Chapter 28

vaginal orifice

The opening of the vagina

dartos (skinned) muscle,

The wall of the scrotum is composed of an external layer of skin, a thin layer of superficial fascia immediately internal to the skin, and a layer of smooth muscle,immediately internal to the fascia.

cervical canal

Within the cervix is a narrow channel=connects to the vagina inferiorly - The superior opening of this canal is the *internal os* (os = mouth) - The inferior opening of the cervix into the lumen of the vagina is the *external os*.covered with nonkeratinized stratified squa- mous epithelium

urogenital triangle

contains the clitoris and the urethral and vaginal orifices in females and the base of the penis and the scrotum in males. Within the urogenital triangle are the muscles that surround the external genitalia, called the ischiocavernosus, bulbospongiosus, and superficial transverse perineal muscles.

Sexual union between male and female ?

copulation (copulatio = a joining), coitus (to come together), or sexual intercourse.

nipple

cylindrical projection on the center of the breast. It contains multiple tiny openings of the excretory ducts that transport breast milk

parous

woman who has given birth

nulliparous

woman who hasn't given birth

Ducts within the Testis

• The *rete testis* receive sperm from seminiferous tubules • *Efferent ductules* connect the rete testis to the epididymis

Blood Supply

• Uterine arteries, which are branches from the internal iliac arteries, supply the uterus

cryptorchidism

A testis that has not descended completely into the scrotum.

sex hormones

(estrogen and progesterone in the female and androgens in the male), which affect maturation, development, and changes in the activity of the reproductive system organs.

raphe

, ridgelike seam at its midline outside of scrotum

germinal epithelium

- Surrounding the ovary is a thin, simple cuboidal epithelial layer -so named because early anatomists erroneously thought it was the origin of the female germ (sex) cells.

primary follicle

- forms from a maturing primordial follicle -consists of a primary oocyte surrounded by one or more layers of cuboidal follicular cells, which are now called granulosa cells -secretes estrogen as it continues to mature-changes in uterine lining

vesicular follicle

-(also called a mature follicle or Graafian follicle) forms from a secondary follicle -contains a *secondary oocyte* (surrounded by a zona pellucida and the corona radiata), numerous layers of granulosa cells, and a large, fluid-filled, crescent-shaped antrum

Wall of the Uterus

-*perimetrium*:The perimetrium is continuous with the broad ligament.Outermost layer; composed of serosa -*myometrium* is the thick, middle tunic of the uterine wall formed from three intertwining layers of smooth muscle. In the nonpregnant uterus, the muscle cells are less than 0.25 millimeter in length. During the course of a pregnancy, smooth muscle cells increase both in size *(hypertrophy)*and in number *(hyperplasia)*. Some cells may exceed 5 millimeter in length by the end of gestation. -*endometrium*innermost tunic of the uterus,Mucosa composed of a simple columnar epithelium and an underlying lamina propria; lamina propria is filled with *uterine glands*, which enlarge during the uterine cycle

tunica albuginea (white spot)

-Deep to the germinal epithelium is a connective tissue capsule -which is homologous to the tunica albuginea of the testis.

outer cortex and inner medulla

-Deep to the tunica albuginea, the ovary can be partitioned into these two -The cortex contains ovarian follicles (described next), while the medulla is composed of areolar connective tissue and contains branches of the ovarian blood vessels, lymph vessels, and nerves.

Childhood

-During childhood, a female's ovaries are inactive, and no follicles develop - main event that occurs during childhood is *atresia* (a-̆ tr̄ ź ̄-a;̆ a = not, tresis = a hole), in which some primordial follicles degenerate. By the time a female child reaches puberty, only about 400,000 primordial follicles remain in the ovaries.

Functions of Uterus

-Site of implantation -uterus then supports, protects, and nourishes the developing embryo/fetus by forming a vascular connection that later develops into the placenta - Ejects the fetus during labor

Uterine (Menstrual) Cycle and Menstruation

-The *uterine cycle* (or menstrual cycle) consists of three distinct phases -*menstrual (men ś troo-al̆ ; menstrualis = monthly) phase* occurs approximately during days 1-5 of the cycle. This phase is marked by sloughing of the functional layer and lasts through the period of menstrual bleeding. -The *proliferative (proles = offspring, fero = to bear) phase* follows, spanning approximately days 6-14. The initial development of the functional layer of the endometrium overlaps the time of follicle growth and estrogen secretion by the ovary -*secretory phase*, which occurs between approximately days 15-28. During the secretory phase, increased progesterone secretion from the corpus luteum results in increased vascularization and development of uterine glands. If the secondary oocyte is not fertilized, the corpus luteum degenerates, and the progesterone level drops dramatically. Without progesterone, the functional layer lining sloughs off, and the next uterine cycle begins with the menstrual phase.

