The Nervous System Flashcards
difference between central nervous system and peripheral nervous system
CNS: brain and spinal cord
PNS: cells called nerves branching from CNS to all of body
What is the nervous system responsible for
allows organisms to react correctly to stimulus in their environment so that they can survive
Def. of stimulus
Any change in our environment
Impulse def.
An electrical message that is carried along a nerve cell
Receptor def.
A sense organ that detects the stimulus.
Eg. Eye, Ear, Nose
Effector def.
Receives a message and carries out the action/ response
eg. Muscle/Gland
Nerve cells
Function
another name
types
Function: carry impulses to and from the CNS to allow us to react correctly to stimulus
Another name: Neurons
Types:Sensory, Inter, Motor
Sensory neuron function and other name
Function: Carries impulses from Receptor to the CNS
Another name: Afferent Neuron
Interneuron
Function
Another name
Function:Connects sensory and motor neurons and carries messages within CNS-within brain and spinal cord to brain
Another name: Intermediate/Relay/Association
Motor neuron
Function
Another name
Function: Carries messages from CNS to Effector
Another name: Efferent
Process of response
- Stimulus occurs
- Receptor detects stimulus
- Sensory neuron sends impulse to CNS, Interneuron sends impulse to brain.
- Brain decides on a response
- Motor neuron sends an impulse to the effector.
- Effector carries out response
Structure of a neuron
Three types
(in direction of impulse)
Receptor-Dendrites-Dendron-axon hillock-cell body(soma)-axon-axon terminal
Along dendron/axon: The myelin sheath-schwann cells. Node of Ranvier in between schwann cells
Sensory: soma/Cell body sticks up and receptor at start.
Inter: Soma is on the dendron in the middle
Motor: Soma is near dentrites-no dendron, effector at end.
Functions of cell body
contains nucleus
makes other parts of the neuron
connects to the dentrites and passes the impulse to the axon
Functions of dendrite
Nerve endings
connects to another neuron or receptor and receives the information/impulse
Functions of dendron
Short fiber that receives information from the dendrite and carries it toward the cell body
Functions of axon
carries impulses away from cell body
Functions of axon hillock
part where cell body connects to axon
Functions of schwann cell and myelin sheath
makes the myelin sheath which insulates and protects the neuron.
Functions of node of ranvier
gap between each schwann cell.
speeds up the impulse
Functions of axon terminal
release chemicals known as neurotransmitters to pass the impulse to the next neuron