U3 Endocrine system: Relationship between hypothalamus and pituitary gland

Question 1

What does the hypothalamus do?

Answer 1

• Responsible for the regulation of multiple homeostatic mechanisms
• It monitors levels of hormones and other chemicals in the blood passing through it

Question 2

How is the hypothalamus linked to the pituitary gland?

Answer 2

Via a stalk called the infundibrium

Question 3

What are the two parts of the pituitary gland and how do they release hormones?

Answer 3

Anterior lobe
- produces its own hormones
- release of hormones controlled by inhibitory or releasing factors from hypothalamus which travel via tiny blood vessels

Posterior lobe
- hormones made by the hypothalamus are passed on to the posterior lobe
- the release of these hormones is stimulated by nervous conduction from the hypothalamus

Question 4

Why is the posterior lobe of the pituitary gland considered a false gland?

Answer 4

Because it doesn’t produce hormones itself, just stores and releases them

Question 5

What hormones does each lobe of the pituitary gland release?

Answer 5

Anterior lobe
- thyroid stimulating hormone
- adrenocorticotropic homrone
- follicle stimulating hormone
- luteinising hormone
- prolactin
- growth hormone

Posterior lobe
- antiduiretic hormone
- oxytocin

Question 6

What is the target organ and the main effects of thyroid stimulating hormone?

Answer 6

Target organ: thyroid gland

• Stimulates growth and release of hormones from the thyroid gland

Question 7

What is the target organ and the main effects of adrenocorticotropic hormone?

Answer 7

Target organ: adrenal cortex

• Stimulates the release of hormones from the adrenal cortex

Question 8

What is the target organ and the main effects of follicle stimulating hormone?

Answer 8

Target organ: ovaries or testes

• Initiates maturation of follicles in female ovaries
• Initiates production of sperm in male testes

Question 9

What is the target organ and the main effects of luteinising hormone?

Answer 9

Target organ: ovaries or testes

• Causes ovulation and the development of the corpus luteum
• Stimulates the secretion of testosterone

Question 10

What is the target organ and the main effects of prolactin?

Answer 10

Target organ: mammary glands

• Maintains progesterone production from the corpus luteum
• Induces milk production in pregnant females

Question 11

What is the target organ and the main effects of growth hormone?

Answer 11

Target organ: all cells

• Promotes growth of skeleton and muscles
• Controls protein synthesis and general body metabolism

Question 12

What is the target organ and the main effects of antidiuretic hormone?

Answer 12

Target organ: kidneys

• Causes an increase in permeability of the distal convoluted tubules and collecting ducts in the nephrons of the kidney, resulting in increased water reabsorption

Question 13

What is the target organ and the main effects of oxytocin?

Answer 13

Target organ: uterus and mammary glands

• Induces birth by causing uterine contractions
• INduces lactation (secretion of milk from the nipples)