Ancient Greeks

(7th to 8th Centuries B.C)

very curious; contemplated life

only knew what they saw, heared, etc.

period ruled by religion, myth, etc.

Empedocles

*400 B.C.

*suggested that body was composed of four elements: earth, wind, water, and fire

* 400 B.C.

* wanted to control sex of offspring

* males more important for war and manual labor

* suggested that male offspring came from right testicle and the female from the left

400 B.C.

suggested placenta nurtured fetus

460-377 B.C.

"Father of Medicine"

emphasised careful observation based on fact

300 B.C.

described ovaries as "female testies"

384-322 B.C.

studied animals (mainly chickens)

wrote the book "On the Generation of Animals"

dispeled myths

Contributed:

study of chick embyro development

unfertilized egg waits for "signal" from the male

function of placenta and umbilical cord

Dominated science for 2,000 years

Dark Ages

(400 to 1300 AD)

religion discouraged research and forbid dissection of corpses and animals

intellectual inguiry declined ---> myths resurfaced

Some non-invasive studies

1100s, non-invasive study of the eye

"Father of opthomology"

Renaissance

(1300 to 1600 AD)

rebirth of science

rise of philosophical class

scientific progress

1325 AD

conducted public dissections

1452 - 1519 AD

detailed observations and drawings

(some still used today)

mid-1500s AD

discovered and described the oviduct

"Fallopian tube"

1672

thorough description of the ovary

discovered the antral follicle; "Graafian follicle"

thought the whole follicle was the egg

1677

invented the microscope

discovered and described spermatozoa

throught sperm contained whole, "preformed" mini-animals

supported "preformist" theory

1600s

discovered that blood circulates

didn't believe in preformation

promoted "epigenetic" theory

1700s

observed embryos developed from globules

(probably blastocytes)

established "epigenesis" as natural truth

late 1700s

hypothesised that sperm were the fertilizing agents

first successful AI in dogs

proved both sperm and egg where necessary

late 1700s

removed 1 ovary in a pig, other ovary increased ovulation rate

implied ovaries were controlled by central factor

mid-1800s

described oocyte within antral follicle was the "egg"

"Father of Embryology"

1896

reported first successful embryo transfer

put embryos from white rabbit into a black rabbit and produced white babies

1901

ovary secretes substance that affects body

suggested ovary was an endocrine body

1924

extracted and purified estrogen from follicles

1927

small gland at base of brain controls the ovaries

"pituitary gland"

first A.I. organization formed (daires in NJ)

prostoglandins discovered in seminal fluid

didn't discover purpose til 1970s

brain communicates with pituitary gland

search began for signal(s) from brain

first successful embryo transfer in sheep

cryopreservation (freezing) of sperm

discovered by Sir Polge

rapid advances in lab technology (eg. RIA)

allowed measurment of very tiny concentrations of hormones

progestin--product of ovary--used commercially to synchronize estrus

marketed as MGA (feed) and Syncro-Mate-B (implant)

GnRH finally discovered and sequenced

marketed as Cystorelin

Prostaglandin F2alpha identified in uterus

marketed as Lutalyse

commercial applications of:

 invitro fertilization

 sex pre-selection

Research applications of:

 cloning 

 transgenics

Female Reproductive Anatomy

Anatomical Location

Retroperitoneal (behind peritoneum)

below rectum

allows for "transrectal" palpation and ultrasound

identify:

corpus luteum, follicles, and cysts

transcervical AI

pregnancy diagnosis

soundwaves from "linear transducer"

monitor bounce back from tissue (white/gray)

goes through water (black)

image reveals density and distance from probe

used to find:

ovarian structures

pregnancy diagnosis

sexing of embryo

vagina, cervix, uterus, and oviducts all have tubular-like structure

central fluid filled passageway

allows movement of sperm, eggs, embryo, etc.

thin, inner-most layer

contact with eggs, sperm, etc.

