Pathophysiology 546 Musculoskeletal Lecture Notes
Musculoskeletal Physiology
Be familiar with bones and muscles of body
3 types of muscle skeletal, smooth, cardiac attaches muscle to bone, decreasing angle of joints during contraction proximal part of esophagus doesn’t connect to bone, proximal (upper) conscious control is primary skeletal, distal is involuntary and smooth muscle
T- tubules: inside is ECS, deep invaginations of plasma membrane in muscle cell PM is sarcolemma allows high concentration of Ca, like other EC spaces (IC is low)
Ca floods into cell through T-tubules at uniform and fast rate
Ca signals contraction
Triads - t tubes with sarcoplasmic recticulum (also high in Ca) on each side, SR is resirvior for Ca
Ca comes in from SR & T-tubule
Motor Unit & Neuromuscular Junction 22.1.2
Skeletal muscles are all innervated by somatic nerves, conscious control
Neuron goes directly to the muscle and onnervateds it
Motor unit is a single axon and all the muscle fibers it innervates
Short distance from terminal of axon and muscle fiber, d/t aCH dumped into synaptic cleft and bind to receptors on skeletal muscle, when Ach withdrawn muscle relaxes
Nerve impulse down axon, when hits the exon terminus it causes a voltage gated Ca channel to open, wave of depolarization causes Ca to come into cell (Ca tells cells to do what it does best) and axon terminus releases it’s neurotransmitters. (ACH)
ACH vesicle fuses with plasma membrane, what was inside the vesicle is now outside the cell, ACH drifts across synaptic cleft to bind to an ACH channel, when 2 ACHs bind - the channel opens, this allows Na to move into the muscle fiber. Na wants to go into cell anyways (+ inside). Na floods into cell causing muscle fiber to depolarize, causing voltage gated Na channel causing further depolarization. Ultimately causing voltage gated Ca channel on a T-tubule to open, then Ca flows into cytoplasm from SR. Rapid influx of Ca throughout muscle cell.
Ca channels: 1) Voltage gated Ca channel also
Be familiar with bones and muscles of body
3 types of muscle skeletal, smooth, cardiac attaches muscle to bone, decreasing angle of joints during contraction proximal part of esophagus doesn’t connect to bone, proximal (upper) conscious control is primary skeletal, distal is involuntary and smooth muscle
T- tubules: inside is ECS, deep invaginations of plasma membrane in muscle cell PM is sarcolemma allows high concentration of Ca, like other EC spaces (IC is low)
Ca floods into cell through T-tubules at uniform and fast rate
Ca signals contraction
Triads - t tubes with sarcoplasmic recticulum (also high in Ca) on each side, SR is resirvior for Ca
Ca comes in from SR & T-tubule
Motor Unit & Neuromuscular Junction 22.1.2
Skeletal muscles are all innervated by somatic nerves, conscious control
Neuron goes directly to the muscle and onnervateds it
Motor unit is a single axon and all the muscle fibers it innervates
Short distance from terminal of axon and muscle fiber, d/t aCH dumped into synaptic cleft and bind to receptors on skeletal muscle, when Ach withdrawn muscle relaxes
Nerve impulse down axon, when hits the exon terminus it causes a voltage gated Ca channel to open, wave of depolarization causes Ca to come into cell (Ca tells cells to do what it does best) and axon terminus releases it’s neurotransmitters. (ACH)
ACH vesicle fuses with plasma membrane, what was inside the vesicle is now outside the cell, ACH drifts across synaptic cleft to bind to an ACH channel, when 2 ACHs bind - the channel opens, this allows Na to move into the muscle fiber. Na wants to go into cell anyways (+ inside). Na floods into cell causing muscle fiber to depolarize, causing voltage gated Na channel causing further depolarization. Ultimately causing voltage gated Ca channel on a T-tubule to open, then Ca flows into cytoplasm from SR. Rapid influx of Ca throughout muscle cell.
Ca channels: 1) Voltage gated Ca channel also