They are plate like structures that form z-bands in muscles.
What is the T-tubular system?
A system in the muscle cytoplasm, when activated Ca+2 ions are released from the sacroplamic reticulum (Smooth ER). This triggers the cross bridges between actin and myosin
What is actin?
Thin filaments found in muscle
What is myosin?
Thick filaments found in the muscle.
What are the two types of skeletal muscle?
White and red muscle
What are the characteristics of red muscle.
has a large blood supply, many mitochondria, and many myoglobin contracts for long periods of time. Does not need to be fast.
What are the characteristics of white muscle.
White muscle has a low blood supply, few mitochondria, less myoglobin. Moves quickly.
What do motoneurons release?
Where do muscles and nerve fibers meet?
neuromuscular junctions or end plates.
How does the whole process of moving a muscle go?
ACh binds to receptors causing Na+ and Ca+2 to enter the cytoplasm of the muscle cell. This depolarization activates voltage- sensitive T-tubule membranes. This releases the Ca+2 ions from the SR. Ca+2 binds to actin and myosin forming a cross bridge and activating myosin. The myosin heads than rotate causing the actin and myosin filaments to slide over.
What is a flexion?
When the muscle contraction causes the angle of the joint to be smaller.
What is an extension?
Angle joint increases.
What is isometric contraction?
equal amounts of flexion and extension no movement. exa: holding a weight still.
How is precision of movement affected?
the number of motoneurons innervating muscle fibers effects muscle fibers.
How is strength determined?
It is determined by the number of contractile fibers a muscle contains.
How do lesions of cortical motor areas affect the body?
loss of capacity of a damaged system (weakness) and positive sings which are abnormal responds that may emerge ( release phenomena) Cause involuntary movements.
What is voluntary movement?
purposeful, goal directed, movements that can be learned and performance improves with practice.
What is rhythmic motor pattern?
typically only the initiation and termination are voluntary.
What is a reflex response?
rapid stereotyped and involuntary movement.
What parts of the brain are in charge of setting up series of orders to move?
cerebral cortex and the basal ganglia.
What is the contraction of muscles dependent on?
ATP and Ca+2
Where does information do when going to the spinal cord?
Where does information leave the spinal cord
Where are motoneurons located in the spinal cord?
The ventral horn.
Where are the tracts of the spinal cord located?
They are located in the gray matter.
What is a motor unit?
It is a single motoneuron and all the muscle fibers it innervates.