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GCSE Edexcel Biology grade 9-1 course, topics 6-9 > Topic 7 > Flashcards

Topic 7 Flashcards

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1
Q

What hormone(s) does the pituitary gland produce?

A
  • Follicle-stimulating hormone (FSH)
  • Luteinising hormone (LH)
  • Anti-diuretic hormone (ADH)
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2
Q

What hormone(s) does the thyroid gland produce?

A

thyroxine

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3
Q

What hormone(s) does the adrenal gland produce?

A

adrenalin

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4
Q

What hormone(s) does the pancreas produce?

A

insulin

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5
Q

What hormone(s) does the ovaries produce?

A

oestrogen

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6
Q

What hormone(s) does the testes produce?

A

testosterone

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7
Q

Where is the pituitary gland located?

A

in the brain

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8
Q

where is the thyroid gland located?

A

in the neck (thyroid)

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9
Q

where is the adrenal gland located?

A

just above the kidneys

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10
Q

where is the pancreas located?

A

near the kidneys

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11
Q

where are the ovaries located?

A

just below the hip

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12
Q

where are the testes located?

A

just below the hip

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13
Q

how does adrenalin affect heart rate?

A
  • adrenalin increases heart rate because it increases pressure in the coronary arteries.
  • increased pressure in the coronary arteries leads to increased heart rate because the more frequently the heart beats, the higher the blood pressure as more blood is being pumped through the arteries.
  • additionally, adrenaline affects the relaxation and contraction of the muscles in the heart, this results in the heart contracting more frequently and therefore heart rate increases.
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14
Q

how does adrenaline affect blood flow?

A
  • adrenaline increases blood flow by increasing the pressure in the coronary artery which leads to increased heart rate. Therefore blood flow increases as the heart contracts to pump blood through the arteries.
  • blood flow will increase as blood pressure and heart rate increase as all of the factors are linked and correlate.
  • as the heart rate increases, more blood is pumped around the body more quickly, blood pressure increases resulting in the blood having to flow more quickly, however, exceedingly increased blood pressure decreases the blood flow due to the blood pressure making it more difficult for the blood to flow quickly and easily (efficiently.)
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15
Q

how does adrenaline affect blood pressure?

A
  • adrenaline increases blood pressure as adrenaline increases heart rate. The increased heart rate forces blood to flow more quickly through narrow arteries, resulting in increased blood pressure.
  • adrenaline also narrows arteries which increases blood pressure as the blood has less area to flow through - much like when cholesterol prevents blood from flowing as quickly - increasing blood pressure.
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16
Q

how does adrenaline affect blood sugar levels?

A
  • as well as binding to specific receptors in the heart to increase heart rate, adrenaline binds to receptors in the liver which causes the liver to release glucose (by breaking down its glycogen stores as in homeostasis).
  • the glucose is added to the blood and therefore blood sugar levels increase.
  • adrenaline stimulates the liver to release glucose so that there is enough energy available for the “fight or flight” response which adrenaline prepares the body for.
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17
Q

What mechanism controls thyroxine levels to maintain metabolic rate?

A

the negative feedback mechanism

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18
Q

what happens when thyroxine levels are too high?

A
  • the hypothalamus is stimulated to inhibit the release of the thyrotropin releasing hormone (TRH)
  • reduced Thyrotropin releasing hormone (TRH) reduces the production of thyroid stimulating hormone (TSH) in the pituitary gland.
  • reduced thyroid stimulating hormone (TSH) reduces the production of thyroxine in the thyroid gland.
  • the thyroxine level decreases/reduces.
  • the thyroxine levels return to normal.
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19
Q

what happens when thyroxine levels are too low?

A
  • the hypothalamus is stimulated to release thyrotropin releasing hormone (TRH)
  • thyrotropin releasing hormone (TRH) stimulates the pituitary gland to release thyroid stimulating hormone (TSH)
  • thyroid stimulating hormone (TSH) stimulates the thyroid gland to release thyroxine.
  • the thyroxine level increases
  • the thyroxine levels return to normal
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20
Q

how many stages are there to the menstrual cycle?

A

there are 4 stages to the menstrual cycle

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21
Q

what happens during the first stage of the menstrual cycle?

