Physiology Highlights Flashcards
What form of peptide hormone:
• Enters the ER
• Exits the ER
• Exits the Golgi
Enters ER as PreProHormone, Exits ER as ProHormone, and Exits the Golgi as the Hormone
Thyroid Hormone needs to act on a receptor in the nucleus but is hydrophilic, so how does it get there?
Na+ exchanger
What hormones work via the cAMP signaling pathway?
FLAT ChAMP + Calcitonin, GHRH, and Glucagon
FSH
LH
ACTH
TSH
CRH hCG ADH (V2 receptor) MSH PTH
What hormones work via the Gq pathway?
GOAT HAG
GnRH
Oxytocin
ADH (V1 receptor)
TRH
Histamine (H1 receptor)
Angiotensin II
Gastrin
What molecules signal through the growth hormone pathway?
Insulin and Growth Factors (IGF-1, FGF, Prolactin, PDGF, EGF)
What molecules signal through the JAK/STAT pathway?
PIGGET
Prolactin Immunomodulators (IL's, Cytokines) GH G-CSF Erythropoietin Thrombopoietin
What side of a follicular cell faces the blood vessel?
Basal Side of Follicular Cells Faces the blood Vessel
What is the major product of the thyroid?
T4
How does thyroglobulin that has undergone internal rearrangement and endocytosed get cleaved to T3 and T4?
Fusion of the thyroglobulin containing lysosome with an endosome allows for this
T or F: Iodine entry into follicular cells is ATP dependent
True, it requires co-transport with sodium (Sodium gradient created by Na/K ATPase
What is the only endocrine organ requiring a trace element to operate?
Thryoid
What is the half life of T4?
• T3?
T4 half life is 8 days
T3 half life is 24 hours
Where are type I 5’/3’ monodeiodinases found?
Liver
Kidney
Thyroid
Where are type II 5’/3’ monodeiodinases found?
Brain
CNS
Placenta
Where are type I and III 5/3 monodeiodinases found?
All tissue
What is the only organ to express deiodinase during starvation?
Brain - always expressed
What happens to thyroid hormone in the gut?
Enterohepatic Cycling (due to glucoronidases of bacteria)
What conditions lead to an increase in thyroid binding globulin?
Pregnancy
Oral Contraceptives
What conditions lead to a decrease in thyroid binding globulin?
Hepatic Failure
Steriods
What are the 5 main actions of Thyroid hormone?
- Increased Metabolic Rate
- Heart Effects
- Catabolic Effects
- Bones
- CNS
How does thyroid hormone raise the basal metabolic rate?
Increased Na/K ATPase
How does thyroid hormones causes heart problems?
Increased O2 consumption by tissue - increased workload
Increased Ca2+ ATPase
Increased Beta1-receptors
Increased Myosin
What is the role of Thyroid Hormone in bone development?
Synergistic Effect with GH to Mature Bones
What type of neurons are in the Hypothalamic-Hypophyseal tract?
Magnocellular Neurons - large and unmyelinated