Hormones

Question 1

What are hormones?

Answer 1

A hormone is a chemical substance produced in minute quantities by an endocrine gland. It is transported in the bloodstream to target organs where it carries out a function. Eventually, the hormones are destroyed at the liver.

Question 2

Where are hormones produced?

Answer 2

Hormones are produced by glands. Hormones are produced by ductless glands hence hormones are secreted directly into the bloodstream. Ductless glands are called endocrine glands.

Question 3

Different types of glands?

Answer 3

1. Pituary gland
2. Hypothalamus
3. Ovary(In females)
4. Testes(In male)
5. Adrenal gland(Medulla)
6. Pancreas

Question 4

Function of Pituitary gland?

Answer 4

It secretes a number of hormones. It also secretes antidiuretic hormone(ADH).

Question 5

Function of the Hypothalamus?

Answer 5

An endocrine gland that regulates the secretion of some pituitary hormones.

Question 6

Function of the ovary?

Answer 6

It secretes oestogen and progesterone.

Question 7

Function of the testes?

Answer 7

It secretes testosterone.

Question 8

What is the function of the Adrenal gland(medulla)?

Answer 8

The adrenal gland secretes adrenaline.

Question 9

What is the function of the Pancreas?

Answer 9

Islets of Langerhans in the pancreas secrete insulin and glucagon.

Question 10

What happens in lack of insulin secretion?

Answer 10

1. Glucose cannot be stored or used by the tissue cells. Hence, blood glucose concentration in blood increases. (This causes a disease called diabetes mellitus)
2. Since muscle cells have no reserves of glycogen, the body becomes weak and loses weight.
3. The body oxidises fats instead of glucose to produce energy. This reaction gives out a poisonous substance called ketones which are excreted in urine.

Question 11

What happens in over-secretion of insulin?

Answer 11

1. Abnormal decrease in blood glucose concentration.
2. Low blood glucose level results in a condition shock.
3. Coma and death may occur.

Question 12

Characteristics of Type 1 diabetes?

Answer 12

1. Type one diabetes is also known as early-onset diabetes.
2. The islets of langerhans are unable to produce or secrete sufficient insulin.
3. Genetically inherited by parents.

Question 13

Characteristics of Type 2 diabetes?

Answer 13

1. Type 2 diabetes is also known as late-onset diabetes.
2. Target cells, such as muscle cells, do not respond well to insulin.
3. Overweight people are more likely to develop diabetes.

Question 14

Effects of glucagon?

Answer 14

1. Glucagon is produced by the Islets of Langerhans.
2. Glucagon increases blood glucose concentration by stimulating the conversion of glycogen into glucose.
3. Glucagon converts fats and amino acids into glucose

Question 15

Effects of adrenaline?

Answer 15

1. Simulates the liver to convert glycogen to glucose so that more glucose is available for muscle contraction.(This increases the blood glucose level.)
2. Increases metabolic rate. This means more energy is released in tissue respiration.
3. Increases the rate of heartbeat and cause a rise in blood pressure so that oxygen and glucose are carried faster to the muscles
4. Increase the rate and depth of ventilation. This increases the rate of uptake of oxygen by lungs.
5. Increasing the rate of blood clotting.
6. Dilate pupils to enhance vision.
7. Increases the rate of blood clotting.
8. Arterioles in skin and gut constrict.

Question 16

What happens in normal secretion of insulin?

Answer 16

1. Increases the permeability of cell membranes to glucose(Increasing the amount of glucose intake by cells)
2. Simulates the liver and muscles cells to convert glucose into glycogen (storage)
3. Increasing oxidation of glucose during tissue respiration

Question 17

What are the differences between endocrine and nervous control?

Answer 17

Endocrine involves hormones(chemical)
Nervous involves nerve impulses (electrical)
Hormones are transported by blood
impulses are transported by neurones
Endocrines-slow response
nervous-quick responses
Endocrine-Affect more that one organ
Nervous-Localized