A
  • during days 1-7 menstruation begins.
  • the lining of the uterus breaks down and is released.
  • FSH (follicle stimulating hormone) is released by the pituitary gland and causes a follicle (an egg and its surrounding cells) to mature in one of the ovaries.
  • the FSH production stimulates oestrogen production.
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22
Q

what happens during stage 2 of the menstrual cycle?

A
  • oestrogen production is stimulated by FSH production and is released by the ovaries.
  • the uterus lining (the endometrium) is repaired from day 4 to day 14 as oestrogen causes the endometrium to thicken and grow.
  • the endometrium become a thick spongy layer of blood vessels in preparation for a fertilised egg to implant there.
  • a high level, of oestrogen stimulates a surge in LH (luteinising hormone) production.
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23
Q

what happens during stage 3 of the menstrual cycle?

A
  • at day 14 LH is released by the pituitary gland and stimulates ovulation.
  • the follicle ruptures and the egg is released from ovary, this is ovulation.
  • LH stimulates the remains of the follicle to develop into a structure called the corpus luteum.
  • the corpus luteum secretes progesterone.
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24
Q

what happens during stage 4 of the menstrual cycle?

A
  • progesterone is released by the corpus luteum following ovulation.
  • progesterone maintains the endometrium and inhibits the production of LH and FSH.
  • if fertilisation has not taken place then the corpus luteum fades away. as the corpus luteum secrets progesterone the progesterone level will decrease.
  • when the levels of progesterone decrease and there is a low oestrogen level, the endometrium breaks down.
  • the uterine lining detaches at around day 28,
  • the low progesterone level allows FSH to increase so the menstrual cycle starts again.
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25
Q

what is the endometrium?

A

the uterus lining

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26
Q

what does FSH stand for?

A

Follicle stimulating hormone

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27
Q

what does LH stand for?

A

luteinising hormone

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28
Q

where is FSH released from?

A

the pituitary gland

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29
Q

where is oestrogen released from?

A

the ovaries

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30
Q

where is LH released from?

A

the pituitary gland

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31
Q

where is progesterone released from?

A

the corpus luteum

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32
Q

what is the function of FSH?

A

FSH stimulates oestrogen production and causes a follicle to mature in one of the ovaries. a follicle is an egg and it’s surrounding cells.

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33
Q

what is the function of oestrogen?

A

oestrogen causes the lining of the uterus to thicken and grow. The uterus lining (the endometrium) thickens until day 14 when ovulation begins. Following ovulation oestrogen production decreases if the egg is not fertilised.

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34
Q

what is the function of LH?

A

A high level of oestrogen stimulates an LH surge. The LH surge stimulates ovulation (at day 14).

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35
Q

what is the function of progesterone?

A
  • Progesterone is released after ovulation.
  • Progesterone maintains the lining of uterus and inhibits the release of FSH and LH.
  • The uterus lining (the endometrium) breaks down if there is a low oestrogen level and a low progesterone level.
  • The low progesterone level allows FSH to increase and then the menstrual cycle begins again.
  • If the egg is not fertilised then the level of progesterone will decrease, therefore the menstrual cycle begins again if the egg is not fertilised.
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36
Q

why are men who have had their testes removed at Moore risk of developing brittle bones?

A

they are more at risk because testosterone leads to denser bones in males compared to females. As the testes are glands which produce testosterone, if the testes are removed then less testosterone will be produced so there is an increased risk of brittle bones.

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37
Q

What are the methods of contraception?

A
  • the diaphragm
  • female condom
  • the male condom
  • IUD
  • Combined pill
  • mini pill
  • combined patch
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38
Q

what are the barrier methods of contraception?

A
  • diaphragm
  • female condom
  • male condom
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39
Q

what are the hormonal methods of contraception?

A
  • IUD
  • combined pill
  • mini pill
  • combined patch
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40
Q

how does the diaphragm work as a method of contraception?

A
  • inserted into the vagina before sexual intercourse
  • it blocks the cervix
  • it has to be used with a spermicide to be effective
  • it stops the sperm from reaching the egg and the spermicide kills the sperm and the cap stops the sperm.
  • it has to stay in the vagina for at least 6 hours after sex for prevention of pregnancy
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41
Q

what are the advantages of the diaphragm as a method of contraception?

