Transcript Chapter 26

Chapter 26
Male reproductive system
Primary & secondary sex organs
Testes are the primary sex organ of the male
reproductive system. They manufacture and
store spermatozoa for fertilization of ova and
reproduction of the species.
Produce the sex cells or gametes = spermatozoa in
males
Produce testosterone
Secondary or accessory sex organs include:
– The scrotum, epididymis, ductus (vas) deferens,
urethra, ejaculatory duct, prostate gland,
bulbourethral gland, seminal vesicles, and penis.
Male reproductive organs
Scrotum
Divided pouch of skin that contains the testes and is suspended
outside of the body where it keeps the temp ~ 3.5 degrees
cooler and prevents the sperm from dying.
Covered with stratified squamous epithelium and sparse pubic
hairs it is divided in the middle by a septum that separates the
two testicles. Externally the septum is marked by a seam the
perineal raphe which extends from the inferior surface of the
penis, around the scrotum to the margin of the anus.
In cold weather the scrotum can retract by contraction of the
cremaster muscle (sk.m.) to bring the testicles up closer to the
body for warmth. The cremaster muscle is an extension of the
ext. oblique muscles. The dartos muscle, a thin layer of smooth
muscle in the superficial fascia, causes the scrotum to wrinkle
and thicken the skin in order to preserve heat in the cold, as
well.
Scrotum
The scrotum is richly supplied by many sensory and
motor nerve fibers
It is also highly vascularized by the testicular artery to
provide nourishment and oxygen to the spermatogenic
apparatus necessary for production of sperm.
The pampiniform plexus is a network of veins that
surround the testicular artery and serve as a heat
exchanger to cool the blood in the testicular artery
and allow for production of live sperm.
Testes
Testes
Location:
Contained within the scrotum inferior and outside of the abdominal
cavity at the root of and posterior to the penis.
Structure: Enclosed in a serous sac tunica vaginalis from peritoneum
tunica albuginea “white coat”, fibrous outer capsule of the testes.
Septal extensions of the t. albuginea form 200-300 lobules.
lobules – compartments; contain 1-4 seminiferous tubules
seminiferous tubules – tightly coiled “sperm factories” lined with
germinal epithelium and sustentacular or Sertoli cells. The “S” cells
protect the germinal epithelium and form a blood-testes-barrier to
prevent the immune system antibodies from attacking the sperm
septum – divides testis into numerous wedge shaped compartments
that arise from tunica albuginea.
Interstitial cells (Cells of Leydig) – produce androgenic hormones
(testosterone, etc.); sourround seminiferous tubules and secrete fluid
into surrounding interstitial fluid.
Testes
SEM of seminiferous tubules
Spermatic ducts
Consists of those ducts that carry sperm from the
seminiferous tubules in testes → urethra.
Includes the rete testis, efferent ductules, epididymis,
ductus (vas) deferens and ejaculatory duct.
Rete testes network of vessels off of seminifeous
tubules and lead into head of epididymis.
Efferent ductules are 12 small ducts that carry sperm
from the seminiferous tubules to the epididymis. They
are lined with clusters of ciliated cells that help the
sperm move along.
Epididymis
Coiled tube ~ 20 feet long on posterior surface of testicles.
Serve as storage sites and place of maturation of the sperm
produced in the seminiferous tubules.
Has a head, body and tail and is lined with pseudostratified
columnar epithelium covered with stereocilia.
Upon entering the epididymis it may take up to 20 days for
sperm to mature and become motile and capable of fertilizing
an ova.
Sperm are stored in the epididymis for 20 days before they are
phagocytized and destroyed by surrounding epithelial cells.
At the time of ejaculation, the sperm are expelled from the tail
of the epididymis into the ductus deferens.
Sperm do not begin swimming until ejaculated into the vagina.
They are expelled from the sperm ducts by intense peristaltic
contractions.
Ductus (vas) deferens
Thick muscular tube that extends from tail of
epididymis to the ejaculatory duct.
~ 45 cm long and 2.5 mm in diameter.
Runs superiorly through the inguinal canal and
spermatic cord up the anterior wall of pelvic cavity
over and behind the urinary bladder and turns
anteriorly to join the duct of the seminal vesicles which
form the ejaculatory duct.
Propels sperm from epididymis to ejaculatory duct by
peristaltic contractions.
Lined with pseudostratified columnar epithelium.
Ampulla
Seminal vesicle
Ductus deferens
Epididymis
Glans of
penis
Prepuce
Testis
Scrotum
Ejaculatory duct
Prostate gland
Bulbourethral
gland
Rectum
Ejaculatory duct
A short segment of spermatic duct system the
ejaculatory duct is formed by the convergence of the
ductus deferens and seminal vesicle duct.
It is ~ 2 cm long and passes into the prostate gland
where it empties into the urethra.
