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General overview:
- spermatic cord
- scrotum
- testes (seminiferous tubules, Sertoli and Leydig cells,
- spermatogenesis and spermiogenesis)
- epididymis
- ductus deferens (vas)
- urethra
- penis
- seminal vesicles
- prostate gland
- bulbourethral glands
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Descent of the Testes:
- intra abdominal near the kidney
- they are translocated inferiorly and anteriorly to the abdominal wall
- gubernaculum testis
- during the third trimester they move through the abdominal wall and take with them a pocket of the peritoneal cavity
- as the testes move through the wall they are accompanied by the ductus deferens, blood vessels, nerves and lymphatics
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Spermatic Cord:
- fascia, connective tissue and muscle
- wrap the blood vessels, nerves and lymphatics that supply the testes
- starts at the deep inguinal ring, extends through the inguinal canal and comes through the superficial inguinal ring into the scrotum
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Scrotum:
- sac of skin and fascia outside of the abdominopelvic cavity
- midline septum divides it into two compartments
- keeps the testes from body temperature
- dartos (means skinned) muscle: located in the skin of the scrotum
- cremaster (the suspender) muscle: deep in scrotal wall
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Testes:
- 4-5 cm long, 2.5-3 cm in diameter
- tunica vaginalis: extension of the peritoneum, covers lateral and anterior surfaces of the testes
- tunica albuginea: fibrous coat or capsule, extension penetrate the testes dividing it into approximately 250-300 compartments called testicular lobules
- testicular lobules: contains seminiferous tubules, loose connective tissue and lots of blood vessels
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seminiferous tubules of the testes:
- the actual sperm factories
- approximately 80 cm long
- total length in both testes is approximately 0.5 miles
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Leydig cells:
- located in the loose connective tissue between the seminiferous tubules
- produces and secretes testosterone
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blood supply:
- testicular arteries (branches of the abdominal aorta)
- testicular veins pampiniform plexus surround the testicular arteries
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innervation:
- autonomic nervous system
- sensory
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Spermatogenesis:
- spermatogonia: stem cells that form during embryonic development
- process stimulated by LH, FSH and testosterone
- through cell division form spermatogonia and primary permatocytes (meiosis I) and spermatids (meiosis II)
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Spermiogenesis:
- maturation of spermatids resulting in spermatozoa
- occurs with the help of the Sertoli cells
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Sertoli cells:
- create blood-testes barrier
- support spermatogenesis and spermiogenesis
- Secrete inhibin and androgen binding protein (ABP)
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Structure of a Sperm:
- approximately 65 um long
- head, neck, middle piece, tail
- head: flat and oval, contains the nucleus and acrosomal cap (bag of enzymes)
- neck: connects the head to the middle piece, contains the cellular components that form the flagellum
- middle piece: continuation of the neck, mitochondrial collar
- tail: flagellum, source of movement for the sperm
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