Male Reproductive System Flashcards
Male reproductive system components and function of components
. Testes: sperm/hero one production
. Genital duct system: intratesticular ducts and excretory ducts
. Accessory glands: seminal vesicles, prostate gland, and bulbourethral glands
. Penis: copulatory organ
Genital duct system components and functions
. Intratesticular ducts: straight tubules/tubuli recti, rete testis, efferent ductules (carry sperm from seminiferous tubules to epididymis
. Excretory ducts: epididymis, vas deferens, ejaculatory duct, urethra (transport sperm from scrotum to penis)
Testis structure
. Post. Surface assoc. w/ epididymis
. Suspended in scrotal sac by spermatic cord
. Surrounded by tunica albuginea made of dense CT that thickens on post. Site to form mediastinum testes (rete testis there)
. Divided into 250-300 lobules by septa from mediastinum testes
. Each lobule 1-4 seminiferous tubules
. Leydig cells btw seminiferous tubules make testosterone
Spermatic cord contents
. Vas deferens . Testicular a. . Pampiniform plexus . Lymph vessels . Nerves
Role of testosterone
. Promotes development of secondary male sex characteristics
. Luteinizing hormone (LH) stimulates testosterone production
Embryological development of testes
. In post. Wall abdominal cavity
. Descends into scrotum
. During migration each testes caries layer of peritoneum that forms tunica vaginalis
. Outer, parietal layer covers scrotum, visceral layer covers tunica albuginea
Seminiferous tubules
. Sperm production
. Tubule is loop linked by short straight tubule to rete testis
. Had CT tubular wall w/ contractile myoid cells and seminiferous epithelium
. Basement membrane separates wall from epithelium
Seminiferous epithelium cells
. Spermatogenic cells: spermatogonial stem cells (SSC), spermatogonia, spermatocytes, and spermatids
. Sertoli cells: columnar, support, protect, and nourish spermatogenic cells
. Don’t divide after puberty
. Linked by tight junctions to form blood-testes barrier
. Basal compartment( spermatogonia there)
. Adluminal compartment (spermatocytes and spermatids there)
Sertoli cells functions
. Phagocytose cellular debris
. Facilitate release of spermatids in lumen (spermiation) and secrete fluid that carries sperm out
. Produces androgen-binding protein: concentrates testosterone (stimulated by FSH)
. Inhibin to suppress FSH production
. Antimullerian hormone (AMH): in fetal testis, prevents embryonic Müllerian ducts that are female parts
Spermatogenesis
. 1st part sperm production
. Starts in puberty
. SSC proliferates and 1 daughter cell remains SSC and other becomes progenitor cell (spermatogonium)
. Spermatogonia mitotically divide to become type A/B spermatogonia
. During this cytokinesis is incomplete and all spermatogonia are joined by cytoplasmic bridges
. Final division of type B cells produce 2 primary spermatocytes that replicate DNA (46C) and undergo 1st meiotic division to make secondary spermatocytes (23C)
. Secondary cells meiotically divide to make spermatid haploid
What occurs during 1st meiotic division of spermatocytes?
