What is the size and shape of the testis?
Oval, laterally compressed, about 5 × 3 × 2.5 cm, weight 10–15 g.
What are the poles, borders, and surfaces of the testis?
Poles: upper (spermatic cord), lower (scrotal ligament). Borders: anterior (free), posterior (epididymis). Surfaces: medial and lateral.
What is the mediastinum testis?
Thickened posterior part of tunica albuginea from which septa arise, dividing testis into lobules.
What structures are found in each lobule of the testis?
1–3 seminiferous tubules → straight tubules → rete testis → efferent ductules → epididymis.
List the coverings of the testis in order.
Skin → Dartos fascia → External spermatic fascia → Cremasteric fascia & muscle → Internal spermatic fascia → Tunica vaginalis (parietal & visceral) → Tunica albuginea.
What are the two layers of tunica vaginalis?
Parietal layer (lines scrotum, internal to internal spermatic fascia) and visceral layer (covers testis & epididymis except posterior border).
What is the arterial supply of the testis?
Testicular artery (from abdominal aorta at L2).
Describe the venous drainage of the testis.
Pampiniform plexus → testicular vein. Right → IVC; Left → left renal vein.
Where do lymphatics of the testis drain?
Para-aortic (lumbar) lymph nodes at L1 level.
What is the nerve supply of the testis?
Testicular plexus (sympathetic fibers T10–T11). Pain referred to umbilical region (T10 dermatome).
What is the clinical significance of the tunica vaginalis cavity?
Contains thin fluid for movement; abnormal accumulation → hydrocele.
What is the embryological origin of the testes?
Genital ridge (mesoderm) in posterior abdominal wall.
When do the testes begin their descent?
Around the 7th month of intrauterine life.
what structure guides testes’ descent
gubernaculum
Through which pathway do the testes descend into the scrotum?
Through the inguinal canal.
What peritoneal extension accompanies the testes during descent?
The processus vaginalis, which later forms the tunica vaginalis.
What is cryptorchidism?
Failure of one or both testes to descend into the scrotum.
What is the optimum temperature for spermatogenesis?
About 2–3 °C below body temperature (~34 °C).
Which anatomical features help maintain the lower testicular temperature?
Location in scrotum, Cremaster muscle, Dartos muscle, Pampiniform plexus (countercurrent heat exchange).
How does the pampiniform plexus regulate testicular temperature?
Venous blood cools the arterial blood entering the testis by countercurrent heat exchange.
What happens if temperature regulation of the testis is impaired?
Impaired spermatogenesis → reduced fertility (as in cryptorchidism or varicocele).
