Module 5: Hormonal communication

Question 1

Both the nervous system and endocrine system work together to prepare the body for action by …

Answer 1

1. Increasing heart rate.
2. Stimulating the breakdown of glycogen.
3. Redistributing blood to the core.

Question 2

What is cell signalling and why is it important for us?

Answer 2

Where cells communicate with each other by releasing chemicals that has an effect on another cell (target cell). For example, cells in nervous system communicate by secreting neurotransmitters that send signals to adjacent cells.
In order to survive.

Question 3

What is the endocrine system?
Give some examples of endocrine glands.

Answer 3

The endocrine glands secretes hormone directly into the bloodstream to send info about changes in environment.
Pancreas, adrenal glands, pituitary gland.

Question 4

Function of the pituitary gland?

Answer 4

Produces ADH which increases water absorption in kidneys.

Question 5

Function of the thyroid gland?

Answer 5

Produces thyroxine which controls rate of metabolism and rate that glucose is used up in respiration.

Question 6

Function of adrenal glands?

Answer 6

Produces adrenaline which increases heart and breathing rate and raise blood sugar level.

Question 7

Function of thymus?

Answer 7

Produces thymosin which produces white blood cells.

Question 8

What does the pancreas secrete?

Answer 8

Insulin and glucagon.

Question 9

Function of ovary?

Answer 9

Produces oestrogen which controls ovulation and secondary sexual characteristics.
Progesterone which prepares the uterus lining for receiving an embryo.

Question 10

Function of testes?

Answer 10

Produces testosterone which controls sperm production and secondary sexual characteristics.

Question 11

What is an exocrine gland?

Answer 11

Secrete chemicals through ducts into organs/to surface of body.

Question 12

Explain what steroid hormones are.

Answer 12

Lipid soluble so they diffuse through phospholipid bilayer and bind to steroid hormone receptors. The receptors may be present in cytoplasm or nucleus.
The hormone receptor complex formed acts as a transcription factor which facilitates or inhibits the transcription of a specific gene. E.g oestrogen.

Question 13

What are non-steroid hormones?

Answer 13

Hydrophilic/water soluble so they can’t directly diffuse through phospholipid bilayer as they won’t fit through channel proteins as they’re too big. They bind to specific records on plasma membrane of the target cell.
This triggers a cascade of reactions mediated by chemicals called second messengers. E.g adrenaline.

Question 14

Comparisons between hormonal and nervous system?

Answer 14

Nervous - by nerve impulses by neurones, very quickly, response is localised and short lived.

Hormonal - hormones travel in bloodstream, longer lasting and widespread effect as hormones are not broken down as quickly as neurotransmitters, slower transmission than nervous as hormones aren’t directly released onto target cells.

Question 15

Describe the 2 distinct parts (surrounded by a capsule) that make up the adrenal gland.

Answer 15

Adrenal cortex - outer region that produces hormones, released from pituitary gland in brain, vital to life such as cortisol and aldosterone.
Medulla - inner region that produces non-essential peptide hormones such as adrenaline.

Question 16

The adrenal cortex produces what 3 main types of hormone?

Answer 16

Glucocorticoids, mineralocorticoids, androgens.

Question 17

Type of glucocorticoid hormone.

Answer 17

Cortisol released by adrenal gland regulates blood pressure and cardiovascular function in response to stress. It also works with insulin to maintain blood glucose levels.
Another glucocorticoid hormone released by adrenal cortex is corticosterone (made using cholesterol): works with cortisol to regulate immune response and suppress inflammation.
Release of these hormones are controlled by hypothalamus.

Question 18

Type of mineralocorticoid.

Answer 18

Aldosterone - helps control blood pressure by maintaining salt (Na+ and K+) and water balance in blood and bodily fluids.
Release is mediated by signals triggered by the kidney.

Question 19

Cortisol and aldosterone stimulate the breakdown of …

Answer 19

Proteins and fats into glucose, so increases amount of energy to fuel brain/muscles.

Question 20

Androgens

Answer 20

Sex hormones for male and female that coordinate ovary function and fertility.

Question 21

When does the adrenal medulla release hormones?

Answer 21

When the sympathetic nervous system (activate flight or fight response) is stimulated. This occurs when body is stressed.

Question 22

What are 2 hormones released by adrenal medulla and describe their function.

Answer 22

1. Adrenaline - increases hr by sending blood quickly to muscles and brain. Also rapidly raises blood glucose by converted glycogen to glucose in liver.
2. Noradrenaline - works with adrenaline in response to stress. Widens pupils, increases hr, narrowing blood vessels in non-essential organs.

Question 23

What is melatonin?

Answer 23

Hormone that helps you sleep.

Question 24

Explain the EXOCRINE function of the pancreas.
What 3 digestive enzymes does the pancreas produce?

Answer 24

Produces digestive enzymes that are secreted into ducts which eventually lead to pancreatic duct. here they are released into duodenum.
Amylase - break down starch into simple sugars.
Lipase - break down lipids into fatty acids and glycerol.
Protease - break down proteins into amino acids.

Question 25

Describe briefly how the pancreas is also an endocrine gland.

Answer 25

Within the exocrine tissue of the pancreas, there are small regions of endocrine tissue called islets of Langerhans, which produces and secretes insulin and glucagon into the bloodstream.

Question 26

Within the Islets of Langerhans there are 2 types of cell called …

Answer 26

Alpha cells - produce and secrete glucagon.
Beta cells - produce and secrete insulin.
Alpha cells are larger and more numerous than beta cells.

Question 27

Does diet increase glucose concentration in blood?

Answer 27

Yes, carbohydrate rich foods such as pasta and cakes are broken down to glucose in the digestive system. The glucose is reabsorbed into bloodstream, so conc rises.

Question 28

Explain the two processes that happen when blood glucose concentration is low (so we need to increase glucose).

Answer 28

Glycogenolysis - glycogen stored in liver and muscle cells are broken down into glucose.
Gluconeogenesis - production of glucose from non-carbohydrate sources. E.g liver can make glucose from lipids and amino acids.

Question 29

Explain two processes that happen when blood glucose concentration is high (so we need to decrease glucose).

Answer 29

Glycogenesis - produces glycogen in liver.
respiration - some glucose in blood is used by cells to release energy. the higher physical activity, higher the demand for glucose so greater decrease in blood glucose concentration.

Question 30

How does insulin released by beta cells lower blood glucose?

Answer 30

1. Increasing the absorption of glucose into cells - when insulin binds to its glycoprotein receptor, it causes a change in tertiary structure of glucose transport channels. This causes channels to open to allow more glucose into the cell.
2. Increasing rate of glycogenesis.
3. Inhibiting the release of glucagon from alpha cells.
4. Increasing rate of respiration in cells so higher uptake of glucose from blood.