Pituitary-Hypothalamic Functional Relationship Flashcards
What is the primary function of the hypothalamus in the endocrine system?
a) Producing all hormones in the body
b) Acting as a control center for homeostasis
c) Directly releasing hormonesx into the bloodstream
d) Storing hormones for later release
Answer: b) Acting as a control center for homeostasis
What structure connects the hypothalamus to the pituitary gland?
a) Sella turcica
b) Pituitary stalk
c) Intermediate lobe
d) Adenohypophysis
Answer: b) Pituitary stalk
Which part of the pituitary gland is also known as the neurohypophysis?
a) Anterior pituitary
b) Intermediate lobe
c) Posterior pituitary
d) Pituitary stalk
Answer: c) Posterior pituitary
The anterior pituitary receives regulatory signals through:
a) Direct nerve fibers from the hypothalamus
b) Portal blood vessels
c) Neurophysin proteins
d) Spinal cord pathways
Answer: b) Portal blood vessels
Which of the following hormones is released from the posterior pituitary?
a) Oxytocin
b) Growth hormone
c) Prolactin
d) Thyroid-stimulating hormone
Answer: a) Oxytocin
What triggers the release of hormones from the posterior pituitary?
a) Direct hormone synthesis by the pituitary
b) Action potentials in neurons from the hypothalamus
c) Blood vessel contractions
d) Direct stimulation by the adrenal gland
Answer: b) Action potentials in neurons from the hypothalamus
Apart from the pituitary, where else is prolactin produced?
a) Liver and kidneys
b) Hypothalamus, uterus, placenta, breast, and lymphocytes
c) Heart and lungs
d) Pancreas and intestines
Answer: b) Hypothalamus, uterus, placenta, breast, and lymphocytes
What is the primary function of hypothalamic-hypophysiotropic hormones?
a) They act on specific membrane receptors
b) They degrade pituitary hormones
c) They prevent hormone release from the pituitary gland
d) They only affect non-endocrine tissues
Answer: a) They act on specific membrane receptors
Which of the following statements about prolactin (PRL) is true?
a) PRL is structurally unrelated to growth hormone (GH)
b) PRL receptors utilize the JAK/STAT signaling pathway
c) PRL secretion is primarily stimulated by dopamine
d) PRL is always bound to serum proteins
Answer: b) PRL receptors utilize the JAK/STAT signaling pathway
What is a key role of hypothalamic-hypophysiotropic hormones?
a) They regulate their own receptors
b) They inhibit all pituitary hormone secretion
c) They function exclusively in the immune system
d) They act on intracellular receptors only
Answer: a) They regulate their own receptors
The hypothalamo-hypophysial portal system primarily connects:
a) The hypothalamus and posterior pituitary
b) The hypothalamus and anterior pituitary
c) The adrenal gland and pituitary gland
d) The pancreas and hypothalamus
Answer: b) The hypothalamus and anterior pituitary
Which neurotransmitter is the primary inhibitor of prolactin secretion?
a) Serotonin
b) Dopamine
c) Acetylcholine
d) Glutamate
Answer: b) Dopamine
Which of the following factors increases prolactin secretion?
a) Somatostatin
b) Dopamine
c) Breastfeeding and exercise
d) High cortisol levels
Answer: c) Breastfeeding and exercise
How does estradiol modulate prolactin (PRL) release?
a) Increases sensitivity of lactotrophs to TRH
b) Increases sensitivity of lactotrophs to dopamine
c) Blocks the JAK/STAT signaling pathway
d) Prevents prolactin from binding to its receptor
Answer: a) Increases sensitivity of lactotrophs to TRH
What is a key characteristic of prolactin (PRL) in circulation?
a) PRL is always bound to serum proteins
b) PRL circulates unbound to serum proteins
c) PRL requires a carrier protein for transport
d) PRL is stored in red blood cells before release
Answer: b) PRL circulates unbound to serum proteins
What is the primary effect of somatostatin on prolactin secretion?
a) It stimulates PRL release
b) It inhibits PRL secretion
c) It converts PRL into another hormone
d) It increases PRL receptor expression
Answer: b) It inhibits PRL secretion
Which hormone is not a prolactin-releasing factor (PRF)?
a) Thyrotropin-releasing hormone (TRH)
b) Angiotensin II
c) Substance P
d) Cortisol
Answer: d) Cortisol
What effect does stress have on prolactin secretion?