Accessory glands of male reproductive
system
Includes three sets of accessory glands:
– The seminal vesicles
– The prostate gland
– The bulbourethral (Cowper) glands
Seminal vesicles
Paired glands ~ 5 cm long and dorsal to the urinary
bladder. Internally they are a complex labyrinth of
ducts
Produce a yellowish secretion that is ~ 60% of the
semen volume.
Prostate gland
A bulbous gland situated at the base of the urinary
bladder and consists of smooth muscle and
connective tissue.
Composed of 30-50 tubuloacinar glands that empty
into the urethra.
Milky secretion is ~ 30%
of ejaculate volume.
Bulbourethral gland
Two brownish spherical glands ~ 1 cm diameter.
They are located just superior to the bulb of the penis
and their duct empties into the penile urethra.
Their secretion neutralizes the residual acidic urine in
the urethra and serves as a pre-ejaculate to lubricate
the penis for easy insertion into the vagina.
Semen
Is a complex mixture of sperm and glandular
secretions released upon ejaculation.
Typical volume is ~ 2 to 5 ml/ ejaculate.
Sperm count is 50 to 120 million/ ml. of semen.
It consists of:
– ~ 10% spermatozoa
– 30% prostatic fluids
– 60% seminal fluids
– High in fructose and enzymes to neutralize vaginal
secretions and bacteria.
Spermatozoa
Three distinct regions: 1) head, 2) mid piece
and 3) tail.
– Head is a flattened oval containing chromosomes.
Tip contains Acrosomal cap with enzymes that will
aid in penetration of the ova membrane.
– Mid piece is joined to head by a short neck and
contains centrioles and mitochondria.
– Tail is a flagellum that propels the spermatozoa
through the female reproductive tract.
Spermatozoa
Urethra
Consists of three regions in males
– Prostatic urethra
– Membranous urethra
– Penile “spongy” urethra
Penis
Tubular organ that empties urine through the distal
urethra and introduces semen into the vagina during
sexual intercourse.
Internal half is the root and external half is a shaft and
glans. Together the penis and scrotum constitute the
external genitalia of males.
The skin of the penis is loose and slides distally over
the glans to form a “foreskin” or prepuce.
Internally the penis consists of 3 long cylindrical
bodies of erectile tissue. These erectile bodies fill with
blood during arousal and engorge the penis creating
an erection.
The erectile bodies are: a single corpus spongiosum,
a paired corpus cavernosa (dorsally).
Penile structure
Root = bulb + crus
Shaft = body + glans
Erectile tissue:
Corpus cavernosa
Corpus spongiosum
Vascular supply:
Internal pudendal art.
Nerve supply:
Parasym. → erection
Sym. → ejaculation
Urinary bladder
Ureter
Ampulla
Seminal vesicle
Ejaculatory duct
Prostate gland
Bulbourethral gland
Bulb
Crus
Ductus deferens
Corpus cavernosum
Corpus spongiosum
Epididymis
Testis
Urethra
Glans of penis
Penis
Chapter 26
Female reproductive system
Primary sex organ
Ovaries suspended in the retroperitoneal
abdominal cavity, superior and lateral to the
uterus. They contain the ova for reproduction of
the species.
They are somewhat almond shaped and are ~3
cm ↑, 1.5 cm → and 1 cm thick.
Each ovary contains 6 – 7 million ova and only
a single ova is released at the time of ovulation.
Female reproductive system
Primary and secondary female sex organs
Ovaries are the primary female sex organs that
manufacture and release a single ova for
fertilization with each ovarian cycle.
Secondary accessory sex organs include:
– The mons pubis, labia minora, labia majora, clitoris,
vagina, cervix, uterus, fallopian tubes, fimbria and
mammary glands.
Ovary
Structure:
Tunica albuginea – fibrous outer covering on ovary.
Cortex – outer layer of ovary where the oocytes reside
in primordial follicles “little bags” before maturation.
Follicles – tiny scale-like structures that contain the
ova.
(Graafian or vesicular follicle) – a mature follicle that
bulges out onto the surface of the ovary just prior to
ovulation (release of the ova). Only 1 ova is released.
Corpus luteum – luteal body left after ovulation.
Medulla – inner connective tissue core of the ovary,
contains blood vessels and nerves.
Ovary
Ovary
Ligaments– ovarian ligament anchors ovary to
uterus; suspensory ligament anchors ovary to pelvic
wall; mesovarium ligament suspends ovary in
between uterus and fallopian tubes.
Both suspensory and mesovarium form broad
ligament which tents over the uterus and supports
the uterine tubes, uterus and vagina.
It receives its vascular supply from the ovarian artery
and the ovarian branch of the uterine artery.
Function of ovary:
– a. To produce ova for fertilization
– b. Produce estrogen and progesterone
Internal female reproductive organs
Uterine or Fallopian tubes
Consist of fimbriae, infindibulum, ampullae, and
isthmus.
