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Biology GCSE Paper 2 > Topic 5b- The Endocrine System > Flashcards

Topic 5b- The Endocrine System Flashcards

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1
Q

What are hormones?

A

Hormones are CHEMICAL MOLECULES released directly into the BLOOD.

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2
Q

How are hormones carried around the body?

A

They are carried in the blood plasma (liquid part of blood) to other parts of the body, but only affect particular cells in particular organs (called TARGET ORGANS).

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3
Q

What is the role of hormones?

A

Hormones control things in organs and cells that need CONSTANT ADJUSTMENT.

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4
Q

What’s the definition of hormones?

A

Hormones are chemical messengers which travel in the blood to activate target cells.

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5
Q

True or false? Hormones affect all organs.

A

False.

They only affect particular organs called target organs.

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6
Q

Where are hormones produced and secreted?

A

Hormones are produced in (and secreted by) various GLANDS, called ENDOCRINE GLANDS.

These glands make up your ENDOCRINE SYSTEM.

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7
Q

What is the role of the endocrine system?

A

The endocrine system uses HORMONES to react to changes in the environment or changes inside the body.

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8
Q

What are the 6 glands that secrete hormones in the endocrine system called?

A

1) The Pituitary Gland
2) Ovaries
3) Testes
4) Thyroid
5) Adrenal Gland
6) The Pancreas

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9
Q

What is the role of the pituitary gland?

A

The pituitary gland produces MANY HORMONES that regulate BODY CONDITIONS.

It is sometimes called the ‘MASTER GLAND’ because these hormones act on OTHER GLANDS, directing them to RELEASE HORMONES that bring about CHANGE.

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10
Q

What is the role of the pancreas?

A

This produces INSULIN, which is used to regulate the BLOOD GLUCOSE LEVEL.

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11
Q

What is the role of the thyroid?

A

This produces THYROXINE and GLUCAGON, which is involved in regulating things like the RATE OF METABOLISM, HEART RATE and TEMPERATURE.

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12
Q

What is the role of the adrenal gland?

A

This produces ADRENALINE, which is used to prepare the body for a ‘FIGHT OR FLIGHT’ response.

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13
Q

What is the role of ovaries (females only)?

A

Produce OESTROGEN, which is involved in the MENSTRUAL CYCLE.

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14
Q

What is the role of testes?

N.b. learn where all glands are found in body on pg 73 cgp.

A

Produce TESTOSTERONE, which controls PUBERTY and SPERM PRODUCTION in males.

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15
Q

Which produces a fast response- nerves or hormones?

A

Nerves produce a very FAST action.

Hormones have a SLOWER action.

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16
Q

How long do nerves and hormones act for?

A

Nerves act for a very SHORT TIME.

Hormones act for a LONG TIME.

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17
Q

Where do nerves and hormones act?

A

Nerves- act on a very PRECISE AREA.

Hormones- act in a more GENERAL way.

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18
Q

How do nerves and hormones travel in the body?

A

Nerves- via NEURONES.

Hormones- in the BLOOD (plasma).

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19
Q

What should you consider when deciding wether a response is nervous or hormonal?

A

1) If the response is REALLY QUICK, it’s probably NERVOUS. Some info needs to be passed to effectors really quickly (e.g. pain signals, or info from your eyes telling you about the danger heading your way), so it’s no good using hormones to carry the message-they’re too slow.
2) But is a response LASTS FOR A LONG TIME, it’s PROBABLY HORMONAL. For example, when you get a shock, a hormone called adrenaline is released into the body (causing the fight or flight response, where your body is hyped up ready for action). You can tell it’s a hormonal response despite it acting quickly because you feel a bit wobbly for a while afterwards.

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20
Q

What is glucose?

A

Glucose is a type of sugar. Throughout the day the blood glucose level varies.

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21
Q

What causes glucose levels in the body to change throughout the day?

A

1) Eating food containing CARBOHYDRATE puts GLUCOSE (a type of sugar) into the BLOOD from the gut.
2) The normal METABOLISM of cells REMOVES GLUCOSE from the blood.
3) Vigorous EXERCISE removes MUCH MORE glucose from the blood.
4) EXCESS glucose can be stored as GLYCOGEN in the liver and in the MUSCLES.

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22
Q

What monitors and controls the level of glucose in the body?

