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
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)
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
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 negatively geotropic
- Shoots are positvely phototropic
- Roots are positively geotropic
How are hormones released (1)
- Directly into the blood
