Organization of Endocrine System Flashcards
SRIH/GHRH – GH –
Peripheral tissues
MIH/MRH – MSH –
Peripheral tissues
TRH – TSH –
Thyroid gland
CRH/ADH – ACTH/End –
Adrenal cortex
GnRH – FSH & LH –
Gonadal steroid secreting cells
DOPA/salsolinol – Prl –
Milk secretion by mammary alveolar tissue
CRH
Corticotropin-releasing hormone
Regulates secretion of ACTH
TRH
Thyrotropin-releasing hormone
Regulates secretion of TSH
GnRH
Gonadotropin-releasing hormone/gonadoliberin
Regulates secretion of GnRH, LH and FSH
SRIH
Somatostatin
Inhibits secretion of GH
GHRH
Growth hormone-releasing hormone
Stimulates secretion of GH
DOPA
Dopamine
Inhibits secretion of Prl
SAL
Salsolinol
Stimulates release of Prl in ruminants
MIF
Melanocyte stimulating hormone (MSH)-inhibiting factor
Inhibits MSH secretion
MRF
Melanocyte stimulating hormone (MSH)-releasing factor
Stimulates MSH secretion
3 major “families” of anterior pituitary hormones
- POMC
- Somatomammotropic
- Glycoprotein
POMC (peptides)
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
Somatomammotropic (proteins)
GH – growth & metabolic regulation *regeneration
Prl – lactation (adipocyte glucose/lipid metabolism) *CV; CNS
SL (somatolactin) – role not known
Glycoprotein
TSH – regulates thyroid gland activity
FSH
LH – regulates gonadal activity & sexual development in both sexes
MC1-R
Primary α-MSH-R
- Melanocytes (cell proliferation, melanin synthesis)
- Immune system cells (anti-inflammatory response)
MC2-R
Primary ACTH-R
- Adrenal cortex (stimulation of glucocorticoid and androgen synthesis)
- Adipocytes (stimulates lipolysis)
MC3-R
Interacts with γ-MSH > α-MSH
- CNS (hypothermia regulation)
- Heart (bradycardia and hypotension)
MC4-R
All MSH isoforms and ACTH
- CNS (inhibition of feeding behaviour, appetite)
MC5-R
Interacts with α-MSH > γ-MSH
- Adipocytes, adrenal, leukocytes, gonads, CNS, pituitary (unknown function)
Pars Nervosa Hormones (octapeptide)
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
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
c. supraoptic nucleus − ADH − paraventricular nucleus − oxytocin
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.
b. Corticotropes produce ACTH and β-lipotropin.
Pars Distalis (Cellular Composition)
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)
