Anatomy and Physiology of
Animal Reproductive Systems
E VERY LIVING THING has a number of
organ systems operating to perform
specific functions. If you were to examine
one of these systems, you would observe a
number of parts working for distinct pur-
poses. An organ system resembles a run-
ning machine. Like a machine with gears
and gadgets working like clockwork to do a
single task, an organ system comprises
organs working together to carry out a par- (Courtesy, Agricultural Research Service, USDA)
ticular function. A reproductive system is an
organ system for the creation of offspring. Explore this E-unit to learn more about each part
of a reproductive system and the role it plays in the reproduction of life.
Objective:
þ Identify and describe the male and female reproductive organs in mammals.
Key Terms:
Ñ bladder
cervix
mucosal cells
ova
sperm
spermatozoa
clitoris ovaries testicles
copulation oviducts testosterone
Cowper’s gland parturition urethra
epididymis penis urine
fallopian tubes prostate gland uterine horns
follicles retractor muscle uterus
gestation scrotum vagina
glans penis semen vas deferens
infundibulum seminal vesicles vulva
labia majora sheath zygote
labia minora sigmoid flexure
E-unit: Anatomy and Physiology of Animal Reproductive Systems
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, The Male Reproductive System
A successful livestock producer needs a complete understanding of the male reproductive
organs. Usually, a livestock farm will have only a limited number of males available for breed-
ing purposes.
The male reproductive system has several interconnected working parts that must function
together for successful mating to occur. In the reproductive system of a male mammal, the
major organs are the testicles, epididymis, scrotum, vas deferens, urethra, seminal vesicles,
prostate gland, Cowper’s gland, and penis.
The testicles play a major role in animal reproduction by producing sperm, or the male
sex cells, also called spermatozoa. Testicles also produce a hormone, testosterone, which
causes the appearance and behavior of the animal to have masculine traits. Every male animal
has two testicles.
Sperm cells enter the epididymis attached to each testicle. They are stored there while
they mature.
The scrotum is a two-lobed sac that contains and protects the two testicles. It also regu-
lates the temperature of the testicles, which must be maintained below body temperature.
When the environmental temperature is lower than the desired temperature, the scrotum con-
tracts, pulling the testicles toward the body for warmth. When the environmental temperature
is higher than the desired temperature, the scrotum relaxes, permitting the testicles to drop
UNDER INVESTIGATION…
LAB CONNECTION: Semen Samples
Find out what semen looks like under a microscope. Have a beef, dairy, or swine producer
supply you and your classmates with a few samples of semen. Be sure to ask how to handle the
samples properly so that the sperm cells will be viable when examined.
Put some of the semen on a clean microscope slide and use a cover slip. Look at the semen
through the microscope and identify the sperm cells. Use the accompanying drawing to learn the
parts of a sperm cell. See if you can find
the parts in your sample sperm cells.
Determine how long the sperm cells
Tail
stay viable under the microscope. Also,
think about how the environment you are
exposing the sperm cells to affects their Neck
viability. Was the slide cold, wet, or
unclean when you placed the sample on
it? Try to relate these factors to the envi-
Head (chromosomes
ronment of the vagina when semen has contained in nucleus
Body of head)
been deposited in it.
The anatomy of a sperm cell.
E-unit: Anatomy and Physiology of Animal Reproductive Systems
Page 2 u www.MyCAERT.com
Copyright © by CAERT, Inc. — Reproduction by subscription only. E010008
Animal Reproductive Systems
E VERY LIVING THING has a number of
organ systems operating to perform
specific functions. If you were to examine
one of these systems, you would observe a
number of parts working for distinct pur-
poses. An organ system resembles a run-
ning machine. Like a machine with gears
and gadgets working like clockwork to do a
single task, an organ system comprises
organs working together to carry out a par- (Courtesy, Agricultural Research Service, USDA)
ticular function. A reproductive system is an
organ system for the creation of offspring. Explore this E-unit to learn more about each part
of a reproductive system and the role it plays in the reproduction of life.
Objective:
þ Identify and describe the male and female reproductive organs in mammals.
Key Terms:
Ñ bladder
cervix
mucosal cells
ova
sperm
spermatozoa
clitoris ovaries testicles
copulation oviducts testosterone
Cowper’s gland parturition urethra
epididymis penis urine
fallopian tubes prostate gland uterine horns
follicles retractor muscle uterus
gestation scrotum vagina
glans penis semen vas deferens
infundibulum seminal vesicles vulva
labia majora sheath zygote
labia minora sigmoid flexure
E-unit: Anatomy and Physiology of Animal Reproductive Systems
Page 1 u www.MyCAERT.com
Copyright © by CAERT, Inc. — Reproduction by subscription only. E010008
, The Male Reproductive System
A successful livestock producer needs a complete understanding of the male reproductive
organs. Usually, a livestock farm will have only a limited number of males available for breed-
ing purposes.
The male reproductive system has several interconnected working parts that must function
together for successful mating to occur. In the reproductive system of a male mammal, the
major organs are the testicles, epididymis, scrotum, vas deferens, urethra, seminal vesicles,
prostate gland, Cowper’s gland, and penis.
The testicles play a major role in animal reproduction by producing sperm, or the male
sex cells, also called spermatozoa. Testicles also produce a hormone, testosterone, which
causes the appearance and behavior of the animal to have masculine traits. Every male animal
has two testicles.
Sperm cells enter the epididymis attached to each testicle. They are stored there while
they mature.
The scrotum is a two-lobed sac that contains and protects the two testicles. It also regu-
lates the temperature of the testicles, which must be maintained below body temperature.
When the environmental temperature is lower than the desired temperature, the scrotum con-
tracts, pulling the testicles toward the body for warmth. When the environmental temperature
is higher than the desired temperature, the scrotum relaxes, permitting the testicles to drop
UNDER INVESTIGATION…
LAB CONNECTION: Semen Samples
Find out what semen looks like under a microscope. Have a beef, dairy, or swine producer
supply you and your classmates with a few samples of semen. Be sure to ask how to handle the
samples properly so that the sperm cells will be viable when examined.
Put some of the semen on a clean microscope slide and use a cover slip. Look at the semen
through the microscope and identify the sperm cells. Use the accompanying drawing to learn the
parts of a sperm cell. See if you can find
the parts in your sample sperm cells.
Determine how long the sperm cells
Tail
stay viable under the microscope. Also,
think about how the environment you are
exposing the sperm cells to affects their Neck
viability. Was the slide cold, wet, or
unclean when you placed the sample on
it? Try to relate these factors to the envi-
Head (chromosomes
ronment of the vagina when semen has contained in nucleus
Body of head)
been deposited in it.
The anatomy of a sperm cell.
E-unit: Anatomy and Physiology of Animal Reproductive Systems
Page 2 u www.MyCAERT.com
Copyright © by CAERT, Inc. — Reproduction by subscription only. E010008