A
  • doesn’t have to be used all the time
  • no associated health risks
  • can add extra spermicide
  • suitable for unplanned sex
  • reusable
  • has no effect on periods
  • fertility returns to normal afterwards
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42
Q

what are the disadvantages of the diaphragm as a method of contraception?

A
  • not as effective as other types of contraception
  • only provides limited protection against STIs
  • cystitis can be a problem for some women
  • latex and spermicide can cause irritations for some women and their partners
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43
Q

how does the female condom work?

A
  • it is worn inside the vagina

* it stops sperm getting into the uterus

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44
Q

what are the advantages of using a female condom as a method of contraception?

A
  • protects against STIs and pregnancies
  • no medical side effects
  • can be inserted up to 8 hours before sex
  • protects both partners
  • made from polyurethane so can be used for people allergic to latex
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45
Q

what are the disadvantages of using a female condom as a method of contraception?

A
  • aren’t reusable
  • can split or tear if not used correctly
  • not as widely available as other contraception
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46
Q

how does the male condom work?

A
  • worn over the penis

* stops sperm getting into the uterus

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47
Q

what are the advantages of using a male condom as a method of contraception?

A
  • protects against STIs and pregnancies
  • no medical side effects
  • protects both partners
  • can be made of materials other than latex
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48
Q

what are the disadvantages of using a male condom as a method of contraception?

A
  • aren’t reusable
  • can split or tear is not used correctly
  • not reusable
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49
Q

what does IUD stand for?

A

Intra uterine device

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50
Q

how does IUD work as a method of contraception?

A
  • releases copper to change fluids in the womb and fallopian tubes so stops sperm from surviving.
  • can also stop fertilised eggs from implanting in the womb.
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51
Q

What are the advantages of using IUD as a method of contraception?

A
  • most women can use an IUD
  • It works straight away once fitted
  • It lasts for up to 10 years (or until removed)
  • normal fertility returns to normal as soon as it is taken out
  • it is not affected by other medicines
  • can be used by breastfeeding mothers
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52
Q

What are the disadvantages of using IUD as a method of contraception?

A
  • periods may last longer, become heavier, or more painful
  • Doesn’t protect against STIs
  • can lead to pelvic infections if an STI is contracted while using it
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53
Q

How does the combined pill work as a method of contraception?

A
  • contains oestrogen and progesterone
  • the progesterone stimulates the production of thick cervical mucus in the cervix so it is harder for sperm to reach eggs in the uterus
  • the combination of both hormones thins the lining of the womb so there is less chance of a fertilised egg implanting or being able to grow.
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54
Q

How does the mini pill work as a method of contraception?

A
  • contains progesterone
  • produces thick cervical mucus in the cervix so it’s harder for sperm to penetrate the uterus and reach eggs to fertilise them
  • prevents ovulation
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55
Q

what is the difference between IUD and IUS?

A

IUD is hormone free and IUS is hormonal

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56
Q

How does the combined patch work as a method of contraception?

A
  • delivers oestrogen and progesterone through the skin
  • prevents ovulation
  • progesterone produces thick cervical mucus in the cervix so it’s harder for sperm to reach eggs in the uterus
  • combination of both hormones thins the lining of the uterus so there is less chance of a fertilised egg implanting or being able to grow
  • works the same as the combined pill but in patch form.
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57
Q

What does ART stand for?

A

Assisted Reproductive Technology

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58
Q

What is ART?

A
  • ART includes all fertility treatments which involve handling eggs or embryos outside of the body.
  • The techniques involve treatments which deal with both the female’s eggs and the male’s sperm.
  • It works by removing eggs from a woman’s body and mixing them with sperm to make zygotes. Finally, the zygotes are put back into the female’s body.
  • procedures are usually used with fertility drugs to increase success rates
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59
Q

What does IVF stand for?

A

In Vitro Fertilisation

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60
Q

What is IVF?

A

When drugs, hormones and medicines are used for ART.

IVF is carried out using the female’s eggs and the male’s sperm and/or sperm from donors.

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61
Q

describe the process of IVF.

A
  • The woman’s natural menstrual cycle is suppressed with medication
  • FSH and LH are used to stimulate the ovaries to produce more eggs than normal
  • the eggs are monitored and hormones are used to help them mature
  • the eggs are collected
  • the eggs are out in contact with the sperm and left for a few days to fertilise
  • one or two embryos are placed into the womb
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62
Q

How are hormones used in IVF?

