Lecture 22

Question 1

Compare the endocrine system to the exocrine system:

Answer 1

The endocrine system is ductless and secretes into the surrounding interstitial fluid/blood. The exocrine system involves products secreted on the epithelial surfaces of the skin via ducts.

Question 2

Name the three different types of hormones and briefly describe them:

Answer 2

• Classical hormones that are secreted by endocrine organs that then enter the blood
• Neurohormones- released from the end of the neurons and travel to the target cell
• Local hormones- immediate facility, paracrine- neighbouring cells,

Question 3

What are the three main classifications of hormones based on their structure?

Answer 3

• Amide hormones- single amino acid
• Protein hormones- synthesised as much larger non active hormones
• Steroid hormones- lipid molecules derived from the cholesterol, example is glucocorticoids (cortisol)

Question 4

What are the main methods of communication for hormones with target cells?

Answer 4

• surface receptors, hormone doesn’t enter the cell

- binds to the surface receptor activating a second messenger

Question 5

What are the two lobes of the pituitary gland?

Answer 5

• anterior pituitary

- posterior pituitary

Question 6

What is the function of hypo-physiotropic hormones?

Answer 6

Tropic hormones can be inhibitory or stimulatory in acting on the anterior pituitary gland.

Question 7

What is the main function of the hypothalamus and anterior pituitary gland?

Answer 7

This system regulates the release of a wide variety of other hormones

Question 8

What is the main function of the hypothalamic/pituitary portal system?

Answer 8

connects the hypothalamus and the anterior pituitary system together

Question 9

What is the function of thyrotropes?

Answer 9

Stimulates the release of thyroid stimulating hormone from the anterior pituitary, this then activates the thyroid gland to release a wide variety of thyroid hormones

Question 10

What is the function of gonadotropes?

Answer 10

Releases luteinising hormone (LH) and follicle stimulating hormone (FSH) that will then produce male androgens and female (oestrogen and progesterone)

Question 11

What is the function of lactotropes?

Answer 11

Release prolactin from the breast

Question 12

What is the function of corticotropes?

Answer 12

Adrenocorticotropic hormone (ACTH) which then acts on the adrenal cortex to release cortisol.

Question 13

What is the function of somatotropes?

Answer 13

Release growth hormone that then acts on the liver and other cells throughout the body

Question 14

Where is oxytocin synthesised?

Answer 14

supraoptic and paraventricular nuclei of the hypothalamus

Question 15

Where is oxytocin stored?

Answer 15

posterior pituitary

Question 16

What are the signals for the release of oxytocin?

Answer 16

massage of the udder, stretching of the cervix, sound of young

Question 17

What is the function of oxytoxin?

Answer 17

Parturition-increasing the strength and frequency of uterine contractions

Question 18

Where is antidiuretic hormone synthesised?

Answer 18

supraoptic and paraventricular nuclei of the hypothalamus

Question 19

Where is antidiuretic hormone stored?

Answer 19

pituitary gland

Question 20

What are the signals for release of anti-diuretic hormone?

Answer 20

Osmoreceptors - increase in extracellular fluid osmolality

Baroreceptors - low blood volume and/or pressure

Question 21

What is the function of ADH?

Answer 21

• acts as a second messenger to increase water re-absorption

Question 22

What are the two different feedback mechanisms that occur for the release of the pituitary gland hormones?

Answer 22

Short feedback loops- inhibition from the anterior pituitary hormones to the hypothalamus
Long feedback loops- inhibition from the target cell.

Question 23

What are the two main types of diabetes insipidus that occur and what usually causes them?

Answer 23

Diabetes is a form of diabetes associated with insulin. Central DI failure of ADH secretion/synthesis. Nephrogenic DI inappropriate renal response to normal levels of ADH

Question 24

How can you tell the difference between the two different types of diabetes insipidus?

Answer 24

If administering ADH results in urine production then the problem will be central.