Nervous System Flashcards
(18 cards)
CNS
central nervous system (brain, spinal cord)
PNS
peripheral nerves (sympathetic nerves; response to stress and exercise, parasympathetic nerves; respond to relaxation)
Somatic Nerves
- skeletal muscle, bones and skin
- sensory and motor somatic nerves
Autonomic Nerves
- special motor nerves that control the internal organs
- sympathetic nervous system and parasympathetic nervous system
Neuron
conduct a nerve impulse; a nerve is a bundle of many neurons
Motor Neurons
carry impulses from the CNS to effectors (muscles, organs, glands)
Sensory Neurons
a) sensory receptors; photoreceptors in eyes (light), chemoreceptors in nose and skin (chemicals), and thermo-receptors in skin, hypothalamus (hot/cold)
b) ganglia; cluster of sensory nerve cell bodies located just outside the CNS
Interneurons
link neurons within the body (found mostly in CNS)
Reflex Arc
simplest nerve pathway; neural circuit through the spinal cord that provides a framework for a reflex action
Synapse
regions between neurons
Action Potential
the voltage difference across a nerve cell membrane when the nerve is excited
Resting Potential
the voltage difference across a nerve cell membrane during the resting stage
Neurotransmitter
chemicals released from vesicles into synapses
Depolarization
diffusion of sodium ions into the nerve cell resulting in charge reversal
All or none
nerve firing is all or none response, it fires maximally or not at all
Repolarization
process of restoring the original polarity of the nerve membrane
Refractory Period
recovery time required before a neuron can produce another action potential
Threshold level
maximum amount of material that can be moved across the nephron
