HISTOLOGY REVIEW Reproductive System Dr. Tim Ballard Department of Biology and Marine Biology

Male Reproduction -- Testis Seminiferous tubule– cross section – H&E – 10x objective lumen Each testis contains 250 – 900 seminiferous tubules that are responsible for the production of spermatozoa and testosterone.

Male Reproduction -- Testis Seminiferous tubule– cross section – H&E – 10x objective lumen nests of interstitial cells (of Leydig) in connective tissue surrounding tubules basement membrane Each seminiferous tubule is formed of an epithelium resting on a basement membrane. The cell types seen are in various stages of meiosis.

Male Reproduction -- Testis Seminiferous tubule– cross section – H&E – 10x objective spermatogonium spermatogonium lumen basement membrane spermatogonium Spermatogonia (2n2c) lie on the basement membrane and are mitotic. Some respond to FSH and enter meiosis, moving off the basement membrane and towards the lumen.

Male Reproduction -- Testis Seminiferous tubule– cross section – H&E – 40x objective spermatogonia (2n2c) 1º spermatocytes (2n4c) sustentacular (Sertoli) cell 2º spermatocytes (1n2c) spermatids (1n1c) spermatozoa (1n1c) lumen Spermatogenesis is the process of meiosis in the male wherein one spermatogonium becomes 4 spermatids. The spermatids then enter spermiogenesis, associated with the Sertoli, and transform anatomically into anatomically mature spermatozoa. 2º spermatocytes and spermatids cannot be distinguished morphologically.

Male Reproduction -- Penis Primate penis– cross section – H&E – 4x objective dorsal vein corpus cavernosum corpus cavernosum deep artery deep artery tunica albuginea urethra corpus spongiosum The erectile tissues consist of lacunae, spaces that fill with blood, surrounded by collagenous connective tissue (the tunica albuginea).

Female Reproduction -- Ovary secondary follicle primary follicles primordial follicles cortex tertiary follicle medulla ovulation corpus albicans corpus luteum Review the basic structure of the ovary and the stages of follicular development before looking at the slides.

Female Reproduction -- Follicles Mammalian ovary– section – H&E – 4x objective primordial follicles Look along the periphery of the ovary for clusters of primordial follicles. Each consists of a primary oöcyte (2n4c) surrounded by a single layer of flattened follicle cells. Primordial follicles are quiescent structures, awaiting stimulation from FSH before reentering their developmental pathway.

Female Reproduction -- Follicles Mammalian ovary– section – H&E – 4x objective primary multilaminar follicle primary oöcyte follicle cells Several events occur here. Follicle cells become cuboidal, begin mitosis, and begin to secrete estrogen. The primary oöcyte becomes unarrested from prophase I and begins its first meiotic division. Once stimulated, by FSH, 30-50 primordial follicles reenter development, and become primary follicles.

Female Reproduction -- Follicles Mammalian ovary– section – H&E – 10x objective zona pellucida At this stage the developing ovum is likely to be a secondary oöcyte (1n2c) now, having finished its first meiotic division. It now becomes arrested at metaphase II. As it matures, the primary multilaminar follicle has 5-7 layers of follicle cells and develops a glycoprotein coat just outside the cell membrane of the oöcyte called the zona pellucida.

Female Reproduction -- Follicles Mammalian ovary– section – H&E – 4x objective cumulus oophorus zona pellucida stratum granulosum secondary oöcyte antrum The follicle becomes a secondary follicle when there is a clearly discernable antrum or cavity within the follicle. As the follicle continues to get larger, the antrum enlarges and the ovum becomes more eccentric (off center). The last stage, the tertiary follicle, has the same basic structure as above, just larger with the ovum more eccentric.

Female Reproduction -- Uterus Mammalian proliferative uterus– section – H&E – 10x obj. uterine glands In the proliferative stage of the uterine cycle, under control of rising estrogen from the developing follicles, the stratum basalis is regrowing the stratum functionalis, which was shed during the previous menstrual flow. The diagnostic feature of this stage are the long and straight uterine glands which are not yet functional. When you start this slide, scroll through the whole thickness and identify where the endometrium with its glands stops and the myometrium begins.

Female Reproduction -- Uterus Mammalian secretory uterus– section – H&E – 40x objective uterine glands In the secretory stage of the uterine cycle, under the control of estrogen and progesterone from the corpus luteum, the uterine glands of the stratum functionalis begin to be functional, producing glycogen. The diagnostic feature of this stage are the curvy, serrated-looking glands. When you start this slide, scroll through the whole thickness and identify where the endometrium with its glands stops and the myometrium begins.

Female Reproduction -- Uterus Mammalian menstrual uterus– section – H&E – 4x objective uterine cavity myometrium shedding stratum functionalis In the menstrual stage of the uterine cycle, under the control of lack of estrogen and progesterone from the dead corpus luteum, the stratum functionalis dies and loses its anatomical integrity, breaking lose and shedding from the stratum basalis. When you start this slide, scroll through the whole thickness and identify where the endometrium with its glands stops and the myometrium begins.

Female Reproduction -- Uterus Mammalian menstrual uterus– section – H&E – 4x objective uterine cavity myometrium shedding stratum functionalis Compare the anatomical integrity of this endometrium with the previous slides of proliferative and secretory uterus. This is a mess as it comes completely undone. When you start this slide, scroll through the whole thickness and identify where the endometrium with its glands stops and the myometrium begins.