Anatomy & Physiology of the
Reproductive System
ANATOMY & PHYSIOLOGY 13 -14
Sexual v. Asexual Reproductive Strategies
ASEXUAL
PRO:
◦ Fast
◦ Limited structures necessary
◦ Genetic Conformity
CON:
◦ Genetic Conformity
SEXUAL
PRO:
◦ Genetic Diversity
CON:
◦ Need for genetically distinct
partners
◦ Structural requirements
◦ Haploid gametes
Diploid v. Haploid/Monoploid
DIPLOID
Genetic material
occurs in
homologous pairs
Somatic Cells
HAPLOID
Genetic complement
contains only one half of
each homologous pair
Required for gametes, to
prevent polyploidy postfertilization
Male Reproductive Tract
SCROTUM
Protected by scrotum
◦Extension of perineum
◦Muscle and integumentary
◦Analogous to labia majora in
females
TESTES
The “Witness of Virility” (testis unus, testis nullus)
Redundant anatomical feature
Historically, men who wanted male offspring would
have their left testicle removed.
Site of meiotic division/production of sperm but
NOT the production of semen
INTERNAL ANATOMY OF TESTES
Tunica vaginalis and Tunica
albuginea – protective coverings
over germ cells
Germ Cells: Meiotic cells clustered
into functional units called lobules,
separated by septa
Meiotic division occurs inside of
seminiferous tubules (250+ ft.)
Seminiferous Tubules
Maturation of germinal cells
(diploid) into spermatozoa
(motile, haploid gametes)
occurs here
Non-motile spermatozoa
release into the lumen of the
seminiferous tubule
Sertoli Cells
Blood-Testis Barrier =Developing
spermatids are protected from
the autoimmune responses of
the blood by Sertoli Cells, which
“nurse” the developing germinal
cells
Leydig Cells
Located in-between
seminiferous tubules
Responsible for the production
of testosterone
Epididymis
6-7 meter coiled tubule connecting the efferent ducts of
the seminiferous tubules to the Vas Deferens
Non-motile spermatozoa stay in caput (head) region of
epididymis for 2-3 months after their production in the
seminiferous tubules.
Final maturation (capacitation) of sperm does not occur
until spermatozoa are in the female reproductive tract
Epididymitis
Spermatic Cord
Contents:
Tunica vaginalis
(protective covering)
Vas Deferens
(connective duct)
Cremaster Muscle
Vas (Ductus) Deferens
Appx. 1ft long, 3-5 mm wide
ciliated tube
During ejaculation, peristalsis
occurs, propelling sperm from
epididymis to the urethra
Deferentectomy (Vasectomy)
Cremaster Muscle
Part of spermatic cord
Allows body to retract or extend
testes relative to body
Important in terms of
temperature regulation
Sperm development best at just
below 37 °C
Seminal Vessicles & Ejaculatory Duct
Seminal Vessicles: produce seminal fluid
which contains
◦Fructose (to nourish spermatozoa)
◦Vitamin C
◦Prostaglandins (hormones)
◦Mucus
Ejaculatory Duct connects Vas Deferens
to Seminal Vessicles and directs contents
to prostate gland
PROSTATE GLAND
“Protector”/”Guardian”
Walnut-sized exocrine organ
surrounding the urethra
Secretes an alkaline, zinc-rich prostatic
fluid that comprises 50-75% of the
volume of semen
Alkalinity of semen required to
neutralize acidic vaginal environment
Prostatitis & Prostate Cancer
BULBOURETHRAL GLANDS
Produce pre-ejaculate to kill
bacteria in urethra
Produce Prostate-SpecificAntigens (PSAs), which are
markers for prostate cancer.
ANATOMY OF THE PENIS
Corpus Cavernosa = engorgement with blood to
provide erection
Corpus Spongiosum = prevents closure of urethra
Urethra = passage for urine and/or semen
Glans = head of structure
Meatus = opening through which urine and/or
semen passes
OVARY
Latin for “egg”/”nut”
Pearl-white 4x3x2cm oval in lateral wall
of pelvis (ovarian fossa)
Two ends to ovary
◦ Tubal extremity
◦ Uterine extremity
Connected to body wall via ovarian
ligament (uterine extremity) and
mesovarium (tubal extremity)
Internal Anatomy of Ovary
Ovarian Cortex
◦Ovarian Follicles
◦Stroma
Ovarian Medulla
◦Contains blood
vessels but lacks
follicles
Anatomy of the Ovarian Follicle
Oocyte = single germinal cell
◦Develop PRIOR to birth
◦May remain viable for up to 50 yrs
Granulosa = cells surrounding oocyte
that produce hormones critical for
development of oocyte
Thecal – Fibro-vascular protective coat
Fallopian Tube
Ciliated epithelial tube lined with visceral muscle
Oocyte passes from ovary to uterus via the fallopian tube
Site of fertilization of oocyte
Comprised of Four Major Regions/Structures
◦ Fimbriae = surrounds ovary, sweeps ovule into
fallopian tube
◦ Infundibulum = produces tubal fluid to nourish sperm
◦ Ampullary = site of fertilization
◦ Isthmal = narrowing
◦ Interstitial = joins to uterus
Uterus
Primary hormone-responsive sex organ of the
female reproductive tract
Appx. 1kg, superior to bladder, inferior to ovary
◦ Most are anteversion (tipped forward)
Simplex = all parts of uterus are fused into one
structure (unlike most mammals)
Two regions:
Corpus Uteri = Body of Uterus
Cervix Uteri = Neck/Opening of Uterus
Uterine Layers
Perimetrium – outer protective
covering
Myometrium – muscular inner
layer
Endometrium – innermost
glandular layer; point of
implantation for fertilized zygote
Endometriosis
Growth of endometrial
tissue outside of uterus,
often in peritoneum
Common cause of
infertility
CERVIX
Lower narrow portion of uterus
Function:
◦ Sphincter = dilation allows passage
into and out of uterus
◦ Vacuum = suction pulls sperm upward
into the uterus/fallopian tubes
◦ Lubrication = cervical mucus
◦ Barrier = prevent bacteria from
entering uterus
CERVICAL CANCER
5th most dangerous cancer for women
Almost all cases of cervical cancer are
causally connected to the Human
Papilloma Virus (HPV)
Pap Smear = Test for cervical cancer
VAGINA
Latin: “scabbard”/”sheath”
Extends from cervix to vulva, angled backward at 45-60
degrees depending upon location.
pH ranges from 7 pre-puberty to 3.5-4 during childbearing years
Expands in length and width during intercourse and
child-birth due to vaginal rugae
Lubricated via Bartholin’s Glands
Internal Structure
◦ Endothelium
◦ Visceral Muscle
◦ Adventitia
Internal Structure of Vagina
Internal Structure
◦ Epithelium
◦ Visceral Muscle
◦ Adventitia
Expands in length and width during
intercourse and child-birth due to
vaginal rugae
Lubricated via Bartholin’s Glands
Anatomy of the Vulva
Vulva = collective term for external
female anatomy
Labia Minora = cover vagina and urethral
opening
Labia Majora = two folds extending from
mons pubis. Analogous to scrotum
Hymen = tissue covering vaginal
opening. May or may not be present