Endocrine system

Question 1

What are endocrine glands?

Answer 1

They are comprised of tissue and secrete a substance or substances. In particular, they secrete hormones into the blood through extracellular fluid (bloodstream).

Question 2

What are the effects of hormones?

Answer 2

These tend to be long-lasting, and are involved in the process of growth, sexual development and control of cell metabolism

Question 3

Communication within the body involves…

Answer 3

…hormones.

Question 4

What are target cells?

Answer 4

The specialised cells on which hormones act. The membranes of these cells consist of specific protein receptor molecules. These receptors detect the presence of hormones outside the cell, and carry the message across the cell through a series of enzyme reactions.

Question 5

What is the pituitary gland?

Answer 5

It releases a variety of hormones that either have a direct effect, or cause other endocrine glands to release their specific hormones. It allows feedback to control the release of a hormone (e.g., TSH/Thyroxine model).

Question 6

What are the types of hormones?

Answer 6

They can be either proteins or steroids (a type of lipid).

Question 7

Describe steroid hormones.

Answer 7

They are lipid soluble (cholesterol) and are able to pass through the cell and nuclear membrane, directly affecting receptor molecules within the cell.

Question 8

Describe protein hormones.

Answer 8

They are unable to pass through membranes, and they bind with protein receptors on the cell membrane.

Question 9

Describe the location of endocrine glands throughout the body.

Answer 9

Brain: pituitary, hypothalamus and pineal
Neck: thyroid
Abdomen: adrenal and pancreas
Pelvis: female gonads (ovaries)
Scrotum: male gonads (testes)

Question 10

Describe the hormone oxytocin.

Answer 10

Located in: pituitary
Action(s): uterine contractions during childbirth

Question 11

Describe the hormone antidiuretic (ADH)

Answer 11

Located in: pituitary
Action(s): reabsorption of water in the kidneys

Question 12

Describe the growth hormone (GH).

Answer 12

Located in: pituitary
Action(s): growth of body cells and tissues

Question 13

Describe the follicle stimulating hormone (FSH).

Answer 13

Located in: pituitary
Action(s): stimulates ovaries and testes

Question 14

Describe the luteinising hormone (LH).

Answer 14

Located in: pituitary
Action(s): stimulates ovulation in females and the release of testosterone in males

Question 15

Describe the thyroid-stimulating hormone.

Answer 15

Located in: pituitary
Action(s): stimulates the activity of the thyroid gland

Question 16

Describe the thyroxine hormone.

Answer 16

Located in: thyroid
Action(s): stimulates metabolism and heat production

Question 17

Describe the parathyroid hormone (PTH).

Answer 17

Located in: parathyroid
Action(s): stimulates release of calcium from bone

Question 18

Describe the hormone insulin.

Answer 18

Located in: pancreas
Action(s): lowers blood sugar

Question 19

Describe the hormone glucagon.

Answer 19

Located in: pancreas
Action(s): raises blood sugar

Question 20

Describe the hormone adrenalin.

Answer 20

Located in: adrenal
Action(s): increases blood sugar and constricts blood vessels

Question 21

Describe the hormone testosterone.

Answer 21

Located in: testes
Action(s): male characteristics and controls sperm production

Question 22

Describe the hormones oestrogen and progesterone.

Answer 22

Located in: ovaries
Action(s): female secondary sexual characteristics; maintain uterine lining

Question 23

Describe the hormone thymosin.

Answer 23

Located in: thymus
Action(s): stimulates production of lymphocytes

Question 24

How are hormone levels maintained?

Answer 24

By a negative feedback system, where negative feedback is a mechanism that maintains the balance of supply and demand between hormone levels and the needs of target cells. This involves the response reversing the stimulus.

Question 25

How are endocrine glands prompted to stop secretion?

Answer 25

They will continue to secrete hormones until messages come back from target cells that sufficient amounts of the specific hormone is present. These messages (enzymes) are secreted by the target cells and inhibit hormone secretion in the endocrine gland.

Question 26

Describe the main differences between the nervous system and endocrine system: pathway.

Answer 26

Nervous: direct through axons or nerve cells Endocrine: indirect through bloodstream

Question 27

Describe the main differences between the nervous system and endocrine system: message.

Answer 27

Nervous: electrochemical impulse/nerve impulse Endocrine: chemical

Question 28

Describe the main differences between the nervous system and endocrine system: site of action.

Answer 28

Nervous: highly specific Endocrine: target cells - can be widespread

Question 29

Describe the main differences between the nervous system and endocrine system: speed of action.

Answer 29

Nervous: fast Endocrine: slow

Question 30

Describe the main differences between the nervous system and endocrine system: duration.

Answer 30

Nervous: short-term Endocrine: long-term

Question 31

What provides a 'bridge' between the nervous and endocrine systems?

Answer 31

The hypothalamus, as part of the CNS, receives signals through afferent nerves, sends nerve impulses through autonomic nerves, and secretes hormones and hormone-like substances that control the secretion of hormones by the pituitary gland.