b3 - organism level systems (copy)

brain and spinal cord

• take in sensory information,

• process information

• send out orders to the rest of the body

nuerones, receptors and effectors

• collecting information

• sending it to the cns

• acting on instructions from the cns

nerve cells which are adpated to carry electrical impulses from one place to another

a change in the enviroment we react to

detects a stimulus and stimulate electrical impulses in response.

Sensory neurones carry electrical signals - nerve impulses - towards the central nervous system (spinal cord and brain).

carry nerve impulses away from the central nervous system to the effectors.

a muscle/ gland which acts in response to a stimulus

stimulus →receptor → sensory nuerone → relay nuerone (CNS) → motor nuerone → effector → response

the axon

called dendrites and they mean they can connect with lots of other nuerones

a fatty sheath surrounding some axons in a neuron which acts as an electrical insulator speeding up the electrical impulse

connecting with another nuerone slows the impulses down

synapse

• when an electrical impulse reaches the end of a neurone (dendrites) it causes the release of chemicals (neurotransmitters)

• these chemicals then diffuse across the synapse and stimulate the next neurone to carry another electrical impulse

automatic actions to stop you from injuring yourself

1. The receptor in the skin detects a stimulus - the change in temperature.

2. The sensory neurone sends nerve impulses to the spinal cord.

3. The relay neurone, which is located in the spinal cord, carries the nerve impulses from sensory neurones to motor neurones.

4. The motor neurone sends nerve impulses to the effector.

5. The effector - the biceps muscle in the arm - contracts so that the hand is moved away.

they are automatic and dont involve conscious parts of the brain which allows us to be protected from harm

maintaining constant internal body conditions

chemical messengers that are secreted by the glands in the endocrine system into the bloodstream

cells with the specific receptor for the hormone that produce an effect when the hormone binds

1. Glands are organs that release small chemicals called hormones.

2. These chemicals are normally released into the bloodstream, allowing them to travel around the body.

3. They can then bind to specific cells that have the correct receptors. 

4. This will bring about some change within the cells.

a hormone produced by the adrenal glands (which are ontop of your kidneys)

during the flight or fight response when you get scared, stressed or need to exercise. It prepares the body for activity

• increases heart rate

• increases breathing rate

• increases blood pressure

• increases blood flow to muscles

• increases blood sugar (glucose levels) by stimulating liver to break down glyogen into glucose

sends nerve impulses to adrenal glands, respond by secreting adrenaline

produced by the thyroid gland found in your neck

its main role is to increase your metabolic rate (the rate at which chemical reactions are taking place)

• the pituatry gland produced TSH (thyroid stimulating hormone) which stimulates the thyroid gland to produce thyroxine.

• thyroxine then inhibits the production of TSH from the pituitary gland

• the pituitary gland will release TSH.

• This then stimulates the thyroid gland to release more thyroxine so thyroxine levels in the blood increase back up to normal.

• the thyroxine will inhibit the pituitary gland from producing TSH.

• Less TSH means that the thyroid gland won't release as much thyroxine so thyroxine levels in the blood fall back to normal.

If levels of thyroxine rise too high, it will bring about changes to lower the levels, and if they fall too low, it brings about changes to raise them back up.

• is a network of glands

• glands release hormones into the blood stream

• these hormones can then bind to specific cells with the correct receptors which will bring about some change in the cells

organs that release chemicals called hormones

Chemicals produced in various glands which bind to receptors on a target cell

any cell that has the correct receptor for a particular hormone to bind to

is the master gland and tells other glands to secrete their hormone in the endocrine system

regulates blood glucose

only found in males , secrete testosterone

in females, secrete oestrogen

When your body detects that the level of a substance has gone above or below the normal level, it triggers a response to bring the level back to normal again. e.g. thyroid regulating the metabolic rate

oestrogen, progesterone

FSH, LH

• FSH(follicle stimulating hormone) and LH (luetinising hormone) are released from the pituitary gland and help support the menstrual cycle

Causes egg to mature

stimulates ovaries to produce oestrogen

main female sex hormone produces in the ovaries which is involved in mesntrual cycle and devloping femal charcteritics (e.g. breasts)

causes lining of uterus to thicken

stimulates production of LH

inhibits production of FSH so that only one egg is released in each cycle

stimulates release of egg (ovulation)

indirectly stimulates progesterone production

hormone produced in the ovaries to help support ovaries and also is involved in the menstrual cycle

maintains uterus lining. when level falls and there's low oestrogen -lining breaks down

inhibits production of FSH and LH

low levels allow FSH to increase- whole cycle starts again

menstruation - period of bleeding as the uterus lining breaks down

building up of the uterus lining

ovulation - release of the egg from the ovaries

maintenance of the uterus lining

stimulate sperm production from the testes

some women have low levels of FSH so there eggs can't mature- no ovulation takes place- cant get pregnant

by injection of FSH and LH

1. First, a woman is given FSH and LH to stimulate their eggs to mature.

2. These eggs can then be collected from the woman's ovaries. Sperm is also collected from the male.

3. The eggs are then fertilised by the sperm.

4. These fertilised eggs are then left to grow into embryos in a laboratory incubator.

5. Once the embryos are large enough, they are transferred to the women's uterus, so that they can develop into a foetus.

to prevent pregnanacy

injection -up to 3 months

implant- inserted beneath skin if the arm for 3 years

the coil (ius) - t shaped piece of plastic inserted into uterus 3-5 years

mini pill( progesterone only pill) has to be taken every day

• stimulates production of thick cervical mucus making it less likey for the sperm to get through

• thins lining of uterus to make it less likely for egg to implant

• prevents ovulation by inhibiting production of lh and fsh

combined pill - taken in a 21 day pill, 7 days no pill cycle

patch- worn in skin in 4 week cycle

prevents ovulation by inhibiting FSH

stop the egg and sperm meeting

condoms, female condoms and diaphragm

• intrauterine devices-IUDS

• natural planning

• sterilisation

its non hormonal t shaped device made from copper inserted into the uterus and it works by stopping the sperm and egg from surviving in the womb or fallopian tubes.

not having sex when the womans most fertile

surgical procedure to cut/tie tubes in reproductive system

• side effects

• possibility of doing/taking it wrong so is ineffective

• dont protect against sti’s

long lasting methods- don't have to worry about it every day

Diabetes is a disease in which the body is unable to produce any or enough insulin causing elevated levels of glucose in the blood.

the pancreas produces little or no insulin

through insulin therapy - injecting insulin several times a day (often at mealtimes)

stops level of glucose in blood from getting too high- very effective

• the body cells lose their sensitivity ( no longer respond to insulin being produced)

• makes it difficult to control blood glucose levels

healthy diet, exercising regularly ( increases amount of energy used up by body and decreases amount of stored body fat) and losing weight if necessary

• being overweight

• too much saturated fat which increases blood cholesterol

lowers blood glucose levels and made in pancreas

increases blood sugar levels and made in pancreas

a sugar used to make energy and is made in the liver

Glycogen is a carb stored in liver and muscles. It's a quick energy source made up of glucose molecules.

• pancreas is stimulated

• insulin is secreted

• insulin stimulates glucose uptake from blood

• blood glucose level falls

• pancreas is stimulated

• glucagon is secreted

• glucagon stimulates liver to release glucose

• blood glucose level rises