A

FSH and LH are used to stimulate egg production so that more than one egg can be collected for IVF

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63
Q

What is clomifene therapy?

A

Clomifene therapy is a drug treatment to stimulate ovulation.

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64
Q

How does clomifene therapy work?

A
  • Clomifene is a drug which blocks the effect of oestrogen, this makes the body increase the amounts of the two hormones essential for ovulation: FSH and LH.
  • FSH causes the eggs to mature in the ovaries and LH triggers the release of one or more mature eggs from the ovaries (ovulation)
  • by knowing when the woman will be ovulating the couple can have intercourse during this time to increase the chance of becoming pregnant.
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65
Q

What is the target organ for insulin?

A

The liver or a muscle

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66
Q

When insulin is present which substance is formed from glucose in the target cells?

A

glycogen

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67
Q

Why must blood glucose concentration be controlled?

A

To maintain a constant internal environment for the body’s enzymes to function correctly. Too little or too much glucose can damage organs, resulting in unconsciousness or death.

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68
Q

What is the cause of type 1 diabetes?

A

the person’s insulin-producing cells have been destroyed, so they do not release insulin.

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69
Q

Which parts of the body are involved in thermoregulation in the epidermis?

A

the sweat pore and hair

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70
Q

Which parts of the body are involved in thermoregulation in the dermis?

A
  • sweat gland
  • blood vessels
  • fat layer
  • temperature receptors
  • oil gland
  • hair erector muscle
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71
Q

what is the function of the blood vessel near the skin’s surface in thermoregulation?

A

it helps regulate body temperature by vasoconstriction and vasodilation

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72
Q

what is the function of the hair erector muscle in thermoregulation?

A

it contracts to make hairs stand upright when the body is too cold and relaxes to make hairs lie flat when the body is too hot

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73
Q

what is the function of the sweat pore in thermoregulation?

A

secretes sweat produced by the sweat gland on to the surface of the skin

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74
Q

what is the function of the hair in thermoregulation?

A

controlled by the hair erector muscle. when upright traps an insulating layer of air on the skin surface to increase body temperature

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75
Q

what is the function of the epidermis in thermoregulation?

A

provides a waterproof barrier on the skin surface

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76
Q

what is the function of the dermis in thermoregulation?

A

provides flexibility and strength to the skin

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77
Q

what is the function of the sweat gland in thermoregulation?

A

produces sweat to be secreted by the sweat pore. helps with thermoregulation when the body is too hot

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78
Q

what is the function of the fat layer in thermoregulation?

A

insulates the body and gives an extra padding layer t the skin

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79
Q

what is the function of the sensory cells in thermoregulation?

A

respond to stimuli and transmit information to the brain. provide information about the external temperature to the brain

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80
Q

What is the name of the condition in which the body gets too cold? What does this lead to?

A

hypothermia, death

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81
Q

What is the name of the condition in which the body gets too hot? What does this lead to?

A

heat stroke, death

82
Q

what are the structures in the urinary system?

A
  • kidney
  • renal artery
  • renal vein
  • ureter(s)
  • bladder
  • sphincter muscle
  • urethra
83
Q

what is the function of the kidney?

A

filters the blood

84
Q

what is the function of the renal artery?

A

transports blood containing waste from the body to the kidney

85
Q

what is the function of the renal vein?

A

transports blood with waste removed to the body

86
Q

what is the function of the ureter(s)?

A

tube that connects each kidney to the bladder, urine flows down it

87
Q

what is the function of the bladder?

A

stores urine

88
Q

what is the function of the sphincter muscle?

A

controls the bladder opening and closing

89
Q

what is the function of the urethra?

A

tube that urine flows out of the body from

90
Q

where does the filtration of blood happen in the kidney?

A

in the cortex

91
Q

where does selective reabsorption happen in the kidney?

A

in the medulla

92
Q

what happens in the first stage of how blood is filtered in the nephron?

A

blood enters the Bowman’s capsule under high pressure. Blood is filtered by the kidney, this is called ultrafiltration. Red blood cells and protein molecules are too big to pass out of the blood.

