Download Chapter 16: The Reproductive System

Chapter 16: The
Reproductive System
Students will be able to understand the
male reproductive and female
reproductive systems
The Reproductive System
 General Information
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1. Divided into male and female
2. Both systems contain gonads or primary sex
organs
 Produce gametes
I. Male Reproductive Anatomy

A. Primary reproductive organs are the testes
(male gonads)
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Have both exocrine (sperm-production) and
endocrine (testosterone-production) function
B. Secondary reproductive organs are those
used for storage and movement of sperm


1. Ducts and Tubules
2. Also called accessory reproductive structures
Testes
Mammal Testes
I. Male Reproductive Anatomy
 C. Testes
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1. Are approximately 4 cm long
2. Are approximately 2.5 cm wide
3. The tunica albuginea, (a fibrous connective
tissue), surrounds the testes
4. The septa are extensions of the tunica
albuginea that divide the testes into lobules

a. Lobules contain 1-4 tightly coiled seminiferous
tubules
 Seminiferous tubules form the sperm
Tunica Albuginea – Cross Section
Seminiferous Tubules
Seminiferous tubules – Cross Section
I. Male Reproductive Anatomy
 C. Testes
 Interstitial cells, lie in the soft connective tissue
surrounding the seminiferous tubules, which produce
androgens (i.e. testosterone)
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
5. The rete testis are tubules the sperm move
into after production
6. Sperm move through the rete testis into the
first duct or storage unit

a. Lies along the external surface of the testes
Testicular Cross Section with
Spermatocytes (spermatogonia)
I. Male Reproductive Anatomy
 D. Duct System

1. Consists of the:
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a. Epididymis
b. Ductus deferens
c. Ejaculatory duct
d. Urethra
Epididymis
I. Male Reproductive Anatomy
 D. Duct system

a. epididymis
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Lies along the exterior surface of the testes
Comma-shaped
Highly coiled
Can be 6 m long (approx. 20 ft)
Lies superior to the testes, runs down the
posterolateral side
Temporary storage system
Takes 20 days to pass through
I. Male Reproductive Anatomy
 D. Duct system
 b. Ductus Deferens
 Also called the vas deferens
 Runs upward from the epididymis
 Moves through the inguinal canal into the pelvic cavity
 Arches over the urinary bladder to the prostrate gland
 The tube is enclosed by the spermatic cord
 Also has blood vessels and nerve bundles

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Propels live sperm from storage to the ejaculatory duct
Vasectomy occurs along this duct (cut and cauterize)
I. Male Reproductive Anatomy
 D. Duct System

c. Ejaculatory Duct
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Passes through the prostate gland
Merges with the urethra
Smooth walls create peristaltic waves during
ejaculation
 Squeezes sperm forward
I. Male Reproductive Anatomy
 D. Duct System

d. Urethra

Extends from the base of the bladder to the tip of
the penis
 3 regions
 Prostatic urethra: surrounded by the prostate
gland
 Membranous urethra: between the prostrate and
the base of the penis
 Spongy urethra: length of the penis
I. Male Reproductive Anatomy
 E. Accessory glands and semen
 1. Seminal Vesicle
 a. Located at the base of the bladder
 b. Produces 60% of the fluid (by volume) of the semen
 c. The secretion is rich in sugar (fructose), vitamin C,
prostoglandins, etc..
 Used to nourish sperm
 Provide energy conversion capabilities
 May play a role in ovulation and corpus luteum function

