Chapter 19 -Reproductive Systems
Reproductive System:
What is the function of the male and female reproduction systems? Produce and nurture sex cells, and transport them
to site of fertilization so that the species can reproduce itself from generation to generation
Male:
The male sex organs are designed to transport sperm to eggs.
__Primary______ sex organs (gonads) produce sperm and hormones while _secondary____ sex organs
have a supportive function.
The Testes:
The testes are ovoid structures suspended by a ___spermatic___ cord in the skin-covered pouch called the
___scrotum___.
Each of the testes is made up of about 250 lobules separated by connective tissue; each lobule holds one to four highly
coiled ___seminiferous tubules___. They are lined with stratified epithelium that
produces __sperm cells_____.
___Interstitial____ cells lie between the seminiferous tubules and produce the male hormones.
What is the function of the epididymis? Functions for maturation and storage of sperm cells
Spermatogenesis:
In the male embryo, the _spermatogenic__ cells are undifferentiated and are called _spermatogonia__; each
contains 46 chromosomes.
During spermatogenesis, these cells enlarge and become primary __spermatocytes______.
These new cells undergo division by meiosis I and form haploid secondary _spermatocytes__ with 23
chromosomes. How does meiosis differ from mitosis? Daughter cells have only 23 chromosomes (haploid)
These haploid cells divide again to form __spermatids______, each of which matures into a sperm cell.
Describe the parts of a sperm.
Male accessory organs:
The accessory organs of the male reproductive tract include the epididymides, vasa deferens, ejaculatory ducts,
urethra, seminal vesicles, prostate gland, and bulbourethral glands.
Epididymis:
Each epididymus is a tightly coiled tube lying adjacent to the _testis___ and leading from it to the
___vas deferens___.
What happens in the epididymis? Sperm maturation
Vas deferens & spermatic cord:
The vas deferens is a muscular tube 45 centimeters in length leading from the epididymus up into the body cavity
to the __ejaculatory duct____, where it unites and empties its contents into the urethra.
What else is found in the spermatic cord besides the vas deferens? (hint, what would an organ like the testis need to
survive?) blood vessels
Seminal vesicles:
The seminal vesicle is a saclike structure attached to the ___vas deferens___ near the base of
the urinary bladder.
During emission, seminal vesicles secrete an alkaline fluid containing _fructose___ to nourish sperm and
___prostaglandins__ to cause muscular contractions in the female tract to help propel sperm to the egg cell.
Prostate gland:
The prostate gland in a chestnut-shaped structure surrounding the _urethra__ at the base of the urinary
bladder.
The prostate gland secretes a thin, milky alkaline fluid. What is its purpose? Enhances sperm motility
The _bulbourethral glands___ are small structures located inferior to the prostate
that secrete mucus to lubricate the tip of the penis during sexual arousal.
Semen:
Using all of the above information, what is contained in semen? Sperm, fructose, prostaglandins, mucous, etc.
Urethra:
What is the reproductive function of the urethra? Passageway for semen leading to the outside of the body
Male External Reproductive Organs:
The male external reproductive structures are the scrotum, which houses the testes, and the penis.
Scrotum:
Where is it located? Suspended from lower abdomen posterior to the penis
What is it composed of? Skin and subcutaneous tissue
What is its function? Contains the testes
Penis:
The penis is a cylindrical organ made up of specialized erectile tissue (namely the two _corpora cavernosa_
and the __corpus spongiosum ) and is designed to convey both __urine___ and
___semen__to the outside. The enlargement at the distal end is called the __glans penis_.
Erection, Orgasm, and Ejaculation
During sexual arousal, parasympathetic impulses trigger increased blood flow into the _erectile__ tissues
of the penis, producing an erection.
The culmination of sexual stimulation is orgasm, which in the male consists of __emission__(movement of
sperm cells and accessory gland secretions into the urethra) and _ejaculation_ (forcing semen to the outside).
Male hormones:
GnRH:
Which organ secretes this hormone? hypothalamus
What is its function in the male? Triggers production and release of gonadotropic hormones from anterior pituitary
FSH:
Which organ secretes this hormone? Anterior pituitary
What is its function in the male? Stimulates cells of seminiferous tubules to mature and grow to cause production of
sperm cells
LH (ICSH):
Which organ secretes this hormone? Anterior pituitary
What is its function in the male? Stimulates interstitial cells in testes to secrete male sex hormones
Testosterone:
Which organ secretes this hormone? testes
What is its function in the male? Stimulates development of male reproductive organs, and male secondary sexual
characteristics at puberty
Regulation of male hormones:
How are these hormones regulated? (hint, how are most hormones regulated?)
By a negative feedback system involving the hypothalamus
Female Reproductive System:
The organs of the female reproductive system are specialized to produce and maintain the _egg_ cells, to transport
these cells to the site of __fertilization_, to provide a favorable environment for a developing __fetus_,
to give birth, and to produce female sex hormones.
Primary sex organs are the___ovaries__. The others are called _accessory___ organs.
Ovaries:
The ovaries are solid, ovoid structures located within the lateral _pelvic____ cavity.
The ovaries are subdivided into an inner __medulla___ and an outer __cortex___.
Primordial Follicles:
During prenatal development, small groups of cells form millions of primordial follicles, each of which consists of a
Primary __oocyte____ surrounded by __follicular___ cells.
Early in development, the primary oocytes begin to undergo meiosis, but the process halts and does not resume until
_puberty___.
Only 400,000 oocytes remain at puberty. What percentage will be released from the ovary during the reproductive
life of the female? .01%
Oogenesis:
Beginning at puberty, some oocytes are stimulated to continue _meiosis______.
