Lesson 2 - The structure and function of neurons Flashcards
What are neurons?
Specialised nerve cells that move electrical impulses to and from the CNS
What does the nucleus contain?
Contains the genetic material
What do dendrites do?
Receive action potential from other neurons OR sensory receptors
What is an axon?
A long fibre that carries the electrical impulse from the cell body to the axon terminal
What is a synapse?
The ending of a neuron
What is the synaptic knob and what does it contain?
The swelling at the end of the neuron (synapse)
Contains many vesicles that will release neurotransmitters
What is the synaptic cleft?
The small microscopic gap between one neuron and the next (pre-synaptic neuron and post-synaptic neuron)
What is the myelin sheath?
An insulating layer that protects the axon and speeds up the transmission of the action potential
What are the Nodes of Ranvier and what do they do?
Gaps in the myelin sheath that speed up the electrical impulse along the axon
Forces the impulse to jump across the gaps
What are receptor site?
Proteins on the surface of each cell that acts as receivers to the messages of chemical molecules
Like a lock-and-key
Where are sensory neurons found?
In sensory receptors
E.g. eyes, ears
What do sensory neurons do?
Convert information from sensory receptors into electrical impulses
They carry electrical impulses from the sensory receptors to the CNS via the Peripheral Nervous System
What allows reflexes to occur quickly?
Some sensory neurons terminate at the spinal cord so the delay of sending impulses to the brain (to convert it into sensations) doesn’t happen
Where are relay neurons found?
CNS
What do relay neurons do?
Connect sensory neurons to motor neurons so that they can communicate with one another
What do motor neurons do?
They send electrical impulses via long axons to the glands and muscles to trigger a response (movement)
What are ‘effectors’?
Glands and muscles
What is the cell body?
Control centre of the neuron
What is ‘action potential’?
Electrical impulse
What do Schwann cells do?
Make up the myelin sheath
Where are motor neurons found and describe them?
Located in the CNS but project their axons outside of the CNS
How do muscles move?
motor neurons are stimulated -> release neurotransmitters -> these bind to the receptors on muscles
What happens to relay neurons during a reflex arc?
Relay neurons in the spinal cord are involved in an analysis of the sensation and decide how to respond (without waiting for the brain to process the pain)
E.g. you lift your hand when you touch a hot hob