d. Joins the urethra at the connection with the vas
deferens (the combination is called the ejaculatory
duct)
Seminal Vesicle
Seminal Vesicle
I. Male Reproductive Anatomy
 E. Accessory Glands and Semen
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2. Prostate Gland
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a. Single gland
b. Encircles the urethra
c. Secretes a milky white fluid that activates the
sperm
d. Alkaline, which protects the sperm from the
acid environment of the vaginal area
e. Prostrate glandular secretions is
(approximately) 40% of the fluid by volume
Prostate Gland
I. Male Reproductive Anatomy
 E. Accessory Glands and Semen
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3. Bulbourethral glands
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a. Once called Cowper’s glands
b. Are pea-sized
c. Produce a thick clear mucus
d. It is the first fluid down the urethra during
stimulation
e. Used to lubricate
f. There is some debate over “whether there is
sperm leaked into this fluid during stimulation”
Cowper’s Gland (Bulbourethral
glands)
I. Male Reproductive Anatomy
 E. Accessory Glands and Semen
 4. Semen
 a. Milky white mixture
 b. It is sticky
 c. Has sperm and other glandular secretions
 40 to 2.5 million sperm
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d. The liquid is a transport medium
e. Has nutrients and chemicals (used to protect
sperm)
f. The pH is between 7.2 – 7.8
g. Contains seminalplasmin, relaxin, and several
enzymes
 Sp helps to coagulate the semen, after 15 minutes
becomes liquid again
I. Male Reproductive Anatomy
 F. External Genitalia

1. 2 parts
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a. The scrotum
 The testes hang outside of the male body
 Sperm are not produced at normal body temperature
 The temperature is about 5 degrees cooler
 If the outside temperature cools the testes are pulled
toward the body
I. Male Reproductive Anatomy
 F. External Genetalia
 1. 2 parts (cont)
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b. The penis
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Hangs outside of the body
Is designed to deliver sperm to the female body
Has a shaft
An enlarged tip (glans penis)
A loose skin, that folds to cover the tip, foreskin or
prepuce
 Circumcision is the removal of the foreskin
 Internally the spongy urethra is surrounded by 3
areas of erectile tissue that fills with blood during
stimulation
I. Male Reproductive Anatomy

G. Male reproductive functions
• 1. Spermatogenesis
a. The production of sperm via meiosis
 b. Creates 4 sperm with each meiotic event

• Each sperm is haploid (half the chromosomes)
• Allows for genetic variation

c. Spermatogonia are stem cells in the
seminiferous tubules which produce more
stem cells until puberty and then divide
meioticly to form other cells
I. Male Reproductive Anatomy

G. Male reproduction functions
• 1. Spermatogenesis (cont)

d. The change over occurs due to the
hormone, follicle stimulating hormone (FSH)
• During cell division a stem cell is produced (type
A), and a primary spermatocyte (type B)
• Spermatocytes will then undergo meiosis and
produce sperm
I. Male Reproductive Anatomy

H. Testosterone Production
• 1. Produced by the interstitial cells
• 2. Most important hormone produced by the
testes
• 3. Are activated by the hormone luteinizing
hormone (LH)
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a. Also called interstitial cell – stimulating hormone
(ICSH)
b. Released by the anterior pituitary gland
• 4. Activate other secondary sex characteristics
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a. Deeper voice, increased hair growth, enlargement
of the skeletal muscles, etc.
II. Female Reproductive system

A. General Information
• More complex than the male reproductive
system
• Must produce gametes
• Must nurture and protect developing fetus
II. Female Reproductive system
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B. Ovaries
• 1. Primary reproductive organ
• 2. Produce both endocrine products
•
•
(estrogens and progesterone) and exocrine
products (eggs/ova)
3. The size of almonds
4. Has many sac-like structures called ovarian
follicles
Ovaries
Ovaries
Ovarian Follicles
Ovarian Follicles
II. Female Reproductive system
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B. Ovaries
• 5. Ovarian follicles carry an immature egg
called an oocyte
• a. Surrounded by follicle cells
• b. Ova mature over time, the follicle enlarges,
becomes fluid filled (central region is called the
atrum)
• The follicle is now called a Graafian or vesicular
•
•
follicle, containing a mature ova called a secondary
oocyte
Will be ejected during ovulation
The follicle is now called a corpus luteum
Oocyte
Oocyte
Oocyte development
II. Female Reproductive system
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B. Ovaries
• 6. Ovulation occurs approximately every 28
•
•
•
days
7. Supported by suspension ligaments
8. Anchored to the uterus by ovarian
ligaments
9. Held in place by peritoneum called the
broad ligament
II. Female Reproductive system
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C. Duct system
• 1. Uterine tubes
• 2. Uterus
• 3. Vagina
Uterus
Uterus with Cancerous tumor
II. Female Reproductive system