93
Q

what does blood contain?

A
  • urea
  • water
  • mineral ions
  • glucose
  • red blood cells
  • proteins
94
Q

what happens in the second stage or how blood is filtered in the nephron?

A

the liquid filtrate passes down the proximal convoluted tubule in the loop of Henle

95
Q

what happens in the third stage of how blood is filtered in the nephron?

A

ALL glucose is selectively reabsorbed. SOME water and mineral ions are selectively reabsorbed back into the blood in the loop of Henle

96
Q

what happens in the fourth stage of how the blood is filtered in the nephron?

A

from the distal convoluted tubule the filtrate flows into the collecting duct

97
Q

what happens in stage five of how blood is filtered in the nephron?

A

urine is formed in the collecting duct from water, mineral ions and urea

98
Q

what happens in stage six of how blood is filtered in the nephron?

A

urine flows out of the kidney via the renal pelvis into the ureter. the ureter connects the kidney to the bladder. Urine is stored in the bladder and leaves the body through the urethra during urination.

99
Q

what substances are too big to pass into the Bowman’s capsule to be filtered?

A

red blood cells and protein molecules

100
Q

what is inside the Bowman’s capsule? What is it made up of?

A

the glomerulus, it is made up of capillaries

101
Q

what structures in the nephron are in the renal cortex of the kidney?

A

the Bowman’s capsule, the distal convoluted tubule, and the collecting duct

102
Q

what structures in the nephron are in the renal medulla of the kidney?

A

the proximal convoluted tubule and the loop of Henle,

103
Q

What are the tiny filtering units in a kidney called?

A

nephrons (or Bowman’s capsule)

104
Q

what is the process when blood is squeezed under high pressure in osmoregulation called?

A

ultrafiltration

105
Q

during ultrafiltration what are examples of the molecules which leave the blood and enter the renal tubule?

A

water, glucose, mineral ions and urea

106
Q

what is the process by which some water, salt (mineral ions) and all of the glucose re-enters the blood in osmoregulation?

A

selective reabsorption

107
Q

what is the waste liquid in osmoregulation called?

A

urine

108
Q

what are the tubes called where urine leaves the kidneys?

A

the ureters

109
Q

where does urine collect?

A

the bladder

110
Q

where is glucose reabsorbed into the blood?

A

in the loop of Henle by diffusion and active transport (at low concentrations)

111
Q

where are water and mineral ions reabsorbed into the blood?

A

in the loop of Henle by osmosis (water) and by diffusion and active transport for mineral ions (at low concentrations)

112
Q

what is osmoregulation?

A

the regulation of the amount of water in the body

113
Q

by what process does glucose move from the liquid in a nephron into the blood?

A

diffusion

114
Q

for which substances is the concentration of the substance the same in the renal vein as it is in the renal artery (in osmoregulation)?

A

glucose and protein

115
Q

for which substances is the concentration of the substance lower in the renal vein than it is in the renal artery (in osmoregulation)?

A

water and sodium (mineral ions/salt)

116
Q

how would animal cells be affected if there was too much or too little water or mineral ions in the blood?

A

cells may take in too much or lose too much water due to osmosis. this may damage cells because water in cells allows all of the molecules in the cytoplasm to undergo chemical reactions. Water is also needed to maintain cell structure, without water animal cells would shrink and with too much water animal cells would undergo lysis (burst)

117
Q

what does ADH stand for?

A

Antidiuretic hormone

118
Q

what is ADH?

A

ADH is a hormone which alters the permeability of the collecting duct in the nephron as part of osmoregulation.

119
Q

where is ADH stored?

A

in the pituitary gland

120
Q

what is ADH released into the blood by?

A

the pituitary gland

121
Q

what is ADH’s target organ?

A

the kidney

122
Q

what happens if the body is dehydrated?

A

more ADH is released by the pituitary gland, the collecting duct becomes more permeable, more water is absorbed so less water passes into the urine and more water passes into the blood

123
Q

what happens if there is a lot of water in the blood?

A

Less ADH is released by the pituitary gland, the collecting duct becomes less permeable, less water is reabsorbed so more water passes into the urine and less water passes into the blood

124
Q

what happens to urine when salty foods are eaten?

