Exam 5: Lecture 74: Melatonin and Eicosanoids: AI Questions Flashcards

1
Q

Melatonin is synthesized in the pineal gland from:
A) Tyrosine
B) Serotonin
C) Dopamine
D) Epinephrine

A

B

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2
Q

The primary stimulus for melatonin secretion is:
A) Exposure to blue light
B) Darkness
C) High serotonin levels
D) Increased body temperature

A

B

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3
Q

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

A

C

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4
Q

The circadian rhythm of melatonin is regulated by:
A) The adrenal cortex
B) The pituitary gland
C) The suprachiasmatic nucleus
D) The hippocampus

A

C

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5
Q

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

A

B

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6
Q

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

A

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7
Q

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

A

B

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8
Q

The primary precursor for eicosanoid synthesis is:
A) Cholesterol
B) Eicosapentaenoic acid (EPA)
C) Arachidonic acid
D) Linoleic acid

A

C

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9
Q

Eicosanoids derived from omega-3 fatty acids are typically:
A) Pro-inflammatory
B) Anti-inflammatory
C) Neutral in their effects
D) Vasoconstrictive

A

B

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10
Q

Which enzyme catalyzes the release of arachidonic acid from cell membranes?
A) Lipoxygenase
B) Cyclooxygenase (COX)
C) Phospholipase A2
D) Glutathione peroxidase

A

C

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11
Q

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

A

C

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12
Q

Non-steroidal anti-inflammatory drugs (NSAIDs) primarily inhibit:
A) Phospholipase A2
B) COX1 and COX2 enzymes
C) Lipoxygenase
D) Arachidonic acid synthesis

A

B

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13
Q

Eicosanoids synthesized via the lipoxygenase pathway include:
A) Thromboxanes
B) Leukotrienes
C) Prostaglandins
D) Prostacyclins

A

B

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14
Q

Which eicosanoid is most associated with bronchoconstriction and asthma?
A) Thromboxane A2 (TXA2)
B) Leukotriene D4 (LTD4)
C) Prostaglandin I2 (PGI2)
D) Lipoxin A4

A

B

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15
Q

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

A

C

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16
Q

Which NSAID is selective for COX2 inhibition?
A) Aspirin
B) Ibuprofen
C) Celecoxib
D) Flunixin

A

C

17
Q

Omega-6 fatty acids are converted to arachidonic acid, which is:
A) Anti-inflammatory
B) Pro-inflammatory
C) Inactive
D) Neuroprotective

A

B

18
Q

Melatonin secretion typically peaks:
A) In the early afternoon
B) During the night (2-4 AM)
C) Just before sunrise
D) During midday

A

B

19
Q

Eicosanoids have a short half-life because they are:
A) Stored in vesicles for immediate release
B) Rapidly degraded by enzymes
C) Synthesized in response to chronic stimuli
D) Transported in the blood by binding proteins

A

B

20
Q

Lipoxins, a type of eicosanoid, are unique because they:
A) Promote inflammation
B) Inhibit inflammatory responses
C) Stimulate platelet aggregation
D) Increase blood pressure

A

B

21
Q

The pineal gland’s response to light involves:
A) Direct stimulation by norepinephrine
B) Suppression via the retinohypothalamic tract
C) Stimulation by cortisol
D) Inhibition by serotonin

A

B

22
Q

The synthesis of melatonin in the pineal gland is inhibited by:
A) Light exposure
B) Darkness
C) High levels of serotonin
D) Increased dopamine release

A

A

23
Q

Which of the following best describes the function of prostacyclin (PGI2)?
A) Inhibits platelet aggregation and promotes vasodilation
B) Stimulates bronchoconstriction and vasoconstriction
C) Enhances clot formation and increases blood pressure
D) Increases stomach acid secretionA

A

A

24
Q

The primary precursor for melatonin synthesis in the pineal gland is:
A) Tryptophan
B) Tyrosine
C) Dopamine
D) Histidine

A

A

25
Q

Which eicosanoid is most likely involved in the resolution of inflammation?
A) Prostaglandin E2 (PGE2)
B) Thromboxane A2 (TXA2)
C) Leukotriene B4 (LTB4)
D) Lipoxin A4

A

D

26
Q

The action of melatonin on the reproductive axis typically leads to:
A) Inhibition of GnRH release
B) Increased FSH and LH secretion
C) Stimulation of ovulation
D) Enhanced prolactin release

A

A

27
Q

The cyclooxygenase (COX) pathway is responsible for the synthesis of:
A) Prostaglandins, thromboxanes, and prostacyclins
B) Leukotrienes and lipoxins
C) Serotonin and melatonin
D) Dopamine and norepinephrine

A

A

28
Q

The release of arachidonic acid from cell membranes is primarily triggered by:
A) Phospholipase A2 activation
B) COX enzyme inhibition
C) Increased melatonin levels
D) Elevated cortisol levels

A

A

29
Q

Which eicosanoid is known to cause potent bronchoconstriction and is implicated in asthma?
A) Prostaglandin I2 (PGI2)
B) Thromboxane A2 (TXA2)
C) Leukotriene C4 (LTC4)
D) Prostaglandin F2α (PGF2α)

A

C

30
Q

In the regulation of circadian rhythms, melatonin acts as a:
A) Chronobiotic, helping to reset the biological clock
B) Inhibitor of cortisol secretion
C) Stimulator of serotonin release
D) Regulator of thyroid hormone synthesis

A

C

31
Q

The anti-inflammatory effects of omega-3 fatty acids are mediated through the production of:
A) Resolvins and protectins
B) Prostaglandin E2 (PGE2)
C) Thromboxane B2 (TXB2)
D) Lipoxin A4

A

A

32
Q

Melatonin secretion is typically highest:
A) During the night
B) In the early morning
C) During midday
D) In response to cortisol release

A

A

33
Q

Which enzyme is targeted by selective COX-2 inhibitors?
A) Cyclooxygenase-2 (COX-2)
B) Lipoxygenase
C) Cyclooxygenase-1 (COX-1)
D) Phospholipase C

A

A

34
Q

The role of melatonin in seasonal breeders is to:
A) Inhibit reproductive activity during long nights
B) Stimulate reproductive activity during long days
C) Increase cortisol levels during mating season
D) Enhance thyroid hormone release during winter

A

A

35
Q

The primary anti-inflammatory eicosanoids derived from omega-3 fatty acids are:
A) Resolvins
B) Prostaglandins
C) Leukotrienes
D) Thromboxanes

A

A