. Homologous chromosomes separate
Hormonal regulation of spermatogenesis
. FSH activates Sertoli cells
. LH controls testosterone production
. FSH and LH required regulators of spermatogenesis
Spermiogenesis
. Final phase sperm production
. No cell division occurs, temp. Sensitive
. Acrosome forms (hydrolytic enzymes)
. Condensation and elongation of nucleus
. Form flagellum (9+2 axoneme) from centriole that acts as basal body
. Shed excess cytoplasm as residual body
. Lose intercellular cytoplasmic bridges
. Moronically mature but not mobile cells released from Sertoli cells
. Tail movements powered by ATP in mitochondrial sheath in tail’s proximal region
Cryptorchidism
.failure of 1 or both testes to not descend from abdomen
. Causes infertility if not correct by age 2-3
Testicular cancer
. Most involves germ cell tumors (95%)
. Only appear after puberty
Tubuli recti/straight tubules
. Link seminiferous tubules to rete testis
. Prox. Portion lined by Sertoli cells
. Distal portion lined by simple cuboidal epithelium
Rete testis
. Network of channels in mediastinum testis
. Lined by simple cuboidal epithelium
. Drains into efferent ductules
Efferent ductules of testis
. 15-20 convoluted ducts that drain into epididymis
. Single layer epithelium of cells of varying heights (non-ciliated cuboidal and taller ciliated cells)
. Looks scalloped
. Ciliary movement proves still immobile sperm towards epididymis
. Non-ciliated cells absorb some of fluid from seminiferous cells
Epididymus
. Sperm maturation and storage
. Spermatozoa develop motility
. Efferent ductule unit to form 1 long convoluted duct (4-5m)
. Sperm divided into head, body, and tail
. Wall made of smooth muscle
. Lined by pseudostratified epithelium
. Tall principal cells have stereocilia
Vas (ductus) deferens
. Conducts sperm from epididymis to urethra
. Part of spermatic cord
. Traverses inguinal canal, passes over bladde
. Widens to form ampulla of vas deferens
. Joins duct of spinal vesicle
. Thick-walled straight muscular tube (45 cm) lined by pseudostratified epithelium
. Carries sperm by strong peristaltic contractions from epididymis to ejaculatory ducts
Ejaculatory duct
. Sperm and secretions from seminal vesicle mix
. Short, formed by union of ampulla of vas deferens and duct of seminal vesicle
. Move obliquely through prostate gland
. 2 ejaculatory ducts from each side converge to join urethra as it passes through prostate gland
. Lined by pseudostratified and simple columnar epithelia
. Supported by tissue of prostate gland
Urethra in males
. 20 cm long tube w/ 4 segments
. Preprostatic: w/in bladder neck
. Prostatic: 3-4 cm, in prostate gland, lined by transitional epithelium
. Membranous: short, passes through external sphincter of striated muscle, lined by stratified columnar and pseudostratified
. Penile (spongy) urethra: enclosed in corpus spongiosum, lined by pseudostratified columnar, distally by SSNK
Seminal vesicles
. Paired, densely coiled tubes enclosed by capsule
. On post. Bladder surface
. Highly folded mucosa gives lumen honeycomb look
. Epithelium secrete alkaline fluid w/ proteins, fructose, and prostaglandins
. Produces 70-80% of ejaculate volume
Prostate gland
. Surrounds urethra
. Alkaline secretion compromises 30%. Ejaculate volume
. Contains PSA
. Branches tubuloalveolar gland w/ 3 zones
. Transition zone (1st part by prostatic urethra)
. Central zone (mucosal glands post. To transition zone, surround ejaculatory duct)
. Peripheral zone: largest zone (70% tissue), main gland, lined by simple or pseudostratified columnar epithelium
Prostatic concretions
. Also called corpora amylacea
. Secretory material from prostate that has condenses
. Normal present in lumens of prostatic glands
. Inc. w/ age
Benign prostate hyperplasia
. Periurethral glands of central and transition zones undergo hyperplasia
. Can restrict urine flow
Prostate cancer
. From main prostate glands of peripheral zone
. Detected by digital palpation, inc. PSA serum, or back pain from vertebral metastasis
Bulobourethral glands
. Cowper glands
. 3-5 mm diameter, paired tubuloalveolar glands
. Drain into prox. Part penile urethra
. Mucus-like secretion lubricates urethra and precedes emission of semen
Penis
. 3 cylindrical masses of erectile tissue
. Paired corpora cavernosa: dorsal, contain blood sinuses supplied by anastomosing helicine aa., fill during erection and compress draining venous channels
. Corpus spongiosum: ventrally, surrounds urethra, forms glans penis at distal end
.
Innervation of male genitalia
. SNS: stimulates contraction of vas deferens, seminal vesicles, prostate gland, and prostatic urethra
. PNS: mediates dilation of helicine aa. Causing erection
