Male reproductive system

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Male reproductive system

• JP slovak

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Testes

• Description
• 5 cm in length
• Ovoid in shape
• Suspended by spermatic cord
• Contained within scrotum
• Descent
• Originate near kidney
• month before birth they descend
• Pass through abdomen into scrotum
• DHT stimulates testes to descend
• Gubenaculum aids movement
• cryptorchidism

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Testes

• Structure
• Enclosed by tunica albuginea
• Septa dvide each teste into lobules
• Lobules contain seminiferous tubules
• Rete testis
• Give rise to ducts that join epidydymis
• Sertoli cells
• Leydig cells secrete androgens

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Formation of sperm cells

• Sertoli cells
• Columnar and tall
• Extend entire epithelium
• Nourish and regulate spermatogenic cells
• Spermatogenic cells
• Spermatogonia diploid
• Primary spermatocytes (arrested until puberty)
• Review meiosis

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Structure of Sperm cell

• Head
• Nucleus
• Haploid
• Acrosome
• Midpiece
• Many mitochondria
• Tail
• microtubules

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Male internal accessory organs

• Epididymis
• Tighly coiled tube
• Connected to ducts in teste
• Inner lining secretes glycogen
• Immature sperm are immature until they reach
  epididymis
• Do not swim until after ejaculation

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• Vas deferens
• Muscular tube
• Begins at lower end of epididymis
• Passes medially through spermatic cord
• Courses over the pelvis
• Ends behind urinary bladder
• Near end dilates (ampulla)
• Outside prostate it becomes slender
• Ejaculatory duct fusion of seminal vesicles and
  vas deferens

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• Seminal Vesicles
• Convoluted saclike structure
• Attached to vas d. near base of the bladder
• Secretes alkaline fluid
• Has fructose and prostaglandins
• Prostate gland
• Chesnut shaped (4cm diameter)
• Surrounds the beginning of urethra
• Secretes alkaline solution
• Enhances motility of sperm
• Helps neutralize acidic vagina

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• Bulbourethral glands
• Located inferior to prostate
• Lateral to urethra
• Fluid released by sexual stimulation
• Lubricates end of the penis
• Semen
• Sperm cells
• Various secretions
• Has PG and nutrients
• 2 to 6 ml
• Capacitiation
• Can be frozen

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Male External Accessory glands

• Scrotum
• Pouch that hangs from lower abdomen
• Lacks subq fat
• Contains a layer of smooth muscle (dartos)
• Cold causes dartos to contract
• Cremaster also contracts
• Has medial septum

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• Penis
• Three columns of tissue
• Dorsal pair copora cavernoss
• Single ventral corpora spongiosum
• Tunica albuginea surrounds columns
• Urethra extends through spongiosum
• Glans penis
• Prepuce (foreskin)
• At the root of penis the columns separate
• Cavernosa attach to pubic arch
• Spongiosum attach to the perineum

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Erection

• During sexual stimulation
• PNS cause release of NO
• Cause dilation of arteries
• Compress veins of penis (blood accumulates)
• Ejaculation
• Occurs in response to SNS
• Stimulate contractions of smooth muscle
• Urethra fills with semen
• Signal to spinal cord to cause skeletal muscles
  at the base of the penis to contract
• Sequence bulbourethral glands gt prostate gt
  sperm cells gt seminal vesicles
• After SNS causes constrict of arteries (flaccid
  state)