This slide has good examples of the corpus luteum and the corpus albicans. A corpus luteum can be very large a centimeter in diameter and therefore occupy nearly your whole section on the slide. Granulosa lutein cells are closest to the central connective tissue core of the corpus luteum and produce progesterone.
Theca lutein cells are smaller cells than the former with dark-staining nuclei. These cells produce estrogen and are located peripherally between the folds of the granulosa lutein cells. The tunica albuginea is the thick connective tissue capsule of the ovary. Slide 18 Uterine tube. The epithelium has ciliated columnar cells or nonciliated columnar cells also called Peg cells.
Glands are absent from the uterine tube. External to the mucosa and muscularis is the serosa visceral peritoneum. Slide 98 Uterine tube, intrauterine. This slide contains the intrauterine intramural portion of the uterine tube. It is within the wall of the uterus look for a small simple columnar-lined tube in the "sea" of muscle of the uterine wall.
Slide 99 Fimbria and isthmus. This slide contains the fimbria and isthmus portions of the uterine tube. Note that the finger-like projections of the fimbria appear to be part of the mucosa "turned inside out" with the epithelium exposed to the peritoneal cavity. The isthmus has less complicated mucosal folds and more muscle in the muscularis than the ampulla.
Slide 18 Ampulla. The ampulla of the uterine tube is indicated by the complicated folding of the mucosa and small amount of muscle in the muscularis. The endometrium mucosa of the uterus consists of simple columnar epithelium and lamina propria. Note also the thick myometrium composed of interconnecting bundles of smooth muscle arranged in four ill-defined layers. The uterus is covered by a serosa or adventitia. Compare slides 19, 20 and These slides represent different phases of the endometrial cycle.
Compare the thickness of the mucosa and the shapes of the uterine glands. The fibrous theca externa merges with the surrounding stroma. The oocyte , zona pellucida and the follicular cells surrounding the ooctye known as the corona radiata are all expelled at ovulation, and enter the fallopian tube. Once released, the oocyte begins its second meiotic division, as far as metaphase II. Division only carries on if the ovum is fertilised. After ovulation, the ruptured follicle collapses and fills with a blood clot corpus haemorrhagicum which then forms the corpus luteum.
The granulosa cells enlarge, and become vesicular, and are now called the granulosa lutein cells. The spaces between the folds are filled with theca interna cells, which also enlarge and become glandular , and are now known as the theca lutein cells. The zona granulosa cells begin to secrete progesterone granulosa lutein cells. The corpus luteum also secretes oestrogen which inhibits FSH and relaxin which relaxed the fibrocartilage of the pubic symphysis.
If pregnancy does not occur, then the corpus luteum degenerates into the corpus albicans , and levels of oestrogen and progesterone fall, allowing release of FSH and LH.
If pregnancy does occur, then the syncytiotrophoblasts of the placenta release human chorionic gonadotrophin , and the corpus luteum persists. About 20 primordial follicles start developing in each cycle, but only ONE makes it! This image shows a corpus luteum in a human ovary.
This image shows an atretic corpus luteum or corpus albicans. The cellular elements have degenerated, and macrophages phagocytose the dead cells. Fibrous tissue is left behind. The corpus albicans looks pale. It will continue to shrink, eventually forming a small scar on the side of the ovary. Ovarian follicles. Corpus Luteum After ovulation, the ruptured follicle collapses and fills with a blood clot corpus haemorrhagicum which then forms the corpus luteum.
Corpus albicans This image shows an atretic corpus luteum or corpus albicans. The presentation is based on data obtained mainly in rodents in which follicular development occurs postnatally. The peak activity of follicular growth occurs during the 1st week of life, but not until the 5th day is follicular development clearly dependent upon gonadotrophin stimulation.
The formation of the theca layer and zona pellucida, differentiation of the vascular system and competence to respond to gonadotrophins are acquired during the 2nd week.
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