Endocrine System

Question 1

What are the 2 main functions of the endocrine system?

Answer 1

Communication and control - in response to external environment

Maintenance of homeostasis - constant internal environment

Question 2

Which of the endocrine or nervous responses lasts longer and which acts faster?

Answer 2

The endocrine system is not as quick to act, however, can be much longer-lived, whilst the nervous system responses can be almost immediate, yet do not persist.

Question 3

What are the three ways a hormone can communicate with a target cell?

Answer 3

• Autocrine
• Paracrine
• Endocrine

Question 4

Explain Autocrine communication.

Answer 4

This involves a cell producing a\the hormone which then acts on the same cell.

Question 5

Explain Paracrine communication.

Answer 5

This involves a cell producing the hormone that acts on other cells nearby.

Question 6

Explain Endocrine communication.

Answer 6

This involves a hormone being secreted into the bloodstream by a specialised ‘endocrine gland’, this then travels to multiple sites throughout the body.

Question 7

What are the three main categories of hormones?

Answer 7

Peptides/proteins, steroids and amines.

Question 8

List the three main categories of hormones in order from smallest to largest.

Answer 8

Amines, steroids, peptides/proteins.

Question 9

How soluble are peptides/proteins and how do we administer them?

Answer 9

Readily soluble (water) and can get broken down by stomach acids therefore usually injected.

Question 10

What are some examples of peptides/proteins that are administered to humans/animals?

Answer 10

• Insulin
• Growth hormones

Question 11

How soluble are Steroids and how do we administer them?

Answer 11

Somewhat soluble (not water but is in fats). mainly administered by injection to muscle, skin cream or implant beneath the skin as cannot be injected to the bloodstream due to fat solubility.

Question 12

What are some examples of steroids that are administered to humans/animals?

Answer 12

• Hydrocortisone
• Progesterone

Question 13

How do we administer Amines? What is the issue with using these as opposed to the other 2 main hormone types?

Answer 13

Generally orally, used to treat amino acid deficiencies such as the one that results in thyroid issues.
The main issue with amine’s is that they are harder to predict the outcome due to their chemical structure.

Question 14

What are trophic hormones?

Answer 14

They are messenger hormones that are released from the pituitary gland and travel to other glands to signal production of another hormone at those sites.

Question 15

What is an example of a trophic hormone?

Answer 15

Thyroid-stimulating hormone (TSH)

This gets emitted from the pituitary, then travels to and stimulates the thyroid glands to produce thyroxine.

Question 16

What is an ‘episodic’ hormonal rhythm?

Answer 16

Bursts of release

EG: Growth Hormone

Question 17

What is a ‘diurnal’ hormonal rhythm?

Answer 17

A day/night cycle

EG: Cortisol.
Rises early in the morning and decreases throughout the day, remains low at night. (Reversed for nocturnal animals).

Question 18

What is a ‘seasonal’ hormonal rhythm?

Answer 18

Responds to environmental changes with the seasons

Can be triggered by the changing lengths of day or the temperature of the seasons etc

EG: Melatonin, responds to changing daylengths and peaks in Autumn

Question 19

Briefly explain how the hypothalamus monitors and controls hormone release.

Answer 19

Receptors in the hypothalamus sense concentrations of the hormones, when they receive a weak signal, they produce more releasing factor and vice versa for a strong, more inhibitory factor.

Question 20

List the 8 important endocrine glands.

Answer 20

• Pineal gland
• Hypothalamus
• Pituitary gland
• Thyroid glands
• Parathyroid glands
• Gonads
• Adrenal gland
• Pancreas

Question 21

What is the main function of the Pineal gland?

Answer 21

Controls the sleep/wake cycle and seasonal cycles such as breeding.

Question 22

What is the main endocrine function of the hypothalamus?

Answer 22

Coordinates the body’s response to changes in the external or internal environment, to maintain homeostasis.

Question 23

What is the main function of the Pituitary gland?

Answer 23

Produces a wide range of hormones

Is instructed by both the nervous system (neurochemicals such as dopamine & noradrenaline) and hypothalamus (peptide-hormone messengers) in what is needed.

Question 24

What is the main function of the Thyroid glands?

Answer 24

Plays an important role in controlling metabolic rate.

produce triiodothyronine (T3) and thyroxine (T4)

Question 25

What is the main function of the parathyroid glands?

Answer 25

Maintains the appropriate concentration of calcium in the blood.

• Important for strong bones
• Also important role in keeping the heart and nervous system running

Question 26

What is the main function of the gonads (ovaries/testes)?

Answer 26

To produce the sex steroids.

Question 27

What is the main function of the Adrenal gland?

Answer 27

Fuels the flight or fight response of stress
- Adrenaline/noradrenaline
- cortisol and aldosterone (manages sodium levels)

Question 28

What is the main function of the Pancreas?

Answer 28

Controls blood/glucose levels

Insulin decreases glucose levels
Glucagon increases glucose levels

Question 29

What are the main endocrine ways to influence growth in animals?

Answer 29

Animal growth is influenced by:
- anabolic protein (Growth Hormone)
- steroid (testosterone, oestrogen) hormones
- hormones such as cortisol, which have a catabolic effect at high concentrations.

Question 30

Which type of cell in the pancreas makes glucagon?

Answer 30

Alpha cells

Question 31

Which type of cell in the pancreas makes insulin?

Answer 31

Beta cells