nervous system

function of the nervous system

-Interprets stimuli and coordinates other organ systems to respond to stimuli

-made up of cells called neurons

parts of the nervous system

-sensory— Detection

-Motor— Movement or action

-Interneurons— Integration

sensory neurons

-Transmit impulses from the environment to the spinal cord and brain

Motor neuron

-carrying instructions from the brain and spinal cord to muscles and glands

nerve impulses (Action potentials)

-what all neurons use to work

-an electrical signal that travels like a wave over the length of a neuron

-Caused by positive ions, moving into the neuron

-impulse: begins when a neuron is stimulated by another neuron or by the environment

cell body

contains the nucleus and other organelles

dendrites

receive stimuli and conduct impulses toward the cell body

axon

Carries impulses away from the cell body

myelin sheath

composed of glial cells called Schwann cells and insulate the axon

axon terminals

At the end of the axon & pass on the message

synapse

-The space between a neuron and another cell

-where one neuron communicates with another neuron

neurotransmitter

-chemicals that are stored in the axon terminals in released into synapse when triggered by impulse

-send message to the next neuron

Central nervous system (CNS)

-Brain & Spinal cord

-bridge between sensory and motor neurons of the PNS

-interpret sensory signals and works with gland/organs to coordinate the motor activities of all body systems

peripheral nervous system (PNS)

-Cranial & Spinal nerves

-Divided into somatic nervous system and autonomic NS

somatic NS

-responsible for skeletal muscle contraction (Usually voluntary)

autonomic NS

-Responsible for involuntary responses (ex: the digestive system)

-sympathetic division: Ready body for action, “Fight or fight” response

-parasympathetic division: reduces an animals readiness for action, “rest and digest”

reflex

-Automatic, involuntary response to stimulus

-Independent of the brain

-occurs before the brain has a chance to interpret stimulus