nervous system Flashcards
(20 cards)
what are the 3 main section of the nervous system
- central nervous system (brain and spinal cord)
- peripheral nervous system (most communication nerves that carry signals to the cns) - cranial and spinal nerves
- autonomic nervous system - involuntary physiological processes
function of the peripheral nervous system
sensory neurons take information from sense organs to the brain, motor neurons take infomation from brain to muscles
what do afferent (sensory) neurons do
recieve infomation from the external situation through receptors and sends signal to other neurons
what do efferent (motor) neurons do
receive infomation and send it to muscles / glands
what are dendrites
treelike extensions that increase surface area of the cell body, they receive stimuli and carry information to the cell body
what are axon
the string like part between both ends of the nerve cell. transmits signals away from the cell body via impulses being transmitted over long distances.
what are axon terminals
the tree like extensions at the end of the nerve cell (smaller end)
what are schwann cells
the cells wrapped around axon. they contain myelin which insulates the axon
what are nodes of renvier
gaps between the shwann cells on the axon. they allow oxygen and nutrients to enter the cell
how do synapses work
impulses move down the axon to the axon terminals into the presynaptic neuron
neurotransmitters (chemicals) are released from vescles and move across the synaptic cleft (the gap)
neurotransmitters are recieved by receptors in the post synaptic neuron
electrical impulse moves down the neuron
what are the 2 parts of the autonomic nervous system
parasympathetic
sympathetic
what are the 2 parts of the peripheral nervous system
cranial nerves
spinal nerves
what are the 2 parts of the central nervous system
spinal cord
brain
what is the function of the autonomic nervous system
- governs fight / flight
- controls internal organs
- involuntary control
what is the function of the parasympathetic nervous system
- in control when animal is at rest
- prepares body for activities that gain and conserve energy by:
- stimulating salivary glands and digestive juices
- decreasing the heart and respiratory rate
- conserves energy
- digestion and salivation increase
- heart rate decrease
what is the function of the sympathetic nervous system
- prepares the body for energy consuming activities like flight / fight by:
- inhibiting digestive system and salivation
- increasing heart and respiratory rates
- encouraging liver to release glucose into blood
- stimulating adrenal glands to release hormones
- increase energy
- heart rate, sweat gland activity and blood pressure increase
what is the reflex arc
stimulus
receptor
sensory neuron
relay neuron
relay neuron
motor neuron
effectors
response
what do sensory neurons do
carry impulses from receptors to the CNS
what do relay neurons do
found in the CNS, electrical impulses passed to relay neurons in the spinal cord to then be moved to motor neurons
what do motor neurons do
carry impulses to muscles / glands