A

The LEVEL OF GLUCOSE in the BLOOD must be kept STEADY.

CHANGES are monitored and controlled by the PANCREAS.

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23
Q

What hormones are produced and secreted by the pancreas?

A

The pancreas produces and secretes the hormones INSULIN and GLUCAGON which help to control the blood glucose level in a negative feedback cycle.

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24
Q

Define negative feedback.

A

A mechanism that restores a level back to optimum in a system.

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25
Q

What effect does insulin have on a body’s cells?

A

INSULIN a hormone produced by the pancreas.

It decreases the blood glucose level when it gets too high.

It causes cells to take in more sugar from the blood and into cells which lowers blood sugar levels.

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26
Q

Explain how insulin decreases the level of sugar in the blood stream after eating a meal containing carbohydrates.

A
  1. After a meal containing carbohydrate, a person’s blood glucose level rises. This rise is detected by the pancreas.
  2. The pancreas responds by producing insulin, which is secreted into the blood.
  3. Insulin causes the body cells to take up more glucose from the blood. Cells in the liver and muscles can take up glucose and convert it into a storage molecule called GLYCOGEN.
  4. This causes the blood glucose level to fall.
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27
Q

What is glucagon?

A

GLUCAGON is another hormone produced by the pancreas. It INCREASES the blood GLUCOSE LEVEL when it gets too low.

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28
Q

Explain how glucagon increases glucose level.

A
  1. If a person’s blood glucose level decreases, the fall is detected by the pancreas.
  2. The pancreas responds by producing glucagon, which is secreted into the blood.
  3. Glucose can be stored in the muscles and liver as glycogen. Glucagon causes the glycogen to be converted back into glucose, which enters the blood.
  4. This causes the blood glucose level to rise.
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29
Q

What is the difference between glucagon and glycogen?

A

Glycogen is the storage compound of glucose.

Glucagon is a hormone which convert the stage compound of glucose (glycogen) back into glucose.

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30
Q

What is diabetes?

A

Diabetes is a condition that affects your ability to CONTROL your blood sugar level. There are two types.

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31
Q

What are the two types of diabetes called?

A
  • Type 1 diabetes

and

  • Type 2 diabetes
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32
Q

What is type 1 diabetes?

A

Type 1 diabetes is where the PANCREAS produces LITTLE or NO INSULIN.

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33
Q

Why is type 1 diabetes dangerous?

A

This means a person’s blood glucose level can RISE to a level that can KILL THEM.

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34
Q

How can type 1 diabetes be controlled?

A

There are 3 ways to control type 1 diabetes. This includes:

  1. Insulin therapy
  2. Limit the intake of foods rich in simple carbohydrates
  3. Regular exercise.
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35
Q

What is insulin therapy and how can it help control type 1 diabetes?

A

Insulin therapy- this usually involves several INJECTIONS of insulin throughout the day, most likely at mealtimes. This makes sure that GLUCOSE is REMOVED from the blood quickly once the food has been DIGESTED, stopping the level getting too high. It’s a VERY EFFECTIVE TREATMENT.

36
Q

How much insulin is injected?

A

The amount of insulin that needs to be injected depends on the person’s DIET and how ACTIVE they are.

37
Q

How can limiting the intake of foods rich in simple carbohydrates control type 1 diabetes?

A

LIMIT THE INTAKE of foods rich in SIMPLE CARBOHYDRATES- i.e. sugars (which cause the blood glucose level to rise rapidly).

People with type 1 diabetes are also advised to SPREAD their intake of STARCHY CARBOHYDRATES (e.g. pasta, rice, bread etc) throughout the day and to pick varieties of these foods that are absorbed more slowly- so they don’t cause such a sharp rise in the blood glucose level).

38
Q

How can regular exercise help to control type 1 diabetes?

A

Regular exercise- this helps to lower the blood glucose level as the increased metabolism of cells during exercise removes more glucose from the blood.

39
Q

What can prolonged periods of high glucose levels cause?

A

Prolonged periods of high glucose levels can cause damage to organs such as the eyes, heart and kidneys, resulting in long-term health problems.

40
Q

What is type 2 diabetes?

A

Type 2 diabetes is where a person becomes RESISTANT to their OWN INSULIN (they still produce insulin but their body’s cells don’t respond properly to the hormone).

This causes a person’s BLOOD SUGAR LEVEL to RISE to a dangerous level.