A
  • the sodium ions increase
  • the level of ADH stored in the pituitary gland decreases, more ADH enters the blood
  • the amount of water selectively reabsorbed into the blood increases
  • the urine becomes more concentrated, decreased volume of urine produced
  • dehydration is prevented
125
Q

what happens to urine when too much water is drunk?

A
  • the water increases
  • the level of ADH stored in the pituitary gland increases, less ADH enters the blood
  • the amount of water selectively reabsorbed into the blood decreases
  • the urine becomes more diluted, increased volume of urine produced
126
Q

how is urea made?

A
  • protein enters the body in food
  • the protein is digested by enzymes (proteases) into small molecules of amino acids
  • the amino acids are absorbed into the blood stream in the small intestine during digestion
  • excess amino acids are taken in the blood to the liver to be broken down
  • the liver breaks down the amino acids in a process called deamination which produces urea which is a toxic waste product
127
Q

what are the enzymes which break down proteins?

A

proteases

128
Q

what is deamination?

A

when the liver breaks down excess amino acids to produce urea

129
Q

what are hormones?

A

hormones are chemicals released directly into the blood, which affect target cells. Hormones control ‘things’ in organs and cells that need constant regulation and adjustment.

130
Q

what glands make up the endocrine system?

A

endocrine glands

131
Q

what are endocrine glands?

A

where hormones are produced

132
Q

what are the target organs for the pituitary gland?

A

the ovaries, the kidney

133
Q

what are the endocrine glands that you need to know?

A
  • the pituitary gland
  • the thyroid gland
  • the ovaries
  • the testes
  • the adrenal glands
  • the pancreas
134
Q

what are the differences between neurones and hormones?

A

neurones: fast action, act for a short amount of time, act in a precise area.
hormones: slower action, act for a long amount of time, act in a more general way.

135
Q

why are neurone responses quick? why can’t hormones be used for these types of responses?

A

the information needs to be passed to the effectors really quickly, for example, pain signals or warnings from your eyes, hormones can’t be used for these types of responses because the hormones are too slow to carry the information quickly.

136
Q

what response does adrenalin prepare the body for?

A

fight-or-flight response

137
Q

describe the process in which adrenalin prepares the body for a fight-or-flight response.

A
  • adrenalin binds to specific receptors in the heart which causes the heart muscle to contract more frequently and more forcefully so heart rate and blood pressure.
  • this increases blood flow to the muscles so the cells receive more oxygen and glucose for increased respiration
  • adrenalin binds to receptors in the liver to cause the liver to break down its glycogen stores to release glucose.
  • this increases blood glucose level so there’s more glucose in the blood to be transported to cells.

overall, heart rate increases, blood pressure increases, blood flow increases, blood glucose levels increases, and respiration increases in cells for more energy in the fight-or-flight response.

138
Q

what system controls the levels of hormones in the blood?

A

the negative feedback system

139
Q

what can an underactive thyroid gland cause?

A

weight gain because less thyroxine means that the metabolic rate decreases, this results in less of the glucose which is taken into the body being broken down in respiration and so more is stored as fat.

140
Q

what is the menstrual cycle?

A

a monthly sequence of events in which the female body releases an egg and prepares the uterus in case the egg is fertilised.

141
Q

what is another name for the uterus?

A

the womb

142
Q

what is the womb also known as?

A

the uterus

143
Q

what happens if a fertilised egg implants in the uterus?

A

the woman becomes pregnant and the level of progesterone will remain high to maintain the lining of the uterus during pregnancy

144
Q

what are the main methods an infertile couple could resort to in order to become pregnant?

A

clomifene therapy and IVF

145
Q

how does IVF work?

A

eggs are collected from the female’s ovaries and they are fertilised in a lab using the male’s sperm. before egg collection FSH and LH are given to stimulate egg production. when the embryos have developed into balls of cells on or two of them are implanted into the uterus to improve the chance of pregnancy.

146
Q

how can oestrogen be used as a contraceptive?

A

oestrogen can be used to prevent the release of an egg. although oestrogen is naturally used to stimulate the release of eggs, if it is taken every day to maintain a high level of oestrogen then it inhibits the production of FSH and as a result egg development and egg production stop.

147
Q

how can progesterone be used as a contraceptive?

