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what are nerves?
groups of neurons
Neurons are covered by a membrane called?
what's the function of the axon?
to conduct nerve impulses to and from the cell the cell body
The axon is insulated by a covering of fat called the?
what are schwaan cells?
individual segments of myelin sheaths which gives advantage by allowing signals to travel faster
What are the little gaps between schwaan cells called?
nodes of ranvier
what's the last neuron called? what is the neuromuscular junction?
- terminal neuron
- it's the space between the terminal neuron and skeletal muscle
what's a motor unit?
are made up of a individual neuron and the number of muscles fibers it innervates
what are the 3 factors affecting force of contraction?
- motor units: more motor units, greater the force of contraction
- velocity/speed: as velocity increases, force decreases
- length of muscle fibers
CNS initiates nerve impulse through brain and spinal cord. Describe the one exception.
reflex contraction: muscle stimulus initiated from receptors on skin instead of brain
what is the interneuron? where is it located?
- interneuron analyzes info coming in from skin receptors
- located between a sensory neuron and a motor neuron
what is the cerebral cortex?
outer part of the brain
define sensory cortex.
the terminating area for afferent impulses
what's the motor cortex?
this is where output of efferent impulses are initiated
what 4 structures of the body require minimal stimuli to contract a single muscle? (really sensitive)
define premotor cortex.
- sports skills area of brain
- allows complex movement like ballerina and tight rope walking
what is function of the cerebellum?
compares info from efferent impulses to feedback from sensory receptors, and creates a revised impulse (correction factor) from the cerebral cortex where the original impulse was initiated
what's the name of the function of the cerebellum?
feedback circuit of the cerebellum
what is proprioception?
- aspect of nervous system that provides info about movement
- along with cerebellum, also important for reaching high level of movement
what are proprioceptors and where can they be located?
- receptors that pick up stimuli like dynamic of movement, quality of movement
- can be located in muscles and tendon
what is the feeling of movement called?
Name the 3 types of proprioceptors.
- muscle spindle
- Golgi tendon organ
- pacinian corpuscle
what is the function of the muscle spindle and where is I located?
- detects stretching of muscle, by detecting length along the fibers, especially rapid stretching
- located in muscle tissue, along muscle fibers
what does the muscle spindle do when it picks up a stimulus?
- it initiates a protective response (stretch reflex)
- tells muscle to contract to prevent injury
Muscle spindles are facilatory. what does this mean?
it means the stimuli will result in a movement, in this case muscle contracting
what is the name of the stretching for pro athletes?
proprioneuro facilatory stretching (PNF)
what's the function of the Golgi tendon organ? where is it located?
- detects increasing stretching/tension of a tendon
- located in tendon
What is the response to a Golgi tendon organ? (3)
- allows for movement to continue slowly
- allows us to perform muscle contraction with control
what is the function of pacinian corpuscle? (2) where is it located?
- picks up changes in joint movement
- picks up info on limb position
- located at joints
transfer of impulse from neuron to neuron
Pre-synaptic neuron releases acetylcholine for the transfer of impulse to post-synaptic neuron. what is acetylcholine?
its a transmitter substance that aids in the transfer of impulse from neuron to neuron between synapses
In order to contract a muscle or conduct an impulse, what must be reached?
action potential must be reached
Define action potential.
It's a sudden change in electrical activity across the cell membrane, usually due to a rapid flow of Na+ across the membrane into the cell