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biology - Y11 > Homeostatis And Hormonal Control > Flashcards

Homeostatis And Hormonal Control Flashcards

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1
Q

What are hormones

A

chemical messengers released by glands and into the bloodstream, where it’s carried to target cells or organs.

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2
Q

what is the endocrine system made up of

A

made up of glands which secrete hormones directly into the bloodstream to target cells

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3
Q

What does the endocrine system control

A

Water levels in blood
blood glucose levels
body temperature and metabolic rates

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4
Q

what do receptors do

A

detect change in stimuli

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5
Q

what do co-ordinators do

A

process information from receptors

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6
Q

what do effectors do

A

bring about responses

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7
Q

what glands does the endocrine system consist of

A

-pituitary glands (master gland)
- thyroid
-adrenal glands
-pancreas
-testes
-ovary

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8
Q

what does the pancreas secrete

A

Insulin and glucagon, to control blood glucose levels

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9
Q

what does the thyroid secrete

A

thyroxine, to control metabolic rate, heart rate and temperature of body

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10
Q

What kind of feedback are thyroxine levels controlled by

A

negative feedback

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11
Q

how are thyroxine levels kept relatively stable

A

by the pituitary glands that secrete TSH (thyroxine stimulating hormone)

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12
Q

What happens when thyroxine levels fall?

A

change is detected by the hypothalamus and more TSH is secreted by the pituitary gland, and more thyroxine is secreted

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13
Q

What happens when thyroxine levels rise?

A

Change is detected in hypothalamus, Less TSH is secreted from the pituitary glands, and less thyroxine is secreted.

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14
Q

Why do hormones only affect certain tissues or organs

A

Target cells in the certain tissue/organ have special chemical receptors for the particular hormone

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15
Q

Those who have an underactive thyroid may be what?

A

Overweight, since the rate of metabolism is slower

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16
Q

those who have an overactive thyroid may be what?

A

underweight, since the rate of metabolism is faster

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17
Q

what is diabetes

A

a non-communicable disease and there are two types

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18
Q

What is the cause of type 1 diabetes

A

it is genetic. The body’s immune system destroys any insulin producing cells. auto-immune disease. diagnosis tends to be in childhood/adolescence

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19
Q

Cause of type 2 diabetes

A

The body becomes resistant or no longer responds to insulin produced by the pancreas, leading to uncontrolled glucose levels.

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20
Q

treatment for type 1 diabetes

A

insulin injection

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21
Q

treatment for type 2 diabetes

A

-losing weight
-healthy or balanced diet
-exercising more often

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22
Q

3 ways of managing type 1 diabetes

A

-glucose sticks (where you urinate on it)
-glucose meter
-continuous glucose monitor (continuously monitors blood glucose levels and it is wearable

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23
Q

disadvantages of a glucose strip test

A
  • the data it provides is qualitative -> the data is not numerical and can be subjective.
  • Unhygienic as you need to collect a urine sample
  • doesn’t measure current blood glucose levels
  • you can’t do it in public
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24
Q

disadvantages of a glucose meter

A

people may have a fear of needles ( you need to have a blood sample)

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25
Q

advantages of glucose meter

A

quantitative data
gives an exact reading of blood glucose levels in numbers
Can be used anywhere

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26
Q

When doing an investigation on blood glucose levels, why must the person not eat within a certain amount of time

A

Food can cause blood glucose levels to change, affecting results (we don’t know the original blood glucose level)

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27
Q

excretion of waste - examples

A

carbon dioxide, urea, water and mineral ions

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28
Q

Why is carbon dioxide a waste product and how is it produced

A

Carbon dioxide is a product of aerobic respiration. It causes the blood to become acidic, affecting enzymes. it is removed by exhalation (gas exchange)

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29
Q

why is urea removed and how is it produced

A

The liver turns excess amino acids from proteins into ammonia. Ammonia is toxic, so it is converted into urea. A build up of urea can cause damage to cells.
The kidneys filter urea out of the bloodstream into urine or sweat.

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30
Q

why are water and mineral ions removed and how are they produced

A

water: product of aerobic respiration
mineral ions: excess in our diet, dissolved in water
They must be removed so cells don’t take up the water via osmosis and burst.
WATER POTENTIAL IN CELLS AND BLOOD MUST BE THE SAME, or body won’t function properly

31
Q

how are water and mineral ions removed

A

by sweating, urination and exhalation.

32
Q

what does digestion of protein result in

A

excess amino acids

33
Q

The higher the BMI the ….?

A

the higher the BMI, the more likely you are to develop type 2 diabetes.

34
Q

risk factor of type 2 diabetes?

