Summary of Male Spermatogenesis and Regulation

Cell Types: Sertoli cells analogous to granulosa cells; theca cells comparable to Leydig cells in males.
Receptors:
- Sertoli (FSH receptor positive) & Leydig (LH receptor positive).
- FSH stimulates Sertoli cells, LH stimulates Leydig cells for androgen production.

GnRH pulses regulate FSH and LH.
FSH promotes Sertoli cell function; LH drives androgen synthesis from cholesterol.
Androgens can convert to estrogen in Sertoli cells, with estradiol offering feedback to the hypothalamus.

Definition: Process from diploid spermatogonia to haploid spermatozoa capable of fertilization.
Phases:
1. Mitosis (rounds of cell division).
2. Meiosis (two divisions reducing chromosomal content).
3. Differentiation (spermiogenesis).
Stem cells regenerate throughout male reproductive life, producing millions of sperm daily post-puberty.

Mitosis: Maintains spermatogonia stem cells and produces primary spermatocytes.
Meiosis:
- Primary spermatocytes undergo two rounds to create haploid spermatids.
- Each sperm is genetically unique due to chromosomal crossover during meiosis.

Transformation: Round spermatids morph into spermatozoa.
- Golgi phase: Golgi apparatus forms acrosome, important for fertilization.
- Cap phase: Acrosome matures, defining sperm head; mitochondria localize for energy.
- Acrosomal phase: Acrosome completes formation; elongated tail structure develops.
- Cytoplasm reduces, making the sperm more aerodynamic for transport.
Key structural components of mature sperm: head (nucleus + acrosome), mid piece (mitochondria), tail (flagellum).

Protamines replace histones for tight DNA packing; poor protamine ratios linked to infertility.
Chromatin integrity is crucial; any damage affects sperm motility and function.
Sertoli cells manage germ cell homeostasis and clear apoptotic cells.