29 Questions
What is the origin of Oxytocin?
Produced in Paraventricular nuclei in the hypothalamus
Which defect causes Nephrogenic Diabetes Insipidus?
Autosomal mutation of V2 receptors gene in the kidney
Why do patients with Diabetes Insipidus experience polyuria?
Excessive water loss with no increase in other constituents
What mechanism of action does Oxytocin have?
Binds to receptors coupled to a G Protein enzyme and induces an increase in cytoplasmic Ca2+ for muscle contraction
What causes Central Diabetes Insipidus?
Lesion in the supraoptic nucleus
Why do patients with Diabetes Insipidus develop polydipsia?
To prevent dehydration due to excessive polyuria
Which protein carries 2/3 of T4 and 1/2 of T3 in the blood?
Thyroxine binding globulin (TBG)
Why is T3 more active than T4?
It has a higher affinity to thyroid receptors
Which type of thyroid receptor does T3 specifically bind to?
α 1, α 2, and β 2
Where are extranuclear thyroid receptors found?
Mitochondria
Which of the following is NOT a non-genomic action mediated by extranuclear receptors?
DNA replication
What is the primary physiological effect of Thyroid Hormones on metabolism?
Stimulation of metabolic rate
What effect do excessive thyroid hormones have on mitochondria?
Mitochondrial swelling and increased uncoupling of oxidative phosphorylation
How do thyroid hormones affect Na/K ATPase enzyme activity in cell membranes?
Increased enzyme activity
What effect do thyroid hormones have on protein metabolism?
Increased protein synthesis
How do thyroid hormones affect fat metabolism?
Increase lipolysis and free fatty acid oxidation
Which process is NOT affected by thyroid hormones?
Cholesterol synthesis
What is the consequence of increased activity of Na/K ATPase enzyme due to thyroid hormones?
Increased energy consumption
What stimulates the osteoblasts production of IL-6 and RANKL?
PTH
Which cells have no receptors for PTH?
Osteoclasts
What does PTH do to phosphate reabsorption in the renal proximal convoluted tubules?
Decreases it
What is the role of 1,25(OH)2D3 (dihydroxycholecalciferol) in the kidneys?
Activates enzyme production
What effect does PTH and 1,25(OH)2D3 have on calcium reabsorption in the distal part of renal tubules?
Increases it
What effect do PTH and 1,25(OH)2D3 have on calcium and phosphate absorption by the intestine?
Increase both
How is calcium primarily absorbed in the upper small intestine?
Passive diffusion
Which factor affects the solubility of calcium salts in the gastrointestinal tract?
Acidic food products
What is the role of vitamin D3 in calcium absorption?
Stimulates calcium absorption
Which compound plays a crucial role in cell phosphorylation and dephosphorylation reactions?
ATP
What happens when the concentration of cations and anions in a solution exceeds the solubility product?
Precipitation of the salt occurs
Learn about the two main types of Diabetes Insipidus (DI): Central DI and Nephrogenic DI. Central DI is caused by a lesion in the supraoptic nucleus, while Nephrogenic DI is due to congenital defects of renal V2 receptors. Explore the differences in causes and mechanisms of these two forms of DI.
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