When a primary oocyte undergoes this division, it gives rise to a large, haploid __secondary_ oocyte and a smaller
_polar body__.
A second, unequal cytoplasmic division gives rise to an egg cell and another __polar body___.
What is the function of these smaller cells? Allows a large egg cell with lots of cytoplasm to produced
Follicle Maturation
At puberty, FSH initiates follicle maturation during which the follicle enlarges, follicular cells proliferate, and a fluidfilled cavity forms the secondary follicle.
The mature follicle contains the secondary __oocyte__ that is surrounded by the _zona pellucida__, attached to the
corona _radiata____.
Ovulation:
A process called ovulation releases the secondary oocyte from the surface of the ovary surrounded by layers of
follicular cells.
If the oocyte is not ___fertilized__ shortly after its release, it will degenerate.
Female accessory organs:
The female internal accessory organs consist of a pair of uterine tubes, a uterus, and a vagina.
Fallopian tubes = uterine tubes = oviduct:
These tubes are suspended by the __fallopian____ligament and lead to the __uterus___.
Near each ovary, the uterine tube expands to form a funnel like __opening (infundibulum)__ with finger-like
__fimbrae_ on its margins.
The cells lining the tubes bear ___cilia_, which beat in unison, drawing the egg cell into the uterine tube.
Uterus:
The upper two-thirds of the uterus is called the _body of the uterus__ and it has a dome-shaped top.
The lower one-third of the uterus is the __cervix___ that extends into the vagina.
The uterine wall has three layers: an inner, glandular __endometrium_, a muscular wall or _myometrium_
and an outer _perimetrium___.
Vagina:
The vagina is a fibromuscular tube that extends from the __cervix__ to the _outside___.
The vaginal orifice is partially covered by a membrane called the_hymen__.
The vaginal wall consists of three layers: the inner __mucous___ layer, a middle _muscular__ layer,
and an outer __fibrous______ layer.
Female External Reproductive Organs
The external organs of the female reproductive system (vulva) include the labia majora, labia minora,
clitoris, and vestibular glands.
Vulva:
The labia majora enclose and protect the other external reproductive organs; they correspond to the __scrotum_
of the male.
The labia minora are flattened, longitudinal folds between the labia majora that form a hood around the
__clitoris__.
Clitoris:
The clitoris is a mass of erectile tissue at the anterior end of the vulva between the labia minora.
It corresponds to the __penis____ of the male and has a similar structure.
Female hormones:
Hormones secreted by the hypothalamus, the anterior pituitary, and the ovaries control female reproduction and
development of secondary sexual characteristics.
GnRH:
Where is it produced? hypothalamus
When does it start to appear in the female? About 10 years old
What does it do? Stimulates anterior pituitary to begin to production of FSH and LH
What are the hormones of the anterior pituitary that are involved in female reproduction? FSH and LH
What is their general function? FSH stimulates production of eggs and release of estrogens: LH stimulates ovulation
and production of estrogen and progesterone
What are the hormones produced by the ovaries? Estrogens and progesterone
What is their general function? Estrogens are responsible for female secondary sexual characteristics, while
progesterone triggers uterine changes during the menstrual cycle
Female Reproductive Cycle:
 The __menstrual____ cycle is characterized by monthly changes in the uterine lining that lead to flow as the
endometrium is shed.
 This cycle is started by _FSH___, which stimulates the maturation of a follicle in the ovary.
 Follicular cells surrounding the developing oocyte secrete _estrogen___, which is responsible for maintaining
secondary sexual characteristics as well as the thickening of the _endometrium____ lining.
 Ovulation is triggered by a mid-cycle surge in___LH___________.
 Following ovulation, follicular cells turn into a glandular ___corpus luteum__ that
secretes increasing amounts of what two hormones? Estrogen and progesterone
 If pregnancy does not occur, this structure degenerates, hormone levels decline, and the _endometrium_
lining disintegrates and is shed.
 During the cycle, estrogen and progesterone inhibit the increased release of __FSH__ and _LH_, when
estrogen and progesterone levels fall, the secretion of __FSH__ and__LH___ increases.
Menopause
___menstrual__ cycles continue throughout middle age until menopause, when the cycles cease.
The cause of menopause is the aging of the ovaries when __follicles_ no longer mature and _estrogen__
levels decline.
Mammary glands:
The mammary glands are accessory organs of the female reproductive system that are specialized to produce and
secrete __milk_______ after pregnancy.
A nipple is located at the tip of each breast surrounded by an area of pigmented skin called the areola___
A mammary gland is composed of irregularly shaped lobes containing glands and a __lactiferous_ duct
leading to the nipple.
Birth Control:
What is birth control? Voluntary regulation of the number of offspring (requires contraception)
Summarize the various methods outlined in the chapter.
Coitus interruptus: withdrawal of penis prior to ejaculation. Rhythm method: abstinence during the days when
the female is fertile. Mechanical Barriers: such as a condom or diaphragm. Chemical barriers: spermcides. Oral
Contraceptives: pills containing estrogen and progesterone to disrupt the normal cycle of hormones. Injectable
contraception or implants: work in a similar manner to oral contraceptives. Intrauterine devices: small objects
inserted into the uterus that interfere with implantation. Surgical methods: vasectomy or tubule ligation
Sexually Transmitted Diseases:
There are __20 recognized sexually transmitted diseases (STDs), which are often silent or go
unnoticed, especially in females.
One possible complication of the STDs gonorrhea and chlamydia is _pelvic inflammatory_____disease, which may
lead to infection and sterility in females.
Acquired immune deficiency syndrome (AIDS) is a sexually transmitted disease most frequently transmitted during
unprotected intercourse or by sharing needles.