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The male external genital organs include:
Penis
Scrotum
Testes (partly external)
Spermatic cords
These structures lie in the perineal region, anterior to the pubic symphysis.
Functionally associated with urination and sexual intercourse.
Identify the penis, scrotum, and spermatic cord emerging from the superficial inguinal ring.
Reflect the skin to observe:
Superficial fascia of penis (Dartos fascia)
Deep fascia (Buck’s fascia) enclosing erectile tissues and vessels.
Expose the three erectile bodies and trace the urethra running within the corpus spongiosum.
Composed of root, body, and glans penis.
Consists of three erectile masses enclosed in a fascial sheath:
One corpus spongiosum (contains urethra).
Two corpora cavernosa (main erectile tissues).
Fixed part, attached to the perineal membrane.
Formed by:
Bulb of penis (posterior enlargement of corpus spongiosum).
Two crura of penis (posterior ends of corpora cavernosa).
Muscles covering root:
Bulbospongiosus → covers bulb; aids in ejaculation and emptying urethra.
Ischiocavernosus → covers each crus; compresses veins to maintain erection.
Relations:
Lies between perineal membrane (superiorly) and superficial perineal fascia (inferiorly).
Traversed by urethra within corpus spongiosum.
The free pendulous portion extending from the root to the glans.
Enclosed by deep fascia (Buck’s fascia), which binds the erectile tissues together.
Components:
Two corpora cavernosa — dorsal position, surrounded by tough tunica albuginea.
One corpus spongiosum — ventral position, enclosing the spongy urethra.
Blood supply:
From deep arteries of penis (branches of internal pudendal artery).
Dorsal arteries run on each side of deep dorsal vein.
Venous drainage:
Superficial dorsal vein → external pudendal vein.
Deep dorsal vein → prostatic venous plexus.
Nerve supply:
Sensory: Dorsal nerve of penis (from pudendal).
Parasympathetic (S2–S4): Erection via pelvic splanchnic nerves.
Sympathetic (L1–L2): Ejaculation and detumescence.
Each corpus (cavernosum or spongiosum) contains trabeculae of smooth muscle and connective tissue, enclosing blood-filled cavernous spaces.
Tunica albuginea is thick around corpora cavernosa, thin around corpus spongiosum.
The central lumen of corpus spongiosum is the urethra, lined by stratified columnar epithelium, becoming stratified squamous near meatus.
Endothelial-lined vascular spaces fill with blood during erection, leading to rigidity.
Expanded distal end of corpus spongiosum covering the tips of corpora cavernosa.
Contains external urethral meatus at its summit.
Margin projects as the corona glandis, separated by the neck from the body.
Prepuce (foreskin): Fold of skin covering glans; attached by frenulum preputii.
1. Phimosis:
Prepuce too tight → cannot retract over glans.
May cause pain, infection, and urinary obstruction.
2. Paraphimosis:
Retracted tight foreskin constricts glans → venous congestion and pain.
3. Hypospadias:
Urethral opening on ventral surface of penis (due to incomplete urethral fold fusion).
4. Epispadias:
Urethral opening on dorsal surface, often with bladder exstrophy.
5. Priapism:
Prolonged painful erection due to venous drainage failure.
6. Circumcision:
Surgical removal of prepuce; prevents infection and carcinoma.
7. Carcinoma Penis:
Common in uncircumcised males; spreads via inguinal lymph nodes.
8. Erectile Dysfunction:
Failure of parasympathetic-mediated vasodilation in penile arteries.
The scrotum is a cutaneous pouch that contains the testes, epididymides, and lower parts of spermatic cords.
It is divided into right and left compartments by a median septum, visible externally as the raphe.
From superficial to deep:
Skin – thin, pigmented, rich in sweat and sebaceous glands.
Superficial fascia (Dartos fascia) – contains smooth muscle fibres (dartos muscle) but no fat.
Responsible for wrinkling of scrotal skin and thermoregulation.
External spermatic fascia – from external oblique aponeurosis.
Cremasteric fascia and muscle – from internal oblique; raises the testis.
Internal spermatic fascia – from fascia transversalis.
Tunica vaginalis – serous sac around testis (parietal and visceral layers).
Anterior one-third: L1 (ilioinguinal + genital branch of genitofemoral).
