Nervous System Study Guide
sympathetic
"fight or flight" - stress response (ex. increased heart rate, dilated pupils, digestive system slows)
parasympathetic
"rest and digest" (ex. decreased heart rate, digestive functions increase)
Which portion of the neuron receives incoming signals? Which part conducts signals away from the cell body?
Dendrites receive the incoming message; axon sends the signal away from the cell body
reflex
an involuntary response due to a stimulus which involves the spinal cord of the central nervous system (CNS)
ventricles
spaces or cavities within the brain that the cerebrospinal fluid moves through
efferent
moving away from the CNS (stimulus is moving)
afferent
moving towards the CNS (stimulus is moving)
disorders of demyelination
multiple sclerosis and mercury poisoning
synapse
the gap between the terminals of one neuron and the dendrites of the next neuron
somatic
voluntary movement (ex. high-five, standing up)
cranial nerves
12 nerves that originate from the brain or brain stem and serve different functions
neurotransmitter
a chemical messenger released from one axon terminal; acts in the synapse to affect the neighboring neuron
How is the reflex arc different than a typical muscle action?
bypasses the brain
demyelination
degeneration of the myelin; which causes scar tissue on the axon, which prevents the formation of an action potential
myelin
fatty sheath that covers the axon of a neuron; does not cover dendrites
interneurons
integrate messages from the sensory neurons and send signals to the motos neurons
autonomic
involuntary movement (ex. digestion, beating heart)
meninges
layers of protection that surround the CNS; contains the cerebrospinal fluid
motor neurons
receive signals from the CNS and cause contraction of muscles
Sensory neurons
receive signals from their environments
stimulus
something that causes your neurons to fire an action potential; this can be pressure, heat, vibration, temperature, pain, sensation