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biology > P2B7 - Hormones, homeostasis > Flashcards

P2B7 - Hormones, homeostasis Flashcards

1
Q

What are hormones?

A

Chemical substances which act as ‘messenger’ molecules in body.

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2
Q

Where are hormones produced?

A

Endocrine glands

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3
Q

Where are hormones released?

A

Into the blood

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4
Q

What are the 6 Endocrine glands?

A

Testis
Ovaries
Thyroid
Adrenal
Pituitary
Pancreas

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5
Q

Where are the testis and what hormone do they produce?

A

Testosterone produced in the scrotum

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6
Q

Where are the ovaries and what hormone do they produce?

A

Oestrogen + Progesterone produced in the female reproductive system

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7
Q

Where is the thyroid and what hormone do they produce?

A

Thyroxine produced in the throat

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8
Q

Where is the adrenal pituitary and what hormone do they produce?

A

Adrenaline growth hormone produced in the kidneys

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9
Q

What does the pancreas produce?

A

The pancreas produces insulin and glucagon, both of which are involved in regulating blood glucose levels.

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10
Q

What is insulin and glucagon involved in?

A

Regulating blood glucose levels.

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11
Q

What does thyroxine regulate?

A

Thyroxine regulates our metabolism, heart rate and temperature.

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12
Q

What does the endocrine system coordinate?

A

The body’s response to changes in the environment using chemical messengers (hormones).

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13
Q

What does oestrogen control?

A

Puberty
One of the main hormones that regulate the period.

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14
Q

What does testosterone control?

A

Puberty
Sperm production

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15
Q

What is the main gland/master gland?

A

Pituitary gland

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16
Q

What is the master gland linked to?

A

Hypothalamus

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17
Q

Whats the differences between CNS and the Endocrine system?

A

CNS :
- Triggers rapid response.
- Uses electrical signals that are carried by neurones.
- Response is very short.
- Acts on a very precise part of the body.

ES :
- Triggers a slower response.
- Uses chemical messengers that are carried by blood.
- Response can be long-lasting.
- Can act on large areas of the body.

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18
Q

What happens if the conc of thyroxine in the blood is low?

A
  1. Hypothalamus produces TRH (Thyrotropin releasing hormone)
  2. Which causes pituitary to produce TSH (Thyroid stimulating hormone),
  3. Stimulating the release of thyroxine by the thyroid gland.
  4. Once thyroxine is regulated, TRH reduces, which reduces TSH and thyroxine.
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19
Q

What is vasoconstriction and what does it do during adrenaline?

A

When blood vessels constrict.

  • Increases heartrate and blood pressure.
  • Increase in blood flow
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20
Q

How does the liver respond when adrenaline is secreted?

A

The liver converts stored glycogen back into glucose, raising the blood sugar levels.

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21
Q

What 4 hormones control the menstrual cycle?

A

Follicle Stimulating Hormone (FSH)
Oestrogen
Luteinising Hormone (LH)
Progesterone

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22
Q

What does FSH stand for?

A

Follicle stimulating hormone

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23
Q

Where is FSH and LH released?

A

Pituitary gland

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24
Q

What does FSH cause?

A

An egg to mature
Also stimulates oestrogen production

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25
Q

Where is oestrogen and progesterone produced?

A

Ovaries
(Progesterone is produced after ovulation)

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26
Q

What does oestrogen cause?

A

The development of a thick, spongy uterus lining.
Also stimulates the production of luteinising hormone (LH) and inhibits production of FSH

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27
Q

What does inhibit mean?

A

Stops

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28
Q

What does LH stand for?

A

Luteinising hormone

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29
Q

What does LH cause?

A

Stimulates release of mature egg on Day 14 which is called ovulation.

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30
Q

What is ovulation?

A

The release of a mature egg on day 14 of menstrual cycle.

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31
Q

What is progesterone responsible for?

A

Maintaining uterus lining on days 14-28.

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32
Q

What happens when progesterone levels drop?

A

This triggers the breakdown of the lining. (This marks day 1 of the next menstrual cycle.)
Progesterone also inhibits release of LH and FSH.

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33
Q

What are the stages of the menstrual cycle?

A

Stage 1 (days1-4) : Uterus lining breaks down (Period)

Stage 2: (days 4-14) : Uterus lining builds a thick, spongy layer full of blood vessels again.

Stage 3 (day 14) : Mature egg is released from ovaries. (Ovulation)

Stage 4 (day 15-28) : Uterus lining is maintained by progesterone where it waits for a fertilised egg.