Posterior two-thirds: S3 (pudendal and perineal branches of posterior cutaneous nerve of thigh).
Arteries: External pudendal, internal pudendal, and cremasteric arteries.
Veins: Follow arteries and drain into external pudendal veins.
Drain into superficial inguinal lymph nodes.
Scrotal oedema: Due to dependent position and loose areolar tissue.
Sebaceous cysts: Common due to rich sebaceous glands.
Difficult anaesthesia: Supplied by distant dermatomes (L1 and S3).
Hydrocele: Fluid accumulation in tunica vaginalis; may be:
Vaginal, Infantile, Congenital, or Encysted.
Procedure of tapping hydrocele: Needle passes through
skin → dartos → external spermatic fascia → cremasteric fascia → internal spermatic fascia → parietal tunica vaginalis
Volume 2, BD Chaurasia’s Human …
.Other scrotal conditions: Tumour, epididymitis, varicocele, spermatocele.
Male gonad homologous with the ovary.
Suspended in the scrotum by the spermatic cord.
Left testis lies slightly lower than the right.
Oval, slightly compressed laterally.
3.75 cm long, 2.5 cm broad, 1.8 cm thick.
Weight: 10–15 g.
Tunica vaginalis – parietal and visceral layers (from processus vaginalis).
Tunica albuginea – dense white fibrous capsule forming mediastinum testis.
Tunica vasculosa – innermost vascular coat.
Testis divided by septa into 200–300 lobules.
Each lobule contains 2–3 seminiferous tubules (each ~60 cm long if uncoiled).
Tubules unite to form straight tubules → rete testis → efferent ductules → epididymis
Volume 2, BD Chaurasia’s Human …
.Testicular artery — branch of abdominal aorta at L2 level.
Accompanied by pampiniform plexus of veins, which form the testicular vein:
Right → drains into inferior vena cava.
Left → drains into left renal vein
Volume 2, BD Chaurasia’s Human …
.Lymphatics:
Drain to preaortic and para-aortic lymph nodes (L2 level).
Nerve Supply:
Sympathetic fibres from T10 via renal and aortic plexuses.
Lined by 4–8 layers of cells:
Spermatogenic cells – spermatogonia → primary → secondary spermatocytes → spermatids → spermatozoa.
Sertoli (sustentacular) cells – tall, columnar; support, nourish, and regulate developing germ cells.
Leydig (interstitial) cells between tubules → secrete testosterone under control of ICSH (LH).
Spermatogenesis regulated by FSH
Volume 2, BD Chaurasia’s Human …
.Monorchism/Anorchism: Absence of one or both testes.
Cryptorchidism (Undescended Testis):
May lie in lumbar, inguinal, or upper scrotal region.
Prone to malignancy, infertility, and torsion.
Ectopic Testis: Deviates from normal descent; may lie in thigh, perineum, or near penis.
Varicocele: Dilated veins of pampiniform plexus (more common on left).
Torsion of testis: Twisting of spermatic cord → acute ischemia.
Orchitis: Inflammation, often post-mumps infection.
Highly coiled tubular organ, acts as a reservoir and site of maturation for spermatozoa.
Parts:
Head (Caput): Formed by coiled efferent ductules, connected to upper pole of testis.
Body (Corpus): Middle portion, formed by a single coiled duct (duct of epididymis).
Tail (Cauda): Lower end, continuous with ductus deferens.
Arterial supply: From a branch of testicular artery, which anastomoses with the artery to ductus deferens.
Venous and lymphatic drainage: Similar to that of the testis.
Nerve supply: Sympathetic fibres from testicular plexus (T11–L1).
Epididymitis / Epididymo-orchitis: Inflammation due to tuberculosis, filariasis, gonococcal or pyogenic infections.
May present with painful scrotal swelling, tenderness, and fever.
Chronic infection can lead to fibrosis and infertility.
Lining: Pseudostratified columnar epithelium with stereocilia.
Supporting tissue: Rich in connective tissue and smooth muscle to aid sperm movement.
Testis develops from three sources:
Spermatogenic cells: From endoderm of dorsocaudal yolk sac.
Sertoli cells: From coelomic epithelium.
Leydig cells: From mesoderm.
Descent of Testis:
Develops near mesonephros (T10–T12 level).
