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Biology Paper 2 > B11 Hormonal coordination > Flashcards

B11 Hormonal coordination Flashcards

1
Q

What is a hormone?

A

A large molecule/chemical produced in endocrine gland that provides body’s chemical coordination, carried around the body in the blood to target organs where it produces an effect.

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2
Q

What is an endocrine gland?

A

A gland that produces hormones and secretes them directly into the blood

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3
Q

What is the endocrine system?

A

The glands that produce hormones that control many aspects of the development and metabolism of the body

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4
Q

How is blood glucose concentration monitored and controlled by the body?

A
  • Controlled by the pancreas
  • BLOOD GLUCOSE CONCENTRATION RISES: The pancreas produces the hormone insulin, which allows glucose to move from the blood into the cells and to be stored as glycogen in the liver and muscles
  • BLOOD GLUCOSE CONCENTRATION FALLS: The pancreas produces glucagon, which allows glycogen to be converted back into glucose and released into the blood
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5
Q

Key differences between nervous control and hormonal control

A

Nerves:
- very fast action
- act for a very short time
- act on a very precise area

Hormones:
- slower action
- act for a long time
- act in a more general way

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6
Q

Rapid response hormones - examples

A

Insulin and adrenaline

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7
Q

Slow response hormones - examples

A

Growth and sex hormones

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8
Q

The main endocrine glands in the body

A

Pituitary gland, Thyroid gland, Adrenal gland, Pancreas, Ovary gland (female), Testis gland (male)

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9
Q

Pituitary gland - role of hormones

A
  • Controls growth in children
  • Stimulates the thyroid gland to make thyroxine to control the rate of metabolism
  • In women, stimulates the ovaries to produce and release eggs and make the female sex hormone oestrogen
  • In men, stimulates the testes to make sperm and the male sex hormone testosterone
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10
Q

Thyroid gland - role of hormones

A

Controls the metabolic rate of the body

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11
Q

Pancreas - role of hormones

A

Control the levels of glucose in the blood

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12
Q

Adrenal gland - role of hormones

A

Prepares the body for stressful situations - ‘fight or flight’ response

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13
Q

Ovaries - role of hormones

A

Controls the development of the female secondary sexual characteristics and is involved in the menstrual cycle

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14
Q

Testes - role of hormones

A

Controls the development of the male secondary sexual characteristics and is involved in the production of sperm

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15
Q

Which gland secretes adrenaline?

A

Adrenal gland

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16
Q

Which gland secretes FSH?

A

Pituitary gland

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17
Q

What does the thyroid control?

A

Metabolic rate

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18
Q

What does the pancreas control?

A

Blood glucose concentration

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19
Q

Where is testosterone secreted from?

A

Testes

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20
Q

Where is progesterone and oestrogen secreted from?

A

Ovaries

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21
Q

What happens when you get scared?

A

Adrenal glands (located at the top of your kidneys) secrete lots of adrenaline that is carried rapidly around the body, in the blood, affecting lots of organs.
Adrenaline causes:
- Increase in heart and breathing rate
- Stored glycogen in the liver converted to glucose for respiration
- Pupils dilate to let in more light
- Mental awareness to increase
- Blood to be diverted away from digestive system to the big muscles of the limbs, boosts delivery of oxygen in preparation for fight or flight

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22
Q

Which two hormones do Thyroxine inhibit?

A

TSH and TRH

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23
Q

What is sugar used for in the body?

A

Respiration

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24
Q

Thyroxine and negative feedback

A
  • If thyroxine levels rise, TSH levels fall, so thyroxine levels return to normal
  • If thyroxine levels fall, TSH levels rise, so thyroxine levels return to normal
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25
Q

The pancreas - endocrine and exocrine

A

Endocrine = secretes hormones into the bloodstream
Exocrine = secretes enzymes through pancreatic duct

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26
Q

Which enzymes does the exocrine system secrete?

A

Amylase, protease, lipase

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27
Q

Endocrine and exocrine system - the pancreas cross-section

A

Endocrine
- α cells secrete glucagon
- β cells secrete insulin

Exocrine
- cells that secrete enzymes

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28
Q

Function of insulin and glucagon

A

Insulin
- Causes cells in the body to take in glucose
- Causes cells in the liver to convert glucose into glycogen, for storage

Glucagon
- Causes cells in the liver to convert glycogen into glucose

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29
Q

What is the benefit of blood being diverted away from your digestive system and towards your muscles when adrenaline is secreted?

