Male Sexual Anatomy and Physiology

1
Male Sexual Anatomy and Physiology

• Chapter 4

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External Sex Organs
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External Sex Organs
4
External Sex Organs

• Penis
• Male organ of sexual intercourse
• Corpora cavernosa
• Spongy tissue that becomes congested with blood
  and stiffens during sexual arousal
  
• Corpus spongiosum
• Spongy body that runs along the bottom of the
  penis

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External Sex Organs

• Corona
• Ridge that separates the glans from the body of
  the penis
  
• Frenulum
• Sensitive strip of tissue that connects the
  underside of the penile glans to the shaft

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External Sex Organs

• Root
• Base of the penis
• Shaft
• Body of the penis
• Foreskin
• Loose skin that covers the penile glans

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External Sex Organs

• Circumcision
• Surgical removal of the foreskin of the penis
• Penis size

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External Sex Organs

• Scrotum
• Pouch of loose skin that contains the testes
• Spermatic cord
• Suspends a testicle within the scrotum
• Vas deferens
• Conducts sperm from the testicle to the
  ejaculatory duct of the penis

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External Sex Organs

• Cremaster muscle
• Raises and lowers the testicle in response to
  temperature changes and sexual stimulation
  
• Dartos muscle
• Contracts and relaxes in response to temperature
  changes

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Internal Sex Organs Testes

• Testes
• Male sex glands, suspended in the scrotum
• Produce sperm cells and male sex hormones
• Testosterone
• Male steroid sex hormone

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Internal Sex Organs Testes

• Interstitial cells
• Secrete testosterone
• Leydigs cells
• Secondary sex characteristics
• Distinguish the genders
• Not directly involved in reproduction

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Internal Sex Organs Testes

• Sperm
• Male germ cell
• Seminiferous tubules
• Tiny, winding, sperm-producing tubes
• Spermatogenesis
• Process by which sperm cells are produced and
  developed

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Internal Sex Organs Testes

• Spermatocyte
• Early stage in the development of sperm cells
• Spermatids
• Cells formed by the division of spermatocytes
• Spermatozoa
• Mature sperm cells

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Internal Sex Organs Vas Deferens

• Vasectomy
• Sterilization procedure in which the vas deferens
  is severed
  
• Prevents sperm from reaching the ejaculatory duct

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Internal Sex Organs

• Seminal vesicles
• Small glands that secrete fluids that combine
  with sperm
  
• Ejaculatory duct
• Formed by the convergence of a vas deferens with
  a seminal vesicle
  
• Cilia
• Hairlike projections

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Internal Sex Organs

• Prostate gland
• Secretes prostatic fluid
• Cowpers glands
• Empty their secretions into the urethra during
  sexual arousal
  
• Bulbourethral glands
• Semen
• Whitish fluid that constitutes the ejaculate

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Diseases of the Urogenital System

• Urethritis
• Inflammation of the bladder or urethra
• Cancer of the testes
• Cryptorchidism
• Testicles fail to descend from the abdomen into
  the scrotum
  
• Self-examination of the testes

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Diseases of the Urogenital System

• Disorders of the prostate
• Benign prostatic hyperplasia
• Enlargement of the prostate gland due to hormonal
  changes
  
• Cancer of the prostate
• Prostatitis
• Inflammation of the prostate gland

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Male Sexual Functions Erection

• Erection
• Enlargement and stiffening of the penis as a
  consequence of its engorgement with blood

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Male Sexual Functions Erection

• Spinal reflex
• Simple, unlearned response to a stimulus
• Mediated by the spine rather than the brain
• Reflex arc
• Role of the spinal cord
• Sacrum

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Male Sexual Functions Erection

• Role of the brain
• Role of the autonomic nervous system (ANS)
• Sympathetic
• Parasympathetic
• Premature ejaculation
• Erectile abnormalities
• Peyronies disease

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Male Sexual Functions Ejaculation

• Orgasm
• Climax of sexual excitement
• Emission phase
• Contractions of the prostate gland, seminal
  vesicles, ampulla
  
• Expulsion stage
• Muscles contract rhythmically
• Forceful expulsion of semen

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Male Sexual Functions Ejaculation

• Retrograde ejaculation
• Ejaculate empties into the bladder