C. Duct System
• 1. Uterine (Fallopian) Tubes
• a. The initial part of the duct system
• b. Provide a fertilization site
• c. Receives the secondary oocyte
• d. The tubes are approximately 10 cm long
• e. Empty into the super region of the uterus
• f. The distal end contains infundibulum
• Funnel shaped, with finger-like projections called
fimbriae (surround the ovary)
II. Female Reproductive system

C. Duct system
• The fimbriae create fluid currents to pull the oocytes
into the fallopian tubes
• g. Oocytes are carried toward the uterus by
peristalsis and rhythmic beating of cilia
• h. Oocytes take 3-4 days to reach the uterus
• i. Oocytes are only viable for 24 hrs after ovulation
• j. Fertilization usually occurs in the fallopian tubes
II. Female Reproductive system

C. Duct system
• 2. Uterus
• a. Located in the pelvis
• b. Between the urinary bladder and rectum
• c. It is hollow
• d. Functions to receive, retain and nourish the
fertilized egg
• e. Held in place by ligaments (anteriorly-round,
posteriorly-uterosacral)
II. Female Reproductive system

C. Duct system
• 2. Uterus
• f. The major portion of the uterus is called the body
• g. The entrance of the uterine tubes are called
fundus
• h. The entrance into the vagina is called the cervix
• i. The uterine wall is thick and has 3 layers
• Inner (mucosa) layer is the endometrium
• Middle (myometrium) layer is thick with smooth
•
muscle, used during delivery
Outer (serous) layer is the perimetrium
II. Female Reproductive system

C. Duct system
• 3. Vagina
• a. Thin walled tube
• b. It is 3-4 inches long
• c. Runs from the surface to the cervix
• d. Called the birth canal
• e. Receives the penis
• f. A thin membrane (mucosa) closes the distal end,
called the hymen
II. Female Reproductive system
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D. External Genitalia
• 1. Also called the vulva
• 2. Includes the following
• a. Mons Pubis
• b. Labia Majora
• c. Vestibule
• d. Greater Vestibular Glands
• e. Clitoris
• f. Perineum
II. Female Reproductive system

D. External Genitalia
• a. Mons pubis
• Fatty rounded area
• Overlying the pubic symphysis
• Covered with hair after puberty
• b. Labia majora
• Runs posteriorly from the mons pubis
• Encloses two hair free folds
• Delicate skin, very sensitive, quickly irritated
• Labia minora
II. Female Reproductive system
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D. External Genitalia
• c. Vestibule
• Is the longitudinal cleft enclosed by the LMaj
• Contains the external organs of the urethra
• Contains the external organs of the vagina
• Covered by the labia majora
• d. Greater vestibular glands
• Flank the vagina
• Lubricate the distal end of the vagina
II. Female Reproductive system

D. External Genitalia
• e. Clitoris
• Anterior to the vestibule
• It is hooded by a prepuce
• Composed of very sensitive tissue
• Becomes swollen with blood, during stimulation
• f. Perineum
• Is the region that includes, the labial folds, the
anus, and the ischial tuberosities
• Diamond shaped
External Female Genitalia
II. Female Reproductive system

E. Oogenesis
• 1. Development starts while the female is still
•
a fetus
2. Oogonia (stem cell) multiply and divide
• a. Producing primary oocytes
• b. Surrounded by single layer of follicle cells and
are now primary follicles
• c. At birth the oogonia no longer exist
• d. At birth women have approximately 2 million
primary oocytes
II. Female Reproductive system

E. Oogenesis
• 3. At puberty the anterior pituitary produces
•
•
FSH
4. Stimulates follicle growth
5. Ovulation will occur each month
• a. Ovarian cycle
• b. At puberty approximately 400,000 oocytes
remain and a small number of oocytes are
activated each month
• c. Only (approx) 500 ova are used in a lifetime
II. Female Reproductive system

