✅Biology PAPER2 homeostasis Flashcards
What is homeostasis
Keeping the conditions in your body and cells at the right level
What does your body use for homeostasis
Control systems
Control systems keep the conditions in your body steady give examples
Temperature, blood glucose level, and water level, they can also control the nervous system or hormones
What three main part of the control system made up of
Receptors, coordination centre, effectors
What does a receptor do
The receptor detects a stimulus (The change in the environment)
it sends information to the coordination centre
Why do the internal conditions of your body need to be kept steady
To maintain the right conditions for cells to work properly
What does the coordination centre do
The coordination centre receives and processes the information and then organises a response
What is an effector
effectors are responses to a stimulation
Name the part of the control system that detect stimuli
Receptors
When does the nervous system come in
When organisms need to respond to stimuli (a change in the environment)
The nervous system detects and reacts to stimuli this means that..
Humans can react to their surroundings and coordinate their behaviour
What are the parts that the nervous system is made up of
CNS (Central nervous system)
Receptors
Sensory neurones
Effectors
Motor Neurones
What is the CNS
your bodies processing centre which manages everything your body does.
What does the CNS consist of
Brain, spinal cord
What are sensory neurones
carry out information from the receptors to the CNS
What are receptors
They detect stimuli, different receptors detect different stimuli
Give an example of a receptor
Receptors in the ears detect sound
What are effectors
Effectors respond to electrical impulses
What two things are effectors
Muscles, glands
How do muscles respond to electrical impulses
They contract
How do youR glands respond to electrical impulses
They release hormones
What is the role of the CNS
It receives information from the receptors
what is a pneumonic that stands for stimulus, receptor, sensory neurone, CNS, motor neurone, effector, response
Six really silly children make enormous rockets
What is a synapse
Where two neurones join together
How do the electrical impulses pass from one neurone to the next
By chemicals
Explain how synapses connect to neurones
The electrical impulses are passed from one neurone to the next by chemicals these chemicals move across the gap, the chemicals set off a new electrical impulse in the next neurone
What are reflexes
Automatic responses that help prevent injury
What is the passage of information in a reflex from a receptor to an effector called
The reflex arc
Where do the neurones go through in a reflex arc
They go to the spinal cord or the brain
An example of how a reflex arc would work if you were stung by a bee
Bee stings your finger
Bee sting is detected by receptors
Impulses are sent along a sensory neuron to the CNS
the CNS and relay neurone pass on the impulses to the motor neurone
Impulses are sent along the motor neurone to the effector
it contracts to move your hand away from the bee
What is a reaction time
The amount of time it takes to respond to a stimulus
What is the required practical to measure reaction time
A person with their arm resting on the edge of a table, the other person hold up a ruler operate between the thumb and forefinger make sure the zero end of the ruler is a level with their thumb and finger, make sure they aren’t gripping the ruler, then let go without warning, the person being tested should try catch the ruler as quickly as they can.
When a person drops a ruler and they get a high number what does that mean
A slow reaction time
What are the control variables in the practical ruler
Use the same person to catch the ruler, the same hand to catch the ruler, the ruler should be dropped at the same height
For the required practical to measure reaction time the results for one of the students before having the energy drink were 242, 256, 253, 249, 235, calculate the mean reaction time
247ms
What are hormones
Chemical messengers
Where are hormones are released from
Glands
Where do glands directly release hormones into
The blood
What are the glands called that release hormones
Endocrine glands
What do endocrine glands make up
The endocrine system
What does the pituitary gland do
the pituitary gland produces many hormones that regulate body conditions
What do the hormones do that are produced by the pituitary gland
Act on the other glands and make the glands release hormones
What does the thyroid gland do
Produces thyroxine, this involves regulating things like metabolism, temperature, heart rate
What does the adrenal gland do
Produces adrenaline that is used to prepare the body for flight or fight response
What do the ovaries do in females
Produces oestrogen, which is involved in the menstrual cycle
What do the testes do in males
Produces Testosterone which controls puberty and sperm production
What does the pancreas do
Produces insulin which is used to regulate the blood glucose level
What are the differences between nerves and hormones
Nerves act fast, for a short amount of time
hormones act slow, for a very long time
What happens after glucose is in the blood
glucose is removed by cells
Name another way glucose can be removed from the body
When you exercise more glucose is removed from the blood
Changes in the blood glucose concentration are monitored and controlled by the…
Pancreas
If the blood glucose concentration gets too high the pancreas…
Releases the hormone insulin
What does insulin do
move glucose from the blood into body cells
Glucose can be stored as…
Glycogen
Where is glucose converted to glycogen
The liver and muscle cells
What two types of diabetes are there
Type one and type two
What is type one diabetes
Type one diabetes is where the pancreas produces little or no insulin
What did people with type one diabetes need to do every day
People with type one diabetes need injections of insulin throughout the day this make sure that the glucose is removed from the blood quickly after the food is digested
What is type two diabetes
Type two diabetes is where person becomes resistant to their own insulin this means that they still produce insulin but their body cells don’t respond to it properly
What can increase your chance of developing type two diabetes
Being obese
How can type two diabetes be controlled
By eating a carbohydrate controlled diet where the amount of carbohydrate eating is carefully measured
Also type two diabetes can be controlled by taking regular exercise
What are the four stages of the menstrual cycle
Stage one – is when the menstrual bleeding starts, the uturus lining breaks down for about four days
Stage two – the lining of the uturus builds up again, Building a thick spongy layer full of blood vessels it’s now ready to receive a fertilised egg
Stage three– An egg develops and is released from the ovary which is called ovulation
Stage four- the wall is then maintained, if no fertilised egg has landed on the uterus, the spongy lining starts to break down and then the whole cycle starts again
The menstrual cycle is controlled by what four hormones
FSH, LH, oestrogen, progesterone
What does the FSH hormone do
Causes an egg to mature in one of the ovaries
What does the LH hormone do
Causes the release of an egg – Ovulation
What does the oestrogen and progesterone hormone do
These hormones are involved in the growth and maintenance of the uterus
What does the hormone FSH stand for
Follicle stimulating hormone
What does the hormone LH stand for
Luteinising hormone
What are contraceptives
Contraceptions of things that prevent pregnancy
What do oral contraceptions do
Stop the hormone FSH from being released which stops eggs maturing
What are the side effects of oral contraceptives
Sickness and headaches
What do hormonal contraceptives do
they Slowly release progesterone which stops eggs from maturing or being released from the ovaries
What is the contraceptive patch and how long does the contraceptive patch last for
A small patch that stuck to the skin, it lasts for one week
What is the contraceptive implant and and how long does the contraceptive implant last for
An implant that is inserted under the skin of the arm, it lasts for three years
What is the contraceptive injection and how long does it last for
Each dose last 2 to 3 months
What is the Intrauterine device
A T-shaped device that is inserted into the uterus and stops fertilised eggs from implanting in the uterus wall
What are two types of non-hormonal contraceptives
Condoms, diaphragms
How does a diaphragm work as a barrier from sperm getting to the egg
A diaphragm is a shallow plastic cup that fits over the entrance to the uterus it has to be used with spermicide which kills sperm
what is the CNs connected to the body by
motor and sensory neurones
