Homeostasis and Hormones Flashcards Preview

GCSE Edexcel Biology - PAPER 2 > Homeostasis and Hormones > Flashcards

Flashcards in Homeostasis and Hormones Deck (47)
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1
Q

What are hormones?

A

Chemicals that target certain organs which create a specific response.

2
Q

What are hormones produced by?

A

Endocrine glands.

3
Q

How do hormones travel to their target organs?

A

They travel through the blood.

4
Q

Where are TRH and CRH produced and what is its target organ?

A

They are both produced in the hypothalamus in the brain.

-They target the pituitary gland.

5
Q

Where are TSH, ADH, FSH, and LH produced and what are their target organs?

A

They are all produced in the pituitary gland.

  • FSH and LH targets the ovaries
  • ADH targets the kidney
  • TSH targets the thyroid gland
6
Q

Where is adrenalin produced and what organs does it target?

A

It is produced in the adrenal gland.

- It targets various organs like the heart, liver, and skin etc.

7
Q

Where are oestrogen and progesterone produced and which organs do they target?

A

They are both produced in the ovaries.

  • Oestrogen targets the ovaries, uterus, and pituitary gland
  • Progesterone targets the uterus
8
Q

Where is testosterone produced and what organs does it target?

A

It is produced in the testis and it targets the male reproductive system.

9
Q

Where are insulin and glucagon produced and what are their target organs?

A

They are both produced in the pancreas.

They both target the liver, and muscle and adipose tissue.

10
Q

Where is thyroxine produced and what organs does it target?

A

It is produced in the thyroid gland and targets the digestive system, the heart, the brain and bones (it is important for good health).

11
Q

What is negative feedback?

A

When a change from the normal level (higher or lower) brings about more changes to restore it to the normal level.

12
Q

What response is adrenalin responsible for?

A

The ‘fight or flight’ response.

13
Q

How does adrenalin affect your body?

A
  • It increases heart rate
  • Dilates blood vessels that take blood to the muscles
  • Constrict blood vessels that aren’t going to vital organs.
  • Causes the liver to convert glycogen into glucose
14
Q

How does thyroxine affect your body?

A
  • It controls your metabolic rate, which is the rate at which cells respire.
15
Q

Which hormones control the menstrual cycle?

A
  • Oestrogen
  • Progesterone
  • FSH
  • LH
16
Q

What is menstruation?

A

It is the break down of the uterus lining after the egg that has been released is not fertilised. This lasts from day 1 for about 5 days.

17
Q

What happens during the second week of the menstrual cycle?

A

The uterus lining gradually builds up.

18
Q

What is ovulation?

A

On around day 14, an egg is released from an ovary.

19
Q

Between which days in the menstrual cycle is fertilisation most likely to take place?

A

From around day 14 to 16.

20
Q

What happens during most of week 3 and week 4 of the menstrual cycle?

A

The uterus lining continues to build up.

21
Q

What happens if fertilisation occurs?

A

The uterus lining is maintained and menstruation does not occur.

22
Q

What happens if fertilisation does not occur?

A

Menstruation occurs and the menstrual cycle repeats.

23
Q

What is contraception?

A

A way to prevent fertilisation.

24
Q

How does hormonal contraception work and what are some examples?

A
It works by releasing hormones to prevent ovulation and thicken the mucus at the cervix to prevent sperm from passing.
It includes:
  - hormone pills
  - hormone implants
  - hormone injections
25
Q

How do barrier methods of contraception work and what are some examples?

A
Barrier methods prevent sperm from reaching the egg with a physical barrier.
These include:
  - condoms (male and female)
  - the diaphragm
  - caps
  - sponges
26
Q

What are the levels of progesterone and oestrogen during menstruation?

A
Progesterone = low
Oestrogen = high
27
Q

What do high levels of oestrogen stimulate?

A

The release of LH.

28
Q

What do low levels of progesterone stimulate?

A

The release of FSH

29
Q

What does FSH do?

A

It stimulates the growth and maturation of follicles.

30
Q

What does LH do?

A

Trigger ovulation.

31
Q

What do maturing follicles stimulate?

A

A rise in oestrogen levels.

32
Q

What happens to progesterone levels when the egg is released?

A

Progesterone levels experience a sudden increase.

33
Q

What does oestrogen do?

A

Builds the uterus wall.

34
Q

What does progesterone do?

A

Maintains the uterus wall.

35
Q

What do increases in oestrogen and progesterone do?

A

Cause thickening in the uterus wall.

36
Q

What does a decrease in oestrogen and progesterone stimulate?

A

It triggers menstruation.

37
Q

What is clomifene?

A

A fertility drug that causes an increase in FSH and LH.

38
Q

What is IVF (In-vitro fertilisation)?

A

Fertilisation outside a woman’s body.

- This is offered to people who struggle conceiving.

39
Q

What is the definition of Homeostasis?

A

Maintaining conditions inside the body at a constant level.

40
Q

What is osmoregulation?

A

It controls how much water is lost in urine and the amount of water in the body.

41
Q

What is thermoregulation?

A

It keeps core body temperature steady at around 37°C.

- It is controlled by the hypothalamus which triggers changes in the skin and muscles.

42
Q

What changes occur in the body when it is too hot?

A
  • Blood vessels near the skin will dilate to flow more blood near the skin.
  • Sweat glands release more sweat onto the skin surface to evaporate.
  • Sebaceous glands produce oil that helps sweat to spread out over the skin.
    • All of this increases transfer of energy (heat) into the surroundings.
43
Q

What changes occur in the body when it is too cold?

A
  • Blood vessels near the skin will constrict to reduce the flow of blood near the skin.
  • Sweat glands stop producing sweat.
  • Body hairs are raised by erector muscles in skin.
  • Shivering
    • All of this reduces the transfer of energy (heat) into the surroundings.
44
Q

What is vasoconstriction?

A

Blood vessels constrict to restrict the amount of blood flow.
- Less in surface capillaries and more in deep skin
vessels.

45
Q

What is vasodilation?

A

Blood vessels dilate to increase the amount of blood flow.

- Less in deep skin vessels and more in surface capillaries.

46
Q

What happens in the pancreas when the blood glucose levels are too high?

A
  • Pancreas detects rise in blood glucose concentration.
  • Pancreas increases the amount of insulin and decreases the amount of glucagon.
  • Increased insulin causes muscles and liver cells to remove glucose from blood and store it as glycogen.
  • Blood glucose concentration decreases.
47
Q

What happens in the pancreas when the blood glucose levels are too low?

A
  • Pancreas detects fall in blood glucose concentration.
  • Pancreas decreases the amount of insulin and increases the amount of glucagon.
  • Increased glucagon causes liver cells to convert stored glycogen into glucose and release it into the blood.
  • Blood glucose concentration increases.