PAPER 2 Flashcards
What is homeostasis
The regulation of the conditions inside your body to maintain a stable internal environment
What three main components make up your automatic control systems?
Receptors, coordination centres and effectors
Why do the internal conditions of your body need to be regulated?
Your cells need the right conditions to function properly including the conditions for enzyme action.
What is negative feedback
When your body detects an imbalance in the levels of something (water or glucose) and so sends a signal to do the opposite
What is a sensory neurone?
Neurones that carry information as impulses from the receptors to the CNS
What is a motor neurone?
A neurone that carries a signal from the CNS to effectors
What is an effector?
A part of the body (muscles and glands) that provides a response to nervous impulses
What is a receptor?
A cell that detects a stimulus
Give 2 examples of receptors
Taste receptors on the tongue
Sound receptors in the ears
How are neurones connected
Synapses
What is a synapse?
A link between two neurones which transfers a signal by chemicals that diffuse across the gap
Whats the purpose of a reflex?
To prevent injury
Give 3 factors that can affect reaction time
Age
Gender
Drugs
How would you measure the effect of caffeine on reaction time?
The ruler drop test, done once without caffeine and repeated again with it
Why might you use a computer to measure reaction time?
It is more accurate, can measure in miliseconds etc
It is more precise, removes human error
Removes the posibility of predicting the drop
What is the pituitary gland?
The ‘master gland’ that controls other glands in the endocrine system
What does the thyroid do?
Produces thyroxine
What does thyroxine regulate? (3)
Heart rate
Temperature
Metabolism
What does the adrenal gland do
Produces adrenaline
What does adrenaline do?
Prepares a ‘fight or flight’ response
What does the pancreas do? (Hormones)
Produces insulin to regulate blood glucose level
What do ovaries do?
Produces oestrogen
What do the testes do?
Produces testosterone that controls puberty and sperm production
Name three differences between nerves and hormones
Nerves are very fast - hormones slower
Nerves are short term - hormones long term
Nerves act on a very precise area - hormones more general
What two hormones are involved in the control of blood glucose levels?
Insulin and glucagon
What happens when blood glucose is too high?
Insulin is added
What happens when blood glucose is too low?
Glucagon is added
What is type 1 diabetes?
When your pancreas produces little or no insulin
What is type 2 diabetes?
When someone becomes resistant to their own insulin
How can you help type 1 diabetes? (3)
Taking injections of insulin
Limit your intake of simple carbohydrates
Do regular exercise
How can you help type 2 diabetes? (2)
Eat a carbohydrate controlled diet
Get regular exercise
What is stage 1 of the menstrual cycle?
The lining of the uterus breaks down for around 4 days
What is stage 2 of the menstrual cycle?
Uterus lining builds back up again into a spongy layer of blood vessels
What is stage 3 of the menstrual cycle?
Ovulation (around day 14)
What is stage 4 of the menstrual cycle?
Uterus lining maintained. If no egg has fertilised, the lining breaks down and the process restarts
What does FSH do and where is it produced? (3)
Pituitary gland
Causes an egg to mature
Stimulates the ovaries to produce oestrogen
What does LH do and where is it produced? (2)
Produced in the pituitary gland
Stimulates ovulation
What does oestrogen do and where is it produced? (4)
Produced in the ovaries
Causes uterus lining to grow
Stimulates LH release
Inhibits FSH release
What does progesterone do and where is it produced? (4)
Produced in the ovaries after ovulation
Maintains uterus lining while present
Inhibits the release of LH
Inhibits FSH release
How can oestrogen be used as contraception?
It prevents FSH release so egg development and production stop
How does progesterone prevent pregnancy?
It creates thick mucus that prevents any sperm getting through
How is the combined oral contraceptive pill different to a progesterone only pill? (2)
It also contains oestrogen
It has more side effects
Name 6 types of female hormone contraception
Combined pill
Progesterone only pill
Patch
Implant
Injection
IUD
How does a contraceptive implant work?
Constantly releases progesterone
How does a contraceptive patch work?
It is stuck to the skin for about a week and contains oestrogen and progesterone
How does a contraceptive injection work?
Contains progesterone, lasts 2 - 3 months
How does an IUD work?
Either releases copper to kill sperm or progesterone. It is inserted into the uterus. Also prevents implantation.
What 3 ways can you prevent pregnancy that arent barrier or homone based?
Sterilisation - (male or female vasectomy)
Natural methods - (not having sex on days where an egg is released)
Abstinence - (dont have sex)
What are the pros and cons of using FSH and LH to increase fertility?
Can allow you to have a child
Can stimulate too many eggs
Doesnt always work which can become expensive