Begins to descend in 2nd month of intrauterine life.
3rd month: Reaches iliac fossa.
4th–6th month: Lies at deep inguinal ring.
7th month: Passes through inguinal canal.
8th month: Reaches superficial inguinal ring.
9th month: Descends into scrotum.
Process guided by gubernaculum (fibrous band connecting testis to scrotum).
Processus vaginalis precedes the testis and later forms tunica vaginalis.
Factors aiding descent:
Hormones (testosterone, maternal gonadotropins)
Differential growth of body wall
Action of gubernaculum
Intra-abdominal pressure and temperature changes
Clinical note:
Failure of descent → cryptorchidism (undescended testis).
Abnormal route → ectopic testis (e.g., thigh, perineum).
Mesonephric (Wolffian) duct forms:
Epididymis
Ductus deferens
Seminal vesicle
Ejaculatory duct
Trigone of urinary bladder
Paramesonephric (Müllerian) duct → vestigial appendix testis.
Mesonephric tubules → rete testis, paradidymis, and aberrant ductules.
3rd week: Mesenchymal cells from primitive streak surround cloacal membrane → cloacal folds.
6th week: Cloacal folds divide into:
Urethral folds (anterior)
Anal folds (posterior)
Genital swellings appear lateral to urethral folds.
Fusion and elongation form genital tubercle, giving rise to penis in males.
SRY gene (Sex-determining Region of Y chromosome):
Encodes Testis Determining Factor (TDF) → initiates testicular differentiation.
SOX9 gene: Works with SRY; activates Müllerian Inhibiting Substance (MIS) gene.
FGF9 (Fibroblast Growth Factor 9): Induces mesonephric tubules to form testicular cords.
SF1 (Steroidogenic Factor 1): Promotes differentiation of Leydig and Sertoli cells, enhances AMH secretion, and stimulates testosterone synthesis.
Testosterone → differentiates mesonephric duct derivatives (epididymis, ductus deferens, seminal vesicles).
Dihydrotestosterone (via 5α-reductase) → forms male external genitalia.
The epididymis acts as a reservoir and site of maturation of spermatozoa; sperm gain motility here.
It consists of head, body, and tail, continuous below with the ductus deferens.
Sertoli cells provide support and nutrition to developing sperm cells and secrete inhibin.
Leydig cells secrete testosterone, the main male sex hormone.
The testicular artery arises directly from the abdominal aorta at L2 level.
Venous drainage forms the pampiniform plexus, which regulates testicular temperature.
Lymph from the testis drains to preaortic and para-aortic lymph nodes, not inguinal nodes.
Gubernaculum guides the descent of the testis from abdomen to scrotum.
The processus vaginalis forms the tunica vaginalis; if it remains patent, may cause congenital hydrocele.
Cryptorchidism (undescended testis) increases risk of infertility and malignancy.
Mesonephric (Wolffian) duct gives rise to epididymis, ductus deferens, seminal vesicle, and ejaculatory duct.
Paramesonephric (Müllerian) duct regresses under the influence of Müllerian Inhibiting Substance (MIS) secreted by Sertoli cells.
SRY gene on the Y chromosome triggers testicular differentiation via Testis Determining Factor (TDF).
Dihydrotestosterone (DHT) derived from testosterone is responsible for development of male external genitalia.
Hypospadias and epispadias result from defects in urethral fold fusion and genital tubercle formation.
Varicocele is more common on the left due to perpendicular drainage of left testicular vein into the left renal vein.
Epididymo-orchitis can follow mumps or urinary tract infection, leading to infertility.
Temperature regulation is vital; testes are maintained 2–3°C below body temperature for normal spermatogenesis.
Cremasteric reflex serves to protect testis by elevating it during cold or threat.
1. A 20-year-old male presents with painless swelling in the scrotum that transilluminates.
→ Diagnosis: Hydrocele due to accumulation of fluid in tunica vaginalis.
→ Anatomical reason: Patent processus vaginalis or imbalance between secretion and absorption of fluid.
2. A 25-year-old man presents with a “bag of worms” feel in the scrotum, more prominent on standing.
→ Diagnosis: Varicocele (dilated pampiniform plexus).
→ Cause: Left testicular vein drains into left renal vein at right angle → venous stasis.
