Male Reproductive System

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Male Reproductive System
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Male Reproductive Anatomy
Prepuce (foreskin)
Penis
Scrotum
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• Essential organs
• testes (2) - one of the pair of male gonads that
  produce semen suspended in the scrotum by the
  spermatic cords descend at 7 months in utero
  into the scrotum accompanied by an evagination of
  muscular and connective tissue of the body wall
  that suspend the testes
• Accessory Organs
• Genital ducts send sperm to outside of body
• epididymis (2)
• vasa deferens (2)
• ejaculatory duct (2)
• urethra
• Accessory Glands produce secretions that
  nourish, transport and mature sperm
• seminal vesicles (2)
• prostate
• bulbourethral (2)
• Supporting structures
• scrotum
• penis
• spermatic cords (2)

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Vas deferens
Vas deferens
Corpus cavernosum
Corpus spongiosum
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Spermatogenesis
Spermatogonia
mitosis
Primary spermatocytes
meiosis
Secondary spermatocytes
meiosis
Spermatids Spermatozoa (motile)
epididymis
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Male Reproductive Cycle

• Organ development in utero testes descend into
  scrotum at 7 months in utero
• Reproductive function at puberty
• high hormone levels stimulate final stages of
  development
• Sperm production
• Spermatogenesis
• mitosis meiosis
• spermatogonia primary spermatocytes
  secondary spermatocytes
• meiosis
• spermatids spermatozoa (motile)
• Sperm
• Produced in seminiferous tubules when reach
  puberty
• Spermatids mature to spermatozoa in epididymis
• There are about 200-500 million of those little
  guys in the average amount of semen produced each
  time a man ejaculates.
• It takes 10 weeks for a single soldier to reach
  maturity.
• Mature sperm can live up to 2 weeks in the
  epididymis
• Healthy males produce about 70-150 million sperm
  a day

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• Spermatozoa
• Acrosome - resembles a toque which covers the
  upper portion of the head of the sperm. The
  covering contains enzymes that help the sperm
  penetrate the egg.
• Head contains the 23 chromosomes (genetic
  material) capable of merging with an egg to
  produce a new individual.
• Midpiece connects the head of the sperm to the
  tail. It contains many mitochondria that produce
  ATP. This ATP is used to move the microtubules in
  the tail and create propulsion for the sperm.
  Once in the female system, sperm will "swim" for
  up to 2 days looking for an egg.
• Tail - flagellum with microtubules. The
  microtublues within the tail move past each other
  and move the tail in a whip-like motion. ATP
  provided by the midpiece is required for this
  movement.

Acrosome
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• Pathway of Sperm
• Sperm travel from the testes
• to the epididymis where they mature
• During ejaculation sperm travel up into the
  abdomen from the epididymis in the vas deferens
  to the ejaculatory ducts.
• The ejaculatory ducts move semen into the
  urethra. Once in the urethra, semen (sperm now is
  bathed in the seminal fluid released from the
  various other reproductive structures) moves
  through the
• prostate gland and down to the urethral opening
  at the tip of the penis.
• The seminal vesicles and bulbourethral glands are
  not included in the path of sperm as they
  contribute to seminal fluid but do not have sperm
  moving through them at any time.

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• Seminal Fluid (Semen)
• Semen
• Sperm 10
• Fluid 90
• Semen only contains about 10 sperm - the rest
  consists of enzymes, vitamin C, calcium, protein,
  sodium, zinc, citric acid and fructose sugar.
• Produced from 3 glands
• Seminal vesicle 60 of seminal fluid
• yellowish fluid rich in nutrients (fructose)
• Prostate 30 of seminal fluid
• spongy, secretes milk, alkaline fluid
• Bulbourethral 10 of seminal fluid
• thin, clear mucus that neutralizes pH of urine
  and lubricates

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Fertility

• Factors
• sperm count
• sperm size
• sperm shape
• sperm motility
• Infertility
• caused by antibodies some men make against own
  sperm
• less than 20 million/mL of semen
• Some things that may reduce sperm number and/or
  quality include
• alcohol, drugs, environmental toxins, including
  pesticides, smoking cigarettes, health problems,
  medicines, radiation treatment and chemotherapy
  for cancer, age

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Male Reproductive Hormones GnRH
gonadotropin releasing hormone LH leutinizing
hormone FSH follicle stimulating hormone
Hypothalamus
GnRH
Pituitary
LH FSH
Testes
Testosterone Sperm

• testosterone secreted by Leydig cells
• develop and maintain secondary sex
  characteristics
• regulate metabolism known as anabolic hormone
• stimulates protein anabolism to promotes bone and
  muscle growth
• early maturation leads to epiphyseal closure
• late maturation, delayed epiphyseal closure
• fluid and electrolyte metabolism
• inhibits anterior pituitary secretion of
  gonadotropins (FSH and LH)

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