Lesson 2 - Neurones Flashcards
What are neurons?
Specialised nerve cells that move electrical impulses to and from the central nervous system
What is the cell body?
It is the control centre of the neuron which contains the nucleus, which contains genetic material
What are dendrites?
Receives electrical impulse (action potential) from other neurons or sensory receptors
Role of the axon?
A long fibre that carries the electrical impulses from the cell body to the axon terminal
Role of the myelin sheath
Insulating layer that protects axon and speeds to transmission and electrical impulse
Role of Schwann cells
Make up the myelin sheath
Role of the nodes of ranvier?
Gaps in the myelin sheath that speed up electrical impulse along the axon
Role and structure of the motor neuron
Located in the CNS and controls muscle movements. They send electrical impulses via the long axons, projected outside of the CNS, to the glands and muscles so they can affect function. Glands and muscles are called effectors. When motor neurons get stimulated, they release neurotransmitters that bind to the receptors on muscles to trigger a response, leading to movement.
Role and structure of sensory neurons
Sensory neurons are found in sensory receptors like the eyes, ears, tongue and skin. They carry nerve impulses from sensory receptors to the CNS via the PNS. Sensory neurones convert information from sensory receptors to electrical impulses. When these impulses reach the brain they get converted into sensations like heat, pain and stuff, so that the body can react appropriately. Some sensory neurons however don’t reach the brain, terminating at the spinal chord, allowing for quick reflex actions
Relay neurones
They are found in the CNS and connect the sensory neurones to the motor neurones so that they can communicate with each other. During a reflex arc, the relay neurones in the spinal chord are involved in an analysis of the sensations and decide how to respond without waiting for brain to process the pain
