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IGCSE Biology - The Nervous System
Key terms from Edexcel IGCSE Biology on the topic of The Nervous System
A change in an animal's surroundings
A reaction to a change in one's surroundings
When energy is changed from one form to another
Central Nervous System (CNS)
Consists of the brain and spinal cord and is linked to sense organs by nerves
A rapid automatic (or involuntary) action in response to a stimulus that is not started by impulses from the brain
The nerve pathway of a reflex e.g. stimulus > receptor > sensory neurone > CNS > relay neurone > motor neurone > effector > response
Where sensory neurones enter the central nervous system
Where motor neurones emerge from the central nervous system
Dorsal root ganglion
A swelling in the dorsal root where the cell bodies of sensory neurones are located
Composed mainly of nerve axons. Forms the outer part of the spinal cord and the middle part of the brain.
Composed of mainly nerve cell bodies. Forms the middle part of the spinal cord and the outside of the brain.
A neurone conducting impulses from receptors to the brain or spinal cord
A neurone transmitting impulses from the brain or spinal cord to a muscle or gland
The long threadlike part of a nerve cell that carries impulses
Fatty insulation that surrounds axons and helps to speed up the conduction of impulses
The fine cytoplasmic extensions of a nerve cell body
A junction between two nerve cells
A special type of synapse where nerve endings from an axon connect with a muscle
A chemical substance released from a nerve cell, allowing an impulse to travel from a nerve cell to another nerve, muscle, organ or tissue
Consisting of two hemispheres, it is the largest part of the brain and is the source of all conscious thought
Folded layers of grey matter covering the cerebral hemispheres
Region of the brain concerned with coordinating the contraction of sets of muscles, as well as maintaining balance.
Connects the spinal cord with the rest of the brain. Is responsible for controlling basic body activities such as heartbeat and breathing rate.
Located at the base of the brain. It secretes a number of different hormones into the blood, including those that regulate reproduction.
A region of the brain that coordinates the activity of the pituitary gland