Expansion
Seminiferous tubules with Sertoli cells; ovarian follicles at successive stages
Expansion
Testis
- Seminiferous tubules lined by Sertoli cells (tall, supporting, forming the blood-testis barrier) and germ cells at successive stages from basal spermatogonia to luminal spermatozoa
- Leydig cells in the interstitium between tubules, with abundant smooth endoplasmic reticulum and lipid, producing testosterone under LH
Ovary
- Cortex containing follicles at all stages:
- Primordial: oocyte with a single flat layer of granulosa cells
- Primary: cuboidal granulosa, zona pellucida appearing
- Secondary (antral): fluid-filled antrum, theca layers
- Graafian (mature): large antrum, cumulus oophorus
- Corpus luteum: after ovulation, luteinised granulosa and theca cells with abundant lipid, secreting progesterone
- Corpus albicans: the hyalinised scar remaining
The two-cell theory links the histology to endocrinology: theca cells make androgen under LH, which granulosa cells aromatise to oestrogen under FSH.
Unlike the testis, the ovary contains a fixed, non-renewing oocyte pool, which is the basis of the decline in fertility with age.