spermatic cord

-The blood vessels and nerves to the testis travel from within the abdomen to the scrotum in a multilayered structure -The spermatic cord originates in the *inguinal canal*, a tubelike passageway through the inferior abdominal wall 3 layers ■ An internal *spermatic fascia* is formed from fascia deep to the abdominal muscles. ■ The *cremaster (a suspender) muscle* and *cremasteric fascia* are formed from muscle fiber extensions of the internal oblique muscle and its aponeurosis, respectively. ■ An external *spermatic fascia* is formed from the aponeurosis of the external oblique muscle. Within the spermatic cord is a singular *testicular artery* that is a direct branch from the abdominal aorta. The testicular artery is surrounded by a plexus of veins called the *pampiniform (pam- pin ́i-form; pampinus = tendril, forma = form) plexus*. This venous plexus is a means to provide thermoregulation by precooling arterial blood prior to reaching the testes. Autonomic nerves travel with these vessels and innervate the testis.

Support of the Uterus

-The muscles of the pelvic floor (*pelvic diaphragm* and *urogenital diaphragm*)hold the uterus and vagina in place and help resist intra-abdominal pressure - *round ligaments*help keep the uterus in an anteverted position - *transverse cervical ligaments* (or cardinal liga- ments) help restrict inferior movements of the uterus -*uterosacral ligaments* (or sacrocervical ligaments)connect the inferior portion of the uterus posteriorly to the sacrum. -*prolapse*Weakness in either the pelvic floor muscles or these ligaments,in which the uterus starts to protrude through the vagina.

Before Birth

-The process of oogenesis begins in a female fetus before birth -At this time, the ovary contains primordial germ cells called *oogonia* (̄-̄-ḡ ń ̄-a;̆ sing., oogonium; oon = egg), which are diploid cells, meaning they have 23 pairs of chromosomes. -Primary oocytes start the process of meiosis but are arrested in the first meiotic prophase.

Uterine Tubes

-also called the fallopian tubes or oviducts (̄duco = to lead), extend laterally from both sides of the uterus toward the ovaries -Fertilization of the secondary oocyte occurs in the lateral part of these tubes, and the pre-embryo begins to develop as it travels toward the uterus. Usually it takes the pre-embryo about 3 to 4 days to reach the lumen of the uterus. -Tubes are 10-12 cm in length and covered by the *mesosalpinx*, part of the broad ligament

ovarian ligament; a suspensory ligament

-each ovary is anchored by this -attaches to the lateral edge of each ovary and projects superolaterally to the pelvic wall. The ovarian blood vessels and nerves are housed within each suspensory ligament, and they join the ovary at its hilum. Smooth muscle fibers within both the mesovarium and the suspensory ligament contract at the time of ovulation to bring the ovaries into close proximity with the uterine tube openings.

secondary follicle

-from primary - contains a primary oocyte, many layers of granulosa cells, and a fluid-filled space called an *antrum*:is a serous fluid that increases in volume as ovulation nears -Surrounding the primary oocyte are two protective structures, the zona pellucida and the corona radiata. The *zona pellucida* (pellucidus = allowing the passage of light) is a translucent structure that contains glycoproteins. External to the zona pellucida is the *corona radiata*, which is the innermost layer of granulosa cells.

