Organization of Endocrine System

Question 1

SRIH/GHRH – GH –

Answer 1

Peripheral tissues

Question 2

MIH/MRH – MSH –

Answer 2

Peripheral tissues

Question 3

TRH – TSH –

Answer 3

Thyroid gland

Question 4

CRH/ADH – ACTH/End –

Answer 4

Adrenal cortex

Question 5

GnRH – FSH & LH –

Answer 5

Gonadal steroid secreting cells

Question 6

DOPA/salsolinol – Prl –

Answer 6

Milk secretion by mammary alveolar tissue

Question 7

CRH

Answer 7

Corticotropin-releasing hormone

Regulates secretion of ACTH

Question 8

TRH

Answer 8

Thyrotropin-releasing hormone

Regulates secretion of TSH

Question 9

GnRH

Answer 9

Gonadotropin-releasing hormone/gonadoliberin

Regulates secretion of GnRH, LH and FSH

Question 10

SRIH

Answer 10

Somatostatin

Inhibits secretion of GH

Question 11

GHRH

Answer 11

Growth hormone-releasing hormone

Stimulates secretion of GH

Question 12

DOPA

Answer 12

Dopamine

Inhibits secretion of Prl

Question 13

SAL

Answer 13

Salsolinol

Stimulates release of Prl in ruminants

Question 14

MIF

Answer 14

Melanocyte stimulating hormone (MSH)-inhibiting factor

Inhibits MSH secretion

Question 15

MRF

Answer 15

Melanocyte stimulating hormone (MSH)-releasing factor

Stimulates MSH secretion

Question 16

3 major “families” of anterior pituitary hormones

Answer 16

1. POMC
2. Somatomammotropic
3. Glycoprotein

Question 17

POMC (peptides)

Answer 17

ACTH – regulates adrenal cortex function
MSH – skin pigmentation in response to UV radiation
End (beta-endorphin) – analgesic roles in CNS
Enk (enkephalin) – analgesic roles in fetus

Question 18

Somatomammotropic (proteins)

Answer 18

GH – growth & metabolic regulation *regeneration
Prl – lactation (adipocyte glucose/lipid metabolism) *CV; CNS
SL (somatolactin) – role not known

Question 19

Glycoprotein

Answer 19

TSH – regulates thyroid gland activity
FSH
LH – regulates gonadal activity & sexual development in both sexes

Question 20

MC1-R

Answer 20

Primary α-MSH-R

• Melanocytes (cell proliferation, melanin synthesis)
• Immune system cells (anti-inflammatory response)

Question 21

MC2-R

Answer 21

Primary ACTH-R

• Adrenal cortex (stimulation of glucocorticoid and androgen synthesis)
• Adipocytes (stimulates lipolysis)

Question 22

MC3-R

Answer 22

Interacts with γ-MSH > α-MSH

• CNS (hypothermia regulation)
• Heart (bradycardia and hypotension)

Question 23

MC4-R

Answer 23

All MSH isoforms and ACTH

• CNS (inhibition of feeding behaviour, appetite)

Question 24

MC5-R

Answer 24

Interacts with α-MSH > γ-MSH

• Adipocytes, adrenal, leukocytes, gonads, CNS, pituitary (unknown function)

Question 25

Pars Nervosa Hormones (octapeptide)

Answer 25

Oxytocin - Milk let-down - Uterine contraction (childbirth) - Smooth muscle contraction during orgasm (male & female) ADH - Water recovery from kidney tubules - Acts with ACTH to regulate adrenal cortex activity - Vasopressor

Question 26

Although there is some overlap, the neurosecretory cells of the _______________ produce mainly _______________ or vasopressin, and those of the _______________ produce ______________. a. retro-optic chiasm − oxytocin − paraventricular nucleus − ADH b. paraventricular nucleus − ADH − supraoptic nucleus − oxytocin c. supraoptic nucleus − ADH − paraventricular nucleus − oxytocin d. median eminence − ADH − paraventricular nucleus − oxytocin e. supraoptic nucleus − POMC − paraventricular nucleus − oxytocin

Answer 26

c. supraoptic nucleus − ADH − paraventricular nucleus − oxytocin

Question 27

Which is true for the pituitary gland? a. The pars nervosa consists of the clusters of protein producing cells, which are characterized by different affinity for various dyes (i.e., acidophils, basophils and chromophobes). b. Corticotropes produce ACTH and β-lipotropin. c. TRH and ACTH are produced in the neurons of the hypothalamus. d. In most domestic animals, the pars intermedia is separated from the pars nervosa by a hypophyseal cleft and is closely associated with the pars distalis. e. Melanotropes (cells producing MSH) are most abundant in the pars distalis and are usually referred to as the Herring bodies.

Answer 27

b. Corticotropes produce ACTH and β-lipotropin.

Question 28

Pars Distalis (Cellular Composition)

Answer 28

Chromophils - Acidophils (60%) Eosin/pink (lactotropes, somatotropes) - Basophils (35%) Hematoxilin/blue (thyrotropes, corticotropes, gonadotrophs) Chromophobes (5%) Epithelial cells (amphophils) Intermediate lobe (chromophobic cells (melanotropes)) Posterior pituitary (magnocellular neurons, non-myelinated)