3. A 30-year-old patient complains of acute pain and swelling in scrotum with fever.
→ Diagnosis: Epididymo-orchitis.
→ Cause: Bacterial infection via vas deferens from urinary tract.
→ Complication: Fibrosis and sterility.
4. A 7-year-old boy has an empty scrotum on one side.
→ Diagnosis: Cryptorchidism (undescended testis).
→ Complication: Infertility and risk of malignant change.
5. A 12-year-old boy has testis located in the upper thigh.
→ Diagnosis: Ectopic testis.
→ Cause: Abnormal migration of gubernaculum during descent.
6. A neonate presents with bilateral inguinal swellings that reduce on lying down.
→ Diagnosis: Congenital inguinal hernia with patent processus vaginalis.
7. A patient has defective spermatogenesis despite normal hormone levels.
→ Diagnosis: Sertoli cell dysfunction → defective spermatogenic support.
8. A young male has ambiguous genitalia with male gonads and female external genitalia.
→ Diagnosis: 5α-reductase deficiency.
→ Cause: Inadequate conversion of testosterone to dihydrotestosterone (DHT).
9. A 40-year-old man reports dull dragging pain in the scrotum.
→ Diagnosis: Varicocele causing venous congestion of pampiniform plexus.
10. A patient complains of infertility with low sperm motility but normal count.
→ Diagnosis: Epididymal dysfunction → impaired sperm maturation.
11. A 3-month-old infant presents with a cystic swelling in the spermatic cord above the testis. The swelling transilluminates and is separate from the testis.
→ Diagnosis: Encysted hydrocele of the cord.
→ Anatomical basis: Partial persistence of processus vaginalis between the internal ring and the upper pole of the testis.
12. A 22-year-old patient presents with severe pain after sudden twisting of the scrotum during sports.
→ Diagnosis: Torsion of testis.
→ Anatomical explanation: Twisting of spermatic cord cuts off testicular artery and venous drainage → ischemic necrosis.
→ Note: More common when gubernaculum or scrotal ligaments are underdeveloped (bell-clapper deformity).
13. A 30-year-old man has pain radiating to the groin during urination. Palpation reveals a thickened epididymis.
→ Diagnosis: Tuberculous epididymitis.
→ Mechanism: Retrograde spread of infection from prostate or seminal vesicle via vas deferens.
14. A 5-year-old boy’s mother notices that one scrotal half enlarges whenever he cries or coughs.
→ Diagnosis: Congenital inguinal hernia.
→ Cause: Persistent processus vaginalis allows abdominal contents to enter the tunica vaginalis.
15. A 32-year-old man with mumps develops painful scrotal swelling a week after parotid symptoms.
→ Diagnosis: Mumps orchitis.
→ Complication: Atrophy of seminiferous tubules → possible infertility due to destruction of germinal epithelium.
16. A 25-year-old male has small, firm testes and azoospermia but normal secondary sexual characteristics.
→ Diagnosis: Sertoli-cell-only syndrome (Del Castillo syndrome).
→ Explanation: Germinal epithelium absent; only Sertoli cells remain → infertility with normal testosterone levels.
17. During inguinal hernia repair, the surgeon accidentally ligates the testicular artery.
→ Outcome: Testis may undergo ischemic necrosis, unless collateral supply from artery to vas deferens and cremasteric artery maintains perfusion.
18. A newborn has ambiguous genitalia with partial fusion of the urethral folds and small phallus.
→ Diagnosis: Hypospadias (glandular or penile type).
→ Cause: Failure of urethral folds to fuse completely in the midline.
19. A teenage boy complains of a dull, aching scrotal pain that worsens on standing and improves when lying down.
→ Diagnosis: Varicocele.
→ Anatomical reason: Vertical drainage of left testicular vein into left renal vein under pressure → venous reflux and dilation of pampiniform plexus.
20. A patient presents with painless, hard swelling in the testis that does not transilluminate.
→ Diagnosis: Testicular tumour.
→ Clinical importance: Lymphatic spread is to para-aortic nodes at the L2 level, not inguinal nodes.
21. A 7-year-old boy develops an infection in the scrotal skin. Later, the inguinal nodes are enlarged.
→ Explanation: Scrotal skin drains into superficial inguinal lymph nodes, whereas testicular infection would enlarge para-aortic nodes.