A

More glucose and oxygen is supplied to muscles, which allows more aerobic respiration in preparation for fight or flight

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30
Q

What causes diabetes?

A

Type 1 diabetes
- Pancreas is unable to produce any insulin
- blood glucose concentration is not controlled

Type 2 diabetes
- Very common type of diabetes
- Linked with obesity, lack of exercise or both
- Also a strong genetic tendency to develop type 2 diabetes
- Pancreas still makes insulin, although it may make less than the body needs
- Body cells stop responding to its own insulin

31
Q

Treating type 1 diabetes

A

Management
- They must inject insulin each day, before meals. This injected insulin allows glucose to be taken into by the blood cells and converted into glycogen in the liver.
- This stops the glucose concentration in the blood from getting too high
- As blood glucose levels fall, the glycogen is converted back to glucose. As a result, blood glucose levels are kept as stable as possible.

Cures
- Pancreas transplant
- Stem cell treatment to replace pancreatic cells that do not function

32
Q

What can type 1 diabetes lead to if uncontrolled?

A

Problems with eyes, kidneys, and nerves

33
Q

Treating type 2 diabetes

A
  • Eating a balanced diet with carefully controlled amounts of carbohydrates
  • Losing weight
  • Doing regular exercise
  • Drugs to help insulin work better on the body cells
  • Insulin injections
34
Q

Main risk factors for developing type 2 diabetes

A
  • AGE: being over the age of 40
  • GENETICS: having a close relative with the condition e.g. parent, brother, sister
  • WEIGHT: being overweight or obese
  • ETHNICITY: South Asian, Chinese, African-Caribbean or black African
35
Q

Name the body organ that detects blood glucose concentration and secretes hormones to control blood glucose concentration

A

Pancreas

36
Q

Under what conditions is insulin secreted?

A

High blood glucose concentration

37
Q

What does insulin do?

A

Increases uptake of glucose by cells, increases conversion of glucose to glycogen in the liver

38
Q

The hormone insulin is a protein. Suggest why swallowing an insulin pill will have no effect.

A

Protease enzymes in the digestive system would break it down

39
Q

Explain why a person may have to inject less insulin on days when they use up a lot of energy.

A

Glucose would be used in respiration so less insulin would be required to reduce levels in the blood

40
Q

Female secondary sexual characteristics

A
  • Starts between the ages of 8-14
  • Trigged by oestrogen
  • Breasts develop
  • Mature eggs start to form
  • Fat deposited on hips, buttocks, and thighs
  • The uterus grows and becomes active and menstruation begins
41
Q

Male secondary sexual characteristics

A
  • Starts between the ages of 9-15
  • Trigged by testosterone
  • Testes grow and become active, producing sperm
  • Facial hair
  • Larynx gets bigger and voice breaks
  • Shoulders and chest broaden
42
Q

Both male and female secondary sexual characteristics

A
  • Growth spurt
  • Pubic hair
  • Underarm hair
  • External genitals grow and skin darkens
  • Brain matures
43
Q

The menstrual cycle

A

STEP 1: Day 1 - FSH produced by the pituitary gland causes both an egg to mature and the ovaries to start producing oestrogen
STEP 2: The rising levels of oestrogen causes the uterus lining to develop, and causes the pituitary gland to stop producing FSH and produce LH instead
STEP 3: Day 14 - LH causes ovulation to take place, the egg moves from the ovary into the fallopian tube
STEP 4: The empty egg follicle secretes progesterone
STEP 5: Progesterone maintains the lining of the uterus, it also inhibits FSH and LH so that no more eggs mature or are released for the time being

44
Q

What happens if the egg is not fertilised?

A
  • Empty egg follicle gradually stops secreting progesterone
  • As progesterone levels fall the uterus lining is lost (menstruation)
  • Lower levels of progesterone also means that FSH and LH are no longer inhibited
45
Q

What happens if the egg is fertilised ?