41
Q

What is a risk factor of getting type 2 diabetes?

A

Being OVERWEIGHT can INCREASE your chance of DEVELOPING Type 2 diabetes, as OBESITY is a major RISK FACTOR in the development of the disease.

42
Q

What are the two ways type 2 diabetes can be controlled?

A
  1. Eating a CARBOHYDRATE-CONTROLLED DIET and getting regular EXERCISE.
  2. REGULAR EXERCISE- this helps to lower the blood glucose level.
43
Q

What are the modern treatment options for people with type 1 diabetes?

A
  1. Diabetics can have a pancreas transplant. A successful operation means they won’t have to inject themselves with insulin again.

But there is possibility that your body could reject the tissue. If this happens you have to take costly immunosuppressive drugs, which often have serious side-effects.

  1. Modern research into artificial pancreases and stem cell research may mean the elimination of organ rejection, but there’s a way to go yet.
44
Q

Why is the water level in cells very important?

A

The water level in cells is very important- organisms need to maintain the concentration of their cell contents at the correct level for cell activity.

The kidneys are really important in regulating water content

45
Q

What is the role of the kidneys?

A

The kidneys make urine by taking WASTE PRODUCTS (and other unwanted substances) out of your blood.

46
Q

How do the kidneys make urine?

What is the filtering process called?

What is the reabsorption called?

A

Substances are FILTERED OUT of the blood as it passes through the kidneys.
This process is called FILTRATION. Useful substances like

GLUCOSE, some IONS and the right amount of WATER are then absorbed back into the blood.
This process is called SELECTIVE REABSORPTION.

47
Q

What is the name of the process in the kidneys where useful substances are absorbed back into the blood?

A

This process is called SELECTIVE REABSORPTION.

48
Q

Name three substances that are absorbed back into the blood in the kidney.

A

Glucose
Water
Ions

49
Q

Name three substances that should be present in the urine of a healthy person.

A

Urea
Water
(excess) Ions

50
Q

What substances are removed from the body in urine?

A

The substances that are removed from the body in URINE include:

  • Urea ( a waste product from the breakdown of proteins)
  • Ions
  • Water
51
Q

How is urea formed?

A

1) PROTEINS (and the AMINO ACIDS that they are broken down into) can’t be STORED by the body- so any EXCESS amino acids are converted into FATS and CARBOHYDRATES, which can be stored.
This occurs in the LIVER and involves a process called DEAMINATION.

2) AMMONIA is produced as a WASTE PRODUCT from this process.
3) Ammonia is TOXIC so it’s immediately converted to UREA in the liver for safe excretion.

52
Q

How is urea removed from the body?

A
  1. Urea is then transported to the KIDNEYS, where it’s FILTERED OUT of the blood and excreted from the body in URINE.
  2. A small, unregulated amount of urea is also lost from the skin in sweat.
53
Q

How are ions absorbed into the body?

A

Ions such as SODIUM are taken into the body in FOOD, and then absorbed into the blood.

54
Q

Why is it important to have the correct ion/water content in the body?

A

If the ion (or water) content of the body is WRONG, this could upset the BALANCE between ions and water, meaning too much or too little WATER is drawn into cells by OSMOSIS.

Having the wrong amount of water can DAMAGE cells or mean they DON’T WORK as well as normal.

55
Q

How is the ion content in the body adjusted?

A

Some ions are lost in SWEAT (which tastes salty).
However, this amount is NOT REGULATED, so the right BALANCE of ions in the body must be maintained by the KIDNEYS.

The right amount of ions is REABSORBED into the blood after filtration and the rest is removed from the body in URINE.

56
Q

Give two ways that water can be lost from the body?

A

The body has to CONSTANTLY BALANCE the water coming in against the water going out.

We lose water from the SKIN in SWEAT and from the LUNGS when BREATHING OUT.

57
Q

Can we control how much water we lose through sweating and exhalation?

A

Water leaves the body via the lungs during exhalation.

Water, ions and urea are lost from the skin in sweat.

There is no control over water, ion or urea loss by the lungs or skin.

58
Q

How is the amount of water in our body regulated?

A

The amount of water is balanced by the amount we CONSUME and the amount REMOVED BY THE KIDNEYS in URINE.

59
Q

How much urine is produced on a hot and cold day?

A

On a cold day, if you don’t sweat, you’ll produce more urine which will be pale and dilute.

