MALE REPRODUCTIVE ORGANS

1
MALE REPRODUCTIVE ORGANS

• Testes-site of production of gametes and
  hormones.
• Accessory sex glands-production of seminal
  plasma. Seminal vesicles, prostate, cowpers,
  ampulla, epididymus.
• External genitalia-sheath and penis.

2
EMBRYOLOGY

• Period of the ovum-from fertilization to hatching
  from the Zona Pellucida and subsequent weak
  surface attachment to the uterine epithelium.
  Day 0 to Day 12. Day 4 enters the uterus at
  about 16 -32 cell stage. Nutrition from energy
  stored in egg and from uterine milk. Hatching at
  Day 8 and membranes of the placenta begin to form.

3
EMBRYOLOGY

• Period of the embryo-Day 13 to Day 45. Formation
  of internal organs and organization of body
  parts. Terminates with firm attachment of the
  placenta to the uterine wall. By about Day 21-22
  the urogenital system is established. In this
  general time period the indifferent stage of
  reproductive development occurs.

4
INDIFFERENT STAGE

• Two ducts systems develop simultaneously.
  Mullerian and Wolffian duct systems. If the
  genetic sex is female the wolffian system
  regresses and the mullerian system develops into
  the tubular reproductive system of the female.
  However, if the genetic sex is male, the Wolffian
  system dominates and mullerian regresses.

5
WOLFFIAN DUCTS

• The temporary kidney of the male is 13 to 15
  tubules which connect the testes to the excretory
  canal. This becomes the ductus efferens.
• The wolffian duct becomes the ductus deferens,
  the epididymus and the seminal vesicles.

6
FREEMARTINS

• The indifferent stage is the stage that is
  present when the freemartin and other intersexes
  are formed in mammals.
• Chorions fuse and arteries anastomose which
  creates a common blood supply. Then either male
  hormones or XY cells masculinize the female
  reproductive tract.

7
EXTRAEMBRYONIC MEMBRANES

• Extra-embryonic membranes are formed at
  approximately this time period.
• Amnion-Inner membrane which surrounds the embryo
  suspending it in fluid and protecting it from
  fusing with other tissues and protecting it from
  shock.
• Allantois-Connects to the bladder of the embryo
  and serves as a urinary receptacle.

8
ALLANTOIS CONT.

• The allantois also contains blood vessels serving
  the embryo through which waste products and CO2
  pass out to the blood of the female and O2 and
  nutrients pass to the blood of the embryo from
  the dam.
• The outermost extra-embryonic membrane is the
  serosa. It along with the allantois grow and
  extend throughout the pregnant and non-pregnant
  horns of the uterus.

9
CHORION

• The allantois and the serosa together form four
  layers of tissue that collectively is called the
  chorion.
• The amnion and the chorion then are present
  throughout the rest of gestation both protecting
  and nourishing the developing embryo and fetus.
• At day 35 to 45 the chorion firmly attaches to
  the wall of the uterus thus implanting.

10
PERIOD OF THE FETUS

• At day 45 the organism is 1.25 inches long and
  weighs 2.5 gm. The body is curved and limbs and
  tail are clearly defined.
• From day 46 to term, differential growth, bone
  and hair formation and other changes occur.
• Total weight at term may be 150 pounds of which
  60 is fetus.

11
FETUS CONT

• Half of the total gain is during the last 60 days
  in cattle. 25 of the final weight is in
  accumulated fluids. 5 of final weight is in
  membranes of the placenta and the rest (10) is
  uterine growth.

12
GESTATION LENGTHS

• Cattle- 278 to 284 days (280 for Brown Swiss).
  Males 1 day longer than females and twin 5 to 10
  days shorter than singles.
• Swine- 114 days
• Sheep and Goats- 154 days
• Horses- 330 days depending on parity, sex of foal
  and season of birth.