Response and Regelation
Just something to help learn response and regulation
- Created by: Owain
- Created on: 03-01-13 18:37
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- Response and Regulation
- Receptor cells
- They are a group a special cells which are sense organs
- They respond to stimuli (changes in the enviroment)
- Receptor cells send this information to the central nervouse system
- The information is sent as electrical signals called Impulses
- The impulses travel along nerve cells called neurons
- Plant responses
- Plant roots grow towards gravity - this is called POSITIVE GRAVITROPISM
- Plant shoots (the parts above the ground) grow towards light - this is called POSITIVE PHOTOTROPISM
- Plants responses are controlled by chemicals called HORMONES
- Homeostasis - These are all the ways in which the body keeps conditions inside the body constant
- Concentration of water
- PH
- Blood glucose (sugar) levels
- If blood sugar levels get too high (e.g. after a meal containing carbohydrates)
- The pancreas releases the hormone insulin into the blood
- Blood glucose levels must be kept within constant range
- The blood carries the insulin to the liver
- The liver changes glucose to insoluble glycogen which it stores
- Blood glucose levels decrease
- Type 1 diabetes
- Doctors can diagnose diabetes by testing urine for glucose
- This is because the pancreas does not produce enough insulin
- We can test artificial samples of urine for glucose by
- Putting the test-tube in a beaker and boiling it
- Adding Benedict's solution to the sample in a test-tube
- There could be a colour change
- Benedict's changes from blue to orange = Glucose present
- Benedict's solution stays blue=No glucose sample
- This is a condition where blood glucose levels may rise fatally high
- Temperature
- Too hot
- Blood vessels
- Less heat los
- Blood vessels become narrower
- Less blood flows through
- Sweating
- Sweat released to surface through sweat pore
- Sweat evapor
- Sweat travels up through sweat duct
- Sweat glands produce more sweat
- Evaporation takes heat away from skin
- Shivering
- No shivering
- Hairs
- Less air trapped
- Hair lies flat
- Less insulation
- Erector muscle relaxes
- More heat lost
- Blood vessels
- Too cold
- Sweating
- Sweat glands produce less sweat
- Hairs
- Layer of air trapped
- Hair pulled upright
- Air is an insulator
- Erector muscles contracts
- Less heat lost
- Shivering
- Shivering = contraction of muscles
- More respiration
- More energy needed
- More heat released
- Blood vessels
- Less blood through
- Blood vessels become narrower
- Less heat lost
- Sweating
- Too hot
- Negative feedback - It is a process which makes sure that any changes that are made are reversed to bring the condition back within normal range
- Receptor cells
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