Section 6 - Coordination and Response Flashcards
What is the job of the conjunctiva and what number is it (2)
- Lubricates and protects the surface of the eye
- 1
What is the job of the cornea and what number is it (3)
- Cornea refracts light into the eye
- Cornea is transparent and has no blood vessels to supply it with oxygen, so oxygen diffuses in from the outer surface
- 3
Explain why a cloudly cornea can cause blindness (2)
- Less light into the eye
- Less light hits retina
What is the job of the iris and what number is it (3)
- Controls the diameter of the pupil
- Therefore how much light enters the eye
- 2
What is the job of the lens and what number is it (2)
- Focuses the light onto the retina
- 5
What is the retina and what number is it (2)
- Light sensitive part covered in light receptors called rods and cones
- 10
What is the difference between rods and cones (3)
- Rods are more sensitive in dim light but can’t sense colour
- Cones are sensitive to colours but aren’t so good in dim light
- Cones are found all over the retina, but there are loads of them at the fovea
What is the optic nerve and what number is it (2)
- Carries impulses from the receptors to the brain
- 8
How does the eye change in very bright light and why (4)
- Bright light can damage the retina, so you have a reflex to protect it
- Reflex is triggered, makes pupil smaller
- Allowing less light in
- Receptors, sensory, brain, relay, motor, contract
What is accomodation (1)
- When the eye focuses light by changing the shape of the lens
How does the eye change when it is looking at distant objects (3)
- Ciliary muscles relax
- Allows suspensory ligaments to pull tight
- Makes the lens go thin, less curved
How does the eye change when it is looking at near objects (3)
- Ciliary muscles contract
- Suspensory ligaments slackens
- Makes the lens more curved
How does being long-sighted affect people (4)
- People are unable to focus on near objects
- Occurs when the cornea or lens doesn’t bend the light enough
- Or the eyeball is too short
- Images of near objects are brought into focus behind the retina
How does being short sighted affect people (4)
- People are unable to focus on distant objects
- Occurs when the cornea or lens bends the light too much
- Or the eyeball is too long
- Images of distant objects are brought into focus in front of the retina
Where are images of near/distant objects brought into focus (2)
Near - behind the retina
Distant - in front of the retina
What are hormones (2)
- Hormones control things in organs and cells that need constant adjustment
- They are chemicals released directly into the blood
What are hormones carried in (1)
- Blood plasma
Properties of hormones (3)
- Produced in various glands
- Travel quite slowly
- Tend to have relatively long lasting effects
What are the six most important hormones in the body (6)
- ADH
- Adrenaline
- Insulin
- Testosterone
- Progesterone
- Oestrogen
Where is ADH produced, what is its role and what are the effects of it (3)
- Pituitary gland
- Controls water content
- Increases permeabilty of the kidney tubules to water
Where is adrenaline produced, what is its role and what are the effects of it (3)
- Adrenal glands on top of the kidneys
- Readies the body for a fight or flight response
- Increases heart rate, blood flow to muscles, and blood sugar level
Where is insulin produced, what is its role and what are the effects of it (3)
- Pancreas
- Helps control the blood sugar level
- Stimulates the liver to turn glucose into glycogen for storage
Where is testosterone produced, what is its role and what are the effects of it (3)
- Testes
- Main male sex hormone
- Promotes male secondary sexual characteristics, e.g facial hair
Where is progesterone produced, what is its role and what are the effects of it (3)
- Ovaries
- Supports pregnancy
- Maintains the lining of the uterus
Where is oestrogen produced, what is its role and what are the effects of it (3)
- Ovaries
- Main female sex hormone
- Controls the menstrual cycle, promotes secondary sexual characteristics, e.g widening of the hips
What are the differences between nerves and hormones (3)
- Nerves : very fast message, hormones : slower message
- Nerves : act for a very short time, hormones : act for a long time
- Nerves : act on a very precise area, hormones : act in a more general way
