midterm 2 Flashcards
What determines genetic sex?
The combination of sex chromosomes (XX for females, XY for males).
What gene is critical for male gonadal development?
The SRY gene on the Y chromosome.
What happens if the SRY gene is absent?
The gonads develop into ovaries, leading to female sexual differentiation.
What hormone is secreted by Sertoli cells to regress the Müllerian ducts?
Anti-Müllerian Hormone (AMH).
What structure develops into the male reproductive tract?
The Wolffian ducts, under the influence of testosterone.
What structure develops into the female reproductive tract?
The Müllerian ducts, in the absence of AMH.
What are the major steps of fertilization?
- Sperm binds to the zona pellucida. 2. Acrosomal reaction releases enzymes. 3. Sperm and oocyte membranes fuse. 4. Sperm nucleus enters the oocyte. 5. Zygote forms and begins cell division.
How is the corpus luteum maintained in early pregnancy?
The embryo secretes hCG, which sustains progesterone production.
What are the primary functions of the placenta?
- Nutrient and gas exchange. 2. Hormone secretion (hCG, progesterone, estrogens). 3. Protection against some infections.
What substances cross the placenta?
Glucose, amino acids, immunoglobulins, lipid-soluble hormones, and some toxins.
What is the role of progesterone during pregnancy?
It maintains the uterine lining and prevents contractions.
What triggers labor?
Fetal cortisol levels rise, stimulating prostaglandins and oxytocin.
What hormone promotes milk production?
Prolactin.
What hormone causes milk ejection?
Oxytocin.
What is the role of GnRH?
It stimulates the release of LH and FSH from the pituitary gland.
How do gonadal steroids regulate the HPG axis?
They provide negative feedback to inhibit GnRH, LH, and FSH secretion.
What triggers the onset of puberty?
Increased pulsatile secretion of GnRH.
What is the function of LH in males?
It stimulates Leydig cells to produce testosterone.
What is the function of FSH in females?
It promotes follicular development and estrogen secretion.
What is the primary function of IGF-1?
It promotes growth and development, especially in response to GH.
How does GH affect metabolism?
It increases protein synthesis, promotes lipolysis, and decreases glucose uptake.
What are the key cells involved in spermatogenesis?
- Spermatogonia (germ cells). 2. Sertoli cells (support and nourish sperm). 3. Leydig cells (produce testosterone).
What is the function of androgen-binding protein (ABP)?
It binds testosterone to maintain high concentrations in the seminiferous tubules.
What are the phases of the ovarian cycle?
- Follicular phase (follicle development, estrogen secretion). 2. Ovulation (LH surge triggers egg release). 3. Luteal phase (corpus luteum secretes progesterone).
How does the corpus luteum regress if pregnancy does not occur?
Prostaglandin F2-alpha induces luteolysis, causing progesterone levels to fall.
