Hormones and Smooth Muscle Relaxation Quiz
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Hormones and Smooth Muscle Relaxation Quiz

Test your knowledge on how hormones act through calcium or phosphatidylinositol to induce relaxation of smooth muscle and vasodilation. Learn about the role of ionized calcium as a regulator in various cellular processes such as muscle contraction and blood clotting cascade.

Created by
@FatihSultanMehmet

Questions and Answers

What is the role of ionized calcium in cellular processes?

Promotes stimulus-secretion coupling

Where are substantial amounts of calcium stored in a cell?

Mitochondria

How does the cell prevent excessive Ca2+ entry?

By activating Ca2+/proton ATPase-dependent pump

What is the function of calmodulin?

<p>Serves as a calcium-dependent regulatory protein</p> Signup and view all the answers

What happens with prolonged elevation of intracellular Ca2+ levels?

<p>Causes toxicity</p> Signup and view all the answers

How does ionized calcium act as an intracellular messenger?

<p>By regulating hormone action</p> Signup and view all the answers

What is the role of caffeine in relation to cAMP?

<p>Acts as an inhibitor of phosphodiesterase</p> Signup and view all the answers

How are the activities of protein phosphatases regulated?

<p>By phosphorylation-dephosphorylation reactions and other mechanisms</p> Signup and view all the answers

Which molecules use cGMP as a secondary messenger?

<p>Atrial natriuretic peptide (ANP) and nitric oxide (NO)</p> Signup and view all the answers

How is cGMP produced from GTP?

<p>By the enzyme guanylyl cyclase</p> Signup and view all the answers

What physiological effects does ANP exert?

<p>Urinary sodium excretion and urine excretion</p> Signup and view all the answers

Which compounds increase cGMP levels by activating guanylyl cyclase?

<p>Nitroprusside and sodium azide</p> Signup and view all the answers

Where are intracellular receptors located?

<p>Nucleus and cytoplasm</p> Signup and view all the answers

Why do steroid hormones travel on specific carrier proteins in the blood?

<p>To reach their target tissues as they are hydrophobic</p> Signup and view all the answers

What happens when a steroid hormone binds to a monomeric type I receptor?

<p>The receptor complex dimerizes</p> Signup and view all the answers

How do lipophilic hormones pass through the plasma membrane?

<p>By simple diffusion</p> Signup and view all the answers

What is the role of intracellular receptors once they interact with lipophilic hormones?

<p>Transcription activation</p> Signup and view all the answers

How do steroid-binding nuclear receptors act in the nucleus?

<p>They bind to hormone response elements</p> Signup and view all the answers

Which of the following is a general feature common to all signal transduction processes?

<p>The ligand interacts with a receptor</p> Signup and view all the answers

G protein-coupled receptors (GPCRs) indirectly activate enzymes through which type of proteins?

<p>GTP-binding proteins (G proteins)</p> Signup and view all the answers

Which type of receptor has enzymatic activity on the cytoplasmic side triggered by ligand binding on the extracellular side?

<p>Receptor enzymes</p> Signup and view all the answers

What type of receptors respond to epinephrine through the β-adrenergic receptor system?

<p>G protein-coupled receptors</p> Signup and view all the answers

Which type of receptors catalyze the phosphorylation of tyrosine residues in specific intracellular target proteins?

<p>Receptor enzymes</p> Signup and view all the answers

Which step marks the conclusion of a general signal transduction event?

<p>The target cell undergoes a change in metabolic activity</p> Signup and view all the answers

What is the consequence of full occupancy of all four Ca2+-binding sites of calmodulin?

<p>It leads to a marked conformational change allowing calmodulin to activate enzymes and ion channels.</p> Signup and view all the answers

Which element in cells is regulated by Ca2+/calmodulin signaling?

<p>Actin-myosin complex of smooth muscle</p> Signup and view all the answers

Which hormones increase calcium transport to the cytosol after receptor binding?

<p>Acetylcholine, antidiuretic hormone (ADH), α1-type catecholamines</p> Signup and view all the answers

Which enzyme catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2)?

<p>Phospholipase C</p> Signup and view all the answers

What is the function of DAG in cellular signaling?

<p>Activating protein kinase C (PKC)</p> Signup and view all the answers

How does IP3 contribute to intracellular signaling?

<p>It promotes calcium release from the endoplasmic reticulum</p> Signup and view all the answers

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