Hormones

Question 1

Define ‘hormone’

Answer 1

Hormones are chemical substances produced by glands, which are carried by the blood, which alters the activity of one or more specific target organs, and is destroyed by the liver

Question 2

What are endocrine glands?

Answer 2

Endocrine glands produce and secrete hormones. They are ductless glands, so hormones are secreted directly into the bloodstream to be distributed around the body.

Question 3

What are the endocrine glands of anti-diuretic hormone (ADH)?

Answer 3

Hypothalamus produces ADH, pituitary gland stores and releases ADH

Question 4

What is the function of ADH?

Answer 4

Osmoregulation: the control of water and solute concentration in the blood to maintain a constant water potential in the blood plasma
ADH increases the permeability of the walls of the collecting duct to water molecules, this encourages water absorption.

Question 5

What is the target organ of ADH?

Answer 5

Walls of collecting duct in kidney nephron

Question 6

What is the endocrine gland of insulin and glucagon?

Answer 6

Pancreas (islets of Langerhans)

Question 7

What is the function of insulin and glucagon?

Answer 7

Blood glucose regulation

Question 8

What is the target organ for insulin?

Answer 8

Liver and muscle cells

Question 9

What is the target organ for glucagon?

Answer 9

Liver cells

Question 10

What is the endocrine gland of adrenaline?

Answer 10

Adrenal glands

Question 11

When is adrenaline released?

Answer 11

Produced under situations of fear, stress, anger, anxiety

Question 12

What are the target organs of adrenaline?

Answer 12

Heart, lungs, pupils of eyes, skin

Question 13

What is the endocrine gland for testosterone?

Answer 13

Testes

Question 14

What are the endocrine glands for oestrogen and progesterone?

Answer 14

Ovaries

Question 15

What is the function of oestrogen/progesterone?

Answer 15

Regulation of menstrual cycle

Question 16

What is the target organ of oestrogen?

Answer 16

Uterine lining of uterus

Question 17

In the islets of Langerhans, which cells produce glucagon?

Answer 17

Alpha cell

Question 18

In the islets of Langerhans, which cells produce insulin?

Answer 18

Beta cell

Question 19

Compare the stimuli of insulin, adrenaline and ADH

Answer 19

Insulin: increase/ decrease in blood glucose levels
Adrenaline: fear, anger, anxiety, stress
ADH: increase/ decrease in blood water potential

Question 20

What happens when there is higher blood glucose above norm?

Answer 20

1. Islets if Langerhans in pancreas us stimulated
2. Insulin is secreted by beta cells of islets of Langerhans. The insulin signals liver and muscle cells to convert excess glucose to glycogen for storage
3. The removal of excess glucose and storing it in the form of glycogen reduces the concentration of glucose in the loop back to norm

Question 21

What happened when there is lower blood glucose below norm?

Answer 21

1. Islets of Langerhans if pancreas is stimulated
2. Glucagon is secreted by alpha cells of islets of Langerhans. This signals liver cells to convert glycogen back to glucose, which is then released into bloodstream
3. The conversion of stored glycogen into glucose helps to raise the blood glucose concentration back to norm

Question 22

What is the cause of Type 1 diabetes?

Answer 22

• the pancreas fails to produce sufficient insulin due to loss of beta cells
• the beta cells that produce insulin are destroyed by autoimmune disease
• tends to develop during childhood

Question 23

How is Type 1 diabetes treated?

Answer 23

Insulin injections to replace missing hormone

Question 24

What is the cause of Type 2 diabetes?

Answer 24

• Insulin resistance contributes to high glucose levels in blood
• islets of Langerhans produces insulin, but target cells do not respond to insulin, cause by down-regulation of insulin receptors on target cells
• tends to develop during adulthood

Question 25

How s Type 2 diabetes controlled?

Answer 25

Controlled by managing diet and lifestyle

Question 26

Immediately after a meal, what happens to a person with diabetes mellitus?

Answer 26

Glucose cannot be stored in the liver and muscles as glycogen, thus blood glucose levels remain high. Blood glucose concentration can reach a level that exceeds the kidney’s ability to completely reabsorb all the glucose. The glucose that is not absorbed is excreted in the ruin.

Question 27

What happens to a person with diabetes mellitus after a period of dieting/starving?

Answer 27

The body oxidizes fats instead of glucose to release energy. | This results in the production of ketones which are excreted in urine as ketonuria, which is more toxic than urea.

Question 28

What are the long-tern effects of diabetes mellitus?

Answer 28

- increased risk of coronary heart disease - kidney failure - blindness

Question 29

What effect does adrenaline have on liver and muscle?

Answer 29

Increased conversion of stored glycogen into glucose, which is needed for respiration tor release energy

Question 30

What effect does adrenaline have on the heart?

Answer 30

Increased heart rate, to increase volume of blood pumped per unit time, increasing glucose and oxygen supply to muscle respiration

Question 31

What effect does adrenaline have on the lungs?

Answer 31

Increased breathing rate to increase absorption of oxygen, which is needed for aerobic respiration

Question 32

What effect does adrenaline have on the brain?

Answer 32

Increased blood flow to brain, so that brain can think more clearly

Question 33

What effect does adrenaline have on muscles?

Answer 33

Increased blood flow to muscle. Blood contains glucose and oxygen can reach muscles, where aerobic respiration occurs to release energy for movement

Question 34

What effect does adrenaline have on the eyes?

Answer 34

Dilation of pupils to allow more light to enter the eyes for enhanced vision

Question 35

What effect does adrenaline have on the digestive system, kidneys and skin?

Answer 35

Reduced blood flow, so that more blood can be transported to brain and muscles