22. A 2-year-old child has a swelling that changes in size and position during the day.
→ Diagnosis: Communicating hydrocele.
→ Cause: Incomplete obliteration of processus vaginalis communicating with the peritoneal cavity.
23. An elderly man presents with testicular atrophy after long-term anabolic steroid use.
→ Explanation: Negative feedback inhibition of pituitary gonadotropins → decreased FSH and LH → suppressed Leydig and Sertoli activity.
24. A man presents with infertility but normal sperm count; motility is markedly reduced.
→ Diagnosis: Epididymal blockage or ciliary defect.
→ Reason: Failure of maturation in epididymal duct or defective stereocilia-mediated absorption of testicular fluid.
25. A 45-year-old diabetic patient develops a rapidly spreading necrosis of the scrotum with foul odour and crepitus.
→ Diagnosis: Fournier’s gangrene.
→ Anatomical note: Involves superficial fascia (Dartos and Colles’), spreading rapidly through continuous fascial planes.
1. What are the coverings of the testis?
→ From inside outward:
Tunica vasculosa
Tunica albuginea
Tunica vaginalis (visceral and parietal layers)
Internal spermatic fascia
Cremasteric fascia
External spermatic fascia
Dartos fascia and skin
2. What are the parts of the epididymis?
→ Head, body, and tail.
Head → receives efferent ductules.
Body → long coiled duct of epididymis.
Tail → continuous with ductus deferens.
3. What is the function of the epididymis?
→ Maturation, concentration, and storage of spermatozoa; absorption of testicular fluid.
4. What is the blood supply of the testis?
→ Testicular artery (from abdominal aorta).
→ Accompanied by pampiniform plexus of veins forming testicular vein.
5. Why is the left testis lower than the right?
→ Because the left spermatic cord is longer.
6. Why is temperature lower in the scrotum than in the body cavity?
→ For spermatogenesis; maintained by pampiniform plexus and dartos muscle thermoregulation.
7. What is the lymphatic drainage of the testis and scrotum?
→ Testis: Preaortic and para-aortic nodes (L2).
→ Scrotum: Superficial inguinal nodes.
8. What is the difference between hydrocele and varicocele?
→ Hydrocele: Fluid in tunica vaginalis.
→ Varicocele: Dilated veins of pampiniform plexus.
9. What are the causes of undescended testis (cryptorchidism)?
→ Defective gubernaculum, hormonal deficiency, or obstruction in inguinal canal.
10. What is the function of Sertoli cells?
→ Nourish and protect developing sperm; secrete inhibin and androgen-binding protein (ABP).
11. What is the function of Leydig cells?
→ Secrete testosterone under LH (ICSH) control.
12. What is the homologous organ of testis in females?
→ Ovary.
13. What is the processus vaginalis?
→ Peritoneal diverticulum descending with testis; forms tunica vaginalis when closed.
14. What is the difference between cryptorchidism and ectopic testis?
→ Cryptorchidism: Testis arrested in normal path of descent.
→ Ectopic testis: Testis deviates to an abnormal position (perineum, thigh, etc.).
15. What are the derivatives of the mesonephric (Wolffian) duct?
→ Epididymis, ductus deferens, seminal vesicle, and ejaculatory duct.
16. What are the derivatives of the paramesonephric (Müllerian) duct in males?
→ Appendix testis and prostatic utricle.
17. What guides the descent of the testis?
→ Gubernaculum testis, a fibrous cord connecting testis to scrotal wall.
18. What hormones influence testicular descent?
→ Testosterone, maternal gonadotropins, and Müllerian inhibiting substance (MIS).
19. What is the role of the SRY gene?
→ Triggers testicular differentiation via Testis Determining Factor (TDF).
20. What happens if the SRY gene is absent?
→ Gonads develop as ovaries (female differentiation).
21. What is hypospadias?
→ Urethral opening on the ventral surface of penis due to failure of urethral fold fusion.
22. What is epispadias?
→ Urethral opening on the dorsal surface of penis, usually associated with bladder exstrophy.
23. What is the difference between spermatic cord and vas deferens?
→ Spermatic cord contains vas deferens, vessels, nerves, and fascial coverings; vas deferens is just one of its components.
