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