Nervous System Flashcards
Nervous System
º acts like internet- receives and responds to information
º two divisions
º central
º peripheral
Stimulus
A change in an organisms environment (internal or external)
Response
º A reaction or behavior to a stimulus
º involuntary or voluntary
Neuron
º nerve cell
º carries information
Cell body
Contains nucleus and dendrites
Dendrites
Receive nerve impulses
Nerve impulse
Message that a neuron carries
Sensory neuron
º picks up stimuli and changes it to a nerve impulse
º nerve impulse travels to a interneuron
Interneuron
They are found between sensory and motor neurons
Motor neurons
º sends impulses to muscles and glands
º respond
Axon
Sends nerve impulses away from cell body
º one way street
º only one per neuron
Myelin sheath
º protective covering of axon
º helps messages send faster
Axon tips
º receive messages from axon
º send messages to other neurons
Synapse
A gap between the dendrites of one neuron and the axon tips of another
Neurotransmitters
The chemical form of electrical nerve impulses
Central nervous system (CNS)
º 2 major structures
Brain
Spinal chord
º directs movement
Peripheral nervous system (PNS)
Consists of nerve fibers that branch off to the rest of the body
Somatic
Voluntary movements
Ex: eating and writing
Autonomic
Involuntary movements
Ex: digestion and breathing
Reflexes
º prevent pain and injury
º autonomic response- occur w/o thinking
º bypass the brain
