Exam 5: Lecture 74: Melatonin and Eicosanoids: AI Questions Flashcards
Melatonin is synthesized in the pineal gland from:
A) Tyrosine
B) Serotonin
C) Dopamine
D) Epinephrine
B
The primary stimulus for melatonin secretion is:
A) Exposure to blue light
B) Darkness
C) High serotonin levels
D) Increased body temperature
B
Which of the following best describes the effect of blue light on melatonin secretion?
A) Increases melatonin production
B) Has no effect on melatonin levels
C) Suppresses melatonin secretion
D) Enhances the conversion of tryptophan to serotonin
C
The circadian rhythm of melatonin is regulated by:
A) The adrenal cortex
B) The pituitary gland
C) The suprachiasmatic nucleus
D) The hippocampus
C
Melatonin’s effects on reproductive function are primarily due to its action on:
A) Cortisol secretion
B) GnRH release
C) Thyroid hormone synthesis
D) Prolactin release
B
Which receptor subtype does melatonin primarily bind to?
A) MT1 and MT2 receptors
B) Beta-adrenergic receptors
C) Alpha-1 adrenergic receptors
D) GABA receptors
A
In veterinary medicine, melatonin is often used to:
A) Treat hypothyroidism
B) Manage alopecia X in dogs
C) Increase cortisol levels
D) Stimulate appetite in cats
B
The primary precursor for eicosanoid synthesis is:
A) Cholesterol
B) Eicosapentaenoic acid (EPA)
C) Arachidonic acid
D) Linoleic acid
C
Eicosanoids derived from omega-3 fatty acids are typically:
A) Pro-inflammatory
B) Anti-inflammatory
C) Neutral in their effects
D) Vasoconstrictive
B
Which enzyme catalyzes the release of arachidonic acid from cell membranes?
A) Lipoxygenase
B) Cyclooxygenase (COX)
C) Phospholipase A2
D) Glutathione peroxidase
C
The primary action of prostaglandin E2 (PGE2) is:
A) Inhibition of platelet aggregation
B) Smooth muscle relaxation
C) Induction of pain, heat, and fever
D) Bronchodilation
C
Non-steroidal anti-inflammatory drugs (NSAIDs) primarily inhibit:
A) Phospholipase A2
B) COX1 and COX2 enzymes
C) Lipoxygenase
D) Arachidonic acid synthesis
B
Eicosanoids synthesized via the lipoxygenase pathway include:
A) Thromboxanes
B) Leukotrienes
C) Prostaglandins
D) Prostacyclins
B
Which eicosanoid is most associated with bronchoconstriction and asthma?
A) Thromboxane A2 (TXA2)
B) Leukotriene D4 (LTD4)
C) Prostaglandin I2 (PGI2)
D) Lipoxin A4
B
The main effect of thromboxane A2 (TXA2) is to:
A) Inhibit platelet aggregation
B) Promote vasodilation
C) Stimulate platelet aggregation and vasoconstriction
D) Induce fever
C