Endocrine - Physiology Flashcards
Hormone Structure:
Which amino acid derivatives are derivatives of tyrosine?
Adrenaline
Noradrenaline
Dopamine
Thyroid hormones
Hormone Structure:
Which amino acid derivatives are derivatives of tryptophan?
Melatonin
Hormones:
Which SHORT polypeptides does the pituitary make?
ACTH, GH and PRL
Hormones:
Which LONG polypeptides does the pituitary make?
TSH, LH, FSH
Hormones:
Which SHORT polypeptides does the hypothalamus make?
ADH, Oxytocin, regulatory hormones
Hormones:
Which SHORT polypeptides does the pancreas make?
Insulin and glucagon
Hormones:
Which SHORT polypeptides does the parathyroid make?
PTH
Hormones:
Which SHORT polypeptides does the C-cells of Thyroid make?
Calcitonin
Hormones:
Which SHORT polypeptides does the heart make?
ANP and BNP
Hormones:
Which SHORT polypeptides does the adipose make?
Leptin and resistin
Hormones:
Which LONG polypeptides does the kidney make?
EPO
Hormones:
Which LONG polypeptides does the reproductive system make?
Inhibin
Second Messengers: cAMP
How is cAMP activated?
Hormone binding to its receptor activates G PROTEIN
G Protein then activates ADENYLYL CYCLASE
Adenylyl cyclase then converts ATP to cAMP
Second Messengers: cAMP
What does cAMP do?
cAMP then activates kinase which phosphorylates
Second Messengers: cAMP
What does phosphodiesterase (PDE) do?
Phosphodiesterase (PDE) is also activated by G PROTEIN and reduces cAMP to AMP
Second Messengers: cGMP
How is cGMP activated?
GUANYLYL CYCLASE converts to GTP to cGMP in response to NITRIC OXIDE
Second Messengers: cGMP
What does cGMP do?
cGMP exerts effects by stimulating PKG (Protein Kinase G)
Second Messengers: Phospholipid Derived
How is Phospholipase C (PLC) activated?
Hormone binds to its receptor to activate G PROTEIN which then activates PHOSPHOLIPASE C (PLC)
Second Messengers: PLC
What does PLC (Phospholipase C) do?
PLC hydrolyses PIP2 in membrane into DAG and IP3
Second Messengers:
What does DAG do?
DAG = diacylglycerol
Increases affinity of protein kinase C for calcium
Second Messengers:
What does IP3 do?
IP3 = inositol triphosphate
Binds to endoplasmic reticulum to trigger release of calcium
What does calmodulin do?
Calmodulin binds to calcium (acting as a second messenger) then activates enzymes (ie smooth muscle contraction via alpha 1 receptors)
How do G Protein Coupled Receptors work?
Composed of alpha and beta subunits.
Alpha subunit binds to GTP and hydrolyses to GDP then mediates signals via second messenger systems
How do Tyrosine Kinase Receptors work?
Name some examples
For signals from insulin and growth factors
After ligand binding the receptor autophosphorylates to interact with intercellular adaptor proteins
ie: insulin receptor activates Raf-Ras-MAPK and the Akt/protein kinase B pathway
How do Cytokine receptors work?
Name some examples
After ligand binding the receptor activates intracellular kinases.
ie Janus kinases (JAKs)
STAT family
Ras
How do Serine Kinase Receptors work?
Mediate action of activins, transforming growth factor beta, and mullerian inhibiting substance and bone morphogenic proteins
Signal via “smad” proteins
Where is the hypothalamus located?
Located ventral part of the diencephalon on either side of the 3rd ventricle extending from the optic chiasm to the mamillary bodies
What nuclei are in the supraoptic region of the hypothalamus?
Supraoptic nucleus
Paraventricular nucleus
What do BOTH the nuclei in the supraoptic region of the hypothalamus secrete?
The supraoptic nucleus and paraventricular nucleus secrete ADH and Oxytocin down the infundibulum to the POSTERIOR pituitary
Paraventricular nucleus secretes WHAT in addition to ADH and oxytoxin?
The paraventricular nucleus of the supraoptic region secretes CRH into the portal system to the ANTERIOR pituitary
What nuclei are in the TUBERAL region of the hypothalamus?
The MEDIAL section:
- ventromedial nucleus
- arcuate nucleus
The LATERAL section
What is the role of the ventromedial nucleus?
The ventromedial nucleus of the hypothalamus = “Satiety Centre”
- control of eating
- Irritability and aggression
A lesion in the ventromedial nucleus of the hypothalamus will result in what?
Overeating
What is the role of the arcuate nucleus?
The arcuate nucleus of the hypothalamus = “infundibular/periventricular nucleus”
- secrete releasing hormones: CRH, GHRH, GNRH, TSH
What is the role of the lateral hypothalamic area?
= “Feeding Centre”
- control of eating
A lesion in the lateral hypothalamic area of the hypothalamus will result in what?
Anorexia
What is the role of the mamillary region of the hypothalamus?
Contains the ‘Posterior Hypothalamic Nucleus’ = Thermoregulatory centre
Contains the Mamillary Nuclei = Memory Centre
What is the memory centre?
Mamillary nuclei
Where is the Thermoregulatory Centre?
Mamillary region posterior hypothalamic nucleus
A lesion in the ANTERIOR posterior hypothalamic nucleus results in what?
Hyperthermia
A lesion in POSTERIOR posterior hypothalamic nucleus results in what?
Hypothermia