On a hot day, you sweat a lot, and you’ll produce less urine which will be dark-coloured and concentrated.
The water lost when it is hot has to be replaced with water from food and drink to restore the balance.

60
Q

What happens when the ion content is too low?

A

If the ion content of the body is too low, or the water content is too high, water will move into the cells by osmosis. This will cause the cells to swell, and possibly burst.

61
Q

What happens when the ion content is too high?

A

If the ion content of the body is too high, or the water content is too low, water will move out of the cells by osmosis and the cells will shrivel up.

62
Q

What are kidney tubules?

A

Tubules just means a very small tube.

The structure in the kidney where filtration and selective reabsorption take place are called the kidney tubules.

63
Q

What is the function of kidney tubules?

A

The kidney can let more or less water move out of the tubules to change the water content of the blood- the more water that leaves the tubules and is reabsorbed into the blood, the more concentrated the urine will be.

64
Q

How is the concentration of urine controlled?

A

The concentration of urine is controlled by a hormone called ANTI-DIURETIC HORMONE (ADH).
This is released into the BLOODSTREAM by the pituitary gland.

65
Q

What is the role of the brain in the release of ADH?

A

The brain MONITORS the WATER CONTENT of the BLOOD and instructs the PITUITARY GLAND to release ADH into the blood according to how much is needed.
When the blood is too concentrated ADH causes more water to be reabsorbed back into the blood from the kidney tubules.

66
Q

How is the process of water regulation in the body controlled?

A

This is controlled by NEGATIVE FEEDBACK.
This means that if the water content gets TOO HIGH or TOO LOW a mechanism will be triggered that brings it back to NORMAL.

N.b negative feedback- is a mechanism that restores a level back to its optimum in a system.

67
Q

Explain how ADH secretion is controlled by negative feedback.

A
  1. A receptor in the brain detects that the water content is too high.
  2. The coordination centre in the brain receives the information and coordinates a response.
  3. The pituitary gland releases less ADH, so less water is absorbed from the kidney tubules.

The opposite happens when the water content is too low. The pituitary gland releases more ADH, so more water is reabsorbed from the kidney tubules.

68
Q

Explain what how the water level is controlled on a hot day when a person is exercising.

A

Imagine that a person is exercising on a hot day.

The body SWEATS to cool down. This means that the body is LOSING WATER.

If the blood becomes too CONCENTRATED, in other words the LEVEL of WATER in the BLOOD FALLS, then the pituitary gland releases the hormone ADH into the bloodstream.

ADH travels to the KIDNEYS and it causes the KIDNEY TUBULES to become MORE PERMEABLE to water.

This means more water can pass out of the kidney tubules.

This means that more water is REABSORBED from the tubules back into the BLOODSTREAM.

Because of this LESS URINE is produced and the AMOUNT OF WATER in the blood rises back to its NORMAL LEVEL.

As the level of water in the blood returns to normal, the pituitary gland stops releasing ADH.

69
Q

What happens if the kidneys fail?

A

The kidneys play a number of important roles in the body.

If the kidneys don’t work properly, WASTE SUBSTANCES BUILD UP in the blood and you lose your ability to CONTROL the LEVELS OF IONS and WATER in your body.
This can cause problems in the heart, bones, nervous system, stomach, mouth etc.

Eventually, kidney failure will result in DEATH.

70
Q

What treatment is available for people who have kidney failure?

A

People with kidney failure can be kept alive by:

  1. Having DIALYSIS treatment- where MACHINES do the job of the kidneys.
  2. Having a KIDNEY TRANSPLANT- where the diseased kidney is replaced by a healthy one.
71
Q

What do dialysis machines do?

A

Dialysis machines take over the role of failing kidneys and filter the blood.

72
Q

How many times does a person with kidney failure have to use dialysis machines?

A

Dialysis has to be done REGULARLY to keep the concentrations of DISSOLVED SUBSTANCES in the blood at NORMAL LEVELS, and to remove waste substances.

73
Q

How does a dialysis machine work?

N.b- substances diffuse from an area of higher concentration to an area of lower concentration. This means that if there’s a higher concentration in the blood, it will diffuse across the partially permeable membrane into the dialysis fluid.

