2 - Neurons Flashcards
What is a neuron?
Specialised nerve cells that move electrical impulses to and from the Central Nervous System
What are the different parts of a neuron?
Cell Body Nucleus Dendrites Axon Myelin Sheath Schwann cells Nodes of Ranvier
What does the cell body do?
Control centre of the neuron
What does the nucleus do?
Contains genetic material.
What do the dendrites do?
Receives an electrical impulse from other neurons or sensory receptors.
What does the axon do?
Carries the electrical impulse from the cell body to the axon terminal.
What does the myelin sheath do?
Insulating layer that protects the axon and speeds up the transmission of the electrical impulse
What do shwann cells do?
Make up the myelin sheath.
What do the nodes of ranvier do?
Gaps in the myelin sheath. They speed up the electrical impulse along the axon.
What else should I do?
Look at a diagram!!
Describe the function of sensory neurons
Carry electrical impulses from sensory receptors (e.g. receptors for vision, taste, touch etc.) to the CNS.
Found in various locations in the body, for example, eyes, ears, tongue, skin etc.
Convert information from sensory receptors into electrical impulses. When impulses reach the brain they are converted into sensations, such as heat, pain etc. so that the body can react appropriately.
Some sensory impulses terminate at the spinal cord. This allows reflexes to occur quickly without the delay of sending the impulses to the brain.
Describe the function of motor neurons
Located in the CNS but project their axons outside of the CNS. These send electrical impulses from the CNS to the glands and muscles so they can affect function.
Glnds and muscles are called effectors.
Describe the function of relay neurons
Connect sensory neurons to motor neurons so that they can communicate with one another.
They are mostly found in the brain and spinal cord. During a reflex arc (e.g. you put your hand on a hot hob) the relay neurons in the spinal cord are involved in an analysis of the sensation and decide how to respond (e.g. to lift your hand) without waiting for the brain to process that you are experiencing pain.
