Chapter 9 Flashcards
Perimysium ?
Layer that divides muscle into bundles called fascicles
What is the epimysium
Dense layer that surrounds entire muscle
Separates muscle from surrounding organ
What’s the endomysium
Surrounds individual muscle fibers
What do muscle cells develop from
Myoblasts
What is the cell membrane of a muscle called
Sacrolemma
What are thin filaments composed of
Actin
What are thick filaments composed of
Myosin
What are z lines
Boundary between adjacent sacromeres
What is the m line
Connects central portion of each thick filament
What is the A I and H band
A band is region containing thick and thin filaments. Length of thick
I band is only thin filaments. One A band to the next
H band is only thick filaments around M line
What are the two regulatory proteins within thin filaments
- Tropomyosin
2. Troponin
What is the 4 steps involved with the sliding filament theory
- H bands and I bands get smaller
- Zones of overlap get larger
- Z lines move closer together
- Width of A band remains constant
How does the sodium potassium pump work
Send 3 sodium ions out of cell
Bring 2 potassium ions in cell
What is a neuromuscular junction
Connection between motor neuron and skeletal muscle fibre
What is the NMJ composed of
- Synaptic terminal - ach
- Motor end plate -ache
- Synaptic cleft - ache
What is the excitation contraction coupling system
Action potential and muscle contraction
What determines the amount of tension produced in a muscle fibre
Fibres resting length
What is the optimal resting length
Maximum number of cross bridges form
What happens when tension is increased and decreased
Increased sacromere is stretched
Decreased sacromere is compressed
What is a muscle twitch
Single stimulus contraction relaxation sequence in a muscle fibre
What’s a fasciculation
Involuntary muscle twitch under skin
What Are the 3 phases of a twitch
- Latent period . No tension
- Contraction phase. Beginning of tension to peak tension
- Relaxation phase. Peak tension to end of twitch
What are the 4 levels of muscle tension
- Treppe
- Wave summation
- Incomplete tetanus
- Complete tetanus
What is treppe
Immediately after relaxation phase.
Most do not experience
Wave summation?
Before relaxation phase completion
Incomplete tetanus
Almost peak tension. Period of relaxation so incomplete tetanus
Complete tetanus ?
Continuous peak tension. No relaxation period
Isotonic contraction
Tension rises and skeletal muscle length changes
Concentric contraction
Tension rises until it exceeds load.
Eccentric contraction
Load is more then peak tension produced
Muscle tears or tendon breaks
Creatine phosphate
Supplies energy for 15 seconds
What is the lactating cycle and what is it also called
The cori cycle. Lactate produced by muscle fibers during strenuous activity
What is oxygen debt
Amount of oxygen needed to return to pre exertion condition
What is muscular hypertrophy atrophy and dystrophy
Hypertrophy is increase in size
Atrophy is decrease
Dystrophy is weakness
