What is homeostasis? - The maintenance of a constant internal environment.
What is a stimulus? - A change in your environment than requires a response. e.g Light, sound,
touch, pressure, pain, chemical or temperature.
What do the receptors do? - Detect the stimulus or change in environment.
Wha...
AQA GCSE Biology Paper 2
What is homeostasis? - ✔✔✔The maintenance of a constant internal environment.
What is a stimulus? - ✔✔✔A change in your environment than requires a response. e.g Light, sound,
touch, pressure, pain, chemical or temperature.
What do the receptors do? - ✔✔✔Detect the stimulus or change in environment.
What happens after the receptors? - ✔✔✔Receptors send messages to the CNS via the sensory
neurone.
What makes up the central nervous system? - ✔✔✔The brain or spinal cord
What is an effector? - ✔✔✔Muscles or glands that bring about a response.
What do the muscles and glands do in response to stimuli? - ✔✔✔Muscles contract and glands secrete
chemical substances(hormones).
What is a sensory neurone? - ✔✔✔A neurone that carry information from the receptors to the CNS.
What is a relay neurone? - ✔✔✔Neurones that carry impulses from the sensory neurone to the motor
neurone.
What is a motor neurone? - ✔✔✔Neurones that carry information from the CNS to the effectors.
,What is the nervous system? - ✔✔✔It is a system that allows you to react to your surroundings.
How do signals travel across a synapse? - ✔✔✔The chemical or neurotransmitter diffuses across the
synapse and binds to a complementary receptor on the neurone (postsynaptic). This causes an electrical
impulse to travel down the next neurone.
What is a synapse? - ✔✔✔A gap between two neurones.
What is the thermoregulatory centre of the brain? - ✔✔✔Near the hypothalamus, monitors the
temperature of blood.
Describe the stages in a reflex arc. - ✔✔✔Stimulus->Receptor->sensory neurone->CNS (relay neurone)
-> motor neurone -> effector -> response
Name responses that reduce body temperature. - ✔✔✔Hairs lie flat, sweat and blood vessels get
wider(vasodilation)
What happens during vasodilation? - ✔✔✔The blood vessels supplying the skin dilate (widen). This
helps to transfer energy to the environment.
Name responses that increase body temperature. - ✔✔✔Hairs stand up, no sweat, shivering and blood
vessels constrict(vasoconstriction)
What happens during vasoconstriction? - ✔✔✔The blood vessels supplying the skin constrict to close
off the skins blood supply.
What is the body's core temp? - ✔✔✔37 degrees Celsius
,What are hormones? - ✔✔✔Chemical messengers that travel in the blood to target organs.
Compare and Contrast the endocrine (hormone) system and the nervous system. - ✔✔✔Nervous is
faster acting than the endocrine system.
Hormones have longer lasting effects compared to electrical impulses. Nerves act on a very specific area
whereas hormones act more general.
What does the thyroid gland do? - ✔✔✔Produces thyroxine which is involved in regulating
metabolism.
What do the adrenal glands do? - ✔✔✔Produce adrenaline which is used to prepare the body for fight
or flight.
What is the role of the pancreas? - ✔✔✔Produces glucagon and insulin which are involved in
regulating glucose levels in the blood.
Name the hormone that is released if blood sugar is too high. - ✔✔✔Insulin
What does insulin do? - ✔✔✔It makes the liver convert glucose into glycogen. This causes blood
glucose levels to decrease.
Name the hormone that is released if blood sugar is too low. - ✔✔✔Glucagon
What does glucagon do? HINT GLU-COSE-GONE - ✔✔✔It makes the liver convert glycogen to glucose.
This causes the blood glucose level to increase.
What is type I diabetes? - ✔✔✔When the pancreas produces little or no insulin.
, What is type II diabetes? - ✔✔✔When a person becomes resistant to their own insulin. Being
overweight can increase your chances of type II diabetes.
How can type I diabetes be treated? - ✔✔✔Insulin injections, limiting intake of foods rich is simple
carbohydrates e.g. sugars and regular exercise.
How can type II diabetes be treated? - ✔✔✔It can be controlled by eating a carbohydrate controlled
diet and getting regular exercise.
What is the role of the kidneys. - ✔✔✔Kidneys make urine by taking unwanted waste products out of
your blood. They are involved in selective reabsorption.
Name three things that are re-absorbed by the kidneys into the blood. - ✔✔✔Glucose, water and ions.
Name three things that are removed from the body in the urine. - ✔✔✔Urea, water and ions.
What is deamination? - ✔✔✔Proteins (excess amino acids) cannot be stored by the body. Excess
amino acids are converted to fats and carbohydrates. This occurs in the liver.
What is produced as a waste product of deamination? - ✔✔✔Ammonia is produced as a waste
product. Ammonia is toxic so it is converted into urea in the liver.
What hormone controls the amount of water absorbed by the kidneys? - ✔✔✔ADH
What happens when the concentration of water in the blood is too low. I.e. the Blood is MORE
concentrated. - ✔✔✔Receptors in the hypothalamus detects the water content is too low. The
coordinator in the brain receives the information and coordinates a response. The pituitary gland
produces MORE (Anti-diuretic hormone) ADH, which makes the kidney tubule MORE permeable. This
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