3.4 Cells Of The Nervous System And Neurotransmitters At Synapses Flashcards
What are neurons composed of?
- Dendrites
- A Cell Body
- Axons
What direction do nerve impulses travel?
Dendrite to Cell Body to Axon
What is the cell body?
- Contains a nucleus and cytoplasm
- Cytoplasm contains a mitochondria to provide energy for impulses and ribosomes which synthesise proteins for the synthesis of neurotransmitters
What is the dendrite?
Receives nerve impulses and carries them towards the cell body
What is the axon?
Carries nerve impulses away from the cell body
What is the myelin sheath?
A layer of fatty material that surrounds the axon that insulates the axon and increases the speed of nerve impulses
What is myelination?
Myelination is not complete at birth and it continues until adolescene
What diseases destroy the myelin sheath causing a loss of coordination?
- Polio
- Multiple Sclerosis (MS)
What do glial cells do?
- Physically support neurons
- Produce the myelin sheath
What is the area called between an axon of one neuron and the dendrite of another?
A synapse
What is the synaptic cleft?
The space that separates the plasma membranes of each neuron
What is the presynaptic cleft?
The neuron before the synaptic cleft
What is the postsynaptic cleft?
The neuron after the synaptic cleft
What are neurotransmitters?
Chemicals that pass messages across synaptic clefts
What are two examples of neurotransmitters?
- Acetylcholine
- Noradrenaline