Fimbriae are finger like ciliated projections at
proximal end of infindibulum. They have a
wave-like motion to sweep the ova toward the
infindibulum.
The infindibulum is lined with cilia. At the time of
ovulation the cilia beat toward the opening into
the fallopian tube pulling the free ova inward,
moving it along by peristaltic contractions into
the ampullae.
Uterine or Fallopian tubes
Fertilization of the ova occurs in the ampullae
near the infindibulum.
The fallopian tubes are made of smooth muscle
and are lined with ciliated columnar epithelium
and are supported by a short mesentery called
the mesosalpinx, a part of the broad ligament.
Colorized SEM of fallopian tubes
Ovaries, fallopian tubes and uterus
Uterus
Is a thick muscular organ where implantation of
the fertilized ovum occurs for development of
the embryo into a fetus.
Location – within retroperitoneal pelvic cavity,
covered by visceral peritoneum.
Structure –looks like an inverted pear
Consists of a fundus, body and cervix.
– Fundus is the dome of the uterus
– Body is the main portion
– Cervix is a thick circular muscular ring that opens into the
vagina
Uterine wall layers and blood supply
Layers of the uterine wall include:
– endometrium – mucosal layer of simple columnar
epithelium with secretory cells and ciliated cells
underlain by a thick lamina propria.
– Two stratum makeup the lamina propria:
Functionalis is highly vascular and under ovarian
hormonal control. It is shed at menstruation if an ovum is
not implanted.
Basalis forms a new functionalis layer after menstruation.
– myometrium – thick muscular layer of interlacing
bands of smooth muscle.
– perimetrium – outer most serous layer = visceral
peritoneum
Uterine wall layers and blood supply
Uterus
Vagina
Hollow thin walled tube that receives the penis during
sexual intercourse and serves as the birth canal at the
time of partuition (birth).
Inferior to the uterus, the cervix opens into the vagina.
Area of the vagina that encircles the cervix is called
the fornix.
Consists of three layers: Outer fibrous CT adventitia;
middle muscularis of smooth muscle and inner
mucosa with transverse rugae.
Lined with stratified squamous epithelium
Vaginal orifice opens to the exterior and in virginal
women is covered by an incomplete diaphragm called
the Hymen
Sagittal view of female reproductive tract
External genitalia or Vulva = Pudendum
mons pubis – fatty area anterior to the pubic
symphysis; covered with pubic hair.
labia majora – large fatty skin fold running posteriorly
to the mons; the female homologue of the male
scrotum.
labia minora – smaller fatty skin fold; medial to the
labia majora.
vestibule – area surrounded by the labia minora;
contains the vaginal and urethral openings; also
contains the vestibular glands which are responsible
for secreting mucous
External genitalia or Vulva = Pudendum
clitoris – small protruding structure of erectile
tissue (corpus cavernosa) located anterior to
the vestibule and within the prepuce (hood).
– Consists of the glans and crus (similar to penis)
– is the female homologue of the male penis and is
highly sensitive to touch.
– Hooded by a fold of skin called the prepuce of the
clitoris.
External genitalia
External genitalia
Clitoris Glans
Crus
Greater
vestibular
gland
Urethral
orifice
Vestibular bulb
Vestibule
Mammary Glands
Present in both sexes, and become functional in
females after giving birth.
They function only during lactation in response to
hormonal stimulation to nourish the infant.
Contain a large lymphatic vascular network.
Two principal regions: Body and axillary tail.
– Body is the pendulous portion and extends to the nipple. The
nipple is in the center of a circular colored zone = areola.
– Axillary tail is at base and extends toward the armpit region.
– Lymphatics in axillary region drain from the mammary glands
and are important route for metastatic breast cancer.
Mammary glands anatomical structure
Mammary Glands
Structure – modified sweat glands; at puberty the female duct
system partially develops, but the increase in breast size is
largely due to fat deposition. It does not become fully
secretory until pregnancy occurs. In non-pregnant females
breast size is determined by presence of fatty tissue within the
breast.
Structure – modified sweat glands; at puberty the female duct
system partially develops, but the increase in breast size is
largely due to fat deposition. It does not become fully
secretory until pregnancy occurs. In non-prenanat females
breast size is determined by presence of fatty tissue within the
breast.
Vascular supply is from lateral and internal thoracic artery as
well as the posterior intercostal artery.
Mammary glands anatomical structure
Consist of:
lobes/interlobar connective tissue – 15 to 25 lobes
formed by strips of the suspensory (Cooper) ligament
and radiate around and open at the nipple.
lobules with alveoli – smaller units that contain alveoli
that produce milk when the female is lactating.
lactiferous duct – tubes that receive milk from alveolar
glands and empty into lactiferous sinus.
lactiferous sinus – dilated region at end of lactiferous
ducts and stores milk prior to release during suckling
by infant.
Mammary glands anatomical structure