3 Endocrinology 2 - Hormones and a bit of insulin

Question 0

What growth hormones does the hypothalamus secrete?

What does it act on?

Answer 0

Growth hormone releasing hormone

Growth hormone inhibiting hormone

Question 1

PRH, PIH, TRH, CRH, GHRH, GHIH and GnRH are all hypothalamic tropic hormones
What are their effects on anterior pituitary tropic hormones, and what system do they act on.

Answer 1

PRH -> activates prolactin -> act on breasts
PIH (dopamine) inhibits prolactin -> breasts
TRH -> activates TSH -> thyroid gland
CRH -> activates ACTH -> adrenal cortex (cortisol)
GHRH -> GH hormones -> liver and other cells (growth factors)
GHIH (somatostatin) -> inhibits GH hormones GnRH -> activates LH and FSH -> gonads

Question 2

What hormone does the growth hormone stimulate release of in the liver.

Answer 2

Insulin-like growth factors - acts as a hormone and a Paracrine

Question 3

What effect does increased growth hormone secretion from the anterior pituitary have on adipose tissue and muscle

Answer 3

Adipose tissue - decreases glucose uptake and increases lipolysis

Muscle - decreases glucose uptake and increases amino acid uptake

Question 4

What is the hormone released from the hypothalamus in control of puberty?

What hormones are released from the anterior pituitary in response to the hormone released from the hypothalamus?

Answer 4

Gonadotrophin releasing hormone (GnRH)

Anterior pituitary - luteinising hormone and follicle stimulating hormone

Acts on the ovaries which release oestrogen and progesterone and the testes which release testosterone

Question 5

What is the cause And effect of excess of growth hormone in adults?

Answer 5

Caused by adenoma in anterior pituitary
Causes acromegaly or gigantisism which causes overgrowth of soft tissue and bones - enlarged skull, coarse facial features, enlarged hands and feet and enlarged organs

Question 6

What are the causes and symptoms of poly cystic ovarian syndrome?

Answer 6

Caused by excess of LH, and deficiency of FSH from anterior pituitary
Causes immature follicles in ovaries
Symptoms : amenorrhea, infertility, hirsutism, acne, weight gain

Question 7

What are islets of langerhansmand where are they found?

Answer 7

Endocrine tissues/cells which are arranged in spherical clusters within the exocrine tissue in the pancreas.

Question 8

What are the 2 precursors to insulin?

Answer 8

Preproinsulin -> pro insulin -> insulin

Question 9

What are the main pancreatic endocrine cells? What do they secrete

Answer 9

Alpha cells - glucagon
Beta cells - 65-80% of total. Insulin secreting
Delta cells - 5-10% of total. Somatostatin.

Question 10

What are the steps of stimulation of insulin secretion in response to a rise of blood glucose?

Answer 10

1) entry of glucose mediated by GLUT2
2) metabolism of glucose
3) binding of ATP to K-ATP
4) depolarisation of plasma membrane triggers opening of Ca2+ channels
5) influx of Ca2+ ions triggers insulin exocytosis

Question 11

What is hypothalamic-pituitary axis feedback control?

Answer 11

Hypothalamus -> Anterior pituitary -> Thyroid glad -> negative feedback to hypothalamus

Question 12

What type of hormones can adipose tissue store?

Answer 12

Lipophilic

Question 13

What increases the half life of hormones?

Answer 13

Being bound to a carrier protein

Question 14

What is antagonism?

Answer 14

The effect of 2 hormones oppose each other

e.g. Insulin:Glucagon

Question 15

What hormone does the anterior pituitary release?

Answer 15

Tropic hormone 2

affects release of other hormones

Question 16

What is the acronym for remembering hormones of the anterior pituitary gland?

Answer 16

Fresh Pituitary Tastes Almost Like Guinness

FPTALG

Question 17

What are the hormones of the anterior pituitary gland, where do they act, what do they do?

Answer 17

GH: Acts on liver, up-regulates insulin growth factors and down regulates insulin
TSH: Acts on the thyroid, thyroxin release
ACTH: Acts on the adrenal cortex, glucococortoid and androgen release
LH + FSH: Acts on reproductive organs, up-reg sex steroids
Prolactin: Acts on mammary glands and reproductive organs. Causes growth of repro. organs and lactation

Question 18

How does sleep and hypoglycaemia affect insulin-like growth factors?

Answer 18

Increases growth hormone releasing hormone

Question 19

How does stress affect insulin-like growth factors?

Answer 19

Reduces growth hormone inhibiting hormone, causing higher growth hormone secretion

Question 20

What are the 2 main ways in which puberty is stimulated? What are the characteristics of puberty?

Answer 20

• Body weight (47kg) and leptin

- Growth spurt, secondary sexual characteristics, fertility

Question 21

How do LH and FSH hormones cause onset of male puberty?

Answer 21

Increased LH causes increased testosterone from Leydig cells

Increased testosterone increases FSH causing spermatogenesis from Sertoli cells

Question 22

How does oestrogen and progesterone affect the endometrium?

Answer 22

Oestrogen causes growth of the endometrium

Progesterone causes maintenance of the endometrium

Question 23

What causes polycystic ovarian syndrome?

Answer 23

Excess LH or deficiency of FSH from the anterior pituitary