24. Why is testicular tumour dangerous?
→ Lymph spreads retroperitoneally to para-aortic nodes near L2, often unnoticed until late.
25. What is the function of Dihydrotestosterone (DHT)?
→ Responsible for development of male external genitalia (penis, scrotum, prostate).
1. The epididymis is derived from:
a. Paramesonephric duct
b. Mesonephric tubules and duct
c. Cloacal folds
d. Mesonephric duct ✅
2. The testicular artery arises from:
a. External iliac artery
b. Internal iliac artery
c. Abdominal aorta ✅
d. Inferior epigastric artery
3. Lymph from the testis drains into:
a. Superficial inguinal nodes
b. Deep inguinal nodes
c. Para-aortic (lumbar) nodes ✅
d. External iliac nodes
4. The left testicular vein drains into:
a. Inferior vena cava
b. Left renal vein ✅
c. Common iliac vein
d. Internal iliac vein
5. The function of the epididymis is:
a. Secretion of testosterone
b. Storage and maturation of spermatozoa ✅
c. Production of seminal fluid
d. Spermatogenesis
6. Which of the following structures prevents the descent of the testis in ectopic testis?
a. Tunica vaginalis
b. Gubernaculum abnormality ✅
c. Processus vaginalis
d. Dartos muscle
7. The processus vaginalis of peritoneum gives rise to:
a. Tunica albuginea
b. Tunica vaginalis ✅
c. Dartos fascia
d. Cremasteric fascia
8. Which of the following cells secrete testosterone?
a. Sertoli cells
b. Leydig cells ✅
c. Germ cells
d. Spermatogonia
9. Which hormone is responsible for the development of male external genitalia?
a. Testosterone
b. Dihydrotestosterone (DHT) ✅
c. Estrogen
d. Müllerian inhibiting substance
10. The epididymis continues below as:
a. Ejaculatory duct
b. Ductus deferens ✅
c. Rete testis
d. Seminal vesicle
11. The failure of closure of processus vaginalis results in:
a. Varicocele
b. Epididymitis
c. Congenital hydrocele or hernia ✅
d. Torsion of testis
12. Which of the following does not pass through the spermatic cord?
a. Vas deferens
b. Testicular artery
c. Ilioinguinal nerve ✅
d. Pampiniform plexus
13. The cremasteric muscle is derived from:
a. External oblique
b. Internal oblique ✅
c. Transversus abdominis
d. Rectus abdominis
14. Which of the following represents the female homologue of the testis?
a. Clitoris
b. Labia majora
c. Ovary ✅
d. Vestibule
15. In descent of testis, the structure that guides its movement is:
a. Gubernaculum ✅
b. Dartos fascia
c. Processus vaginalis
d. Pampiniform plexus
16. Which of the following is derived from the paramesonephric duct in the male?
a. Epididymis
b. Ductus deferens
c. Appendix testis ✅
d. Ejaculatory duct
17. Which of the following structures is not derived from the mesonephric duct?
a. Epididymis
b. Ductus deferens
c. Prostatic utricle ✅
d. Ejaculatory duct
18. The scrotal raphe represents:
a. Site of gubernaculum attachment
b. Line of fusion of labioscrotal swellings ✅
c. Line of descent of testis
d. Fusion of urethral folds
19. In hypospadias, the external urethral opening is present:
a. At the tip of glans
b. On ventral surface of penis ✅
c. On dorsal surface of penis
d. On perineum
20. In epispadias, the urethral opening is present:
a. On ventral surface of penis
b. On dorsal surface of penis ✅
c. In perineum
d. On scrotum
21. The main venous structure involved in varicocele is:
a. Cremasteric vein
b. Deep dorsal vein
c. Pampiniform plexus ✅
d. External pudendal vein
22. The gene responsible for testis differentiation is:
a. SRY gene on Y chromosome ✅
b. SOX9 gene
c. SF1 gene
d. DAX1 gene
23. Which of the following regulates the secretion of testosterone?
a. Luteinizing hormone (ICSH) ✅
b. Follicle-stimulating hormone
c. ACTH
d. Thyroxine
24. The first structure formed during testicular descent is:
a. Processus vaginalis ✅
b. Tunica albuginea
c. Epididymis
d. Dartos fascia
25. Failure of descent of testis into scrotum is known as:
a. Cryptorchidism ✅
b. Ectopic testis
c. Hydrocele
d. Varicocele
Developmental derivatives (Wolffian vs Müllerian)
Descent and coverings of testis
Hormonal and genetic control (SRY, DHT, MIS)
Clinical correlations (cryptorchidism, hydrocele, varicocele, hypospadias)