secretory epithelium

specialized according to tissue type and location:

oviduct= ciliated cells

posterior vagina= stratified squamous cells

fibrous cellular matrix

changing histoarchitecture (construction of tissues)

framework for supporting:

blood vessels, lymphatics, and nerves

Functions:

cell secretions direct local development

two layers of smooth muscle:

inner circular layer

outer longitudinal layer

functions:

peristaltic contractions

gamete transport

parturition and involution

thin outer most tissue layer

signle layer of simple squamous cells

provide:

structural integrity

form

developmentally specialized segment of the peritoneal linning of abdominal cavity

provides the reproductive tract with:

structural attachment

blood supply

lymph drainage

nerve supply

special segment of the broad ligament that supports the oviduct

(salpinx = trumpet shaped)

specialized segment of the broad ligament that supports the ovary

(metrium = womb)

development and release of female gametes

synthesis and release of hormones

estrogen

progesteron

oxytocin

relaxin

inhibin

carried through out the body in the blood system

outermost layer of the ovary

derived from linning of the peritonal cavity

connective tissue layer

provides form and protection

active region, usually outside region

follicle growth --> estrogen production --> ovulation

luteal growth --> prgesteron production --> reduction

dense connective tissue matrix

usually inner region

blood vessels, lymphatics, nerves

connective stalk

conduit for blood, lymph, and nerves

different from other species

active cortex pocket extends down into the medulla

ovulates into the center pocket of the ovary

when the ovary ovulates into the center of the ovary

occurs only in mares

ovum +1 layer of squamous cells around it

immature

microscopic

resting stage (can stay dormant for decades)

initial stage of oocyte maturation

oocyte + 1 layer of activated cuboidal cells/"follicular cells"

oocyte + 2 layers of cuboidal cells

"zona pellucida" forms

non-cellular layer secreted around the egg

Tertiary Follicle

"Antral Follicle"

fluid-filled antrum

contains secretory waste products of cells

loose connective tissue

vascular network:

precursors for hormone synthesis

stimulatory hormones (usually proteins)

distribute synthesized hormones

steriod producing cells

contains receptors for stimulatory hormones

secrete intermediary steroid hormones for furhter biogenisis

seperate theca cells (outside) from granulosa cells

blood vessels do not penetrate the basement membrane

steriod/ protein producing cells

contains receptors for stimulatory hormones

secrete estrogen

secrete inhibin

granulosa cells around oocyte termed "cumulus" cells

1) temporal change in "local" hormones cause change in follicle size

2) tissue disruption at apex of follicle caused by the synthesis of collagenese

3) follicular fluid, oocyte, and accompanying cumulus granulosa cells escape the follicle

4) collapse of tissue in follicle walls

5) hemorrhaging at stigma

6) follicle becomes "corpus hemorrhagicum"

Red Body

yellow body

most highly vascularized tissue in the body 

old follicle wall collapses

basement membrane breaks down

theca and granulosa cells mingle

changes in cell structure and biochemistry

changes in enzyme activity

formation of new blood vessels

regression of the corpus luteum to a white fibrous matrix

programmed cell death:

blood supply decreases

enzyme synthesis stops

cells die

immune system attacks the dead cells to remove them from the body

demise of the corpus luteum

gamete transport

site of fertilization

mucosal secretion:

nurture ova/sustain sperm

support developing zygote

zygote/embryo transport and early development

funnel shapped end of the oviduct

covers ovary during ovulation and catches the ova

covered with fimbriae

finger-like projections

help postion the infidibulum

move ova toward the "ostium"

tubular shape

large diamater which gradually tapers down

ciliated epithelium

mucosal folds

transports ova toward the uterus

site where the ampulla and the isthmus join

site of fertilization

not a well defined area

*in the mare, only fertilized ova move beyond this point

small diameter

thicker muscularis

fewer mucosal folds than ampulla

connects the uterus to the oviduct

transports sperm up stream toward the AIJ

might control sperm access

nurtures new zygote

transports zygote to uterus

under endocrine control

important role in estrous cycle

sperm transport

embryo transport/postioning

recognition of pregnancy

produce "uterine milk" to support embryo until it forms a permanent attachment

nuture fetus

labor/expolsion of the fetus

involution

a central uterine body

two bilateral horns

two cervices

two cervical canals

each horn has a seperate compartment

location of cervix varies

rodents, marsupels, etc. 

