PSL300 Muscle physiology Questions With Complete
Solutions
A motor unit consists of Correct Answers a motor neuron and
the muscle fibers it innervates
anatomy of the neuromuscular junction (NMJ) Correct Answers
- Terminal bouton = axon germinal (motor neuron)
- Motor end plate = specialized muscle membrane at junction
- all motor neurons release acetylcholine
- all synapse are excitatory
ATP is needed for muscle Correct Answers - Myosin ATPase
(contraction)
- Ca2+ ATPase (relaxation)
- Na+/K+ ATPase (restores ions that cross cell membrane during
AP)
cardiac contractile cells Correct Answers depolarize as an
impulse reaches them, then they plateau before repolarizing
AP last for almost as long as the contraction and relaxation
Cardiac muscle AP plateau due to Correct Answers slow Ca2+
channels allows time for forceful contraction from single AP,
allows contraction to last 300ms
cardiac muscle AP shape and duration reflex Correct Answers
Changing permeability to Na+, Ca2+
cardiac muscle cells are Correct Answers Contractile cell and
conductive cells
, Cardiac muscle consist of Correct Answers Contractile
filaments in sarcomeres; striated
Intermediate development of SR
Gap-junctions for synchronous beat
Activity modulated by ANS
Cardiac muscle fibers Correct Answers Striated but Smaller,
branched, and uninucleate.
Cardiac muscle vs skeletal muscle activity Correct Answers
Activity modulated by ANS (unlike skeletal muscle = somatic
nervous system)
Classification of smooth muscle Correct Answers By
communication:
1. Single-unit smooth muscle
2. Multi-unit smooth muscle
By location:
Vascular, gastrointestinal, urinary, respiratory, reproductive,
ocular
Communication at the NMJ Correct Answers AP arrives at
terminal bouton > Ca2+ entry > synaptic vesicles fusion release
Ach > metabolized by acetylcholinesterase(AchE) > at nicotinic
cholinergic receptor, two Ach bind > cation channel opens >
Na+/K+ channel open > net Na+ depolarizers muscle fiber.
crossbridge cycle Correct Answers cyclical formation of links
between actin and myosin resulting in the sliding of thin
filaments along the thick filaments
Solutions
A motor unit consists of Correct Answers a motor neuron and
the muscle fibers it innervates
anatomy of the neuromuscular junction (NMJ) Correct Answers
- Terminal bouton = axon germinal (motor neuron)
- Motor end plate = specialized muscle membrane at junction
- all motor neurons release acetylcholine
- all synapse are excitatory
ATP is needed for muscle Correct Answers - Myosin ATPase
(contraction)
- Ca2+ ATPase (relaxation)
- Na+/K+ ATPase (restores ions that cross cell membrane during
AP)
cardiac contractile cells Correct Answers depolarize as an
impulse reaches them, then they plateau before repolarizing
AP last for almost as long as the contraction and relaxation
Cardiac muscle AP plateau due to Correct Answers slow Ca2+
channels allows time for forceful contraction from single AP,
allows contraction to last 300ms
cardiac muscle AP shape and duration reflex Correct Answers
Changing permeability to Na+, Ca2+
cardiac muscle cells are Correct Answers Contractile cell and
conductive cells
, Cardiac muscle consist of Correct Answers Contractile
filaments in sarcomeres; striated
Intermediate development of SR
Gap-junctions for synchronous beat
Activity modulated by ANS
Cardiac muscle fibers Correct Answers Striated but Smaller,
branched, and uninucleate.
Cardiac muscle vs skeletal muscle activity Correct Answers
Activity modulated by ANS (unlike skeletal muscle = somatic
nervous system)
Classification of smooth muscle Correct Answers By
communication:
1. Single-unit smooth muscle
2. Multi-unit smooth muscle
By location:
Vascular, gastrointestinal, urinary, respiratory, reproductive,
ocular
Communication at the NMJ Correct Answers AP arrives at
terminal bouton > Ca2+ entry > synaptic vesicles fusion release
Ach > metabolized by acetylcholinesterase(AchE) > at nicotinic
cholinergic receptor, two Ach bind > cation channel opens >
Na+/K+ channel open > net Na+ depolarizers muscle fiber.
crossbridge cycle Correct Answers cyclical formation of links
between actin and myosin resulting in the sliding of thin
filaments along the thick filaments