E. Oogenesis
• 5. Ovulation will occur each month (cont)
• a. The follicle grows due to FSH and fluid fills the sac
• b. The center is the atrum
• c. The primary oocyte begins meiosis
•
Producing one egg/ova (secondary oocyte) and 3 polar
bodies
• d. Luteinizing Hormone causes the follicle to rupture the
•
ovary (coronary radiata)
e. Sometimes causes pain in the abdomen
•
Mittelschmerz (middle pain)
II. Female Reproductive system
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E. Oogenesis
• 6. If the secondary oocyte is penetrated by a
sperm it is called an ovum (fertilized egg)
II. Female Reproductive system
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F. Uterine (Menstrual) Cycle
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1. Yes, this is the dreaded PMS!
2. Actually it includes the Pre-Menstrual Syndrome
3. The uterus is only capable of implantation for a short
time each month
4. The endometrium responds to hormone changes each
month
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a. Reacts to the production of estrogen and progesterone,
which are produced by the ovaries
II. Female Reproductive system
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F. Uterine (menstrual) Cycle
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5. There are 3 stages
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a. Days 1-5 Menstrual phase
b. Days 6-14 Proliferative phase
c. Days 15-28 Secretory phase
II. Female Reproductive system
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F. Uterine (menstrual) Cycle
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a. Days 1-5 Menstrual phase
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The endometrial lining is sloughed off
Becomes detached from the myometrium
Bleeding occurs for 3 to 5 days
Lose approximately 50 to 150 ml
At the end, estrogen is being produced by the
ovaries
II. Female Reproductive system
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F. Uterine (menstrual) Cycle
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b. Days 6-14 Proliferative phase
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Stimulated by rising estrogen levels
The basal layer of the endometrium regenerates
Blood supply and glands are increased
Ovulation occurs at some point between day 10
and day 12, at the latest day 14, in response to
the rise in LH in blood stream
II. Female Reproductive system
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F. Uterine (menstrual) Cycle
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c. Days 15-28 Secretory Phase
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Progesterone levels in the blood begin to rise
 Causes the blood supply to the endometrium to increase
 Endometrium glands begin producing nutrients into the
uterus (anticipating fertilization)
 If fertilization does occur, the ovum will produce a
hormone similar to LH to maintain the endometrium until
implantation

LH levels begin to decline
II. Female Reproductive system
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F. Uterine (menstrual) Cycle
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c. Days 15 - 28 Secretory Phase
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As the hormones decline (LH and FSH), the blood
flow to the endometrium will decrease
The endometrium cells die
 Cycles back to the menstrual phase
II. Female Reproductive system
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F. Uterine (menstrual) Cycle (cont)
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6. Menstrual Cycle can vary
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a. Shortest, 21 days
b. Longest (typical), 40 days
c. Longer than 40 days is an indicator of other
problems
II. Female Reproductive system
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G. Hormone Production by the Ovaries
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1. Estrogens
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a. Cause the appearance of secondary sex characteristics
 Enlargement of the accessory organs, uterine tubes, uterus,
vagina, and external genitals
 Development of the breasts
 Appearance of axillary and pubic hair
 Increased deposits of fat beneath the skin, particulary the hips
and breasts
 Widening and lightening of the hips
 Onset of the mensus
II. Female Reproductive system
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G. Hormone Production by the Ovaries
(cont.)
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2. Progesterone
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a. Produced by the corpus luteum
b. Progesterone is produced as long as LH is
present
c. Stops producing progesterone after 10-14 days
d. Helps to maintain the pregnancy, and prepare
the breasts for milk production (lactation)
 Source is now the placenta
II. Female Reproductive system
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H. Mammary Glands
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1. Present in both sexes
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a. Yes, breast cancer CAN happen in males!
2. Stimulated by sex hormones, especially
estrogen
3. Are modified sex glands
4. Contained within the breast

a. Darker pigmented area is called the areola
 Has large numbers of nerve endings
II. Female Reproductive system
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H. Mammary Glands (cont)
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b. Central protruding area is called the nipple
5. Has 15 to 25 lobes, radiating around the
nipple
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a. Lobules contain alveolar glands that produce
milk during lactation
b. Milk moves into the lactiferous ducts, which
open to the surface of the skin