Pituitary gland

Question 1

Two types of hormones?

Answer 1

Peptides- prohormones stored in vesicles

Steroids- synthesised from cholesterol and released immediately

Question 2

Which bone does the pituitary gland sit on?

Answer 2

Sella turcica of the sphenoid bone

Question 3

Neurones in anterior pituitary?

Answer 3

Parvocellular neurones

Question 4

5 endocrine cells in the anterior pituitary and their hormones?

Answer 4

Somatotrophs- growth hormone (somatotrophin)
Lactotrophs- prolactin
Corticotrophs- adrenocorticotrophic hormone (ACTH)
Thyrotrophs- TSH
Gonadotrophs- LH and FSH

Question 5

TSH axis example?

Answer 5

Hypothalamus → Thyrotrophin Releasing Hormone → portal system → stimulates release of Thyroid Stimulating Hormone (TSH) from thyrotrophs → TSH leaves gland via blood to stimulate thyroid gland to release thyroid hormone (thyroxine)

Question 6

6 regulating hormones?

Answer 6

GHRH and somatostatin 
Dopamine
THRH
GRH
CRH

Question 7

Main target cells of anterior hormones?

Answer 7

Growth hormone- body tissues, particularly the river
Prolactin- breasts
Thyrotrophin- thyroid
Gonadotrophins- testes and ovaries
ACTH- adrenal cortex

Question 8

Milk production arc reflex?

Answer 8

Mechanical stimulation of nipples activates afferent pathways
Inhibition of dopamine release in hypothalamus
Less dopamine in hypothalamic-pituitary portal causes less inhibition of lactotrophs
Increased plasma prolactin increases milk secretion in mammary glands

Question 9

2 actions of growth hormone?

Answer 9

Bind to growth receptors on tissues

Stimulate IGF-1 release in the liver

Question 10

Visual problem caused by pituitary tumour?

Answer 10

Bitemporal hemianopia due to tumour pressing on optic chiasm

Question 11

Acromegaly cause and symptoms?

Answer 11

Excess growth hormone after puberty

Macroglossia, sweating, headaches, enlarged feet and hands, coarsening of facial features

Question 12

2 hormones in posterior gland?

Answer 12

Arginine vasopressin

Oxytocin

Question 13

What tissue is the posterior gland made out of?

Answer 13

Neuronal tissue, continuous with hypothalamus

Question 14

Magnocellular neurons?

Answer 14

Long originate in the supraoptic (AVP) and paraventricular (oxytocin) hypothalamic nuclei

Question 15

How are posterior hormones produced?

Answer 15

Hypothalamic neurosecretory cells produce hormones and transport them to posterior pituitary. Excitation of magnocellular hormones stimulates release of hormones into blood

Question 16

How does vasopressin concentrate urine?

Answer 16

Binds to V2 G-protein receptors. Causes aquaporin channels to transport more water from the urine to the blood. This concentrates urine.

Question 17

2 oxytocin actions?

Answer 17

Contractions during labour

Milk ejection