If no fertilised egg is attached to the uterus lining, it breaks down and the cycle begins again.

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34
Q

What are the two main types of contraceptive pill?

A
  • Progesterone only pill
  • Combined pill
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35
Q

What does the progesterone only pill do?

A

Stimulates the production of thick, sticky mucus, which is difficult for sperm to penetrate.
Inhibits the release of FSH, so eggs don’t mature.
Fewer side effects than combined.

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36
Q

What does the combined pill contain and what does it do?

A

Contains both oestrogen and progesterone.
By taking it every day, enough oestrogen builds up in the female body to inhibit the production of FSH so that no eggs mature.

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37
Q

What are the 3 other contraceptive options?

A

Contraceptive patch
Contraceptive implant
Contraceptive injection

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38
Q

How does the contraceptive patch work?

A

It steadily releases progesterone.
Only needs to be changed once a week

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39
Q

How does the contraceptive implant work?

A

Its inserted under the skin and continuously releases small amounts of progesterone.
Can last for 3 years.

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40
Q

How does the contraceptive injection work?

A

Contains progesterone and can last for 3 months.

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41
Q

What are 2 contraceptive methods that are inserted into the womans body?

A

Diaphragm
IUD (Intrauterine devices)

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42
Q

What is a diaphragm?

A

A shallow plastic cup, which is inserted into the vagina prior to sexual intercourse and sits at the entrance to the uterus.
It is designed to prevent the sperm from reaching the egg.
It can also be covered in a spermicide to kill the sperm.

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43
Q

What is an IUD?

A

This is also known as the coil.
They are small t-shaped devices that are inserted into the uterus.
They work by preventing implantation of an embryo (fertilised egg).
Some intrauterine devices also release progesterone.

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44
Q

What are some natural methods of contraceptives?

A

Abstinence (nosex)
Timing

45
Q

How does timing work as a method of contraceptive?

A

Since a female’s body temperature usually rises during ovulation, some women choose to avoid sexual intercourse on days when they know (or feel) that they are ovulating.
However, sperm can last up to six days inside the woman’s body, so this is not a very reliable or effective method of contraception.

46
Q

What is a sterilisation in a woman?

A

For a female, this involves having the fallopian tubes (ducts which connect the ovaries to the uterus) cut so that an egg cannot reach the uterus.

47
Q

What is a sterilisation a man?

A

For a male, this involves having the sperm ducts (the tubes between the testes and the penis) cut so that the sperm are not released on ejaculation.

48
Q

Why does some women not have eggs that are matured?

A

Some women do not have high enough levels of FSH to stimulate the maturation of their eggs.
This means that they are infertile.

49
Q

What are the 2 fertility treatments?

A

Clomifene
In vitro fertilisation IVF

50
Q

How does clomifene work?

A

It triggers ovulation by causing an increase in the release of FSH.
This helps the follicle mature into an egg cell and increases the concentration of LH to cause ovulation.

51
Q

How does IVF work?

A

FSH & LH are given to stimulate the growth of lots of eggs.
Eggs are collected before being fertilised in a dish in a laboratory. They are fertilised using sperm from the father.
These fertilised eggs grow into embryos and are implanted into the woman’s uterus.

52
Q

What are the disadvantages of fertility treatments?

A

Can lead to multiple pregnancies
Stress
Expensive

53
Q

What is homeostasis?

A

All of the processes that happen in a cell or organism to maintain conditions optimal.

54
Q

Why is homeostasis needed?

A

This is needed to respond to changes in the internal and external environment.

55
Q

What conditions do human bodies have to regulate?

A

Temperature
Urea
Water
Blood sugar
Carbon dioxide

56
Q

What 3 parts is the control system made of?

A

Effectors
Coordination centres
Receptors

57
Q

What does the coord centre do?

A

Coordination centres receive and process information arriving from receptor cells.

58
Q

What do effectors do>?

A

Effectors (muscles or glands) carry out responses to stimuli that help to restore optimum levels.

59
Q

What do receptor cells do?

A

Receptor cells detect changes in the environment.

60
Q

What is The Body’s Negative Feedback Loop?

A

An internal condition changes
Change detected
Corrective mechanisms activated
Internal conditions return to normal
Corrective mechanisms deactiivated
Back to start

61
Q

How do receptors on the skin help thermoregulate?

A

Receptors on the surface of the skin monitor the temperature at the surface of the body.