A

progesterone can be used to reduce fertility by stimulating the production of thick cervical mucus, preventing sperm from getting through the cervix and reaching an egg

148
Q

what is the entrance to the uterus also called?

A

the cervix

149
Q

what is the cervix?

A

the entrance to the uterus

150
Q

which types of contraceptives are more effective when used correctly?

A

hormonal contraceptives

151
Q

what is homeostasis?

A

maintaining a constant internal environment

152
Q

what does MACIE stand for?

A

maintaining a constant internal environment.

153
Q

why does the body have to have a constant internal environment?

A

to keep cells in the correct conditions in order to function properly, this includes the correct conditions for enzyme action. it can damage organs and result in unconsciousness or death if the body’s conditions vary too much from normal levels.

154
Q

what are the main processes in homeostasis?

A
  • blood glucose regulation
  • thermoregulation
  • osmoregulation
155
Q

what can the negative feedback mechanism be used for?

A

homeostasis (blood glucose regulation, thermoregulation and osmoregulation) and controlling the levels of hormones in the blood.

156
Q

what is an example of when homeostasis doesn’t work?

A

diabetes

157
Q

what is type 1 diabetes?

A

a condition when the pancreas produces little to no insulin

158
Q

how can a person with type 1 diabetes be treated?

A

with insulin therapy: this usually involves injecting insulin into the blood and is often done at mealtimes so the glucose is removed from the blood quickly once the food has digested.

159
Q

where is insulin normally injected in people with type 1 diabetes?

A

in the subcutaneous tissue - the fatty tissue just underneath the skin

160
Q

what does the amount of insulin someone with type 1 diabetes needs to inject depend on?

A

the person’s diet and how active they are

161
Q

what do people with type 1 diabetes need to consider apart from insulin therapy?

A
  • limiting their intake of foods rich in simply carbohydrates (sugars) which cause the blood glucose level to rise rapidly.
  • taking regular exercise which helps to remove excess glucose from the blood
162
Q

what are the dangers of injecting too much insulin in insulin therapy?

A

it could result in a dangerously low blood glucose level

163
Q

what is type 2 diabetes?

A

a condition when the pancreas doesn’t produce enough insulin or when a person becomes resistant to insulin (their body’s cells don’t respond properly to the hormone)

164
Q

which type of diabetes correlates with obesity?

A

type 2

165
Q

when are people classed as obese?

A

when they have a BMI over 30

166
Q

what does BMI stand for?

A

Body Mass Index

167
Q

How is BMI worked out?

A

mass (kg)
—————
height² (m)

168
Q

what is associated with an increased risk of type 2 diabetes?

A

a lot of fat being stored around the abdomen (tummy area)

169
Q

how can you get an indication about how fat is stored in someone’s body?

A

calculate their waist-to-hip ratio

170
Q

how do you calculate waist-to-hip ratio?

A 
waist circumference (cm)
———————————
hip circumference (cm)
171
Q

a waist-to-hip ratio above what is associated with an increased risk of type 2 diabetes in men? why?

A

1.0, because it indicates that a lot of fat is being stored around the abdomen

172
Q

a waist-to-hip ratio above what is associated with an increased risk of type 2 diabetes in women? why?

A

0.85, because it indicates that a lot of fat is being stored around the abdomen.

173
Q

how can type 2 diabetes be controlled?

A

by eating a healthy diet, getting regular exercise and losing weight if needed. some people with type 2 diabetes also have medication or insulin injections.

174
Q

what is the optimum temperature for enzymes in the body?

A

37°C

175
Q

what happens to enzymes when above their optimum temperature?

A

they begin to denature and so they can’t work at all and enzyme activity stops

176
Q

what happens to enzymes below their optimum temperature?

A

enzyme activity decreases

177
Q

what happens when the body temperature changes?

A

the thermoregulatory centre reverts the body temperature back to 37°C

178
Q

where is the thermoregulatory centre?

A

in the hypothalamus

179
Q

how does the thermoregulatory centre work?

A

it contains receptors that are sensitive to blood temperature in the brain and it receives impulses from nerve endings in the skin which provide information about the external temperature. these nerve endings are in the dermis and epidermis.

180
Q

how does thermoregulation work when you are too hot?

