Week 3- Pituitary Gland

Question 1

What are the 2 main hormones?

Answer 1

Peptide and steroid

Question 2

What are peptide hormones synthesized as?

Answer 2

Prohormones

Question 3

What are steroid hormones synthesized as?

Answer 3

A series of reactions from cholesterol

Question 4

How are peptide hormones stored?

Answer 4

In vesicles

Question 5

How are steroid hormones stored?

Answer 5

They aren’t, they get released immediately

Question 6

What tissue does the anterior pituitary gland contain?

Answer 6

Glandular (NOT neural)

Question 7

What 5 types of endocrine cells make up the anterior pituitary?

Answer 7

Somatotrophs
Lactotrophs 
Corticotrophs
Thyrotrophs 
Gonadotrophs

Question 8

What hormone do somatotrophs release?

Answer 8

Growth hormone (somatotropin)

Question 9

What hormone do lactotrophs release?

Answer 9

Prolactin

Question 10

What hormone do thyrotrophs release?

Answer 10

Thyroid stimulating hormone

Question 11

What hormone do gonadotropes release release?

Answer 11

LH/FSH

Question 12

What hormone do corticotrophs release?

Answer 12

ACTH (adrenocorticotrophic hormone)

Question 13

What is the releasing component of the growth hormone?

Answer 13

Growth hormone releasing hormone

Question 14

What is the inhibiting component of the growth hormone?

Answer 14

Somatostatin

Question 15

What is the inhibiting component of prolactin?

Answer 15

Dopamine

Question 16

What is the releasing component of TSH?

Answer 16

Thyrotropin releasing hormone

Question 17

What is the releasing component of LH/FSH?

Answer 17

Gonadotrophin releasing hormone

Question 18

What is the releasing component of ACTH?

Answer 18

Corticotrophin releasing hormone and Argenine vasopressin

Question 19

Where are growth hormone receptors found?

Answer 19

Liver, muscle and skeleton

Question 20

Where are prolactin receptors found?

Answer 20

Breast

Question 21

Where are thyrotropin receptors found?

Answer 21

Thyroid

Question 22

Where are gonadotrophin receptors found?

Answer 22

Testes for men

Ovaries for women

Question 23

Where are corticotrophin receptors found?

Answer 23

Adrenal glands

Question 24

What is bitemporal hemianopia?

Answer 24

Loss of temporal part of visual field due to a pituitary tumor squashing the optic chiasm

Question 25

What does reduced dopamine do in reference to milk production?

Answer 25

More prolactin is produced so milk is produced

Question 26

What does binding of growth hormone to liver receptors stimulate the production of?

Answer 26

Insulin-like growth factor (IGF 1 is the main one but also IGF 2)

Question 27

What are the 2 mechanisms of action of growth hormone?

Answer 27

1. Binding directly to receptors in muscles/skeleton | 2. Binding to liver receptors causing production of IGF

Question 28

What is the condition where there is excess growth hormone in children? Describe the symptoms

Answer 28

Gigantism- child grows very tall

Question 29

What is the condition where there is excess growth hormone in adults? Describe the symptoms

Answer 29

Acromegaly- bigger nose, tongue, feet, hands etc (small changes over time)

Question 30

What are the 2 posterior pituitary hormones?

Answer 30

``` Arginine vasopressin (AVP aka anti diuretic hormone) Oxytocin ```

Question 31

What does vasopressin do?

Answer 31

Stimulation of water reabsorption in collecting duct, concentrating urine

Question 32

Which receptor does vasopressin work through? Where is the receptor found?

Answer 32

V2 receptor in kidney collecting duct

Question 33

What are the 2 main physiological actions of oxytocin?

Answer 33

1. In the delivery of the baby (uterus at parturition causes contraction of myometrial cells) 2. In milk ejection (causes contraction of myoepithelial cells in the breast during lactation)

Question 34

How do peptide hormones act on receptors?

Answer 34

Receptors are found on the cell membrane and transduce signal using 2nd messenger systems

Question 35

How do steroid hormones act on receptors?

Answer 35

They bind to intracellular receptors and directly change gene expression

Question 36

What is a hormone?

Answer 36

A chemical messenger that is carried from the organ where it’s produced to the organ it affects by the bloodstream

Question 37

How are hormones carried from place to place?

Answer 37

Bloodstream

Question 38

What are the 5 components of the anterior pituitary gland?

Answer 38

``` Optic chiasm Pars tuberalis Pars intermedia Pars distalis Sella turcica of the sphenoid bone ```

Question 39

What are the 5 complements of the posterior pituitary gland?

Answer 39

``` Hypothalamus Mammillary body Pars nervosa Infundibulum Median eminence ```

Question 40

What neurons regulate anterior pituitary function?

Answer 40

Hypothalamic parvocellular neurones

Question 41

What do hypothalamic parvocellular neurons do and where do they terminate?

Answer 41

They terminate in the median eminence and release hypothalamic releasing/inhibitory factors into the capillary plexus of the median eminence. These factors are carried by portal circulation to the anterior pituitary

Question 42

What is the anterior pituitary gland regulated by and via what system?

Answer 42

Hypothalamic releasing/inhibiting factors via the hypohyseal pituitary portal system

Question 43

Describe how the hypothalamo-pituitary system works

Answer 43

Axon terminals of neurosecretpry cells release hormones (RHs and IHs) into the hypothalamo-pituitary portal system RHs and IHs travel in the portal system to the anterior pituitary They stimulate or inhibit the release of hormones from anterior pituitary cells Anterior pituitary hormones leave the gland via blood

Question 44

Where is the optic chiasm found?

Answer 44

Right on top of the pituitary gland

Question 45

Where is dopamine released from?

Answer 45

Dopaminergenic neurons

Question 46

What is the posterior pituitary a continuation of?

Answer 46

The hypothalamus

Question 47

Where do hypothalamic magnocellular neurons originate?

Answer 47

In the supraoptic and paraventricular hypothalamic nuclei

Question 48

Describe the regulation of the posterior pituitary gland

Answer 48

2 sets of hypothalamic neurosecretory cells produce AVP and oxytocin and transport the, to the posterior pituitary Excitation of magnocellular neurons stimulates the release of AVP or oxytocin into the posterior pituitary where they diffuse into blood capillaries

Question 49

What is the action of vasopressin via V1 receptor?

Answer 49

A vasoconstrictor that stimulates ACTH release from anterior pituitary

Question 50

What does oxytocin do in the milk production pathway and via what pathway is it released?

Answer 50

Mechanical stimulation of the nipple causing oxytocin release via ascending sensory pathways, increase of plasma oxytocin increases milk ejection in mammary glands

Question 51

What is the difference in action of prolactin vs oxytocin in regards to lactation

Answer 51

Prolactin: stimulates milk production Oxytocin: stimulates milk ejection

Question 52

What is the alternative name for the anterior pituitary?

Answer 52

Adenohypophysis

Question 53

What is an alternative name for the posterior pituitary gland?

Answer 53

Neurohypophysis

Question 54

What is the stalk like process that connects the hypothalamus and the pituitary?

Answer 54

Infundibulum

Question 55

What is the peptide precursor to ACTH?

Answer 55

Proopiomelanocortin

Question 56

What is the source of inhibitory or stimulatory signals that affect the pituitary?

Answer 56

Hypothalamus

Question 57

Usually what is the cause of acromegaly?

Answer 57

Pituitary adenoma