4.1 Flashcards
What are the components of the male repro system?
Paired testes
Duct system
Accessory sex glands
Penis
What is the scrotum
Cutaneous fibro-muscular sac for the testes and associated structures.
Where is the scrotum situated?
Posteroinferior to the penis and inferior to the pubic symphysis
What is the scrotum derived from and how does it develop?
Genital folds
Folds fuse in the midline: bilateral embryonic formation of the scrotum is indicated by the midline scrotal rap he, which is continuous on the ventral surface of the penix with the penile raphe.
What is deep to the scrotal raphe?
Scrotum septum that divides the scrotum into 2 compartments.
What are the contents of the scrotum?
Testes
Epididymis
Spermatic ford (first part)
Muscle fibres
Where is the epididymis situated?
Posterolateral border of each testicle.
What muscle fibres are found in the scrotum?
Dartos muscle
Sheet of smooth muscle situated immediately under the skin.
Acts to regulate temperature of the scrotum by wrinkling skin, decreasing surface area and reducing heat loa a.
What is the blood supply of the scrotum?
External pudendal A –> Anterior scrotal A
Internal pudendal A –> Posterior scrotal A
What nerves supply the scrotum?
Genital branch of genitofemoral nerve
Anterior scrotal from ilioinguinal
Posterior scrotal from perineal
Where do scrotum lymphatics drain?
Superficial inguinal lymph nodes.
How are the testes suspended in the scrotume?
Spermatic cords
Describe the tunica vaginalis
Double layer of peritoneum
Parietal layer adjacent to the internal spermatic fascia.
Visceral layer adjacent to testis.
Parietal layer is more extensive and extends superiorly for a short distance onto distal spermatic cord.
Small amount o fluid between the two layers allowing free movement.
Describe the tunica albuginea.
Thick fibrous capsule that thickens into a ridge on the posterior aspect as mediastinum of testis.
Mediatinum contains many interconnected channels that provide passageways for sperm to enter duct system.
Describe the mediastinum of the testis and the internal structure. What is located in the mediastinum?
Fibrous ridge on posterior aspect of testis.
Fibrous septa extend into the testis dividing it into 250 pyramid shaped lobules.
Each lobule contains 1-4 seminiferous tubules.
Rete testis is found in mediastinum
What surrounds seminiferous tubules? What cells line them?
Layer of CT with flattened myofibroblasts and inner basement membrane.
Lined by sertoli cells and spermatogonia.
What joins the seminiferous tubules to the rete testis?
Straight tubules
Describe sertoli cells
In seminiferous tubules
Fixed to BM
Cytoplasm of each forms systems of processes that extend upward to the luminal surface
Surrounded by spermatogenic cells
Involved in spermatogenesis and secrete MIH and inhibin
Describe spermatogenic cells.
Primitive cells - spermatogonia- rest on BM.
Later stages are located at higher levels in the epithelium
Primary spermatocytes lie adjacent to spermatogonia
SEcondary spermatocytes rarely seen due to short half life.
Spermatids are located near lumen of tubule
These mature into spermatozoa
Describe leydig cells
Cells in the interstitial tissue between seminiferous tubules
Large spherical nuclei
Small clusters/rows along blood vessels
Secrete testosterone
Where do the testes arise?
Mesonephric ridge in the upper lumbar regions at the lower pole of the kidneys. Originally located in posterior abdominal wall.
What is the gubernaculum? Vestigial remnant?
Fibrous cord attaching the testes to the labioscrotal folds (genital swellings) that pulls them down in descent of the testes.
Scrotal ligament
Describe the descent of the testes.
As the body grows, testes become more caudal. They descend down the abdomen through the inguinal canal to reach the scrotum.
Musculo fascial layer evaginates into the scrotum as it develops together with peritoneal membrane - processus vaginalis
Above the testis the fascia become closely opposed.
What forms the spermatic cord and where does this lie?
Fascial layers, obliterated stem of processus vaginalis, vas defferens, testicular vessels and nerves.
Occupy the inguinal canal.
When does the testes reach: Iliac fossa Travel through inguinal canal Reach external ring? Enter scrotum?
3 months
7 months
8 months
9 months
What is the blood supply to the testes?
Where do they arise and travel?
Abdominal aorta –> Testicular A
Arise just inferior to renal A
Pass retroperitoneally and cross over the ureters and inferior part of the external iliac A to reach deep inguinal rings.
Pass through inguinal canal, emerging through superficial inguinal rings and enter spermatic cord
Describe the venous drainage of the testes.
Asymmetrical.
Veins emerging from the testis and epididymis form the pampiniform venous plexus.
The veins of the plexus converge superiorly forming the L and R testicular veins.
What is the function of the pampiniform venous plexus?
Thermoregulatory system
Where does the right testicular vein drain
IVC