| Homeostasis definition | The regulation of conditions inside your body to maintain a stable internal environment |
| Function of the nervous system | Allows humans to react to their surroundings and coordinate their behaviour |
| Where is the central nervous system? | Brain and spinal cord |
| What are receptors? | Cells that detect stimuli |
| What are sensory neurones? | Carry information as electrical impulses from receptors to CNS |
| What are motor neurones? | Neurones that carry electrical impulses from the CNS to effectors |
| What are effectors? | Muscles and glands that respond to nervous impulses |
| What are reflexes? | Rapid automatic responses to certain stimuli that don't involve the conscious part of the brain |
| How do reflexes prevent injury? | Reduce the chances of being injured |
| What is the thermoregulatory system? | A centre in the brain containing receptors that are sensitive to the temperature of blood flowing through the brain |
| What happens if the thermoregulatory system detects body temperature is too high or too low? | Receptors detect temperature change
System triggers effectors automatically
Effectors produce a response to counteract change
Body cools down/warms up |
| Body responses produced by effectors when temperature is too high | Sweat gland produces sweat
Hair erector muscle relaxed
Vasodilation (blood vessels dilate) so blood flows close to skin surface |
| Body responses produced by effectors when temperature is too low | No sweat is produced
Hairs erect trapping air to insulate
Vasoconstriction (blood vessels constrict) so blood supply is shut off
Shiver so muscles contract warming the body through respiration |
| What is the endocrine system? | A system of endocrine glands that produce and secrete hormones |
| What is the pituitary gland? | 'Master gland' producing many hormones that regulate body conditions |
| What do the ovaries do? | Produce oestrogen |
| What do the testes do? | Produce testosterone and produce sperm |
| What does the thyroid do? | Produces thyroxine which regulates rate of metabolism, heart rate and temperature |
| What does the adrenal gland do? | Produces adrenaline which prepares the body for 'flight or fight' |
| What does the pancreas do? | Produces insulin and regulates blood glucose level |
| Difference between nerves and hormones? | Nerves- fast action, act for a short time, precise areas
Hormones- slower action, act for long time, general areas |
| What happens if blood glucose is too high? | Insulin is added by pancreas |
| What does insulin do? | Makes liver turn glucose into glycogen |
| What happens if blood glucose is too low? | Glucagon is added by pancreas |
| What does glucagon do? | Makes liver turn glycogen into glucose |
| What is type 1 diabetes? | Where the pancreas releases little or no insulin |
| What is type 2 diabetes? | Where a person becomes resistant to their own insulin |
| How is type 1 diabetes treated? | Insulin therapy- several injections of insulin are taken throughout the day |
| How is type 2 diabetes treated? | Exercise and a carbohydrate controlled diet |
| What do the kidneys do? | Filter waste products out of your blood |
| What is the name of when glucose, ions and water are absorbed back into the blood? | Selective reabsorption |
| Name three waste products | Urea, ions, water |
| What is urea? | Ammonia from deamination (amino acids being converted into fats and carbohyrates) converted into urea because it's toxic |
| What is ADH? | Anti-diuretic hormone |
| How is ADH released into the bloodstream? | By the pituitary gland |
| What does ADH do? | Monitors the water content of the blood |
| What does kidney failure lead to? | Build up of waste substances leading to death |
| How can kidney failure be treated? | Dialysis treatment |
| How does kidney dialysis work? | A person's blood flows through partially permeable membranes inside a dialysis machine surrounded by dialysis fluid |
| What does the dialysis fluid do? | Has the same concentration as healthy blood so only waste substances diffuse out |
| How many times does kidney dialysis have to happen per week? | Three times |
| What may be side effects of of dialysis? | Blood clots or infections |
| What is the point of kidney dialysis? | Buys patient valuable time until an organ donor is found |
| What is the cure for kidney failure? | Kidney transplants |
| What can be an issue of kidney transplants? | Donor kidney can be rejected by patient |
| How is adrenaline secreted? | Secreted by adrenal glands after receiving nervous impulses |
| Effects of adrenaline? | Increases oxygen and glucose supply to brain and muscles, increasing heart rate |
| How is thyroxine secreted? | Released from pituitary gland in response to thyroid stimulating hormone |
| What does thyroxine do? | Regulates the basal metabolic rate |
| What is plant growth hormone called? | Auxin |
| What does Auxin control? | Growth near the tips of shoots and roots in response to light (phototropism) and gravity (gravitropism) |
| Where is auxin produced? | Tips of roots and shoots |
| Why do shoots grow towards light? | When a shoot is exposed to light, more auxin accumulates on the shady side. Cells grow faster on the shady side, causing the shoot to curve towards the light |
| Why do shoots grow away from gravity? | When shoots grow sideways, gravity distributes more auxin on the lower side. Cells on the lower side grow faster causing the shoot to curve upwards. |
| Why do roots grow towards gravity? | When a root grows sideways there is more auxin on the lower side. In roots, the extra auxin inhibits growth causing the cells on top to grow faster and the root to curve downwards. |
| Method to investigate light on cress seeds (Required Practical 8) | 10 cress seeds each into 3 labelled petri dishes lined with moist filter paper
Shine light onto one dish from above and two dishes from different directions
Leave seeds for 1 week
Observe responses |
| Identify independent, dependent and control variables for RP8 | Independent- Light direction
Dependent- Plant growth response
Control- Light intensity, number of seeds, seed type, temperature, water amount |
