T5 - hormones: maintaining blood homeostasis

Question 1

What is homeostasis?

Answer 1

Homeostasis is the regulation of the internal environment in order to maintain optimum conditions for function.

Question 2

Why is homeostasis important?

Answer 2

Homeostasis maintains optimal conditions for enzyme action and all cell functions.

Question 3

What conditions are regulated inside the human body as part of homeostasis?

Answer 3

In the human body, homeostasis regulates: blood glucose concentration; body temperature; water levels.

Question 4

True or False? Homeostasis is maintained through voluntary control.

Answer 4

False. Homeostasis is maintained through involuntary (automatic) control involving the brain stem and spinal cord.

Question 5

What are the components of automatic control systems in homeostasis?

Answer 5

Automatic control systems in homeostasis include: receptors; coordination centres; effectors.

Question 6

What is the role of receptors in homeostasis?

Answer 6

Receptors detect stimuli (changes in the environment).

Question 7

What is the role of coordination centres in homeostasis?

Answer 7

Coordination centres, such as the brain, spinal cord, and pancreas, receive and process information from receptors.

Question 8

What is the role of effectors in homeostasis?

Answer 8

Effectors, such as muscles or glands, bring about responses which restore optimum levels.

Question 9

What type of responses may automatic control systems involve?

Answer 9

Automatic control systems may involve nervous responses or chemical responses.

Question 10

What are two types of effectors?

Answer 10

Two types of effectors are muscles and glands.

Question 11

What is the endocrine system?

Answer 11

The endocrine system is composed of glands that secrete hormones directly into the bloodstream.

Question 12

How are hormones transported around the body?

Answer 12

Hormones are carried around the body in the blood.

Question 13

Compare the effects of hormones and the nervous system.

Answer 13

Compared to the nervous system, the effects of hormones are slower but they act for longer.

Question 14

What is the endocrine system?

Answer 14

The endocrine system is composed of glands that secrete hormones directly into the bloodstream, when they reach a target cell/organ, they produce an effect.

Question 15

What are the endocrine glands labelled X, Y and Z?

Answer 15

IMAGE The endocrine glands labelled X, Y and Z are: X = thyroid gland; Y = pancreas; Z = testes.

Question 16

What is the function of the pituitary gland?

Answer 16

The pituitary gland is a ‘master gland’ that secretes several hormones (such as FSH and LH) into the blood in response to body conditions. These hormones act on other glands to stimulate the release of additional hormones.

Question 17

True or False? Hormones act faster than the nervous system.

Answer 17

False. Compared to the nervous system, the effects of hormones are slower but they act for longer.

Question 18

Define the term hormone.

Answer 18

A hormone is a chemical messenger molecule released from glands and transported in the blood. Hormones bring about changes in specific target cells.

Question 19

Name the gland that produces and secretes insulin.

Answer 19

The pancreas is the gland that produces and secretes insulin.

Question 20

True or False? Insulin is a hormone that increases blood glucose levels.

Answer 20

False. Insulin reduces blood glucose levels by increasing the uptake of glucose from the blood into the body cells, where it is converted into glycogen.

Question 21

What hormone does the pancreas produce when blood glucose is too high?

Answer 21

When blood glucose concentration is too high, the pancreas produces the hormone insulin to bring it back down.

Question 22

What happens to excess glucose in liver and muscle cells?

Answer 22

In liver and muscle cells, excess glucose is converted into glycogen (a polymer of glucose) for storage.

Question 23

Define Type 1 diabetes

Answer 23

Type 1 diabetes is a disorder in which the pancreas fails to produce sufficient insulin to control blood glucose levels.

Question 24

Define Type 2 diabetes.

Answer 24

Type 2 diabetes is a disorder where the body cells no longer respond to insulin produced by the pancreas.

Question 25

How is Type 2 diabetes treated?

Answer 25

A carbohydrate-controlled diet and an exercise regime are common treatments for Type 2 diabetes.

Question 26

What is a major risk factor for Type 2 diabetes?

Answer 26

Obesity is a major risk factor for Type 2 diabetes.

Question 27

What is the role of the hormone glucagon? (Higher Tier Only)

Answer 27

The hormone glucagon is produced when the blood glucose concentration is too low. It causes glycogen to be converted into glucose and released into the blood.

Question 28

What happens to body cells if they lose or gain too much water by osmosis?

Answer 28

If body cells lose or gain too much water by osmosis, they do not function efficiently: too much water can cause cell lysis (bursting), and too little water can lead to cell death.

Question 29

What are the two sources of water in the body?

Answer 29

The two sources of water in the body are water produced as a result of aerobic respiration and water in the diet.

Question 30

How is water lost from the body?

Answer 30

Water is lost from the body in the following ways: Via the lungs during exhalation; Through the skin in sweat; Controlled loss via the kidneys when they filter the blood to produce urine.

Question 31

Define deamination (Higher tier only)

Answer 31

Deamination is the process of breaking down excess proteins in the liver, where enzymes split up amino acid molecules, converting the nitrogen-containing part into ammonia, which is then converted to urea for safe excretion.

Question 32

What is the role of the kidneys in the body?

Answer 32

The kidneys help to control the water content of the body and the concentrations of substances (such as sodium and potassium ions) dissolved in the body fluids.

Question 33

What is filtration in the kidneys?

Answer 33

Filtration is the process where high-pressure mass flow forces small molecules like glucose, urea, and water with ions out of the bloodstream into the kidneys, forming filtrate.

Question 34

What happens during selective reabsorption in the kidneys?

Answer 34

During selective reabsorption, substances needed by the body are reabsorbed back into the bloodstream from the filtrate in the kidneys, including all glucose and some ions.

Question 35

What forms urine in the kidneys?

Answer 35

Urine is formed from substances not reabsorbed from the filtrate, including urea, water, and excess ions.

Question 36

What is the role of ADH in the control of water levels? (Higher Tier Only)

Answer 36

ADH affects the permeability of the kidney tubules to water: More ADH makes the tubules more permeable, leading to more water reabsorption when blood water content is low (urine is concentrated); Less ADH makes the tubules less permeable when the blood water content is high (urine is dilute).

Question 37

Define kidney failure.

Answer 37

Kidney failure is a condition where the kidneys do not function properly, leading to a build-up of toxic wastes in the body, which can be fatal if not treated.

Question 38

What is dialysis?

Answer 38

Dialysis is a treatment for kidney failure where a machine acts as an artificial kidney, removing most of the urea and maintaining the water and salt balance in the blood.

Question 39

What is a kidney transplant?

Answer 39

A kidney transplant is a surgical procedure where a healthy kidney from a donor is implanted into a patient with kidney failure, offering a long-term solution compared to dialysis.

Question 40

What are the advantages of a kidney transplant over dialysis?

Answer 40

A kidney transplant provides: more freedom to the patient; a less restrictive diet; lower cost option (instead of dialysis machines); long-term solution (whereas dialysis only works for a limited time).

Question 41

What are the disadvantages of kidney transplants?

Answer 41

Disadvantages include the risk of rejection, the need for lifelong immunosuppressant drugs with side effects, and a shortage of donors.

Question 42

True or False? The kidneys only function to filter blood.

Answer 42

False. The kidneys also play a role in controlling the water content and ion concentrations in the body, as well as reabsorbing necessary substances back into the bloodstream.