8.1.2 - Neurones: Structure & Function Flashcards
What Are Neurones?
Specialised cells of the nervous system, which carry electrical impulses around the body.
What Is A Nerve?
Bundle of neurones.
What Features Are In All Neurones?
(5 Points)
~ Axon.
~ Cell body with a nucleus and other cellular structures.
~ Axon terminal.
~ Dendrons.
~ Dendrites.
What Carries Nerve Impulses Towards The Cell Body?
Dendrites and dendrons.
What Carries Nerve Impulses Away From The Cell Body?
Axons.
What Is The Role Of The Axon Terminals?
Has many nerve endings allowing neurones to connect to it and to receive impulses from other neurones.
Some Neurones Are Myelinated, Meaning That Their Axon Is Insulated By A Fatty Layer Known As What?
The myelin sheath.
What Is The Myelin Sheath?
Electrical insulator.
What Is The Myelin Sheath Made Up Of?
Specialised cells known as Schwann cells, which wrap themselves around the axon.
What Are The Uninsulated Gaps Between Schwann Cells Called?
Nodes of Ranvier.
How Do Electrical Impulses Travel In Myelinated Neurones?
They jump from one node of Ranvier to the next instead of traveling down the whole axon, speeding up transmission.
In Non-Myelinated Neurones, What Is The Axon Not Insulated By?
Schwann cells.
Why Does The Impulse Travel More Slowly In Non-Myelinated Neurones?
Because it moves through the entire length of the axon without insulation.
What Are The 3 Main Types Of Neurones?
~ Motor neurones.
~ Sensory neurones.
~ Relay neurones.
Where Do Sensory Neurones Carry Impulses From & To?
From the receptors to the CNS.
Where Do Relay Neurones Carry Do?
Connect sensory and motor neurones.
Where Do Motor Neurones Carry Impulses From & To?
From the CNS to effector muscles or glands.
Describe The Structure Of The Motor Neurone
(2 Points)
~ Many short dendrites carry nerve impulses from the CNS to the cell body.
~ One long axon carries nerve impulses from the cell body to effector cells.
Describe The Structure Of The Relay Neurone
(2 Points)
~ Many short dendrites carry nerve impulses from sensory neurones to the cell body.
~ An axon carries nerve impulses from the cell body to motor neurones.
Describe The Structure Of The Sensory Neurone
(2 Points)
~ One long dendron carries nerve impulses from receptor cells to the cell body, which is located in the middle of the neurone.
~ One short axon carries nerve impulses from the cell body to the CNS.
What Neurones Is This Showing?
Motor neurone.
What Neurones Is This Showing?
Sensory neurone.
What Neurones Is This Showing?
Relay neurone.
