Nervous System Flashcards
CNS stands for..
The central nervous sytem
PNS stands for…
The peripheral nervous system
What is the nervous system?
How the body responds to internal and external changes
What is a nerve?
Nerve fibres and bundles of axons
What do nerve endings do?
Connect sensory neurons to receptor cells or sense organs
What are dendrites?
Fibres that carry impulses towards the cell body
What do axons do ?.
Carry impulses away from cell bodies
Function of Schwann cells?
Produce the myelin sheath
What is the myelin sheath?
Fat rich layer that insulates electric impulses
What is the cell body?
Contains nucleus and organelles.
Mitochondria provide energy and movement of nerve impulses
Steps carried out by the nervous system …
Reception
Transmission
Integration
Response
Reception is when..
Stimulus is detected by receptors
What are receptors?
Specialised cells that detect changes in the environment
What happens during transmission?
A message passes along the neurons from the brain to the thalamus
What happens during integration?
Messages are sorted and processed
A response is decided upon by the CNS
How is response carried out?
By effectors when stimulated by the neurons
Name the 3 types of neurons
Sensory neuron
Motor neuron
Interneuron
Function of the sensory neuron
Takes a message from a sense organ to the CNS
Function of the motor neuron
Takes a message from the CNS to a muscle or gland
Function of the interneuron
Carries information between sensory neuron and Morton neurons
What do effectors do?
Carry out a response in muscles or glands
What is a neuron?
A nerve cell specialised to carry information from 1 places to the other
What is the threshold?
The minimum stimulus needed to cause an impulse to be carried in a neuron
State the ‘all or nothing law’
If the threshold os reached , an impulse is carried if the threshold is not reached no impulse is carried
What happens at the threshold?
The site of stimulation causes a change in permeability as the neuron becomes more permeable to Na ions , moving from outside to inside the membrane . As this change begins more of the neuron becomes permeable. By this , impulses travel on and pumps Na ions black out
What are the nodes of ranvier?
The location (only)for the change in permeability and movement of ions. It speeds up the transmission of impulse
What is the synapse?
A region where 2 neurons come into close contact. Its made up of pre synaptic neuron and post synaptic neruons
What is the synaptic cleft?.
A tiny gap between 2 neurons at the synapse. Neurotransmitter chemicals are secreted into it
What is a neurotransmitter?
Chemicals released by swellings which diffuse across the synaptic cleft
Examples of neurotransmitters are…….
Dopamine and acetylcholine
What is the function of neurotransmitters?
They diffuse across the synaptic cleft.get broken down by enzymes.the products return to pre synaptic neuron.and are remade
In the presynaptic what is the function of the mitochondria?
They remake the neurotransmitter chemicals as is has atp energy
Cause of Parkinson’s disease…
Unknown
WHat is Parkinson’s disease?
A lack of dopamine in the nervous system
Hat are the symptoms of Parkinson’s?
Tremor
Fixed stare
Stiff joints
What are treatments for Parkinson’s?
Medicine that mimics dopamine
Physiotherapy