a) It dramatically increases PRL secretion
b) It decreases PRL secretion
c) It prevents PRL receptor activation
d) It has no effect on PRL levels
Answer: a) It dramatically increases PRL secretion
What is the main effect of prolactin-releasing factors (PRFs)?
a) They inhibit PRL secretion
b) They increase PRL secretion
c) They block dopamine receptors
d) They bind to serum proteins to transport PRL
Answer: b) They increase PRL secretion
What is the primary function of the hypothalamo-hypophysial portal system?
a) Transmits neural signals to the posterior pituitary
b) Provides blood flow from the hypothalamus to the anterior pituitary
c) Stores hormones for later secretion
d) Transports PRL from the pituitary to target organs
Answer: b) Provides blood flow from the hypothalamus to the anterior pituitary
Which of the following is not an effect of prolactin on the mammary gland?
a) Growth and development of the mammary gland (mammogenesis)
b) Synthesis of milk (lactogenesis)
c) Maintenance of milk secretion (galactopoiesis)
d) Inhibition of milk production
Answer: d) Inhibition of milk production
What is the primary role of prolactin in lactogenesis?
a) Inducing synthesis of milk components such as lactose, casein, and lipids
b) Suppressing milk production during pregnancy
c) Stimulating milk ejection from the mammary gland
d) Preventing lobuloalveolar growth
Answer: a) Inducing synthesis of milk components such as lactose, casein, and lipids
What is the function of galactokinetic hormones in lactation?
a) Stimulating growth of mammary tissue
b) Promoting contraction of myoepithelial cells for milk ejection
c) Maintaining milk production after it has been established
d) Suppressing prolactin release
Answer: b) Promoting contraction of myoepithelial cells for milk ejection
Why does lactation not occur during pregnancy despite high prolactin levels?
a) Low prolactin levels prevent milk production
b) Oxytocin inhibits the prolactin receptor
c) High progesterone levels downregulate prolactin receptors
d) Estrogen directly blocks milk synthesis
Answer: c) High progesterone levels downregulate prolactin receptors
Which of the following describes prolactin’s role in maternal behavior?
a) It stimulates oxytocin release exclusively
b) It allows the development of maternal instinct
c) It suppresses stress hormones to enhance bonding
d) It only functions in milk production and has no behavioral effects
Answer: b) It allows the development of maternal instinct
How does prolactin affect ovulation during breastfeeding?
a) It inhibits GnRH release, leading to lactational amenorrhea
b) It increases estrogen levels, promoting ovulation
c) It stimulates progesterone release to restart the menstrual cycle
d) It decreases dopamine secretion, enhancing ovulation
Answer: a) It inhibits GnRH release, leading to lactational amenorrhea
What role does prolactin play in immune regulation?
a) It only functions in pregnancy-related immunity
b) It has no role in immune function
c) It regulates humoral and cellular immune responses
d) It only affects immune cells during lactation
Answer: c) It regulates humoral and cellular immune responses
How can prolonged breastfeeding influence fertility?
a) It increases GnRH levels, leading to early ovulation
b) It stimulates estrogen production, enhancing fertility
c) It inhibits GnRH release, delaying ovulation
d) It has no effect on fertility
Answer: c) It inhibits GnRH release, delaying ovulation
Which of the following is a function of galactopoietic hormones?
a) Promoting milk synthesis and initiation of lactation
b) Inducing lobuloalveolar growth in the mammary gland
c) Maintaining milk production after it has been established
d) Stimulating contraction of myoepithelial cells
Answer: c) Maintaining milk production after it has been established
Which of the following is not a category of hormones affected by prolactin?
a) Mammogenic hormones
b) Lactogenic hormones
c) Galactokinetic hormones
d) Thyroid hormones
Answer: d) Thyroid hormones
Why might breastfeeding be associated with reduced fertility?
a) Prolactin directly suppresses ovarian function
b) Prolactin inhibits GnRH release, preventing ovulation
c) Dopamine increases during breastfeeding, blocking estrogen production
d) Prolactin stimulates FSH, reducing ovarian follicle maturation
Answer: b) Prolactin inhibits GnRH release, preventing ovulation
What is a key immune-related role of prolactin?
a) It suppresses all immune activity
b) It enhances both humoral and cellular immune responses
c) It only affects immunity during pregnancy
d) It prevents autoimmune diseases
Answer: b) It enhances both humoral and cellular immune responses
