Exam 3 Professor Style Questions

A tumor destroys the anterior pituitary but the hypothalamus remains intact. What happens to testosterone levels?

Testosterone decreases because LH secretion from the pituitary is required to stimulate Leydig cells.

A patient has high GnRH levels but low testosterone. What is the most likely cause?

Primary testicular failure (Leydig cell dysfunction)

A patient has low GnRH, low LH/FSH, and low testosterone. What type of hypogonadism is this?

Secondary (hypogonadotropic) hypogonadism.

A patient has high LH but low testosterone. What condition does this suggest?

Primary hypogonadism (testicular failure)

A man has normal testosterone but low sperm count. Which hormone is most likely deficient?

FSH

What hormone level would be elevated if Sertoli cells are damaged?

FSH (because inhibin decreases)

A newborn male has ambiguous external genitalia but normal internal male structures. Which deficiency is most likely?

5α-reductase deficiency (↓ DHT)

A drug inhibits aromatase. What is the most likely physiological effect?

Decreased estradiol → impaired bone maturation and altered GnRH feedback

A patient has excessive adipose tissue. How does this affect hormone levels?

Increased aromatization → increased estradiol levels

A man with cryptorchidism has infertility despite normal testosterone levels. Why?

Elevated temperature impairs spermatogenesis in seminiferous tubules

What condition results from failure of testes to descend into the scrotum?

Cryptorchidism

Why is testosterone required for spermatogenesis even though it is produced by Leydig cells outside seminiferous tubules?

Sertoli cells concentrate testosterone using androgen-binding protein, allowing it to act locally

A mutation prevents androgen-binding protein (ABP) production. What is the consequence?

Decreased local testosterone concentration → impaired spermatogenesis

A patient has a mutation in LH receptors. What is the expected effect?

Decreased testosterone production

A fetus produces testosterone but lacks Müllerian inhibitory factor (MIF). What occurs?

Development of both male and female internal structures

A genetic male lacks androgen receptors. What is the expected phenotype?

Female external phenotype (androgen insensitivity syndrome)

A fetus lacks SRY gene function. What will develop?

Ovaries instead of testes

An older male is treated with finasteride. What is the mechanism of action?

Inhibits 5α-reductase → decreases DHT

Why does DHT play a larger role in prostate growth than testosterone?

DHT is a more potent androgen receptor activator

A patient has spinal cord injury affecting parasympathetic nerves. What function is impaired?

Erection

A patient can achieve erection but cannot ejaculate. What system is likely damaged?

Sympathetic nervous system

A male presents with:

• Decreased libido

• Low testosterone

• High LH

What is the underlying issue?

Testicular failure (primary hypogonadism)

A patient with obesity has increased estradiol levels. What effect does this have on LH?

Decreased LH due to negative feedback

A male has normal LH and testosterone but impaired spermatogenesis. What is the most likely cause?

Sertoli cell dysfunction or FSH deficiency

A patient has:

• Normal testosterone

• Normal LH

• Elevated FSH

What is the MOST likely explanation?

Sertoli cell dysfunction → decreased inhibin → increased FSH

If aromatase is blocked →

estrogen ↓ but androgens ↑

A woman has low FSH levels during the follicular phase. What is the most likely outcome?

Follicular atresia

FSH is required for granulosa survival; low FSH

apoptosis

Which change triggers the LH surge?

Sustained high estrogen

Switch from negative → positive feedback.

A drug inhibits aromatase. What happens?

↓ Estrogen, ↑ Androgens

Androgens cannot convert → accumulate.

Why does progesterone rise after ovulation?

LH-induced luteinization

LH converts follicle → corpus luteum.

During pregnancy, which hormone maintains the corpus luteum?

hCG

A woman cannot produce placental estrogen. What is the likely defect?

Lack of fetal adrenal contribution

Placenta requires fetal/maternal androgens.

What directly causes menstruation?

Progesterone withdrawal

Why is ovulation considered an inflammatory process?

Enzymatic follicle rupture

Which hormone prevents milk production during pregnancy?

Progesterone

A postmenopausal woman has high FSH. Why?

Loss of inhibin feedback

A patient has normal follicular growth but inadequate endometrial differentiation after ovulation. Which hormone deficiency is most likely responsible?

Progesterone

Which hormonal change is responsible for the transition from the proliferative to the secretory phase of the endometrium?

Progesterone secretion from the corpus luteum

Which effect of estrogen contributes most directly to endometrial growth during the proliferative phase?

Stimulation of epithelial cell proliferation

Why does basal body temperature increase after ovulation?

Increased progesterone

Which hormone stimulates lobular-alveolar development in the mammary gland during pregnancy?

Progesterone

A drug blocks estrogen receptors in the uterus. Which endometrial phase would be most directly impaired?

Proliferative phase

Which mechanism explains progesterone’s ability to prevent premature uterine contractions during pregnancy?

Inducing myometrial quiescence