A

As the egg develops it begins to secrete progesterone which maintains the uterus lining during pregnancy

46
Q

FSH

A
  • Secreted by pituitary gland
  • Causes an egg to mature and ovaries to produce oestrogen
47
Q

LH

A
  • Secreted by the pituitary gland
  • Stimulates the release of the mature egg (ovulation)
48
Q

Oestrogen

A
  • Secreted by the ovaries
  • Causes the lining of the uterus to develop and stimulates the release of LH
49
Q

Progesterone

A
  • Secreted by the ovaries (empty egg follicle)
  • Maintains the lining of the uterus and inhibits the release of FSH and LH
50
Q

Female fertility

A
  • Ovaries of a baby girl contain all the eggs she will ever have
  • After puberty, eggs mature and are released every month, for an average of 35-40 years, except if she is pregnant
  • Eventually the eggs run out and the woman goes through menopause
  • Approaching menopause the woman is less fertile and has a higher risk of having a baby with genetic problems
51
Q

Why is only one egg matured each month?

A
  • FSH is required for an egg to mature
  • As FSH levels start to rise and one egg is matured, it stimulates the secretion of oestrogen, which inhibits the secretion of FSH, so the levels drop
  • In addition, progesterone from the empty egg follicle also inhibits FSH, preventing any further eggs from maturing
52
Q

Hormone contraceptives - progesterone only, progesterone and oestrogen

A

Progesterone only
- inhibits the release of LH and FSH
- Eggs cannot mature and ovulation does not take place
- Causes mucus in the cervix to thicken, making it more difficult for sperm to pass through

Progesterone and oestrogen
- also inhibits the release of LH and FSH

53
Q

Why do people use contraception?

A
  • Do not want a child at the time
  • To prevent STDs
  • To prevent population growth
  • Not in a position to raise a child: financially, emotionally, physically
54
Q

Difficulties conceiving - Male

A
  • Blocked or damaged tubes that carry sperm
  • Poor sperm quality
  • Low sperm count
  • Hormonal problems
55
Q

Difficulties conceiving - Female

A
  • Blocked fallopian tubes
  • Ovaries not releasing eggs
  • Low levels of FSH, eggs don’t mature
  • Problems with uterus lining
  • Hormonal problems
56
Q

Morning after pill

A

Uses progesterone to prevent an egg maturing and ovulation taking place. Must be taken as soon as possible.

57
Q

How is thyroxine made?

A

Iodine and amino acids

58
Q

In vitro fertilisation steps

A
  • FSH and LH are used to stimulate the maturation of several eggs
  • Eggs are collected from the mother and fertilised with sperm from the father
  • The fertilised eggs develop into embryos
  • One or two embryos are inserted into the mother’s uterus
59
Q

What is tropism?

A

A response of a plant to a specific stimulus

60
Q

What is phototropism?

A

The response of a plant’s shoot or root to light

61
Q

What is gravitropism?

A

The response of a plant’s shoot or root to gravity

62
Q

What is auxin?

A
  • A hormone which controls the growth of a plant’s roots or shoots
  • When auxin is unevenly distributed in a growing plant, the rate of growth will also be unequal
63
Q

Shoots

A

Grow towards light and against the force of gravity

64
Q

Roots

A

Grow in the direction of the force of gravity

65
Q

Auxin action - shoots and roots

A

Shoots - stimulates elongation
Roots - inhibits elongation

66
Q

Positive phototropism

A

Growth towards the light

67
Q

How do plant shoots show positive phototropism?

A
  • One side of the shoot is exposed to more light
  • Auxin is redistributed within the shoot so that the concentrations greater on the shaded side.
  • This unequal auxin distribution will result in increased cell elongation on the shaded side.
  • The shoot bends towards the light, increasing the rate of photosynthesis
  • Once light falls evenly on the shoot, the levels of auxin will be equal on all sides and so the shoot grows straight again
68
Q

How do plant shoots show negative gravitropism?

A
  • In a horizontal shoot, more auxin gathers on the lower side due to gravity
  • Increased cell elongation on the lower side, making it bend and grow up away from the force of gravity
  • When it has grown up, the auxin becomes evenly spread again
69
Q

How do plant roots show positive gravitropism?

A
  • In a horizontal shoot, more auxin gathers on the lower side
  • The root grows more on the side with least auxin, making it bend and grow down towards the force of gravity
  • When it has grown down, the auxin become evenly spread again
70
Q

Auxin uses

A
  • Weed killers
  • Rooting powder for cuttings
  • For promoting growth in tissue culture
71
Q

What can excess thyroxine cause?

A

Hyperactivity

72
Q

What can a deficiency of thyroxine cause?

A

Weight gain and sluggishness

73
Q

What are the three plant hormones?

A
  • auxin
  • ethene
  • gibberellin

Biology Paper 2 (10 decks)

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