Microscopic and vascular anatomy
1. What are the coverings of the testis?
→ Tunica vasculosa, tunica albuginea, tunica vaginalis, internal spermatic fascia, cremasteric fascia, external spermatic fascia, dartos fascia, and skin.
2. What is the function of the epididymis?
→ Storage, maturation, and transport of spermatozoa; absorption of testicular fluid.
3. Which part of the epididymis continues as the vas deferens?
→ The tail (cauda).
4. What is the function of Sertoli cells?
→ Support and nourish developing sperm; form the blood–testis barrier; secrete inhibin and androgen-binding protein (ABP).
5. What is the function of Leydig cells?
→ Secrete testosterone under the influence of luteinizing hormone (ICSH).
6. What is the blood supply of the testis?
→ Testicular artery (from the abdominal aorta) and veins forming the pampiniform plexus.
7. What is the lymphatic drainage of the testis?
→ To preaortic and para-aortic lymph nodes at the level of L2.
8. What is the lymphatic drainage of the scrotum?
→ To superficial inguinal lymph nodes.
9. What is the nerve supply of the scrotum?
→ Anterior: Ilioinguinal and genital branch of genitofemoral nerve.
→ Posterior: Pudendal and posterior cutaneous nerve of thigh.
10. Why is the testis located in the scrotum?
→ To maintain a temperature 2–3°C below body temperature, which is optimal for spermatogenesis.
11. What is the significance of the pampiniform plexus?
→ Acts as a countercurrent heat exchanger, cooling arterial blood to maintain testicular temperature.
12. What is cryptorchidism?
→ Failure of one or both testes to descend into the scrotum.
13. What is ectopic testis?
→ Testis deviated to an abnormal site outside its usual path of descent (thigh, perineum, etc.).
14. What is the gubernaculum testis?
→ A fibrous cord guiding descent of the testis from posterior abdominal wall to scrotum.
15. What is the processus vaginalis?
→ A peritoneal diverticulum that precedes the testis during descent and later forms tunica vaginalis.
16. What is the homologous structure of the testis in females?
→ Ovary.
17. What is the homologous structure of the scrotum in females?
→ Labia majora.
18. What is the homologous structure of the penis in females?
→ Clitoris.
19. What are the derivatives of the mesonephric (Wolffian) duct in males?
→ Epididymis, ductus deferens, seminal vesicle, and ejaculatory duct.
20. What are the derivatives of the paramesonephric (Müllerian) duct in males?
→ Appendix testis and prostatic utricle (vestigial remnants).
21. What hormone causes regression of the Müllerian duct in males?
→ Müllerian Inhibiting Substance (MIS) from Sertoli cells.
22. What is the gene responsible for testis formation?
→ SRY gene on the Y chromosome, producing Testis Determining Factor (TDF).
23. What is the function of Dihydrotestosterone (DHT)?
→ Development of male external genitalia (penis, scrotum, prostate).
24. What is hypospadias?
→ Urethral opening on the ventral surface of the penis due to failure of urethral fold fusion.
25. What is epispadias?
→ Urethral opening on the dorsal surface, often associated with bladder exstrophy.
26. Why is varicocele more common on the left side?
→ Left testicular vein drains into left renal vein at right angle, causing higher venous pressure.
27. What is torsion of the testis?
→ Twisting of the spermatic cord → obstruction of blood flow → ischemia and necrosis.
28. What is hydrocele?
→ Accumulation of serous fluid in the tunica vaginalis around the testis.
29. What is the difference between infantile and congenital hydrocele?
→ Infantile: Processus vaginalis closed at internal ring but patent distally.
→ Congenital: Processus vaginalis communicates with peritoneal cavity.
30. What is the effect of failure of testicular descent on fertility?
→ High intra-abdominal temperature damages germinal epithelium → infertility and increased risk of malignancy.
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