Chapter 16 Reproductive System

Chapter 16: Reproductive System
Part A: Male System
1. Gonads
a. Primary sex organs
i. Males = testes
ii. Females = ovaries
b. Produce and secrete
i. Males = sperm
ii. Females = ova (eggs)
2. Male reproductive system overview
a. Testes (2)
b. Duct system
i. Epididymis (2)
ii. Ductus deferens = vas deferens (2)
iii. Urethra (1)
c. Accessory organs
i. Seminal vesicles (2)
ii. Prostate (1)
iii. Bulbourethral glands (2)
d. External genitalia
i. Penis
ii. Scrotum
3. Specialized structures
a. Testes
i. Coverings
1. Tunica albuginea- capsule that surrounds each testis
2. Septa (singular = septum)- extensions of the capsule, divide testis into lobules
ii. Internal structure
1. Lobules contain one to four seminiferous tubules
2. Sperm travels through the rete testis to the epididymis
3. Interstitial cells in the s.t.’s produce androgens (testosterone)
a. Castration removal of testes
b. Duct system
i. Epididymis
1. Comma shaped, tightly coiled tube
2. Functions to mature and store sperm cells (at least 20 days)
3. Expels sperm with the contraction of muscles in walls to the vas deferens
ii. Vas deferens
1. Carries sperm from the epididymis to the ejaculatory duct
2. Passes through the inguinal canal and over the bladder
3. Moves sperm by peristalsis
4. Spermatic cord- cord—ductus deferens, blood vessels, and nerves in a connective tissue sheath
5. Ends in the ejaculatory duct which unites with the urethra
6. Ejaculation—smooth muscle in the walls of the vas create peristaltic waves to squeeze sperm forward
7. Vasectomy- cutting of the ductus deferens at the level of the testes to prevent transportation of sperm
iii. Urethra
1. Extends from the base of the urinary bladder to the tip of the penis
2. Carries both urine and sperm
3. Sperm enters from the ejaculatory duct
c. Semen
i. Mixture of sperm and accessory gland secretions
ii. Advantages of accessory gland secretions
1. Fructose provides energy for the sperm cells
2. Alkalinity of semen helps neutralize the acidic environment of vagina
3. Semen inhibits bacteria
4. Elements of semen enhance sperm mobility
d. Accessory organs
i. Seminal vesicle
1. Located at the base of the bladder
2. Produces thick, yellowish secretion (about 60% of semen)
3. Contains: fructose, vitamin C, and other substances that enhance sperm mobility
ii. Prostate
1. Encircles the upper part of the urethra
2. Secretes milky fluid that:
a. Helps to activate sperm
b. Enters the urethra through several small ducts
3. Enlarged prostate constricts flow through urethra
iii. Bulbourethral gland
1. Pea-sized gland inferior to the prostate
2. Produces thick, clear mucus that
a. Cleanses the urethra of acidic urine
b. Serves as a lubricant during sexual intercourse
c. Secreted into the penile urethra
e. External genitalia
i. Scrotum
1. Divided sac of skin outside the abdomen
2. Maintains testes at 3oC (5oF) lower than normal body temperature to protect sperm viability
ii. Penis
1. Delivers sperm into the female reproductive tract
2. Regions of the penis:
a. Shaft with erectile tissue
b. Glans penis (enlarged tip)- sensitivity
c. Prepuce = foreskin
i. Folded cuff of skin around the proximal end
ii. Often removed by circumcision
3. Internal
a. Three areas of spongy tissue around the urethra
b. Erections occur when this erectile tissue fills with blood during sexual excitement
4. Spermatogenesis
a. Overview
i. Production of sperm cells
ii. Begins at puberty and continues throughout life
iii. Occurs in the seminiferous tubules
b. Spermatogonia = stem cells undergo rapid mitosis to produce more stem cells before puberty
i. Follicle-stimulating hormone (FSH) modifies cell division
1. One cell produced is a stem cell, called a type A daughter cell
2. The other cell produced becomes a primary spermatocyte, called a type B daughter cell
ii. Primary spermatocytes undergo meiosis
1. One primary spermatocyte  four haploid spermatids
2. Spermatids- 23 chromosomes (half as much material as other body cells)
c. Human life cycle
i. Union of a sperm (n or 23 chromosomes) with an egg (23 chromosomes) creates a zygote (2n or 46 chromosomes)
1. N + N = 2N
d. Spermiogenesis
i. Late spermatids develop distinct regions:
ii. Sperm cells result
iii. Entire spermatogenesis process
e. Sperm cell anatomy
i. The only
ii. Three parts
1. Head
a. Contains
b. Acrosome
c. Breaks down and releases
2. Midpiece
3. Tail
f. Testosterone production
i. The most important
ii. Produced in
iii. Luteinizing hormone (LH)
1. This causes
iv. Functions of testosterone
1. Stimulates
2. Underlies
3. Causes
a. Deepening
b. Increased
c. Enlargement
d. Thickening