A

obesity

35
Q

Two ways of managing kidney failure

A

Dialysis
Transplant

36
Q

What is dialysis

A

When a patients blood is drawn through a dialysis machine, where dialysis fluid runs over the blood, allowing urea to be diffused out

37
Q

advantages of dialysis

A

-patient is kept alive
-patients blood is clean
-shorter waiting time for treatment

38
Q

disadvantages of dialysis

A

-diet is restricted
- patients blood must be thinned
- higher risk of infection as the patient is punctured constantly
-more time spent in hospital

39
Q

advantages of a kidney transplant

A

-donors can be alive so there’s a larger volume of donors
- no dietary restrictions
-concentration of urea is automatically controlled
single operation
-less visits to the doctor
-patient is kept alive
-flexible lifestyle

40
Q

disadvantages of a kidney transplant

A

-risk of rejection
-tissue type of donor must be the same as the patient
-patient and donor need to take immunosuppressants for life
-long recovery from surgery
-risk of infection

41
Q

what processes does the kidney do

A

-reabsorption
-filtration
-osmoregulation
-excretion

42
Q

what happens during ultrafiltration

A
  • glucose, mineral ions, water and urea all move from the blood and into the nephron.
  • proteins, enzymes and antibodies which are too large remain in the bllood
43
Q

what happens during reabsorption or selective reabsorption

A
  • all glucose and amino acids are reabsorbed back into the blood
  • volume of water and mineral ions reabsorbed back into the blood stream depends on what the body needs.
    the water moves back via osmosis and mineral ions move back via active transport
44
Q

what happens during excretion

A

all urea is excreted with excess water and mineral ions

45
Q

what happens to cells if blood is too dilute

A

water from the plasma moves into cells via osmosis, causing cells to burst

46
Q

what happens to cells if blood is too concentrated

A

water moves from the cells to the blood, causing the cells to shrivel up

47
Q

what is osmoregulation

A

the control of water levels in the blood.
receptors detect change in water potential and instructs the pituitary glands to release more ADH

48
Q

what is ADH and what does it do

A

Anti Diuretic Hormone and it makes nephron/kidney tubules more or less permeable, changing the volume of water being reabsorbed into the blood

49
Q

describe what happens if the blood is too dilute
(osmoregulation)

A
  • receptors detect that the water potential is too high and instructs the pituitary gland to release less ADH
    -Kidney tubules become less permeable, so less water is reabsorbed back into the blood stream
    -larger volume of dilute urine goes to bladder
50
Q

describe what happens if the blood is too concentrated
(osmoregulation)

A

receptors detect that water potential is too low and instructs pituitary gland to release more ADH
- kidney tubules become more permeable, allowing more water to be reabsorbed back into the blood stream
-blood becomes less concentrated and more dilute.

51
Q

explain how a kidney may be rejected during a transplant

A
  • the immune system sees the kidney as a foreign body
    -antibodies are produced
    -antibodies bind to the antigens on the kidney’s surface and they bind, destroying the kidney
52
Q

describe how a healthy kidney produces urine

A
  • kidney filters urea, glucose, water, mineral ions and urea from the blood
  • ALL glucose which was originally filtered out is reabsorbed into the blood stream
  • some water and some mineral ions are reabsorbed to maintain a constant water level.
  • urea, which is a toxic substance is removed by the kidneys and excreted in urine
53
Q

why do plants produce hormones

A

to co-ordinate and control growth and responses to gravity, light and water

54
Q

what stimuli are plants sensitive to

A

-light
-moisture
-gravity

55
Q

what is a positive response

A

when growth movement is towards stimuli

56
Q

what is a negative response

A

when growth movement is away from stimuli

57
Q

what is phototropism

A

a plant’s response to light

58
Q

SHOOTS

A

positively phototropic and negatively gravitropic

59
Q

ROOTS

A

negatively phototropic and positively gravitropic

60
Q

what is gravitropism or geotropism

A

a plant’s response to gravity

61
Q

what happens to the roots and shoots if a plant pot is knocked over

A

the shoots still grow up and the roots grow down

62
Q

what does an uneven distribution of auxin cause

A

uneven growth in the shoot

63
Q

what do high levels of auxin cause

A

shoot cells to elongate, but auxin inhibits the growth of root cells.

64
Q

what is auxin

A

a hormone responsible for the growth in plants

65
Q

what light conditions does auxin distribute evenly in?

A

all round light or in the dark, causing the shoot to grow directly upwards

66
Q

what happens if the light is unilateral (coming from one side)

A

auxin accumulates on the shaded side, causing the shoot cells to elongate and bend towards the light

67
Q

uses of auxins

A

rooting powders
weed killers

68
Q

uses of ethene

A

causes fruit to ripen
controls cell divison

69
Q

uses of gibberellins

A

promotes flowering and seed germination
ends seed dormancy
increases fruit size

70
Q

RP 8: independent variable

A

light condition or light intensity or direction of light

71
Q

RP 8: dependent variable

A

height of seedlings

72
Q

RP 8: control variables

A

number of seedlings
type of seedlings
temperature seedlings are kept at
volume of water given to seedlings

73
Q

RP 8: METHOD 1

A

1) put cotton wool into 3 petri dishes and add same volume of water to each dish
2) add 10 seeds to each dish, evenly spread out and let them germinate
3) once seeds have germinated, ensure each dish contains the same number of seeds
4) place one dish where there is full light, one in complete darkness and one in partial light
5) measure height of each seedling everyday for one week and record results
6) calculate mean height of the ten seedlings for each day, and compare the mean heights in the 3 different light conditions

biology - Y11 (2 decks)

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