Human Endocrine System

Question 1

What is the difference between an endocrine and exocrine gland?

Answer 1

Exocrine- a gland which has its secretions transported by means of ducts

Endocrine- a gland that pours its secretions (hormones) directly into the blood stream

Question 2

Define hormone

Answer 2

Organic chemical messengers which are mostly protein in nature

Question 3

Explain the hypothalamus

Answer 3

• Location: The underside of the brain
• Hormone: anti-diuretic hormone (ADH)
• Function: controls the amount of water absorbed by the kidneys and which is therefore responsible for osmoregulation

Question 4

Explain pituitary/hypophysis

Answer 4

• location: bony cavity at the base of the brain, attached to the hypothalamus
• hormone:
-growth hormone (growth and development of the skeleton and thus the body as a whole)

• thyroid stimulating hormone (stimulates the thyroid gland to secrete thyroxin)
• follicle stimulating hormone (controls production of ova in Graafian follicle and development of sperms)

-luteinising hormone
> controls the release of the egg from the follicle during ovulation
> causes the Graafian follicle to become the corpus luteum after ovulation
> stimulates the Graafian follicles to produce oestrogen

-prolactin (stimulates the production of milk by the mother

Question 5

Explain the thyroid gland

Answer 5

• location: on either side of side of the trachea just below the larynx, in the anterior part of the neck
• hormone: thyroxin
• functions:
• regulates metabolic rate
• affects the growth and functioning of the heart and nervous system

Question 6

Explain Adrenal glands

Answer 6

• location: on top of each kidney
• hormone: Aldosterone and Adrenaline

• functions:
- Aldosterone
> regulates the amount of salt in blood
> works with ADH to bring about water balance
- Adrenaline
> prepares the body to meet emergencies, whenever danger threatens

Question 7

Explain islets of Langerhans

Answer 7

• location: pancreas
• hormone: insulin + glucagon

• functions:
- insulin (beta)
> lowers glucose level of the blood when glucose level is too high
- Glucagon (alpha)
> when the blood sugar is low and in emergency situations, it increases the blood sugar level by converting stored glycogen from the liver or muscle, into glucose

Question 8

Explain ovaries

Answer 8

• location: female reproductive system
• hormone: oestrogen + progesterone

• functions:
- oestrogen
> responsible for development of girls into sexually mature individuals which involves the development of secondary sexual characteristics in girls
> starts the preparation of the uterus for pregnancy by making it thicker, more vascular and more glandular
- progesterone
> ensures that the uterus wall is fully developed to allow for implantation of the fertilized egg onto the wall of the uterus
> ensuring that the uterus wall is maintained in that state during the entire period of pregnancy
> Inhibits the production of FSH by the pituitary gland so that no further eggs are produced during pregnancy

Question 9

Explain the testes

Answer 9

• location: in scrotum outside abdominal cavity
• hormone: testosterone
• functions: responsible for the development of boys into sexually mature individuals m which involves the development of secondary sexual characteristics in boys

Question 10

What happens when there’s an imbalance in insulin and glucagon

Answer 10

Diabetes mellitus

Question 11

What happens when there’s an imbalance between TSH and thyroxin

Answer 11

Thyroid disorders