62
Q

How do receptors in the brain help thermoregulate?

A

Receptors in the thermoregulatory centre of our brain (called the hypothalamus) monitor the internal body temperature as blood flows through the brain.

63
Q

What happens when body temp is too high?

A

Sweat released from sweat glands.
Hairs lie flat.
Blood vessels dilate to allow more blood to enter capillaries. (vasodilation).

64
Q

What happens when body temp is too low?

A

Muscle contractions increase, causing shivering.
Hairs stand on end.
Blood vessels constrict to reduce blood flow in capillaries.
(vasoconstriction)

65
Q

What happens when shivering

A

When we are too cold, muscles start to contract automatically. This makes us shiver.
This process needs energy, which is generated through respiration.
Respiration produces heat, which warms us up.

66
Q

What happens to our body hair when we’re too hot?

A

When we are too hot, the hair erector muscle relaxes. This causes the hair to lie flat.

67
Q

What happens to our body hair when we’re too cold?

A

When we are too cold, the hair erector muscle contracts.
This causes the hair to stand on end (which pull on the skin giving you goosebumps).
When all the hairs are standing on end, they trap an insulating layer of air around the body.

68
Q

How have ducks evolved so less heat is lost when they’re in cold water?

A

Decreased blood flow to feet.

69
Q

What happens if blood glucose levels are too high?

A

This can have a negative impact on osmosis by affecting concentration gradients.

70
Q

What happens if blood glucose levels are too low?

A

Glucose is important for respiration.
Respiration releases the energy needed by every living cell.
If there is not enough glucose, an organism cannot produce enough energy.

71
Q

What is the optimal blood glucose range for humans?

A

6-8 mmol/dm3

72
Q

How is glycogen involved in the regulation of glucose?

A

If there is too much glucose, it will be converted into glycogen and stored.
If there is too little glucose, the stored glycogen will be converted back into glucose.

73
Q

Whats the process of regulating glucose if the levels are too high?

A
  1. As blood flows thru pancreas, high conc of blood glucose will be detected.
  2. This triggers the pancreas to release Insulin into bloodstream.
  3. Presence of insulin is detected by liver and muscle tissues
  4. Liver and muscle tissues take in excess glucose and convert it into glycogen. Glycogen is a form of glucose that is insoluble. Glycogen can be stored for later use.
  5. This process continues until the pancreas detects a normal blood glucose concentration
74
Q

What is Type 2 diabetes?

A

sufferers can still produce insulin, but their body no longer responds to it.

75
Q

What is Type 1 diabetes?

A

Sufferers are unable to produce enough insulin.

76
Q

Whats the timeline and treatment for Type 1 diabetes?

A
  • Develops during childhood.
  • The main treatment is to inject insulin when blood glucose levels rise too high.
    Sufferers can also manage their diet and exercise regularly to keep blood glucose levels as steady as possible.
77
Q

What is the timeline and treatment for Type 2 diabetes?

A
  • Develops later in life (Old age + overweight)
  • Sufferers must manage their diet and exercise regularly to keep blood glucose levels steady.
78
Q

Why must water levels in body be kept constant?

A

To control the amount of water and ions diffusing in and out of cells..

79
Q

What factors may disrupt the bodys water balance and why?

A
  • Sweating : Water, ions and urea are all lost in sweat.
  • Eating too much salt : Can make blood ion conc too high
  • Exhalation : Water in lungs leave in persons breath
  • Illness : Illnesses that cause fever, vomiting or diarrhoea can result in dehydration (the blood’s water concentration is too low).
80
Q

Why must blood be kept isotonic?

A

So cells don’t burst or shrink

81
Q

How is the conc in hypertonic solutions described?

A

A hypertonic solution has a lower water concentration and a higher ion concentration than cells.

82
Q

What happens if the blood becomes hypertonic?

A

If the blood becomes hypertonic, cells lose water by osmosis and shrink.

83
Q

How is the conc in hypotonic solutions described?

A

A hypotonic solution has a higher water concentration and a lower ion concentration than cells.

84
Q

What happens if the blood becomes hypertonic?

A

If the blood becomes hypotonic, cells gain water by osmosis and burst.

85
Q

How is the conc in isotonic solutions described?

A

An isotonic solution has the same water and ion concentration as cells.

86
Q

How does the blood remain isotonic?

A

Homeostasis works to regulate the blood’s water and ion concentrations so that it remains isotonic.

87
Q

How are kidneys important for homeostasis?

