Lect. 4 Female Anatomy

An Overview of the Female Reproductive Tract

Mammals are the only group to have a true uterus, point of connection between thye mother and her fetus(s) providing the fetus with nutrients

Species of insects, fish, and reptiles hatch eggs inside the body ovoviviparous (producing young by means of eggs which are hatched within the body of the parent)

Mammals are the only group of animals which direct “feed” nutrients from the mother’s body to the fetus

Mammals are only species to use their own bodies to Lactate - The secretion of milk products from mammary glands to provide nutrition for newborn offspring

Why should the producer care?

  • Everything we do with a female animal is dependent on her anatomy

  • Reduction of economic drain

  • Increase production and profits

  • Selection of the most desirable traits

The Vulva and Vagina

Path of sperm cell through the female reproductive tract…

  • Vulva - Protective outer covering of the female reproductive tract, consisting of two lip like structures, termed labis majora and labia minora

  • Serves as a protective outer covering of the reproductive system

  • Separates and protects the vagina from the outside environment

  • Preserves mucosal membranes

Things To Consider:

  • Vulva Conformation

  • Common Vulva Injuries

  • Caslick’s Procedure

Vestibule

Common pathway for reproductive and urinary systems

Hymen - thin piece of mucosal tissue that surrounds or partially covers the external vaginal opening. Physiological function? No nerve endings

Contains the opening to the urethra

Contains the clitoris - a small organ at base of vulva/vestibular junction

  • Comprised of a small amount of erectile tissue

  • High percentage of sensory nerves

  • Signaling the female for correct position for mating

The Vaginal Vault:

Past Vestibule

  • Highly muscular tissue, is capable of both constriction and expansion

Three distinct tissue layers:

  1. The Tunica serosa - the tissue which separates the vagina from other tissues in the peritoneal cavity (The peritoneal cavity is a potential space between the parietal peritoneum and visceral peritoneum, that is, the two membranes that separate the organs in the abdominal cavity from the abdominal wall.)

  2. The Tunica muscularis - the muscle layer

  3. The Tunica mucosa - a glandular epithelial cell layer that lines the lumen of the vaginal canal

Epithelial layer (thin outer portion) and muscle layer respond to hormones

Ex: estrus, the epithelial layer, water mucus to facility sperm movement and act as a lubricant during the time of mating

Muscle cells of the Tunica muscularis, rhythmic contractions move sperm up the track

Vagina - Organ of Copulation

  • In some species, site of sperm deposition, very acidic pH - urine pooling, serves as barrier to bacteria and sperm

    • The vagina has a high concentration of antibodies

      • Prevent or limits infections in the reproductive and urinary tracks

      • Sometimes vagina recognizes sperm as a foreign material leading to decreased fertility and inflammation

            “pH levels of semen are higher than the pH levels of vaginas, which can mess with the growth of healthy bacteria or “vaginal flora”

Parturition, vagina and cervix must open to form the birth canal

  • Due to presence of estrogens and relaxin in the track at once

Vaginal fornix - where vagina and the cervix join together

“blind pouch” inside the vagina

“often mistaken as the opening to the cervix”

Vagina

Functions

  • Copulatory organ

  • Site of semen deposition

  • Absorbs seminal plasma

  • Acidic pH-

  • Ig G and Ig A

  • Antibodies to sperm sometimes found in infertility

  • Birth canal

  • Urinary canal

The Cervix

The Cervix is round in shape and has a hole in the middle

The can running through the cervix lined by a glandular epithelium, secrets mucous which is responsive to progesterone and estrogen

Os - mouth or opening

Os Cervix and Os Uterus

Interior of the canal is irregularly shaped

  • Horse, mucosal folds

  • Sheep and Cows, annual rings

  • Pig, corkscrew shaped

These shapes play an important role in our ability to pass an AI rod through the cervix when we attempt artificial insemination

So what is the function of the cervix???

  • Serves as “plug” for the uterus: pregnancy, non estrus, mucus will be thickened and block sperm movement (a barrier)

  • Serves as “transport tunnel”: estrus, the mucus is thinned, contractions and cilia on the epithelial line help move sperm through the canal

  • The environment in the canal is much more supportive of sperm survival than the low pH of the vaginal vault

  • Some species, most notably the boar with his corkscrew-shaped penis and sometimes the stallion, site of sperm deposition

Cervical canal will become part of the birth canal at parturition: two-millimeter hole must be able to dilate to allow passage of the fetus

Number of hormones which allow the muscles to pull back to the peritoneal wall, forming a much larger opening

Also called cervix uteri

Thick walled, inelastic tube with small lumen

Functions

  • Site of semen deposition

  • Sperm reservoir

  • Prevent microbial contamination of uterus

  • Produces cervical mucous

The Uterus: An Overview of Uterine Function

Unique organ of the mammalian female reproductive system

Two Functions:

  1. Incubator where the developing fetus will grow and develop. During gestation, the placenta attaches to uterus which will supply the nutrients the embryo/fetus need

  2. Makes the hormones

    Relaxin, allows the uterus to large as the fetus grows

    Makes PGF2a which helps with gamete movement and parturition

Uterus: Parts of the Uterus

Three Layers:

  • Serosal layer: which separates the organ from other organs in the peritoneal cavity

  • Myometrium: the muscle layer of the uterus which can relax to allow for space or contract to empty the uterus at parturition

  • Endometrium: Separating the myometrium from the lumen of the uterus

Secretes mucus, nutrients, and hormones supports the growth of the fetus and reservoir for sperm movement.

Irregular shape: Crypts - lining crevices, in response to hormones

Uterus can be both a barrier and reservoir movement

Uterus: Uterine Shapes

Species Specific! Unlike other parts of the reproductive tract

Adapted evolutionarily to accommodate each species

  1. Duplex

  2. Bicornate

  3. Bipartite

  4. Simplex

1) Duplex - no common area (uterine body) and a separate cervical opening

Rat, mouse, rabbit, guinea pig

  • Two cervices

  • No uterine body

  • Uterine horns completely separate

2) Bicornate - a single cervical opening, a small uterine body, and long uterine horns

The body may have a tissue separation across most the body called a septum

  • Pig

  • One cervix

  • Uterine body very small

  • Uterine horns long and convoluted