A
  1. In a dialysis machine the person’s blood flows between PARTIALLY PERMEABLE MEMBRANES, surrounded by dialysis fluid. It’s permeable to things like IONS and WASTE SUBSTANCES, but not BIG MOLECULES like proteins (just like the membranes in the kidney).
  2. The dialysis fluid has the SAME CONCENTRATION of dissolved ions and glucose as HEALTHY BLOOD.
    (This prevents the net movement of glucose across the membrane as n concentration gradient exists).
  3. This means that useful DISSOLVED IONS and GLUCOSE won’t be lost from the blood during dialysis.
  4. Only WASTE SUBSTANCES (such as UREA) and EXCESS IONS and WATER diffuses across the membrane because there is a large concentration gradient.
74
Q

What are the disadvantages of dialysis treatment?

A

1) Dialysis is not a pleasant experience and many patients with kidney failure have to have a dialysis session THREE TIMES A WEEK. Each session takes 3-4 HOURS.
2) Dialysis can lead to INFECTIONS or BLOOD CLOTS.
3) Dialysis patients have to be careful about what they eat to avoid too much of a particular ion building up between dialysis sessions.
4) Patients have to limit the amount of fluid they take in =, as the kidneys play an important role in maintaining the water content of the body. When the kidneys aren’t functioning properly, fluid can build up in the body, which can be dangerous-for example it can cause the volume of blood to increase, leading to high blood pressure.
5) Kidney dialysis machines are EXPENSIVE for the NHS to run.

75
Q

What will the blood leaving the machine and returning into the patient’s arm contain?

A
  1. Greatly reduced levels of urea- it is cleaned blood
  2. NO OVERALL change in blood glucose levels
  3. The CORRECT WATER and ION balance maintained or restored (with only excess ions removed)
76
Q

What is the cure for kidney disease?

A

At the moment, the only CURE for kidney failure is to have a KIDNEY TRANSPLANT.

77
Q

Where do healthy kidneys used for transplants come from?

A

Healthy kidneys are usually transplanted from people who have DIED SUDDENLY. The person who died has to be on the ORGAN DONOR REGISTER or carry a DONOR CARD(provided their relatives agree too).

Kidneys can also be transplanted from people who are still ALIVE (as we all have two kidneys), but there is a small RISK to the PERSON DONATING the kidney.

78
Q

Name one major problem with kidney transplants?

A

The donor kidney can be REJECTED by the patient’s immune system.

79
Q

How are kidneys rejected by a patient?

A

This happens when ANTIGENS on the donor kidney aren’t recognised as being part of the body by the recipient’s white blood cells. The white blood cells produce ANTIBODIES to attack the donor cells as a result.

80
Q

How can kidney rejection be prevented?

A
  • A donor kidney with a tissue-type that closely matches the patient’s is chosen.
  • The recipient is treated with drugs that suppress the immune system.
81
Q

How does a close tissue-type help prevent kidney rejection?

A

Tissue-type is based on a cell’s ANTIGENS. The more similar the tissue-types of the donor and the patient, the more similar the antigens. This reduces the chance of the patient’s white blood cells identifying the donor antigens as ‘foreign’ and producing antibodies to attack the donor organ.

82
Q

How do drugs that suppress the immune system help prevent kidney rejection?

A

These drugs reduce the production and release of antibodies by the white blood cells, so that the immune system won’t attack the transplanted kidney.

83
Q

What are the other problems associated with kidney transplants?

A
  • There are long waiting lists for kidneys.
  • Even if a kidney with a matching tissue-type is found, there’s still the possibility that it’ll be rejected.
  • Taking drugs that suppress the immune system means the person is vulnerable to other illnesses and infections.
  • A kidney transplant is a major operation so it can be risky.
  • Kidney only lasts between 8-9 years.
84
Q

What are the advantages of kidney transplants?

A
  • Patients can lead a normal life without having to spend hours on dialysis or watch what they eat and drink.
  • Only expensive initially, so it costs less for the NHS than years of dialysis treatment.
85
Q

What are the advantages of kidney dialysis?

A
  • Available to all kidney patients (NO SHORTAGE).

- No need for immune-suppressant drugs

86
Q

What are the disadvantages of kidney dialysis?

A
  • Patient must LIMIT their SALT and PROTEIN intake between dialysis.
  • Expensive for NHS
  • Regular dialysis sessions-impacts on the patient’s lifestyle.

Biology GCSE Paper 2 (3 decks)

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