From Puberty to Menopause

-hypothalamus increases its release of GnRH (gonadotropin- releasing hormone) -which stimulates the anterior pituitary to release FSH (follicle-stimulating hormone) and LH (luteinizing hormone). The levels of FSH and LH vary in a cyclical pattern and produce a monthly sequence of events in follicle development called the *ovarian cycle*. -*follicular phase* during days 1-13 of an approximate 28-day ovarian cycle-> FSH and LH stimulate about 20 primordial follicles to mature into primary follicles-> As the follicles develop, their granulosa cells release the hormone *inhibin*, which helps inhibit FSH production, thus preventing excessive ovarian follicle development and allowing the current primary follicles to mature.-> secondary follicles, some that don't mature undergo artesia-> one turns into a vesicular follicle-> Under the influence of LH, the volume of fluid increases within the antrum, and the oocyte is forced toward one side of the follicle, where it is surrounded by a cluster of granulosa cells termed the *cumulus (k̄ ḿ ̄-lus̆ ; heap) oophorus (̄-of ̄́ r-us̆ ; phorus = bearing)*. The innermost layer of these cells is the corona radiata. -*Ovulation* occurs on day 14 of a 28-day ovar- ian cycle and is defined as the release of the secondary oocyte from a vesicular follicle->only one ovary ovulates each month—that is, the left ovary ovulates one month, and the right ovary ovulates the next. Ovulation is induced only when there is a peak in LH secretion. -*luteal phase* during days 15-28 of the ovarian cycle, when the remaining granulosa cells in the ruptured vesicular follicle turn into a corpus luteum. The corpus luteum secretes progesterone and estrogen that stabilize and build up the uterine lining, and prepare for possible implantation of a fertilized ovum;life span of about 10-13 days if the secondary oocyte is not fertilized. - As the corpus luteum degenerates, its levels of secreted progesterone and estrogen drop, causing the uterine lining to be shed as *menstruation*, also called *menses* or a *period* end of luteal phase

scrotum

-ideal temperature for producing and storing sperm is about 3° Celsius lower than internal body temperature -is a skin-covered sac between the thighs, provides the cooler environment needed for normal sperm development and maturation. The scrotum is homologous to the labia majora in the female.

Oogenesis

-is the maturation of a primary oocyte to a secondary oocyte

broad ligament

-mesovarium secures each ovary with this -a drape of peritoneum that hangs over the uterus.

primordial follicle (fetal period)

-most primitive type -consists of a primary oocyte surrounded by a single layer of squamous follicle cells

ovarian artery and an ovarian vein.

-ovarian arteries are direct branches off the aorta, immediately inferior to the renal vessels. -ovarian veins exit the ovary and drain into either the inferior vena cava or one of the renal veins.

Uterus

-pear-shaped, thick-walled muscular organ within the pelvic cavity. It has a lumen (internal space) that connects to the uterine tubes superolaterally and to the vagina inferiorly -Normally, the uterus is angled anterosupe- riorly across the superior surface of the urinary bladder, a position referred to as *anteverted* (an-te-vert é d; ante = before, versio = a turning). -If the uterus is positioned posterosuperiorly (so that it is projecting toward the rectum), this position is called *retroverted* (re t́ r̄-ver-ted). In older women, the uterus may shift from ante- verted to retroverted.

ovaries

-primary sex organs of the female -are paired, oval organs located within the pelvic cavity lateral to the uterus -The ovaries are anchored within the pelvic cavity by specific cords and sheets of connective tissue.

Female External Genitila

-sex organs collectively called vulva -*mons (mountain) pubis*is an expanse of skin and subcutaneous connective tissue immediately anterior to the pubic symphysis -*labia majora*are paired, thickened folds of skin and con- nective tissue. The labia majora are homologous to the scrotum of the male. -*labia minora*are paired folds immediately internal to the labia majora. They are devoid of hair and contain a highly vascular layer of areolar connective tissue. Sebaceous glands are located in these folds, as are numerous melanocytes, resulting in enhanced pigmentation of the folds. -*vestibule* space between labia minor -*urethral opening* within vestibule and vaginal orifice -*bulb of the vestibule*On either side of the vaginal orifice is an erectile body,which becomes erect and increases in sensitivity during sexual intercourse -*greater vestibular glands*are housed within the posterolateral walls of the vestibule. These are tubuloacinar glands that secrete mucin, which forms mucus to act as a lubricant for the vagina. Secretion increases during sexual intercourse, when additional lubrication is needed. These secretory structures are homologous to the male bulbourethral glands. -* clitoris*small erectile body, usually less than 2 centimeters in length, located at the anterior regions of the labia minora. It is homologous to the penis of the male. Two small erectile bodies called *corpora cavernosa* form the *body* of the clitoris. Extending from each of these bodies posteriorly are elongated masses, each called the *crus* (kroos) of the clitoris, which attach to the pubic arch. Capping the body of the clitoris is the *glans* (glanz; acorn). The many specialized sensory nerve receptors housed in the clitoris provide pleasure to the female during sexual intercourse. -*prepuce*external fold of the labia minora that forms a hoodlike covering over the clitoris.

