Endocrine System

Question 1

What is a hormone?

Answer 1

A chemical substance synthesised by a specific tissue + secreted into bloodstream, whereby it is carried to a non-adjacent sites in body + exert its actions

Question 2

What is a neurotransmitter?

Answer 2

A chemical substance synthesised by neuron + secreted directly on to adjacent neurons or tissues, whereby it exerts its actions

Question 3

What are endocrine glands?

Answer 3

Secrete hormones into bloodstream

Question 4

What are target cells?

Answer 4

Have receptors for given hormones so can later activities in response to hormone

Question 5

What is the HPA axis + cortisol activated by?

Answer 5

Stress (physical + mental)

Question 6

Describe HPA axis

Answer 6

Hypothalamus nuclei 
-----> CRH
Anterior pituitary gland 
-----> ACTH
Adrenal cortex 
Cortisol released

Question 7

Why is there a final hormone feedback in HPA axis?

Answer 7

To turn off endocrine system

Question 8

Describe final hormone feedback in HPA axis

Answer 8

Cortisol feeds back to anterior pituitary then hypothalamus nuclei

Question 9

What does cortisol do?

Answer 9

Increase + maintain glucose levels
Increase gluconeogenesis 
Decrease glucose uptake 
Decrease protein synthesis 
Regulate brain function
Immune response/inflammation

Question 10

Why does cortisol decrease protein synthesis?

Answer 10

Amino acids available for gluconeogenesis

Question 11

What is the disorder associated with cortisol?

Answer 11

Cushing’s syndrome

Question 12

What is Cushing’s syndrome?

Answer 12

Hypercortisolaemia = too high cortisol

Question 13

Describe regulation of blood glucose by insulin

Answer 13

Beta cells in pancreas
Glucose undergoes glycolysis 
= increase ATP
ATP acts on K+ channel = closes it
= depolarisation of beta cell
= Ca2+ channels open = Ca2+ enter cell
Release of insulin

Question 14

Describe hypothalamic - pituitary - ovarian axis/tract

Answer 14

Hypothalamus 
----> GRH
Pituitary 
----> FSH & LH
Ovaries 
Ovulation
Oestrogen + progesterone released

Question 15

What is GRH?

Answer 15

Gonadotrophin releasing hormone

Question 16

What is FSH?

Answer 16

Follicle stimulating hormone

Question 17

What is LH?

Answer 17

Luteinising hormone

Question 18

What does oestrogen do?

Answer 18

Sensitises LH releasing cells in pituitary
Proliferation of endometrium
Inhibits FSH = regulates cycle

Question 19

What do progesterone do?

Answer 19

Render endometrium = suitable for implanting of fertilised egg + maintaining endometrium
Inhibits further release of GRH, FSH + LH = regulate cycle + ovulation

Question 20

What are the two options after ovulation?

Answer 20

Fertilisation
OR
No fertilisation

Question 21

Describe what happens if there is fertilisation

Answer 21

Ovum secrets human chorionic gonadotrophin = stimulates corpus luteum to continue secreting progesterone
= maintains endometrium + pregnancy
= inhibits further secretion of GRH, LH + FSH = prevents further follicles developing

Question 22

Describe what happens if there is no fertilisation

Answer 22

Corpus luteum regresses, progesterone levels drop
Endometrium cannot be maintained = menstruation
Lack of progesterone = clamp on GRH, FSH + LH released = cycle starts again

Question 23

What are the causes of Cushing’s syndrome?

Answer 23

Adrenal or pituitary tumour
Side effect of chronic glucocorticoid therapy
Metabolic side effects - eg. increased abdominal fat

Question 24

What type of hormone is cortisol?

Answer 24

Metabolic

Question 25

What are some side effects of Cushing's syndrome?

Answer 25

``` Buffalo hump Moon face Thinning of skin Depression Diabetes ```

Question 26

What is the treatment for Cushing's syndrome?

Answer 26

Removal of tumour | Inhibition of cortisol synthesis by metyrapone

Question 27

Describe the treatment of Cushing's syndrome with metyrapone?

Answer 27

11β -hydroxylating enzyme can be blocked by metyrapone | = decreases amount of cortisol available for secretion

Question 28

Why is cortisol important?

Answer 28

At high levels = inhibit inflammation + immune response

Question 29

What disorders associated with insulin?

Answer 29

Diabetes mellitus Insulin hyposecretion Insulin receptor hyposensitivity

Question 30

Describe type 1 diabetes

Answer 30

Loss of β cell | Substitute with insulin

Question 31

What background intermediate acting insulin is used in type 1?

Answer 31

Isophone insulin

Question 32

What short term fast acting insulin is used in type 1?

Answer 32

Soluble insulin before meal

Question 33

Describe type 2 diabetes

Answer 33

Non-insulin dependant Desensitization of pancreas or β cells Introduce K+ blocker (act similar to ATP)

Question 34

What is cause of type 2?

Answer 34

Metabolic demands of obesity

Question 35

What do oral contraceptives do?

Answer 35

Target negative feedback = clamp secretion of GRH, FSH + LH

Question 36

What do oral contraceptives supply?

Answer 36

Exogenous oestrogen + progesterone | = mimic pregnant state

Question 37

What is the combined pill?

Answer 37

Oestrogen + progesterone

Question 38

What does the combined pill do? | Oestrogen

Answer 38

Oestrogen inhibits secretion of FSH via negative feedback = prevents development of ovarian follicle

Question 39

What does the combined pill do? | Progesterone

Answer 39

Progesterone inhibits secretion of LH = prevents ovulation + males cervical mucus less suitable for passage of sperm

Question 40

What is the mini pill?

Answer 40

Progesterone

Question 41

Why is mini pill mainly effective?

Answer 41

Effect on cervical mucus | DOES NOT block ovulation

Question 42

What are the main hormone-producing glands?

Answer 42

``` Hypothalamus Pituitary Parathyroid Pancreas Thyroid Adrenal gland Pineal gland Ovaries Testes ```

Question 43

What does the hypothalamus control?

Answer 43

Body temp, hunger, mood + release of hormones from other glands

Question 44

What does the pituitary control?

Answer 44

Other glands + make hormones that trigger growth

Question 45

What does the parathyroid control?

Answer 45

Ca2+ in body

Question 46

What does the pancreas control?

Answer 46

Insulin

Question 47

What does the thyroid control?

Answer 47

Hormones associated with calorie burning + HR

Question 48

What does the adrenal gland control?

Answer 48

Cortisol

Question 49

What does the pineal gland control?

Answer 49

Melatonin

Question 50

What does the ovaries control?

Answer 50

Oestrogen, testosterone + progesterone

Question 51

What does the testes control?

Answer 51

Testosterone