The Nervous System Flashcards
purpose of the nervous system
directs and controls the voluntary movement
the central nervous system (CNS) consists of
brain and spinal cord
the peripheral nervous system (PNS) functions
to relay (peredavat’) nervous impulses from CNS to PNS (skeletal msucles etc.) and back.
examples of somatic and autonomic NS
skeletal muscles and cardiac muscle, blood vessels
neuron -
the most basic unit of the NS
motor neuron/ efferent neuron -
the neurons that conduct impulses from the CNS to the skeletal msucles
sensory/ afferent neuron
neurons that carrying impulses from PNS to the CNS (reading info such as stretch, pain, movement, tension)
synapse
site of the communication b/n 2 neurons or neron and a gland/muscle cell etc.
neuromuscular junction
synapse b/n motor neuron and skeletal muscle fiber
dendrites
projections from the neuron cell body; serves to receive excitatory/ inhibitory signals from other neurons
neuron dendrites and cell body are located in the
gray horn of the spinal cord
axon extends outward the spinal cord and may innervate a muscle that is a great distance away from the spine.
The action potential causes release of …
Ach at the neuromuscular junction which leads to the muscle activation
muscle spindle-
- spindle-shaped sensory organ; stretch receptor presented in the most muscles.
- responsible to sense changes in muscle length, particularly when the change is rapid.
spindle structure -
enclosed in a capsule and lies || extrafusal fibers; contains specialized muscle fibers called intrafusal;
have actin and myosin in the ends and lots of sensory nerve endings in the middle.
myotatic or stretch reflex
activation of the muscle as response to the stretch
goldi tendon organ (GTO) located ..; function to…
located at the junction of the muscle and tendon; function to protect muscle from injury;
mechanism of GTO
sense the excessive force of muscle action, send the info to the CNS - relaxation of the working muscle and activation of the antagonist
motor unit
motor neuron and muscle fibers it innervates
motor neuron gives the fibers their … and … characteristics
metabolic and contractile
2 mechanism of the force production
1) motor unit recruitment - vary number of the motor unitsrecruited
2) rate coding - increasing the rate of the motor units already activated;
order of the motor unit recruitment
1) smaller type I are recruited first at the low-force muscle activation
2) type IIa; 3) IIx
2 and 3 require high intensity/load to be activated.
people are able to recruit more motor units with…
training
rate coding
if a muscle is stimulated to contract before it has a change to relax from a previous stimulus, it will produce greater force