After Menopause

-time when a woman is nearing meno- pause is called *perimenopause*:estrogen levels begin to drop, and a woman may experience irregular periods, skip some periods, or have very light periods -When a woman has stopped having monthly menstrual cycles for 1 year and is not pregnant, she is said to be in *menopause*; typically is between 45 and 55 years;no longer any ovarian follicles or the follicles that remain stop maturing. As a result, significant amounts of estrogen and progesterone are no longer secreted. Thus, a woman's endometrial lining does not grow, and she no longer has a menstrual period.

corpus albicans

-white color -When a corpus luteum regresses (breaks down), it turns into a white, connective tissue scar called corpus albicans -

Two Distinct layers of Endometrium

1. *Basal layer*(stratumbasalis):Deeper layer immediately adjacent to the myometrium; undergoes little change during the uterine cycle 2. *Functional layer*(stratumfunctionalis): Changes thickness during the uterine cycle and is shed as menses

wall of uterine tubes are composed of three layers

1.*Mucosa*: Ciliated columnar epithelial cells and a layer of areolar connective tissue2.*Muscularis*: Inner circular layer and an outer longitudinal layer of smooth muscle 3.*Serosa*: External serous membrane covering uterine tube

ductus deferens (vas deferens)

thick-walled tube that travels within the spermatic cord, through the inguinal canal, and then within the pelvic cavity before it nears the prostate gland

dysmenorrhea

Difficult and painful menstruation.

corpus luteum

Following the rupture of the vesicular follicle and the expulsion of the oocyte (ovulation), the remnants of the follicle (minus the oocyte) become the *corpus luteum* - yellow color - no oocyte - *progesterone and estrogen*: help build up uterine lining(endometrium)

testis

Functions include production of sperm and secretion of androgens, such as testosterone -Each testis is covered both anteriorly and laterally by a serous membrane, the *tunica vaginalis* has an *outer parietal* layer and an *inner viscera*l layer that are separated by serous fluid. • Located just deep to the visceral layer and in contact with the testis is a thick, whitish fibrous capsule covering the testis called the *tunica albuginea* projects into the interior of the testis as the *mediastinum testis* through which blood vessels, lymphatic vessels, and some nerves enter and leave the testis • The tunica albuginea projects internally into the testes to form *septa* • The septa subdivide to form about 250 *lobules* • Each lobule contains four convoluted *seminiferous tubules* contain two types of cells: (1) a group of nondividing support cells called the *sustentacular (to hold upright) (Sertoli or nurse) cells*, and make hormone *inhibin* sperm production. and *blood-testis barrier* helps protect developing sperm from materials in the bloodstream and leukocytes (2) a population of dividing germ cells that continuously produce sperm beginning at puberty.

salpingitis

Inflammation of the uterine tubes.

Suspensory ligaments

are broad bands of connective tissue that support the mammary gland by attaching the skin of the gland to the deep overlying fascia of the pectoralis major muscle

afterpains

caused by the increased levels of oxytocin in her bloodstream. These uterine contractions help shrink the uterus to its prepregnancy size.

mucosa

consists of a nonkeratinized stratified squamous epithelium and a highly vascularized lamina propria

gametes

gonads produce sex cells -unite to form a new individual. Female gametes are called oocytes, whereas male gametes are called sperm.

mesovarium

double fold of peritoneum and attaches to each ovary at its *hilum*, which is the anterior surface of the ovary where its blood vessels and nerves enter.

puberty

external sex characteristics become more prominent, such as breast enlargement in females, penis and scro- tum enlargement in males, and pubic hair in both sexes. reproductive organs become fully functional. gametes begin to mature, and the gonads start to secrete their sex hormones. Puberty is initiated when the hypothalamus significantly increases *GnRH (gonadotropin-releasing hormone)* secretion. GnRH acts on specific cells in the anterior pituitary and stimulates them to release *FSH (follicle- stimulating hormone)* and *LH (luteinizing hormone)*. (Prior to puberty, FSH and LH are virtually nonexistent in boys and girls.) As levels of FSH and LH increase, the gonads produce significant levels of sex hormones and start the processes of gamete maturation and sexual maturation.

menarche

first period

posterior rectouterine pouch

forms the space between the uterus and the rectum.

anterior vesicouterine (vesica=bladder,utero=uterus) pouch

forms the space between the uterus and the urinary bladder

Perineum

in both females and males, the perineum is the diamond-shaped area between the thighs extending from the pubis anteriorly to the coccyx posteriorly, and bordered laterally by the ischial tuberosities. An imaginary horizontal line extending from the ischial tuberosities subdivides the perineum into a urogenital triangle anteriorly and an anal triangle posteriorly.

mammary glands subdivided

into *lobes*-> *lobules* contain secretory units called *alveoli*that produce milk-> milk drains into 10 to 20 ducts called *lactiferous ducts* from a single lobe-> as it approaches nipple lumen expands to *lactiferous sinus* space where it is stored in nipple.

anal triangle

is the location of the anus in both sexes. Surrounding the anus is the external anal sphincter.

