5.1.4 - Hormonal Communication

Question 1

What is an endocrine gland?

Answer 1

A group of cells that are specialised to secrete hormones

Question 2

What does the pineal gland produce?

Answer 2

Melatonin, which affects reproductive development and daily cycles

Question 3

What does the pituitary gland produce?

Answer 3

Growth hormone, ADH, and gonadotrophins, which control development of ovaries and testes

Question 4

What does the thymus release?

Answer 4

Thymosin, which promotes production and maturation of white blood cells

Question 5

What does the thyroid gland produce?

Answer 5

Thyroxine, which controls the rate of metabolism and the rate that glucose is used up in respiration, and promotes growth

Question 6

What does the adrenal gland produce?

Answer 6

Adrenaline, cortisol, etc

Question 7

What does the pancreas produce?

Answer 7

Insulin and glucagon

Question 8

What do the testes produce?

Answer 8

Testosterone, which controls sperm production and secondary sexual characteristics

Question 9

What does the ovary produce?

Answer 9

Oestrogen, which controls ovulation and sexual characteristics, and progesterone

Question 10

How do steroid hormones act?

Answer 10

They pass through the lipid component of the plasma membrane and bind to steroid hormone receptors. The complex formed acts as a transcription factor which facilitates or inhibits transcription of a gene

Question 11

How do non-steroid hormones act?

Answer 11

They bind to specific receptors on the plasma membrane of the target cell. This triggers a cascade reaction mediated by secondary messengers, like cAMP

Question 12

What is the adrenal cortex?

Answer 12

Outer region of the adrenal gland that produces hormones that are vital to life, e.g. cortisol and aldosterone

Question 13

What is the adrenal medulla?

Answer 13

Inner region of the adrenal gland which produces non-essential hormones, e.g. adrenaline

Question 14

What are the three main types of hormones produced by the adrenal cortex?

Answer 14

Glucocorticoids, mineralocorticoids, and androgens

Question 15

What are glucocorticoids?

Answer 15

Hormones that regulate metabolism by controlling how the body converts fats, proteins, and carbs to energy. They also regulate blood pressure and cardiovascular function. An example is cortisol

Question 16

What are mineralocorticoids?

Answer 16

Hormones that help control blood pressure by maintaining the balance between salt and water concentrations in the blood and body fluids. An example is aldosterone

Question 17

What are androgens?

Answer 17

Male and female sex hormones

Question 18

What are secreted by the adrenal medulla?

Answer 18

Adrenaline and noradrenaline

Question 19

What is adrenaline?

Answer 19

A hormone that increases the heart rate sending blood quickly to the muscles and brain. It also raises blood glucose concentration levels by converting glycogen into glucose in the liver

Question 20

What is noradrenaline?

Answer 20

A hormone that works with adrenaline in response to stress, producing effects such as an increased heart rate, widening of pupils, widening of air passages in the lungs, and the narrowing of blood vessels in non-essential organs

Question 21

What are the two main functions of the pancreas?

Answer 21

An exocrine gland and an endocrine gland

Question 22

Describe the function of the pancreas as an exocrine gland

Answer 22

Most of the pancreas is made up exocrine glandular tissue (acinar cells). The pancreas produces amylases, proteases, and lipases

Question 23

Describe the function of the pancreas as an endocrine gland

Answer 23

Islets of Langerhans produce insulin and glucagon. Alpha cells produce glucagon while beta cells produce insulin

Question 24

What can increase the blood glucose concentration?

Answer 24

Diet, glycogenolysis, gluconeogenesis

Question 25

What is glycogenolysis?

Answer 25

When glycogen stored in the liver and muscle cells is broken down into glucose

Question 26

What is gluconeogenesis?

Answer 26

When glucose is produced from non-carbohydrate sources, e.g. glycerol and amino acids

Question 27

What can decrease blood glucose concentration?

Answer 27

Respiration and glycogenesis

Question 28

What is glycogenesis?

Answer 28

When glycogen is produced from glucose

Question 29

How does insulin lower blood glucose concentration?

Answer 29

- Increases rate of absorption of glucose by cells - Increases respiratory rate of cells - Increases rate of glycogenesis - Increases the rate of glucose to fat conversion - Inhibits the release of glucagon

Question 30

How does glucagon raise blood glucose concentration?

Answer 30

- Glycogenolysis - Reduces the amount of glucose absorbed by liver cells - Increases gluconeogenesis

Question 31

Where does insulin act and why?

Answer 31

All over the body because all body cells (bar RBCs) have insulin receptors

Question 32

Where does glucagon act and why?

Answer 32

Liver and fat cells, as these are the only cells with the glucagon receptors

Question 33

Describe the mechanism of insulin release by the beta cells

Answer 33

Glucose conc rises, so glucose enters the cell via a glucose transporter. Glucose metabolised, forming ATP. ATP binds to ATP-sensitive potassium channels, which close. Membrane potential increases to -30mV, so Ca+2 ions enter via voltage gated channels. Entrance of Ca+2 causes secretory vesicles to undergo exocytosis, releasing insulin

Question 34

What are the two main types of diabetes mellitus?

Answer 34

Type 1 and Type 2

Question 35

Describe Type 1 Diabetes mellitus

Answer 35

Patients are unable to produce insulin. Disease cannot be prevented or cured. Autoimmune disease

Question 36

Describe type 2 diabetes mellitus

Answer 36

Patients cannot effectively use insulin. Either due to the beta cells not producing enough insulin or the body cells not responding to insulin

Question 37

What treatment is available for type 1 diabetes?

Answer 37

Controlled by regular injections of insulin and is said to be insulin-dependent.

Question 38

What treatment is available for type 2 diabetes?

Answer 38

The main form of treatment is improving diet and exercise, but there are drugs that exist that stimulate insulin production, and insulin injections can be taken

Question 39

How was insulin originally obtained?

Answer 39

From the pancreas of cows and pigs, but this was difficult and expensive, and insulin was sometimes rejected. Also ethical and religious concerns exist

Question 40

How is insulin made now?

Answer 40

Using genetically modified bacteria

Question 41

What are the advantages of using stem cells to give patients beta cells?

Answer 41

Donor availability is not an issue, likelihood of rejection is reduced, and people no longer have to inject themselves with insulin.