A

They control the water and ion levels in the blood.

88
Q

How is the volume of water in the blood monitored?

A

By the hypothalamus in the brain.

89
Q

Why does urea need to be removed from the blood?

A

Because it’s toxic.
When there is too much urea in the bloodstream, it can harm cells and tissues.

90
Q

Why is urea formed?

A

Urea is formed when the digestion of protein results in an excess of amino acids, which can’t be stored in the body.

91
Q

What is the waste product of deamination?

A

Ammonia.

92
Q

What and where is deamination?

A

Amino acids undergo deamination in the liver.

93
Q

What is ammonia from deamination converted into?

A

The ammonia is then converted into urea and must be excreted from the body as urine.

94
Q

What are the two stages in the process of urine production?

A
  • Ultrafiltration
  • Selective reabsorption
95
Q

What is ultrafiltration?

A

The blood capillaries form a knotted cluster called a glomerulus in a part of the nephron called the Bowman’s capsule.
The blood is filtered and all water, urea and salts move into the nephron tubule.
Blood cells and proteins remain in the blood as they are too big to move across the capillary walls.

96
Q

What is selective reabsorption?

A

Useful substances, including glucose and some water, are reabsorbed from the tubule back into the bloodstream.
This leaves all urea, excess salts and excess water in the nephron tubule.
This mixture forms urine, which is collected by the kidneys and travels to the bladder to be stored and then excreted.

97
Q

What happens if theres too much water in the blood?

A

The hypothalamus triggers the pituitary gland to stop the release of anti-diuretic hormone (ADH).
This reduces the permeability of the kidney tubules. This means that less water is reabsorbed back into the bloodstream.
This results in a large volume of dilute urine.

98
Q

What happens if theres too little water in the blood?

A

The hypothalamus triggers the pituitary gland to release anti-diuretic hormone (ADH).
This increases the permeability (ability of things to pass through) of the kidney tubules. This means that more water is reabsorbed back into the bloodstream.
This results in a small volume of concentrated urine.

99
Q

What is dialysis an essential treatment for?

A

People whose kidneys cannot keep the concentrations of urea and salt at an optimum level to ensure that tissue damage does not occur.

100
Q

How does the dialysis machine work?

A

The patient is linked up to the dialysis machine and their blood flows into the machine.
The machine contains a fluid that is designed to have the optimum concentrations of salts (e.g. sodium and potassium ions) and glucose, as would be found in a healthy person’s blood.

101
Q

How does the dialysis fluid work?

A

The patients blood passes over a partially permeable membrane in the machine that is designed to replicate the kidney tubules.
The dialysis fluid is on the other side of the membrane. A concentration gradient is established, allowing excess ions and urea to diffuse from an area of high concentration in the patient’s blood to an area of low concentration in the dialysis fluid.

102
Q

How is the dialysis machine used to replicate a kidneys function?

A

The patient is linked up to the dialysis machine and their blood flows into the machine.
The machine contains a fluid that is designed to have the optimum concentrations of salts (e.g. sodium and potassium ions) and glucose, as would be found in a healthy person’s blood.
The patient’s blood passes over a partially permeable membrane in the machine that is designed to replicate the kidney tubules.
The dialysis fluid is on the other side of this membrane. A concentration gradient is established, allowing excess ions and urea to diffuse from an area of high concentration in the patient’s blood to an area of low concentration in the dialysis fluid.

103
Q

What are the disadvantages of dialysis?

A

Lasts 3-4 hours and is needed 3 times a week.
Increases risk of blood clots and infections.
Expensive process.

104
Q

What are the advantages of dialysis?

A

Dialysis is a life-saving process.
It gives a patient more time to find a donor kidney.

105
Q

What drugs do patients receiving a kidney have to take and what do they do?

A

Immunosuppressants - These drugs suppress the immune system to prevent it from attempting to destroy the foreign cells of the transplanted kidney.

106
Q

What are advantages of kidney trans-lant?

A

The patient does not need to have dialysis treatment, which is time-consuming.
Transplants are cheaper than dialysis in the long run.

107
Q

What are the disadvatges of kidneytranplant?

A

Long waiting lists for kidney transplants.
Kidney rejection.
The patient often has to take immunosuppressant drugs. These can make a patient more prone to other infections.

108
Q

Why do donor kidneys usually come from close relatives?

A

Donor kidneys often come from close relatives as it essential that the antigens on the surface of the organ are not recognised as foreign, triggering the immune response.

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