For these circumstances, is it nerves or hormones that carry out the response (5)
- If the response is really quick
- If some information needs to be passed to effectors really quickly
- If the response lasts for a long time
- When you get a shock
1, 2 - nerves
3,4 - hormones
What is homeostasis (1)
- Homeostasis is the maintenance of a constant internal enviornment
Two examples of homeostasis (4)
- Water content (balance between water you gain and water you lose)
- Body temperature (rid of excess body heat when hot, retain heat when the environment is cold)
Give three ways water is lost from the body (6)
- through the Skin (as sweat)
- via the Lungs (as breath)
- via the Kidneys (as urine)
How does it being a hot day/exercising affect water content (3)
- Sweat more
- Less urine, more concentrated
- Lose more water through your breath when you exercise because you breathe faster
How does it being a cold day/not exercising affect water content (2)
- Don’t sweat much
- Produce more urine, diluted
What temperature do enzymes work best at (1)
- 37 degrees
What body part maintains homeostasis of body temperature (3)
- CNS
- Signals from receptors in the skin
- Activates necessary effectors to maintain homeostasis
Is this response when you’re too hot or too cold (1)
Too hot
Is this response when you’re too hot or cold (1)
Too cold
How does your skin change when you’re too hot (5)
- Lots of sweat is produced
- When it evaporates it transfers heat from you to the enviornment, cooling you down
- Blood vessels close to the skin widen (vasodilate)
- Allows more blood to flow near the surface, so it can radiate more heat into the surrondings
- Hairs lie flat
What happens to your body with vasodilation (3)
- Body cools down
- Allows more blood to flow near the surface
- So it can radiate heat to the surroundings
How does your skin change when youre too cold (5)
- Very little sweat is produced
- Blood vessels near the surface constrict (vasoconstriction)
- So less heat can be transferred from the blood to the surroundings
- Shivering, the movement generates heat in the muscles (same with exercise)
- Hairs stand on end (trap an insulating layer of air which helps keep you warm)
Why do hairs standing on end help when you’re too cold (2)
- traps an insulating layer of air
- which helps keep you warm
What has a larger surface area to volume ratio : small or large organsims (1)
- small
Why is it an advantage/disadvantage for smaller organisms to have a high surface area to volume ratio (3)
- Can gain/lose heat faster because there is more area for the heat to transfer across
- Lose body heat more easily in hot climates (don’t overheat)
- Very vunreable in cold enviornments
How are animals living in cold conditions adapted (3)
- Compact (rounded) shape
- Keeps surface area to a minimum
- Reduces heat loss
What are auxins (3)
- Plant hormones
- Control growth at the tips of roots/shoots
- Move through the plant dissolved in water
What 2 growth responses of plants are auxins involved in (2)
- Geotropism
- Phototropism
Where is auxin produced and where does it move to and why (3)
- Produced in the tips
- Diffuses backwards to stimulate cell elongation process
- Which occurs just behind the tips
Auxin promotes growth in the ……. , but actually inhibits growth in the ……
- shoot
- root
Are shoots positvely or negatively phototropic? How does this affect growth and why (4)
- Positively (grow towards light)
- Shoot tip exposed to light : accumulates more auxin on the side that’s in the shade than the side that’s in the light
- Makes cells elongate faster on the shaded side
- Shoot bends towards light
Are shoots positively or negatively geotropic, how does this affect plant growth and why (4)
- Negatively geotropic (grow away from gravity)
- When a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip
- More auxin on the lower side
- Causes lower side to grow faster
- Bending the shoot upwards
Are roots positively or negatively geotropic, how does this affect the plant and why (5)
- Positively (grow towards gravity)
- A root growing sideways has more auxin on lower side
- In a root, extra auxin inhibits growth
- Cells on top elongate faster
- root bends downwards
What effects are these diagrams showing (3)
- Shoots are positively phototropic
- Shoots are negatively geotropic
- Roots are positively geotropic