common body

two distinct horns

external and internal bifurnication

fusion varies with species

sow: little fusion, long horns

mare: extensive fusion

cow: moderate fusion

near complete fusion

single chambered uterus

no horns

primates

where the placenta of the baby attaches to the uterus

common in ruminant animals (cow, ewe, etc.)

mound-like structures

highly vascularized

non-glandular

common to the sow and mare

increased are for nutrient and gas exchange

common to primates

major portion of the endometrial lining of uterus sloughs off each time CL regresses and progesterine declines

fibrous and firm to the touch

central canal surrounded by folds called annular rings

lubrication during mating

secretes mucus under the influence of estrogen

sperm transport

protective barrier during pregnancy

pocket of folds around the external os

as refered to as a blind pouch

The Cervix: Species Variation

Cow and Ewe

large volume of mucus secreted during estrous

interlocking projections

barrier/slow-release crypts for hold sperm

The Cervix: Species Variation

Sow

minimal mucus secretion

interdigitating rings/pads

accomodates twist of the boar penis

cervix "locks" onto penis

The Cervix: Species Variation

Mare

short in length with loose folds of mucosa

becomes flaccid during estrus

sperm enters uterus directly during ejaculation

female organ of copulation

minimal muscularis

highly developed mucosal epithelium

part of the genitial and urinary systems

stratified squamous cells

grows from the inside out

origin is the Mullerian duct

columnar and secretory cells

grows outside in

origin is the urogenital sinus

junction between the anterior and posterior vaginas in the virginal female

seperates the vagina from the urethra

helps prevent retro flow of urine into the uterus

muscularis contributes to lock up in dogs

external os of the cervix protrudes into the anterior vagina

creates a fornix vaginae

no fornix vaginae

the external genitalia; visible part of the female reproductive anatomy

lips of the vulva

labia majora and labia minora

retain water and swell during estrus; can be used to check estrus

some muscular tone to prevent infection

secrete mucus during estrus

shiny reflective appearance to tissue

female rudiment of the penis

sensory nerve and erectile tissue

tactile stimulation can affect hormone release:

can increase conception rate by 6%

External genitalia

ventral middle line

under the tail

common to the boar and tom

neither perineal nor pedulous

stallion and the dog

pendulous

bull, ram, and man

Testes

male gonades

testes, testeses, testicle, testicles

covers the testes

composed of:

Visceral Tunica Vaginalis

Tunica Albuginea

Tunica Vasculosa

functional outer component

structural inner core

central connective tissue core

dense cellular matrix

houses collecting ducts and rete tubules

excurrent transport ducts

transport sperm out of testeses toward epididymis

outside covering of the testes

made of peritoneal lining

connective tissue capsule

projections extend in, through the parenchyma, to mediastinum

surrounds tubular components

highly vascularized

contains smooth muscle fibers to aid sperm transport

seminferous epithelium

site of spermatogenisis; Sertoli Cells

Iterstial Cells of Leydig

testerone production

houses capillaries, lymphatics, connective tissue, etc.

basement membrane; lamina propria

basal compartment:

sight of spermatagonia

sertoli cells form tight junctions

Adluminal Compartment:

houses developing spermatozoa

support and nurtures developing spermatozoa

posses receptors for FSH and testosterone

produces many compounds

androgen binding protein

Inhibin

sulfated glycoproteins

tissue within lobule surrounding the seminiferous tubules

containes cells of leydig and interstial cells

produces testosterone

Functions of Excurrent Duct System

transport spermatozoa out of testis for further maturation, storage, and ejaculation

series of collecting ducts and tubules:

Rete Testis

Efferent Ducts

Epididymal Duct(Epididymis)

mutiple finger-like transport ducts

transport spermatozoa from rete testis to the epididymis

single duct

 long convuluted tubule

smooth muscle to aid in peristaltic concentrations to help move spermatozoa

3 Segments:

Head (caput)

Body (corpus)

Tail (cauda)

sperm gain motility and the capcity to bind with oocyte

sperm produce at constant rate over time

reserves depleted after each mating

site of sperm maturation

sperm storage in the distal tail

quiesent except during sexual excitement and ejaculation

cytoplasm is forced out of the sperm cells as it matures

forms droplets on outside of sperm cell membrane

location of droplet relfex sperm maturity:

