Session 9 (1) - Normal structure of Pituitary and Adrenal Glands

Question 1

Name 6 hormones produced from pituitatry, and the cells they stem from

Answer 1

TSH is produced in the Thyrotrophs
ACTH produced in the Corticotrophs
Growth hormone produced in the Somatotrophs (largest number of cells)
LH and FSH are produced in the Gonadotrophs
Prolactin is produced in the Lactotrophs

Question 2

Where is the pituitary located?

Answer 2

Base of the brain suspended from the hypothalamus by a stalk

Question 3

How do releasing factors travel from hypothalamus to pituitary gland?

Answer 3

Via hypohyseal portal system, a specialised series of blood vessels.

Question 4

List the three types of hormones released from adrenal cortex and give examples of each

Answer 4

Mineralocorticoids
E.g. Aldosterone (C21 steroid)

Glucocorticoids
E.g. Cortisol and Corticosterone (C21 steroids) major steroids produced

Androgens

Question 5

Give two parts of adrenal gland

Answer 5

Cortex and Medulla

Question 6

What is the name for the three sections of the adrenal cortex, and what does each secrete?

Answer 6

Zona Glomerulosa --> Mineralocorticoids 
E.g. Aldosterone (C21 steroid)
Zona Fasciculata --> Glucocorticoids 
E.g. Cortisol and Corticosterone (C21 steroids) major steroids produced
Zona Reticularis --> Androgens

Question 7

What is released from medulla?

Answer 7

Adrenaline

Question 8

What is the function of TSH?

Answer 8

Stimulates secretion of thyroid hormones from thyroid

Question 9

What is the function of growth hormone?

Answer 9

Affects metabolism, increasing muscle mass

Question 10

What are the functions of LH and FSH?

Answer 10

Affects ovary and testis function

Question 11

What is the function of prolactin?

Answer 11

Affects breast and milk development

Question 12

What is the function of aldosterone?

Answer 12

Stimulates Na+ reabsorption in the kidney in exchange for K+ (or H+).

Question 13

What does over secretion of aldosterone cause?

Answer 13

increases Na+ and water retention and loss of K+ causing hypertension and muscle weakness.

Question 14

What does undersecretion of aldosterone cause?

Answer 14

Undersecretion decreases Na+ and water retention, increases K+. Causes hypotension.

Question 15

What are the functions of androgens?

Answer 15

Stimulate growth and development of male genital tract and male secondary sexual characteristics. Anabolic.

Question 16

Give an example of an androgen

Answer 16

Testosterone

Question 17

What effect does over secretion of androgens have on females?

Answer 17

Hair growth, deepening voice, menstrual problems and acne.

Question 18

What are the functions of Oestrogen?

Answer 18

Stimulate growth and development of female genital tract and female secondary sexual characteristics. Weakly anabolic.
(broad hips, accumulation of fat in breasts, body hair distribution)

Question 19

How do steroids differ in structure from each other?

Answer 19

Number of C atoms
Presence of functional groups
Distribution of C=C bonds

Question 20

Give two distinctive features of steroid hormones

Answer 20

Lipophillic

Synthesised from Cholesterol via progesterone

Question 21

What is CRF secreted in response to, and where is it secreted from?

Answer 21

Physical (temperature, pain), chemical (hypoglycaemia) and emotional stressors.
Secreted from hypothalamus.

Question 22

How is CRF secretion inhibited?

Answer 22

Negative feedback from glucocorticoids

Question 23

What does CRF do?

Answer 23

Causes secretion of ACTH from anterior pituitary

Question 24

What is the precursor for ACTH?

Answer 24

POMC

Question 25

What does post translation processing of POMC produce?

Answer 25

a-melanocyte stimulating hormone ACTH B endorphins

Question 26

What does ACTH cause pigmentation in body when present in large amounts?

Answer 26

MSH sequence contained with ACTH sequence, give ACTH some MSH like activity when in excess.

Question 27

How does ACTH production relate to cortisol secretion rhythmn?

Answer 27

Secreted in pulses following circardian rhythmn

Question 28

Where does ACTH bind and how? What does binding do?

Answer 28

Where Zona fasiculata Zona reticularis How Hydrophillic, interacts with high affinity receptors on cell surface. Binding stimulates cholesterol esterase, which produces cholesterol from which cortisol produced.

Question 29

What is the name of the receptor ACTH binds to?

Answer 29

Melanocortin receptor

Question 30

What does over secretion of ACTH cause?

Answer 30

Pigmentation | Over-production of cortisol

Question 31

What does under secretion of ACTH cause?

Answer 31

Symptoms related to lack of glucocorticoids

Question 32

How is cortisol transported in plasma and why?

Answer 32

Bound to plasma proteins as it is lipophillic

Question 33

Describe mechanism of action for cortisol on target cells

Answer 33

Cortisol can cross plasma membranes and bind to cytoplasmic receptors The hormone/receptor complex enters nucleus and interacts with specific regions of DNA This interaction changes rate of transcription of certain genes

Question 34

Describe the functions of cortisol

Answer 34

1) Increase proteolysis (decreased amino acid uptake + protein synthesis) 2) Hepatic gluconeogenesis and glycogenolysis 3) Increased lipolysis in adipose tissue (HIGH cortisol results in lipogenesis) 4) Decreased peripheral uptake of glucose (ANTI-INSULIN)

Question 35

How is adrenaline synthesised?

Answer 35

Tyrosine --> Dopamine --> Adrenaline

Question 36

What type of hormone is adrenaline?

Answer 36

Amino acid derivative

Question 37

Give four effects of adrenaline

Answer 37

- Cardiovascular system (increased cardiac output, increased blood supply to muscle) - CNS (Increased mental alertness) - Carb metabolism (increased glycogenolysis) - Lipid metabolism (increased lipoysis in adipose tissue)

Question 38

What is adrenaline secreted in response to?

Answer 38

Fright, fight or flight - stress situations

Question 39

What can cause overproduction of adrenaline?

Answer 39

Tumour (phaechromocytoma) in adrenal medulla

Question 40

What can overproduction of adrenaline cause?

Answer 40

Hypertensison, anxiety, palpitations, sweating and glucose intolerance