A
  • the erector muscles relax so the hairs on the skin lie flat so there is not an insulating layer of air
  • lots of sweat (containing water and salt) is produced pub the sweat glands in the dermis. Sweat is released onto the skin and when the sweat evaporates energy is transferred from the skin to the environment, cooling the body down.
  • the blood vessels near the surface of the skin dilate, resulting in more blood flow near the skin surface so more energy is transferred to the surroundings. This is vasodilation.
181
Q

how does thermoregulation work when you are too cold?

A
  • the erector muscles contract and the hairs stand upright on the skin to form an insulating layer of air
  • little sweat is produced
  • blood vessels near the surface of the skin constrict, resulting in less blood flow near the skin surface so less energy is transferred to the surroundings. this is vasoconstriction
  • shivering is your muscles contracting automatically, increasing the rate of respiration, this transfers energy to warm the body.
182
Q

what structures in the skin used for thermoregulation are in the epidermis?

A

the sweat pore and hair

183
Q

what structures in the skin used for thermoregulation are in the dermis?

A

sweat gland, blood vessels, fat layer, temperature receptors, oil gland and hair erector muscle

184
Q

how can the body gain heat apart from processes involved in thermoregulation?

A

exercise generates heat because muscles need to respire to contract more and wearing more clothes insulates the body

185
Q

how can the body lose heat apart from by processes involved in thermoregulation?

A

wearing fewer clothes allows heat loss

186
Q

why is osmoregulation important?

A

to keep cells functioning properly, containing the correct amounts of water

187
Q

what happens to cells if the blood contains too much water?

A

if the concentration of water in the blood is too high then water will move into the body’s cells by osmosis (from an area of higher water potential to an area of lower water potential). if too much water moves into the cells the cells will undergo lysis (burst), animal cells burst when they contain too much water because they don’t have a rigid cell wall (unlike plant cells)

188
Q

what happens to cells if the blood contains too little water?

A

if the concentration of water in the blood is too low then water will move out of the cells into the blood by osmosis (from an area of higher water potential to an area of lower water potential), when the water starts move from the cells the cells will shrink.

189
Q

what are the three main roles of the kidneys in the urinary system?

A
  • removal of urea from the blood
  • adjustment of ion levels in the blood
  • adjustment of water content of the blood
190
Q

how are the structures of the nephron in animals living in drought conditions different to that of humans?

A

they have a longer Loop of Henle to absorb more water

191
Q

what concentration of salts and glucose does dialysis fluid have?

A

the same concentration of salts and glucose as blood plasma so glucose and salts are removed from the patient’s blood in dialysis

192
Q

if the thyroid is overactive what physically happens to it?

A

becomes enlarged and increases in size to form a goiter (like a large lump in the neck where the thyroid is)

193
Q

if the thyroid gland is underactive what physically happens to it?

A

it decreases in size

194
Q

what are some issues to be considered with surrogacy as an infertility treatment?

A
  • difficultly making mother and baby bond
  • baby is not genetically linked to one or both of the parents
  • it is difficult to find a surrogate mother
  • the surrogate mother may not wish to give up the baby
  • health issues / genetic disorders
195
Q

what is one of testosterone’s target organs?

A

the bones

196
Q

what are the target organs for insulin?

A

the liver and muscles

197
Q

why would using some sort of blood glucose monitor help someone with type 1 diabetes?

A
  • it would help them determine the exact dose of insulin needed
  • the monitor would track the long-term effects of diabetes
  • the data would allow patients to understand their condition better
  • the data would be useful to health professionals
198
Q

approximately how long do kidney transplant patients have to wait for a kidney for the transplant?

A

approximately 2 to 3 years

199
Q

what does the patient need to do after a kidney transplant?

A

they must take immunosuppressants for the rest of their life to stop the immune system from attacking the kidney and rejecting it.

also lifestyle changes: no smoking, regular exercise, reducing alcohol intake, not taking drugs, having a healthy diet (avoiding foods with a high level of salt which could increase blood pressure) and avoiding foods with a high risk of food poisoning because the immune system will be weaker due to the immunosuppressants

200
Q

how long does a transplanted kidney last for?

A

on average:
95% last 1 year
85%-90% last 5 years
75% last 10 years

GCSE Edexcel Biology grade 9-1 course, topics 6-9 (3 decks)

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