B5- gcse

what is the process of homeostasis?

is the regulation of conditions inside the body to maintain a stable internal environment, in response to both internal and external conditions

what does automatic control in our body do?

recognise when there are changes from optimal conditions and then send a signal to reverse the change

what do receptors do?

detect a change for example temperature

what are examples of coordination centres, what are they

interprets that change and decides what needs to be done about it eg. the brain and spinal cord

what are the effectors?

things that carry out the change, generally the muscles as they contract and glands which release hormonesw

hat do nervous systems send?

a very fast and precise electrical impulses through the nerves which allows us to respond to things very quickly

what does the endocrine system rely on?

relies on hormones which are small chemicals released into the bloodstream what

what do they effect?

although they travel throughout the entire body they only affect certain cells that have the right receptors

what is the endocrine system compared to the nervous system?

it’s more slower, longer lasting and more generalised than the nervous system

what is negative feedback

whenever the level of something gets too high negative feedback decreases it again to return it to normal

what will negative feedback do if the condition is too low?

increase it back up , does the opposite of the change

what is the loop of how our body detects change?

first the receptors detect the change, such as in our skin → our nervous system will send electrical impulses to the coordination centres such as the brain and spinal cord which interpret the information—> another set of signals are sent to the effectors such as our muscles that carry out useful responses like shivering increasing our body temp.

what are nerve cells adapted to carry?

electrical impulses from one point to another

what are their adaptations?

they’re long, thin and have lots of branched connections to either end

what is a synapse?

the connection between the cellsh

how does it work?

whenever an electrical impulse hits the end of a nerve it causes the release of some chemicalswh

at do these chemicals then do?

diffuse across the gap into the next nerve cell where they can trigger another electrical impulse, these electrical impulses will then continue along the neurone all the way to the other end where it will hit another synapse

what is the central nervous system made up of?

our brain and spinal cord

what does the CNS do?

takes in loads of sensory information which decides what needs to be done about it and then sends out orders to the rest of the body

how does it receive the information?

through sensory neurones which carry information from receptors all over our body to the CNSwhat

what does the CNS do after it’s decided what to do with the information?

sends impulses back out the body via motor neurones

what is the reflex arc

the nerve pathway that underlies our unconscious reflexeswhat

what are the benefits of having these reflexes?

they’re rapid and automatic so we can respond to things really quickly

what happens when you reach out and accidentally touch the end of a pin (e.g)

the pressure of the sharp object is a stimuli and it is detected byb receptors which will stimulate sensory neurones which will carry an impulse from your finger up to the spinal cord which is part CNS which will transfer the impulse to a relay neurone→pass an impulse to a motor neurone where it travels back out the body to an effector

what is the electrical signal temporarily converted into?

a chemical signal so that it can be passed between the different nerve cells

What is the role of a receptor?

To detect a stimulus

What is the role of a sensory neurone?

To transfer a signal from a receptor to the CNS

What is the role of a motor neurone?

To transfer a signal from the CNS to an effector

What is the role of a relay neurone?

To transfer a signal from a sensory neurone to a motor neurone

what is the pathway of a reflex arc

stimulus ➔ receptor ➔ sensory neurone ➔ relay neurone ➔ motor neurone ➔ effector ➔ response

What are the two main types of effectors? 

muscles, glands

What is the role of a motor neurone?

To transfer a signal from the CNS to an effector

what does the endocrine system consist of?

a series of glands that are found throughout the bodywh

what does the endocrine and nervous system have in common?

they all secrete hormones which are small chemical molecules that are passed into the blood and then spread throughout the body in the blood stream

what does this allow hormones?

the hormones to come into contact with wider range of tissues, some of these tissues will have receptors that are specific t the hormoneswha

what can hormone molecules act as?

signals to trigger certain changes inside the cell

what do some hormones tell thew body to do (produced by the pituatary gland)

it tells the body what to do

tells other glands to release their hormones

which gland is in oiur neck?

thyroid glandwh

what does the thyroid gland rproduce?

the hormone thyroxine, which takes part in growth and development

thyroxine play an important role in?

to increase metabollic rate

what gland produces thyroid stimulating hormone

pituitary gland

what does TSH stimulate?