"proximal" while in the head of epididymis

"translocating" while in body

"distal" in the tail

*should be absent by ejaculation

teasing males increases movement of sperm into ejaculatory pool = large quantity of ejaculate

oxcytocin aids in ejaculation

sperm retained too long have decreased fertility:

gradual flushing of old sperm into urine

Conduit for:

cremaster muscle

vascular supply, lymphatics, nerves

Ductus Deferens (excurrent duct) also called the vas deferens

striated muscle

abdominal obligue muscle attached to dorsal pole of testis

raises and lowers the testis to regulate temperature

normal body temp. is lethal to sperm

temp. of test must be aprox. 5 C below body temp.

higher temp = lower sperm motility, lower fertility, and lower survial rate

Cremaster Muscle

Pampiniform plexus -regulated blood temp.

Tunica Dartos muscle- controls thickness of scrotal wall and the depth of the scrotum

counter-current heat exchange mechanism

vein drainning blood from testis coils around the artery supplying blood to the testis and cools it as it runs past

protects and supports the testis

temp. regulation

layers of the scrotal wall:

skin

tunica dartos (muscle layer)

scrotal fascia (fibrous tissue layer)

Parietal vagina tunica

contains sweat glands

sympathetic innervation-sensative to temperature changes

smooth muscle benath scrotal skin

contraction in cold weather pushes the testis toward the body, thickens the scrotal wall, and decreases the surface area of the scrotum

relaxation in warm weather has the opposite effect

can use to manage reproduction

means of controlling reproduction

Surgically make the testis stay close to the body so that body temp. kills the sperm and renders the bull infertile

can still use the bull to check heat on cows since he still has testosterone, but he can't breed her

layer of peritoneal lining of abdominal cavity

lines inside of the scrotum

along with the visceral tunica vaginalis of the testis, allows testis to move freely up and down without friction

Also called the vas deferens

where "vasactomy" comes from

long slender section of the excurrent duct system

transports sperm from tail of epididymis to pelvic area during ejaculation

fluid medium containing sperm at ejaculation

fluids produced by accessory sex glands

secreted into the pelvic urethra during ejaculation to create semen

located in pelvic region

can be paplated and utrasounded to check for normality

require testosterone for normal function, so they regress in castrated males

enlargments of ductus deferens at junction with pelvic urethra

well developed in bull, ram, and stallion

absent in the boar

contribute fluid volume to ejaculate

also called Seminal Vesicles

contribute fluid volume

prominant in the boar but absent in the dog

Shape varies with species

male only gland

contributes:

alkaline secretion to buffer acid of uterine secretion

proteolytic enzymes

formerly called Cowper's Glands

prominent in Stallion and Boar

cotribute gelatinous fraction at end of ejaculation and help seal off cervix after natural service

base (branch roots)- anchors penis to pelvis

shaft- responsible for protrusion or erection

Glans Penis- highly innervated type of the penis

typical of the bull, ram, and boar

mostly dense, rigid connective tissue

minimal cavernous tissue; does not require engorgment of blood for erection

naturally straight and extended

type of muscle in fibroelastic type penis that is responsible for "erection"

pulls the shaft and glans penis back into the sheath when it contracts

contration puts the sigmoid "S" shape in penis

relaxation of the muscle causes erection

typical of stallion, dog, tom, and man

blood sinuses seperated by connective septa:

corpus cavernosum (top)

corpus sponginosum (bottom)

oposite of the fibroelestic penis

penile muscle in cavernous type penis

contraction of the muscle block venous drainage which cuases engorgment of penis

contration of muscle cause erection

cavernous type penis (ishiocavernosus Muscle)

also has a Retractor Penis Muscle

no sigmoid flexure 

around pelvic urethra

forces seminal plasma and sperm into penile urethra

at base of penis

helps clear out excess matter

contains efferent nerves

stimulation induces reflex peristaltic contractions of:

muscles related to erection

tail of epididymis

duct system

accessory sex glands

(responsible for proper ejaculation)

boar has a cork screw twist

urethral process in the ram and stallion

fleshy area that protects retracted penis

very pendulous in some species (Bos indicus): makes it subject to injury

retains semen and urine in boars

cause of the "Boar taint"

STINKS!!