Nervous System Flashcards
Define the term stimulus
A change in the external environment
Define the term receptor
Detects the stimulus
Define the term effector
A muscle or gland that carries out a response to the stimulus
Give the components (in order) of a coordinated response to a stimulus
Stimulus –> Receptor –> Coordinator (CNS) –> Effector –> Response
How do electrical impulses move from receptor to the CNS?
Sensory neurone
How do electrical impulses move through the CNS?
Relay neurones
How do electrical impulses move from CNS to effector?
Motor neurones
How do messages get transmitted from one neurone to another?
Across a synapse (chemically via a neurotransmitter)
State the two components of the CNS
Brain and spinal cord
State three ways in which nervous responses are different to hormonal responses
Faster, shorter-lived, more specific target, electrical (not chemical), travel via neurones (not bloodstream)
Where are receptors found?
In sense organs, e.g. skin, eyes etc.
What is the purpose of reflexes? Give an example
Rapid, quick, unconscious responses to danger; prevent damage. Examples include knee-jerk, withdrawal from a hot object, blinking
What is the name of the hard white outer layer of the eye that holds its shape?
Sclera
What is the jelly like substance contained within the eye that holds the eye’s shape
Vitreous humour
What structure coats the cornea as a protective layer?
Conjunctiva
