Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
19 Cards in this Set
- Front
- Back
|
Testes |
- covered with a serosa of mesothelium and c.t. that blends with the dense irregular c.t. capsule (tunica albuginea) - the tunica albuginea is continuous with the c.t. septa which divide the seminiferous tubules into lobules - the septa converge towards the mediastinum testis which contains channels of the rete testis, large blood and lymph vessels |
|
|
Genital Ducts |
- tubuli recti (straight tubules) connect seminiferous tubules to rete testis - efferent ductules connect the rete testis to the head of the epididymis - epididymis continues into the ductus deferens which leads into the urethra |
|
|
Seminiferous Tubules |
- lined with stratified germinal epithelium mixed with a population of supporting cells known as sertoli cells - the outer wall consists of a basal lamina (basement membrane), collagen fibers, fibroblasts and myoid (contractile) cells - loose c.t. b/n seminiferous tubules containts blood and lymphatic vessels, nerves and hormone producing interstitial cells (leydig) - Leydig cells are large, polymorphous in shape and arranged in clusters - Leydig cells synthesis testosterone - the germinal epithelium produces the haploid male gametes (spermatozoa) by the process of spermatogenesis |
|
|
Spermatogenesis: Part 1 |
- type A spermatogonia multiply via mitosis - at puberty some type A spermatogonia mitotically divide giving rise to type B spermatogonia which develop into primary spermatocytes - type B spermatogonia are diploid cells (2N) with pairs of homologous chromosomes (2C), one member of the pair maternal and one paternal - type B spermatogonia (2N2C) duplicate their chromosomes (each chromosomes now contains 2 sister chromatids) and enter into the 1st meiotic division as primary spermatocytes (2N4C) |
|
|
Spermatogenesis: Part 2 |
- Primary spermatocytes are diploid cells (2N) with duplicated pairs of homologous chromosomes (4C) N= # of homologous chromosomes, C= # of chromatids) - the end of the 1st meiotic division results in the formation of secondary spermatocytes that are haploid with half the humber of homologous chromosomes (1N) and each chromosome contains 2 sister chromatids (2C) - secondary spermatocytes (1N2C) rapidly undergo the 2nd meiotic division whereby the sister chromatids separate resulting in the formation of spermatids (1N1C) that are haploid cells with each chromosome containing 1 chromatid |
|
|
Spermiogenesis |
- spermatids differentiate into spermatozoa - spermatozoa released from the Sertoli cells into the lumen of the seminiferous tubules at the end of spermiogenesis are immotile and incapable of fertilization |
|
|
Sertoli Cells |
- elongated cells that envelop the spermatogenic cells - bases of the Sertoli cells adhere to the basal lamina and apical ends extend into the lumen of the seminiferous tubule - adjacent Sertoli cells are bound together by tight (occluding) junctions at the level of the spermatogonia which lie in a basal compartment that has free access to materials in the blood - during spermatogenesis progeny of spermatogonia travers the junctions and lie in the adluminal compartment where the more advanced stages of spermatogenesis are protected from blood-borne products by a blood-testis barrier formed by the tight junctions between Sertoli cells |
|
|
Functions of Sertoli Cells: basic |
1. Physical support 2. Convey nutrients/metabolites 3. Phagocytosis/Degeneration of Cells 4. Secretory activity: - Fetus: Mullerian inhibitory substance - Prepuberty: substance preventing meiotic division - Mature Testes: androgen binding protein & inhibin 5. Control rate of spermatogenesis (inhibin) |
|
|
Functions of Sertoli Cells |
- physically support the spermatogenic cells - convey nutrients and metabolites between spermatogenic cells and peritubular capillaries - phagocytose residual bodies shed by maturing spermatids, and degenerating cells that fail to complete spermatogenesis - secretory activity varies with sexual maturity, in the fetus they produce a Mullerian inhibitory substance, prepuberty they secrete substance preventing meiotic division of spermatogonia - in mature testes they produce androgen binding protein necessary for normal maturation of the spermatogonia, and inhibin which inhibits the secretion of FSH by the pituitary and thereby plays a role in controlling the rate of spermatogenesis |
|
|
Epithelium of Seminiferous Tubules |
Lined with: - Sertoli Cells - Germinal Epithelium (consists of): Spermatogonia Type A/B - after puberty type B enter 1st meiotic division - Type B -> Primary Spermatocytes (they complete 1st meiotic division) - Primary -> Secondary Spermatocytes (second meiotic division rapidly) - Secondary -> Spermatids -> Spermatozoa
|
|
|
Straight Tubules |
- where seminiferous tubules join the rete testis - initial segment contains only Sertoli cells (loss of germinal epithelium) - main segment lined with cuboidal or columnar epithelium |
|
|
Rete Testis |
- consists of anastomosing channels lined with squamous or cuboidal epithelium - found within the c.t. of the mediastinum testis - produce most of the testicular fluid (transport material for immature and immotile spermatozoa) |
|
|
Efferent Ductules |
- lined with tall ciliated columnar epithelial cells and non-ciliated low columnar epithelial cells (some regions of epithelium appear pseudo-stratified) - non-ciliated cells absorb testicular fluid - ciliated cells sweep sperm towards epididymis - surround by loose c.t. containing smooth muscle cells |
|
|
Epididymis |
- lined with pseudo-stratified epithelium containing tall columnar principle cells and small round basal cells - these cells are supported on a basal lamina surrounded by smooth muscle cells and loose c.t. - apical surfaces of principle cells have long, branched, irregular microvilli called stereocilia that are immotile - basal cells are thought to be the precursors of the principle cells - spermatozoa leaving the testis are immotile and infertile, spermatozoa leaving the epididymis have gained motility and fertility - Fully mature spermatozoa can be stored in the tail of the epididymis |
|
|
Epididymis: Roles of Principle Cells |
1. Absorb testicular fluid 2. Phagocytose and digest denegerate spermatozoa & residual bodies 3. Secrete various substances (enzymes) 4. Play a role in the maturation of the spermatozoa |
|
|
Ductus Deferens |
-epithelial lining is similar to epididymis - surrounded by propria-submucosa of highly vascularized loose c.t. - muscularis of inner/outer longitudinal, middle circular smooth muscle - serosa of c.t. and mesothelium - terminal portion of the ductus deferens contains tubuloalveolar glands in the propria-submucosa Accessory Glands (vesicular, prostate, bulbourethral) - secretions from these tubular/tubuloalveolar glands make seminal fluid |
|
|
Urethra |
- lined with transitional epithelium with patches of simple columnar to stratified columnar or cuboidal epithelium - the c.t. propria-submucosa contains erectile tissue with endothelial-lined vascular spaces |
|
|
Penis |
- the body of the penis consists of a c.t. capsule (tunica albuginea), erectile tissue (corpora cavernosa & corpus spongiosum) and the urethra - c.t. septa from the capsule separates the pair of corpora cavernosa - corpora cavernosa and corpus spongiosum consist of dense c.t. rich in elastic fibers, smooth muscle and vascular sinuses (lacunae) lined with endothelium - corpus spongiosum surrounds the urethra |
|
|
Route of Sperm |
1. Seminiferous Tubules 2. Straight Tubules 3. Rete Testis 4. Efferent Ductules 5. Epididymis 6. Ductus Deferens 7. Urethra |
