Ch. 11 - Muscle Physiology Flashcards
In a muscle cell, what is the network of channels extending throughout the sarcoplasm that stores Ca2+?
Sarcoplasmic Retiuclum
What is the major structural unit of skeletal muscle?
Myofibril
What do thick and thin filaments contain?
- Thick
- Myosin
- Thin
- Actin, troponin, tropomyosin
How many T-tubules lie within a single sarcomere?
2
What cells are responsible for skeletal muscle regeneration?
Satellite Cells
Which parts of the sarcomere get shorter during contraction?
H and I bands
What part of the sarcomere is the dark band and the light band?
dArk band = A band
LIght band = I band
What are the 3 layers of connective tissue surrounding muscles?
- Epimysium - surrounds entire muscle
- Perimysium - surrounds muscle bundles
- Endomysium - surrounds each muscle fiber
What does each motor unit contain?
- Alpha-motor neuron
- Synaptic cleft
- Associated muscle fibers
Where are the sources for ATP for muscle contraction?
- Glycogen stores –> Glycolysis
- TCA cycle –> oxidative phosphorylation
- Creatine Phosphate
How do you remember the difference between type 1 and type 2 twitch speed?
- Type 1
- 1 slow fat red ox
- slow, lipid accumulation, red fibers, oxidative phosphorylation
- Type 2
- 2 fast skinny white chickens
- fast, low lipid accumulation, white fibers
What are extrafusal and intrafusal fibers innervated by?
- Extrafusal - alpha-motor neurons
- Intrafusal - gamma-motor neurons
What type of muscle fibers are the largest and fastest?
Type 1a fibers
What type of fibers are non-adaptive?
Type 2 fibers - flower-spray endings
Tell what reflex type and receptor for each of the following sensitivies:
- Change in length
- Change in tension
- Change in temperature
- ∆ in length - stretch, muscle spindle
- ∆ in tension - tendon, Golgi tendon organ
- ∆ in temp - nociceptor, flexor-withdrawal
What does cardiac muscle behave as?
A functional synctium
How are cardiac muscle fibers linked together?
By desmosomes
What part of cardiac muscle coordinate the action of cardiac mucle cells?
Intercalated discs
What is known as the pacemaker of the heart?
Sinuatrial (SA) node
How is smooth muscle contraction stimulated?
- Autonomic nervous system (SNS, PNS)
- Hormones (epinephrine, oxytocin)
What is the main process by which smooth muscle contracts
- Ca2+ enters cell and binds to calmodulin, which activated myosin light-chain kinase
