Topic: Biological Animal Science
Unit: Animal Reproduction
Frameworks: 6.1, 6.2, 6.3, 6.4
Objectives:
1. Define terms related to animal reproduction in class notes with 100% accuracy.
2. Identify the parts of the male and female reproductive systems and the functions of
each with 90% accuracy.
3. Discuss the sexual reproduction processes of agricultural animals in class notes with
100% accuracy.
Lesson:
 Terms:
o Copulation
o Corpus luteum
o Embryo transfer
o Estrogen
o Estrous cycle
o Estrus
o Follicle
o Follicle stimulating hormone
o Gestation
o Hormone
o Hybridization
o Inbreeding
o Ovulation
o Oxytocin
o Parturition
o Progesterone
o Selective breeding
o Super ovulation
o Testosterone
o Zygote
 Sexual reproduction- begins with copulation (mating of male and female)
o Fertilization occurs when the sperm penetrates the egg.
o Embryo- fertilized egg; new animal
o Embryo transfer- moving an embryo from one female animal to another of the
same species
 Male reproductive system
o Testicles produce sperm (male sex cell) and testosterone (causes the appearance
and behavior of the animal to be masculine
o Epididymis-
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 Storage site for sperm cells
 From the testicles, sperm cells enter the epididymis to mature
 Separate epididymis is attached to each testicle
o Scrotum Sac that contains and protects the two testicles
 Also regulates the temperature of the testicles which is lower than the
body temperature of the animal
 Maintaining the correct temperature is critical because extreme
temperatures can affect the production and vitality of sperm
o Vas deferens Transportation tube that carries the sperm-containing fluid from each
epididymis to the urethra
o Urethra Large, muscular canal extending from the urinary bladder
 Both semen and urine move through the urethra to the end of the penis
o Accessory sex glands Several glands that add volume and nutrition to the sperm-rich fluid
coming from the epididymis
 Seminal vesicles Open into the urethra
 Produce a fluid that protects and transports the sperm
 Prostate gland Produces a fluid that is mixed with the seminal fluid
 Cowper’s gland Produces a fluid that moves down the urethra ahead of the
seminal fluid
o Cleans and neutralizes the urethra which helps protect the
sperm as they move through the urethra
o Mixture of the seminal and prostate fluid and the sperm is
called semen.
o Penis Deposits the semen within the female reproductive system
Female reproductive system
o Ovary Produces female gametes (sex cells)- ova (eggs)
 Follicle- a small blister-like development on the surface of the ovary that
contains the developing ovum
 Follicle stimulating hormone- a hormone produced by the
pituitary gland that promotes growth of ovarian follicles in the
female and sperm in the male
o Oviducts Two tubes that carry the ova from the ovaries to the uterus
 Also called fallopian tubes
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At ovulation, the follicle ruptures, releasing an ovum that is caught by the
infundibulum.
 After copulation, sperm move through the uterus to the oviduct.
 Fertilization occurs in the upper end of the oviduct.
 The zygote (fertilized egg) moves to the uterus 2-4 days after fertilization
o Uterus A Y-shaped structure consisting of the body, two uterine horns, and the
cervix, size and shape of the uterus varies among mammals
 Upper part of the uterus consists of the uterine horns that develop into
the oviducts
 Mammals that normally produce large numbers of offspring at each
breeding have large horns and small body
 Fetus grows within the uterus where it remains until parturition (birth)
 Cervix- lower outlet of the uterus and constitutes the gateway between
the uterus and the vagina
o Vagina Female organ of copulation
 Birth canal
 Passage between the cervix and vulva
 Lining is moist during estrus and dry when the animal is not in estrus
o Vulva External opening of the reproductive and urinary systems
o Clitoris Sensory and erectile organ of the female
 Located just inside the vulva
Reproductive systems of poultry
o Male
 Testicles Held inside the body cavity
 Produce sperm and seminal fluid
 Vas deferens Carries the seminal fluid and sperm cells to the cloaca
 Cloaca Enlarged part where the large intestine joins the end of the
alimentary canal
 Alimentary canal Food-carrying passage that begins at the mouth and ends at the
vent
 Papilla Organ in the wall of the cloaca that puts the sperm cells into the
hen’s reproductive tract
o Female
 Ovaries and oviducts-
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The right ovary and oviduct do not function
Only left ovary and oviduct produce eggs
The ova produced in the ovary develop into egg yolks
Oviduct has 5 parts:
o Funnel- recieves the yolk from the ovary; sperm cells are
stored here
o Magnum- secretes the thick white of the egg
o Isthmus- two shell membranes are placed around the yolk
and thick white
o Uterus- thin white and outer shell are added to egg; egg
remains here for approximately 20 hours
o Vagina- egg stays here until it is laid
It takes approximately 25-27 hours for a chicken to produce one
egg.
Estrous cycle
o the time between periods of estrus
o Estrus- heat; time during which the female will accept the male for copulation
o Begins when a follicle on the ovary begins to develop
o Estrogen (a hormone produced by the ovaries) is produced and causes the
animal to show signs of estrus
o Super ovulation- the stimulation of more than the usual number of ovulations
during a single estrous cycle due to the injection of certain hormones
Ovulation
o Release of the egg cell from the ovary
o Time of ovulation is usually near the end of the estrous period
o Egg cell is contained in the follicle; follicle breaks open, releasing the egg; egg
moves into one of the oviducts
o Shortly after ovulation, the corpus luteum (a reddish-yellow mass that forms in a
ruptured follicle in the ovary of mammals) from on the ovary
 Hormone progesterone is released
 A hormone that maintains pregnancy in the animal
Gestation- length of pregnancy
o Fetus develops in the uterus
o Umbilical cord connects from the navel of the fetus to the placenta
 Supplies nutrients and oxygen and carries off waste products
o Fetus grows slowly
 Most growth occurs in last trimester of gestation period
Parturition- act of giving birth
o Near the end of gestation period, the corpus luteum reduces the production of
progesterone
o Increase in amount of estrogen in body
 Causes the uterine muscles to contract
 Begins process of birth
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o Oxytocin- a hormone that causes contractions of the uterus during breeding and
parturition and causes milk letdown
Selective breeding- the breeding of selected animals chosen because of certain
desirable qualities or fitness
o Hybridization- the production of hybrids by natural crossing or by manipulating
crossing
o Inbreeding- the mating of closely related animals
Review:
Parts of reproductive systems worksheet
Source:
MyCaert.com—Animal Reproduction