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
Where does the left testicular vein drain?
Left renal vein.
Why is blood cooled when it passes through the testicular A.
Testicular A is wrapped in testicular vein.
What innervates the anterior surface of the testes? Posterior and inferior?
Anterior - lumbar plexus
Post. Inf. - sacral plexus
What is the lymphatic drainage of the testes?
Paraaortic nodes
How can malignancy spread from the testiest the nack?
Paraaortic nodes anastomose with intrathoracic and in turn cervical lymph nodes.
What are the three parts of the epididymis?
Head - caput (efferent ductule end)
Body - corpus
Tail - caudal (vas deferens end)
Where is the epididymis located?
Posterolateral surface of the testis
What does the epidermis connect to?
Connects the vas deferens to the seminiferous tubule via the efferent ductules and tete testis.
What the the efferent ductules do?
Transmit sperm to the head of the epididymis
What is the function of the epididymis?
Sperm transport, maturation and storage
what changes occur to sperm in the epididymis? Where are mature sperm stored?
Structural changes to become motile.
Stored in tail until ejaculation.
What is the vas deferens? Function?
Straight muscular tube that emerges from the caudal epididymis. Contained within spermatic cord
Functions to transport sperm rapidly to prostatic urethra.
What forms the ejaculatory duct
Ampulla of vas deferens and seminal vesicle duct
What allows ejaculaiton through the vas deferens.
Rich autonomic innervation of the smooth muscle fibres of the vas deferens permits rapid contractions, propelling the contents towards ejaculatory ducts.
During ejaculation the lumen of the ejaculatory duct and eminal vesicle duct dilate to facilitate entry of sperms and seminal gland secretion.
Describe the course of the vas deferens.
Ascends in the spermatic cord. TRaverses inguinal canal Tracks around the pelvic side wall Passes between the bladder and ureter Forms a dilated ampulla Opens into ejaculatory duct
What lines the ductus epididymis?
Tall, pseudostritified columnar epithelium with tufts of non-motile stereo cilia projecting into lumen.
What is the spermatic cord?
Contains structures running to and from the testes.
Runs from the deep inguinal ring, lateral to the inferior epigastric vessels to the posterior border of the testis via the inguinal canal and the superficial inguinal ring.
What are the on tests of the spermatic cord?
Testicular artery, Cremasteric artery, artery to vas Pampiniform venous plexus Genital branch of genitofemoral nerve. Vas deferens Lymphatics Processus vaginalis
What are the coverings of the spermatic cord?
External spermatic fascia (Aponeurosis of external oblique) Cremasteric muscle (longitudinal, discontinuous striated muscle layer) Cremasteric fascia (internal oblique and transversalis aponeurosis) Internal spermatic fascia (transversalis fascia)
What are the seminal vesicles? Where
2 small glands that lie posterior to prostate, between bladder and rectum.
What does it consist of and join?
Single, highly convoluted tube that joins the ampulla of the vas deferens to form ejaculatory duct.
Descrube the mucosa of the seminal vesicles.
Mucus membrane forms an elaborate system tf thin, branched, anastomosing folds that project into the lumen. The large lumen contains coagulated secretion.
Simple columnar to speudostratified varied epithelium.
Lamina propria is surrounded by smooth muscle coat divided into inner circular and outer longitudinal layer.
What do the seminal vesicles secrete
Alkaline fluid (neutralise acid in ale urethra and female tract)
Fructose (ATP production in sperm)
Prostaglandins (sperm motility and smooth muscle contraction inf female tract)
Clotting factors (help coagulate semen after ejaculation)
Where is the prostate gland?
Surrounds the prostatic orethra at origin from bladder.
What are the associations of the base, apex, muscular anterior, posterior and inferiolateral prostate?
Base - neck of bladder
Apex - Urethral sphincter and deep perineal muscles
Muscular anterior sruface - urethral sphincter
Posterior - ampulla of rectum
Infero-lateral - levator ani
Draw and label the zones of the prostate.
-
What surrounds the prostate gland? Describe internal structure
Fibromsucular capsule with branching septa that divide it infer numerous small compound alveolar glands.
Excretory ducts originate and open independently into the prostatic urethra.
The septa are characterised by discrete bundles of smooth muscle fibres interweaving with the connective tissues.
What do prostatic secretions contain?
Proteolytic enzymes (breaking down clotting proteins from seminal vesicles, allowing semen to reliquary) Citric acid (ATP production) Acid phsosphatase
Describe the histology of the prostate gland.
Epithelium varies from low cuboidal to simple or pseudo stratified columnar.
All cells have pale staining cytoplasm
Epithlium rests on thin almina propria
Bleds of secretion may be seen attached to free cell surfaces and are often seen in the lumen of the glands.
Also present in lumen are concentrically lamellated eosinophilic bodies (prostatic concentrations)
What is the arterial supply to the prostate?
Internal iliac –> Inferior vesicle A
Where are the bulbourethra glands located?
Within the urogenital diaphragm, largely imbedded in the External urethral sphincter.
What do the bulbourethral glands secrete?
Clear water secretion for lubrication
Alkaline fluid to urethra for acid neutralisation
Mucous that lubricates the end to the penis and urethral lining.
What are the parts of the penis?
Root body glans
What is the internal structure of the penis
2 corpora cavernosa dorsally
1 corpus spongiosum ventrally
Corpora are a network-like trabecular of fibromuscular tissue ramified by spaces that become filled with blood during erection.
Surrounded by thick band of CT
What surrounds the corpora cavernosa?
Tunica albuginea of penis.
What are the function of the tunica albuginea and fascial sheaths?
Resist expansion so that internal pressure rises and occludes venous drainage.
Blood front eh cavernous spaces drains into a venous plexus (compressed during erection) and into deep dorsal vein.
This along with increased arterial flow maintains penix rigidity
Whhy does the corpus spongiosum not become rigid?
Tunica albuginea is not as restrictive.
High pressure in the corpus sponiosum would occlude urethra and prevent ejacultaiton.
What is the blood supply to the penis?
AA –> CI –> II –> Anterior division of II –> Internal pudendal –> Deep/dorsal/bulbourethral
What is the venous drainage of the penis?
Venous plexus of the penis –> Deep dorsal vein of the penis –> Prostatic venous plexus –> IIV –> IVC
What are the afferent and efferent of erection?
Pudendal nerve = afferent from glans penis to CNS Pelvic nerve (parasympathetic S2-S4) via inferior hypogastric plexuses promotes erection in erectile tissue through relaxation of smooth muscle in fibrous trabecular and coiled arteries.
What NS controls emission?
Sympathetic
What controls ejaculation
Sympathetic outflow from L1/L2
What leads to depression of erection?
Hypogastric sympathetic nerve by relieving myogenic tone.
Give 2 important muscles in erection in the male perineum.
Bulbospongiosus
Helps to expel last drop of urine and maintain erection.
Ischiocavernosus
Compresses veins, therefore helping to maintain erection.
Give the sections of the urethra
Pre-prostatic (neck of bladder)
Prostatic
Membranous (least distensible)
Spongy
