b3 - organism level systems (copy)

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what does the centeral nervous system consist of

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85 Terms

1

what does the centeral nervous system consist of

brain and spinal cord

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2

what are the central nervous systems main functions

  • take in sensory information,

  • process information

  • send out orders to the rest of the body

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3

what does the peripheral nervous system consist of

nuerones, receptors and effectors

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4

what is the peripheral nerous systems main functions

  • collecting information

  • sending it to the cns

  • acting on instructions from the cns

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5

whats a nuerone

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

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6

whats a stimulus

a change in the enviroment we react to

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7

whats a receptor

detects a stimulus and stimulate electrical impulses in response.

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8

whats a sensory nuerone

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

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9

whats a motor nuerone

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

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10

what are effectors

a muscle/ gland which acts in response to a stimulus

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11

whats the order of a reflex arc

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

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12

where are electrical pulses passed along a nuerone

the axon

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13

why do nuerones have branched endings and what are they called

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

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14

whats a myelin

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

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15

why is a long nuerone better than short ones joined together

connecting with another nuerone slows the impulses down

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16

what is the gap between two nuerones called

synapse

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17

how are electrical impulses sent between nuerones (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

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18

what are reflex actions

automatic actions to stop you from injuring yourself

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19

how do reflex actions work

  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.

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20

why are reflex actions so fast

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

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21

whats homeostatis

maintaining constant internal body conditions

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22

whats a hormone

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

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23

what are target cells

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

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24

how does the endocrine system work

  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.

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25

what is adrenaline

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

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26

when is adrenaline produced

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

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27

What does adrenaline do ?

  • 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

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28

When your brain detects a stressful situation what does it do ?

sends nerve impulses to adrenal glands, respond by secreting adrenaline

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29

where is thyroxine produced

produced by the thyroid gland found in your neck

<p>produced by the thyroid gland found in your neck</p>
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30

what does thyroxine do

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

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31

how is the production of thyroxine regulated

  • 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

<ul><li><p>the pituatry gland produced TSH (thyroid stimulating hormone) which stimulates the thyroid gland to produce thyroxine. </p></li><li><p>thyroxine then inhibits the production of TSH from the pituitary gland</p></li></ul>
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32

what happens if your thyroxine levels are too low

  • 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.

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33

what happens if your thyroxine levels are too high

  • 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.

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34

how is the control of thyroxine levels an example of negative feedback

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.

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35

how does the endocrine system work

  • 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

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36

What is a gland ?

organs that release chemicals called hormones

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37

What are hormones ?

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

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38

what is a target cell

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

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39

what does the pituitary gland do in the endocrine system

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

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40

what does the pancreas do in the endocrine system

regulates blood glucose

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41

what do the testes do in the endorcine system

only found in males , secrete testosterone

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42

what do the ovaries do in the endorcine system

in females, secrete oestrogen

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43

whats negative feedback

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

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44

Name the two sex hormones secreted by the ovaries

oestrogen, progesterone

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45

name the two sex hormones secreted by the pituitary gland

FSH, LH

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46

what is FSH and LH

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

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47

What does FSH do ?

Causes egg to mature

stimulates ovaries to produce oestrogen

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48

what is oestrogen

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

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49

what does oestrogen do ?

causes lining of uterus to thicken

stimulates production of LH

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

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50

What does LH do ?

stimulates release of egg (ovulation)

indirectly stimulates progesterone production

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51

what is progesterone

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

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52

what does progesterone do ?

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

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53

what happens in stage 1 of the menstrual cycle

menstruation - period of bleeding as the uterus lining breaks down

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54

what happens in stage 2 of the menstrual cycle

building up of the uterus lining

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55

what happens in stage 3 of the menstrual cycle

ovulation - release of the egg from the ovaries

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56

what happens in stage 4 of the menstrual cycle

maintenance of the uterus lining

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57

what does testosterone do

stimulate sperm production from the testes

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58

why would low levels of FSH cause infertility ?

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

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59

how can ovulation be stimulated ?

by injection of FSH and LH

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60

explain how ivf works

  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.

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61

what are contraceptives used for ?

to prevent pregnanacy

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62

name the types of hormonal contraception that use progesterone and how long they are effective for

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

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63

how do contraceptive methods involving progesterone work

  • 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

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64

name the methods of hormonal contraception using progesterone and oestrogen

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

patch- worn in skin in 4 week cycle

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65

how does oestrogen prevent pregnancy ?

prevents ovulation by inhibiting FSH

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66

what is a barrier method is contraception?

stop the egg and sperm meeting

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67

Name the barrier methods of contraception

condoms, female condoms and diaphragm

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68

what are the no hormonal methods of contraception

  • intrauterine devices-IUDS

  • natural planning

  • sterilisation

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69

how does an iud work

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.

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70

whats natural planning

not having sex when the womans most fertile

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71

whats sterilisation

surgical procedure to cut/tie tubes in reproductive system

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72

what are bad things about hormonal methods of contraception

  • side effects

  • possibility of doing/taking it wrong so is ineffective

  • dont protect against sti’s

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73

name advantages of hormonal methods of contraception

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

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74

what is diabetes ?

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

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75

whats type 1 diabetes

the pancreas produces little or no insulin

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76

how do you treat type 1 diabetes

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

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

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77

what is type 2 diabetes ?

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

  • makes it difficult to control blood glucose levels

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78

how is type 2 diabetes treated

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

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79

what can increase the chance of getting type 2 diabetes ?

  • being overweight

  • too much saturated fat which increases blood cholesterol

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80

whats does insulin do and wheres it made

lowers blood glucose levels and made in pancreas

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81

what does glucagon do and wheres it made

increases blood sugar levels and made in pancreas

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82

whats glucose and wheres it made

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

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83

whats glycogen

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

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84

what happens of your blood glucose levels are too high

  • pancreas is stimulated

  • insulin is secreted

  • insulin stimulates glucose uptake from blood

  • blood glucose level falls

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85

what happens of out blood glucose levels are too low

  • pancreas is stimulated

  • glucagon is secreted

  • glucagon stimulates liver to release glucose

  • blood glucose level rises

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