Nervous system Flashcards
what are the 3 main functions of the nervous system?
- collect sensory input
- process sensory input
- respond to sensory input
what is a neuron, what are the 3 main parts, what are their main functions/characteristics?
a neuron is a nerve cell.
- cell body
- serves regular cell function - dendrites
- short branched fibers off of cell body
- conducts impulses TOWARDS cell body - axon
- usually long thin fibers
- conducts impulses AWAY from cell body
what is a nervous system made of?
neurons all linked together
what is a myelin sheath, what is its function?
- white fatty coating around axons of neuron cells
- acts like an insulator
- increases the speed of nerve impulse conduction
what are 3 types of neurons?
- sensory
- relay
- motor
What is a sensory neuron?
receptor -> CNS (central nervous system)
- converts external stimuli (or internal conditions) to internal electrical impulses
- converts stimuli to electrical impulses
what is a relay neuron?
CNS -> CNS
- found in brain and spinal cord
- found between sensory and motor neurons and allows them to communicate
- interprets electrical impulses and connects the appropriate motor neurons
what is a motor neuron?
CNS -> effector
- transmit impulses from the spinal cord to skeletal and smooth muscles
- takes information from relay neuron, and carries out task
groups of cell bodies in the PNS are called:
ganglia
groups of cell bodies in the CNS are called:
nuclei, or grey matter
groups of axons in the CNS are called:
tracts, or white matter
groups of axons in the PNS are called:
nerves
what are the 8 systems in the organization of the nervous system?
- CNS
- PNS
- Afferent
- Efferent
- somatic
- Autonomic
- Sympathetic
- Parasympathetic
what does the CNS include?
Brain
Spinal cord
what does the PNS include?
Sensory receptors
Cranial nerves
Spinal nerves
Ganglia
which part of the nervous system is the afferent system found in, what does it do?
PNS
Consists of nerve cells that carry electrical impulses TOWARDS the CNS from receptors
which part of the nervous system is the efferent system found in, what does it do?
PNS
consists of nerve cells that carry electrical impulses AWAY from the CNS to muscles and glands
which part of the nervous system is the somatic system nested under, what does it do?
Efferent system
efferent neurons under voluntary control
Eg. brain -> skeletal muscles
which part of the nervous system is the autonomic system nested under, what does it do?
Efferent system
efferent neurons under involuntary control
Eg. brain -> smooth muscle, or heart, or glands
which part of the nervous system is the sympathetic system nested under, what does it do?
autonomic system
Emergency system -> “fight or flight”
which part of the nervous system is the parasympathetic system nested under, what does it do?
autonomic system
Control under normal situations -> “rest and digest”
Compare and contrast the sympathetic to the parasympathetic systems
similar:
-because both systems happen automatically and are part of the autonomic system
-typically both send signals to same organs/tissues
difference:
sympathetic ->
-Increase heart rate
-Decrease peristalsis
-Constriction of blood vessels
-Increased air flow to lungs
-Increased sweating
parasympathetic ->
-System under control
-Decrease heart rate
-Increase peristalsis
-regular/increased digestive juice
-Regular bowel movements
what are the 2 major functions of the spinal cord, what do they do?
- carries info
- Impulses from PNS to brain
- Motor impulses from brain to PNS - reflex response
- protective response in which the brain is not directly involved
If effector of the reflex arc is in skeletal muscle, what kind of reflex is it? is it voluntary or involuntary?
Somatic Reflex, voluntary
If effector of the reflex arc is in cardiac or smooth muscle, what kind of reflex is it? is it voluntary or involuntary?
Autonomic reflex, involuntary
What are the 5 steps involved in the reflex arc?
- receptor senses stimuli and creates electric impulse (senses the problem)
- sensory neurons send electrical impulse to integrating center
- integrating center interprets impulse and connects to appropriate motor neurons
- motor neurons take electrical impulse to effector
- effector responds to motor nerve impulse
what is a synapse?
is the gap between neurons
how does information travel from one neuron to another if they are not connected, what is an example?
it sends chemicals called Neurotransmitters that communicate with the next neuron.
eg. adrenaline, serotonin, dopamine, endorphins
what is the purpose of a reflex arc?
-Fast, automatic, unconscious sequence of actions in
response to a stimulus
-Important defense mechanism
-Brain not immediately involved
is a neurotransmitter inhibitory or excitatory?
can be either depending upon the area of the nervous system it is used in