the thyroid gland to produce thyroxine

what happens if thyroxine levels are too low?

the pituitary gland releases TSH stimulates the thyroid gland to release more thyroxine, so thyroxine levels in the blood increase back up to normal

what happens if thyroxine levels are too high?

the thyroxine will inhibit the pituitary gland from producing TSH→pituatiry glsand won’t release as much thyroxine→ thyroxine levels in the blood fall back to normal

at is this process called?

negative feedback

where are the adrenal glands?

on top of our kidneys

what do adrenal glands produce?

adrenaline

when is adrenaline normally released?

during the fight or flight response

what does adrenaline do

increases heart rate, blood pressure, blood flow to muscles, increases blood sugar (glucose) levels by stimulating the liver to break glycogen down into glucose

what do we have in front of the kidneys?

the pancreas

what does the pancreas produce|?

hormone called insulin

what does insulin do?

help regulate blood glucose concentrations

where are the testes only found?

in maleswh

at are their two main jobs?

producing the hormone testosterone which controls puberty and producing the male gametes sperm for reproduction

where are the ovaries found?

only in females

what is their main role?

only to produce oestrogen which influences puberty and the menstrual cycle

what do the ovaries also hold?

the female gametes egg cells

what do endocrine systems rely on compared to nervous systems

endocrine= relies on hormones (small molecules secreted by glands, transported by blood) nervous= relies on electrical impulses (transferred along nerve cells)

what does this mean for the speed of nervous and endocrine?

endocrine= spreads more slowly why so effects last longer, nervous= very fast, effects don’t last very long

why is the endocrine system essentially slower than the nervous system?

endocrine=hormones= act more generally as they spread through the entire body which means they interact with loads of different cells, nervous= nerve impulses are sent to one specific area therefore is precise

what does the blood glucose concentration describe?/ why do we need a decent amount of sugar in our blood

the amount of sugar we have in our bloodstream/ so that our cells have a constant supply of glucose that they can use for respiration

what happens if the blood glucose concentratyion gets too high?>

it can start to damage our tissues

how would food be broken down?

they would be broken down in your intestines into lots of glucose molecules which would be absorbed into the bloodstream and cause blood glucose concentration to increase

where does the pancreas sit?

just behind the stomach and in response it will release a hormone called insulin into the bloodstream what

will happen as the insulin travels around the body?

it will bind to receptors on certain cells which tells those cells to take in some of the glucose travelling in the bloodwh

ich two cells take up lots of the extra glucose molecules?

muscles and liver and combine them together to form glycogen (large molecules made up of lots of glucose molecules)

what’s going to happen as a result of the glucose being removed from the blood?

the blood glucose concentration will decrease

where is glucagon released from?

the pancreas (does the opposite of insulin) so increases glucose rather than decreasing it

what happens as glucagon travels around the body?

it would bind to lots of different cells, mainly liver cells and break it down into lots of glucose molecules and then release it into the blood

what would this process do?

bring the blood glucose concentration back up top normal so that all ur cells have a good supply for it for respiration

what does our body always do?

release insulin and glucagon to ensure the amount of gkucose in our blood is always kept at the right levels

what are the 2 main problems in both types of diabetes?

patients can’t regulate blood glucose levels properly as insulin system is messed up

when does type 1 diabetes generally occur?

through childhood/teenage years

what is the condition itself?

lifelong

how does this occur?

pancreas stops producing insulin meaning that the person’s blood glucose levels can rise really highwh

what could this make them feel?

ill, rare cases could kill them

what is the main treatment used?

injecting them with insulin which is normally done into their abdomen or into their thigh

what two main things does the amount of insulin they inject depend on?`

what they’ve eaten, how much exercise they’re doingwh

at would more exercise mean?

they’d need less insulin

how does type 2 diabetes occur?

happens to older people who have had unhealthy diets from a long timew

hat is the problem with type 2 diabetes?

the person’s cells become resistant to insulin

what does this mean?

they don’t respond to insulin anymore and so their cells won’t take in so much glucose from the bloodstream

what is the main treatment for type 2 diabetes?

maintain a healthy, low sugar diet and regular exercise