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
WHAT DOES HOMOSTATIS MEAN?
Keeping the conditions inside the body relatively constant
THE SKIN: WHAT IS THE PURPOSE OF THE ERECTOR MUSCLE?
Contracts to move the hair upright.
THE SKIN: WHAT IS THE PURPOSE OF THE SWEAT DUCT?
Carries sweat to the surface of the skin.
THE SKIN: WHAT IS THE PURPOSE OF THE BLOOD VESSEL?
Helps regulate body temperature by changing diameter.
THE SKIN: WHAT IS THE PURPOSE OF THE SWEAT GLAND?
Gland which secretes a liquid to cool the skin when it evaporates.
THE SKIN: WHAT IS THE PURPOSE OF THE HAIR?
Traps an insulating layer of air when it stands on end.
THE SKIN: WHAT IS THE PURPOSE OF THE SWEAT PORE?
Opens or closes to release sweat onto the surface of the skin.
WHAT HAPPENS WHEN WE ARE TOO HOT?
- The hairs lie flat, so there is no insulating layer of trapped air.
- The sweat gland produces sweat.
- The blood vessels near the skin’s surface dilate.
WHAT HAPPENS WHEN WE ARE TOO COLD?
- The erector muscles contract to make the hairs stand on end.
- Less or no sweat is released from the sweat gland.
- The blood vessels near the skin’s surface constrict.
WHAT ARE HORMONES?
Chemical messengers produced by glands and carried by the blood. They control many body functions.
WHAT IS THE PANCREAS’ ROLE IN REGUALTING BLOOD SUGAR?
Produces insulin to:
1. convert glucose into glycogen for storage (too much sugar)
2. covert glycogen to glucose (not enough sugar)
WHAT IS TYPE 1 DIABETES?
When the body stops producing insulin. As a result blood sugar levels rise so body tries to rid of excess glucose in urine.
WHAT IS TYPE 2 DIABETES?
When the body stops responding to the insulin produced. There is a direct association between type 2 diabetes and obesity.
HOW IS DIABETES TREATED?
TYPE 1 - Regular insulin injections and a low sugar + carb diet
TYPE 2 - Healthy balanced diet
WHAT IS THE HORMONE PRODUCED IN PLANTS CALLED?
Auxin
WHAT IS PHOTOTROPISM?
Plant shoots grow towards the light so they can photosynthesise
WHAT IS GRAVITROPISM?
Plant shoots grow upwards (against gravity) whilst roots grown downwards (towards gravity)