Chapter 16: Reproductive System
Part B: Female System
1. Overview
a. Ovaries (2)- produce eggs and female sex hormones
b. Duct system (transport):
i. Uterine tubes (fallopian tubes) (2)- egg transport
ii. Uterus (1)- embryo/fetal development
iii. Vagina (1)- copulation, birth canal
c. External genitalia- copulation
2. Ovaries
a. Composed of ovarian follicles (sac-like structures)
i. Oocyte (immature egg)
ii. Follicular cells- surround the oocyte
iii. Follicular stages
1. Primary follicle- contains an immature oocyte
2. Graafian follicle- growing follicle with a maturing oocyte
3. Ovulation- when the egg is mature, the follicle ruptures (about every 28 days)
4. The ruptures follicle is transformed into a corpus luteum
b. Support
i. Suspensory ligaments- secure ovary to laternal walls of the pelvis
ii. Ovarian ligaments- attach to uterus
iii. Broad ligament- a fold of the peritoneum encloses suspensory ligament
3. Duct system
a. Fallopian tubes
i. Receive the ovulated oocyte
ii. Provide a site for fertilization
iii. Attach to the uterus
iv. Little or no contact between the ovaries and uterine tubes
v. Supported and enclosed
vi. Anatomy & physiology
1. Fimbriae
a. Finger-like projections at the distal end of the uterine tube
b. Receive the oocyte from the ovary
2. Cilia
a. Located inside the uterine tube
b. Slowly move the oocyte toward the uterus (takes 3-4 days)
3. Fertilization occurs inside the uterine tube since oocyte lives about 24 hours
b. Uterus
i. Located between the urinary bladder and rectum
ii. Hollow organ- pear shape
iii. Functions
1. Receives a fertilized egg
2. Retains the fertilized egg
3. Nourishes the fertilized egg
iv. Support
1. Broad
2. Round
3. Uterosacral
v. Regions of the Uterus
1. Body- main portion
2. Fundus- superior rounded region above where uterine tube enters
3. Cervix- narrow outlet that protrudes into the vagina
vi. Walls of Uterus
1. Endometrium
a. Inner layer
b. Allows for implantation of a fertilized egg
c. Sloughs off if no pregnancy occurs (mensus)
2. Myometrium- middle layer of smooth muscle
3. Perimetrium (visceral peritoneum)- outermost serous layer of the uterus
c. Vagina
i. Extends from
ii. Located between
iii. Serves as
iv. Receives
v. Hymen
4. External genitalia = vulva
a. Mons pubis
i. Fatty area
ii. Covered with
b. Labia =
i. Majora
ii. Minora
iii. Corresponds to
iv. Majora encloses vestibule
1. Contains external openings of
c. Clitoris
i. Contains
ii. Corresponds to
1. Hooded
2. Composed of
3. Becomes swollen
d. Greater vestibular glands
i. One found on
ii. Secretes
e. Perineum
i. Diamond-shaped defined by:
1. Anterior:
2. Posterior:
3. Lateral:
ii. Urethral orifice
iii. Vaginal orifice
5. Oogenesis and ovarian cycle
a. Total supply of eggs are presented at birth
b. Ability to release eggs begins at puberty
c. Reproductive ability ends at menopause
d. Oocytes are matured in developing ovarian follicles
e. The process and steps of oogenesis
i. Oogonia- female stem cells found in a developing fetus
ii. Oogonia undergo mitosis- oogonia undergo mitosis produce primary oocytes
iii. Cells surrounding primary oocytes form primary follicles in the ovary
iv. Oogonia no longer exist
v. Primary oocytes are inactive until puberty
vi. Follicle stimulating hormone (FSH) causes some primary follicle to mature each month
vii. Cyclic monthly changes
f. Meiosis
i. Starts inside maturing follicle
ii. Produces a secondary oocyte and the first polar body
iii. Development to mature stage takes about 14 days
iv. Secondary oocyte ovulates with the release of luteinizing hormone (LH)
1. Secondary oocyte is release and surrounded by a corona radiate (nurturing cells)
v. Is completed
1. Ovum = egg
2. Two additional
vi. Zygote (fertilized egg) =
vii. If no fertilization
viii. Comparison
1. Males
2. Females
ix. Sperm and egg comparison
1. Sperm
2. Egg


Chapter 16: Reproductive System & Development
Part C: Menstrual cycle, Pregnancy
1. Menstrual (uterine) cycle
a. Overview
i. Cyclic changes of the endometrium
ii. Regulated by cyclic production
iii. FSH and LH regulate the production of estrogens and progesterone
iv. Both female cycles are about 28 days in length
v. Ovulation typically occurs about midway through cycle on day 14
1. However,
b. Stages
i. Menstrual phase
1. Days 1-5
2. Functional layer of the endometrium is sloughed
3. Bleeding occurs for 3-5
4. By day 5 growing ovarian follicles are producing more estrogen
ii. Proliferative
1. Days 6-14
2. Regulation of functional layer of the endometrium
3. Estrogen levels rise
4. Ovulation occurs in the ovary at the end of this stage
iii. Secretory
1. Days 15-28
2. Progesterone levels rise and increase the blood supply to the endometrium
3. Endometrium increases in size and readies for implantation
4. If fertilization does occur:
a. Embryo produces a hormone (HCG) that causes the corpus luteum to continue producing its hormones
5. If fertilization does not occur
a. Corpus luteum degenerates as LH blood levels decline
c. Hormones produced by ovaries
i. Estrogen
1. Produced by follicle cells
2. Cause secondary sex characteristics
a. Enlargement of accessory organs
b. Development of breast
c. Appearance of axillary and pubic hair
d. Increase in fat beneath the skin, particularly in hips and breasts
e. Widening and lightening of the pelvis
f. Onset of menses (menstrual cycle)
ii. Progesterone = the hormone of pregnancy
1. Produced by the corpus luteum
2. Production continues until LH diminishes in the blood
3. Does not contribute to the appearance of secondary sex characteristics
4. Helps maintain pregnancy
5. Prepares breasts for milk production
6. Feedback
d. Mammary glands
i. Present in
1. Modified
ii. Function is
iii. Stimulated by