Pulmonary Valve / Artery
Lungs
Pulmonary Vein
L Atrium
Bicuspid Valve
L Ventricle
Aortic Valve
Blood flow to muscles
Arteries
Arterioles
Capillaries (gas exchange)
Venules
Veins
