2.5 RESPONSE AND REGULATION Flashcards
WHAT IS A STIMULUS?
A change in surrounding. e.g. Light, temperature, sound, chemicals, etc.
WHAT ARE SENSE ORGANS?
Detect the stimuli. e.g. Eyes, ears, skin, mouth and nose.
THE EYE: WHAT IS THE PURPOSE OF THE SCLERA?
Protective, tough white outer coat.
THE EYE: WHAT IS THE PURPOSE OF THE CORNEA?
Clear part of sclera allows light to enter and refracts light entering.
THE EYE: WHAT IS THE PURPOSE OF THE PUPIL?
Hole in centre of iris which allows light to enter.
THE EYE: WHAT IS THE PURPOSE OF THE IRIS?
Muscles that alter the size of pupil to control the amount of light entering.
THE EYE: WHAT IS THE PURPOSE OF THE LENS?
Changes shape to focus light onto the retina.
THE EYE: WHAT IS THE PURPOSE OF THE CHOROID?
A pigmented layer which absorbs light to prevent reflection; also contains blood vessels.
THE EYE: WHAT IS THE PURPOSE OF THE RETINA?
Light-sensitive layer; an image is formed here. Impulses sent to optic nerve.
THE EYE: WHAT IS THE PURPOSE OF THE BLIND SPOT?
Where the optic nerve connects to the retina; there are no light-sensitive cells here.
THE EYE: WHAT IS THE PURPOSE OF THE OPTIC NERVE?
Carries impulses from retina to brain.
WHAT CHARACTERISTICS DO REFLEX ACTIONS HAVE?
Fast, automatic and usually protective
WHAT PATH DOES AN IMPULSE FOLLOW FROM STIMULUS TO RESPONSE?
Stimulus -> Receptor -> Sensory neurone -> CNS -> Motor neurone -> Effector -> Response
WHAT IS THE REFLEX ARC?
The pathway an impulse follows that skips the ‘CNS’ and takes the impulse straight along the relay neurone for an even faster reaction.
WHAT IS THE PURPOSE OF THE SYNAPSE?
A small gap at the end of a neuron that allows a signal to pass from one neuron to the next