Spermatogenesis

istheprocess of sperm development that occurs within the seminiferous tubule of the testis. Spermatogenesis does not begin until puberty, when significant levels of FSH and LH stimulate the testis to begin gamete development.

mammary gland, or breast,

located within the anterior thoracic wall and is composed of a compound tubuloalveolar exocrine glands,secretory product (called breast milk) contains proteins, fats, and a sugar to provide nutrition to infants.

testes

male primary sex organs organ of copulation

Homologues

mature reproductive system structures are derived from common developmental structures (primordia) and serve a common function in adult

hymen

membranous barrier formed by the folds of mucosa near the opening of the vagina

Vagina

thick-walled,fibro muscular tube that forms the inferiormost region of the female reproductive tract and measures about 10 centimeters in length in an adult female -Its thin, distensible wall consists of three tunics: inner mucosa, middle muscularis, and outer adventitia

ovarian follicles

thousands within the ovarian cortex -Ovarian follicles consist of an *oocyte* surrounded by *follicle cells* which support the oocyte. There are several different types of ovarian follicles

spermatogonia

primordial stem cells that are turned into sperm -Spermatogonia are diploid cells -lie near the base of the seminiferous tubule, surrounded by the cytoplasm of sustentacular cells. To produce sperm, spermatogonia first divide by mitosis. -*primary spermatocyte* are diploid and an exact copy of spermatogonia. It is the primary spermatocytes that undergo meiosis. -> undergo meiosis 1 *secondary spermatocytes* are haploid, meaning they have 23 chromosomes only-> complete meiosis 2 *spermatids* -> final stage of spermatogenesis, a process called *spermiogenesis*, the newly formed spermatids differentiate to anatomically mature *spermatozoa* or *sperm* - During spermiogenesis, the spermatid sheds its excess cytoplasm, and the nucleus elongates. A structure called the *acrosome cap* forms over the nucleus. This acrosome cap contains digestive enzymes that help penetrate the secondary oocyte for fertilization. As the spermatid elongates, a *tail* (flagellum) forms from the organized microtubules. The tail attaches to a *midpiece* (neck) region containing mitochondria and a centriole. These mitochondria provide the energy to move the tail.

Lactation

process in which breast milk is released -While *prolactin* stimulates production of breast milk, the hormone *oxytocin* is responsible for milk ejection

gonads

reproductive systems have primary sex organs -ovaries in females and testes in males

interstitial spaces

spaces in the seminiferous tubules • *Interstitial cells* reside in these space and produce hormones called *androgens*

areola

the pigmented, rosy or brownish ring of skin around the nipple. Its surface often appears uneven and grainy due to the numerous sebaceous glands, called *areolar glands*, immediately internal to the surface.

Regions of the Uterus

■ The *fundus* (fun̆ ́dus̆ ) is the broad, curved superior region extending between the lateral attachments of the uterine tubes. ■ The major part of the uterus is its middle region, called the body, which is composed of a thick wall of smooth muscle. ■ A narrow, constricted inferior region of the body that is superior to the cervix is called the isthmus. ■ The cervix is the narrow inferior portion of the uterus that projects into the vagina.

Parts of the Uterine Tubes

■ The *infundibulum* (in-fun̆ -dib ̄́ -lum̆ ; funnel) is the free, funnel-shaped, lateral margin of the uterine tube. Its numerous individual fingerlike folds are called fimbriae (fim ́br̄-̄; fringes). The fimbriae of the infundibulum are not attached to the ovary but enclose it at the time of ovulation. ■ The *ampulla*(am-pul ́la;̆ two-handled bottle) is the expanded region medial to the infundibulum. Fertilization of a secondary oocyte typically occurs there. ■ The *isthmus* (is ḿ us) extends medially from the ampulla toward the lateral wall of the uterus. It forms about one- third of the length of the uterine tube. ■ The *uterine part* (intramural part or interstitial segment) extends medially from the isthmus and is continuous with the wall of the uterus.