Ch28 reproductive

primary sex organs gonads

•Ovaries

•Testes

also produce sex hormones, which affect reproductive organs

Gonads produce sex cells gametes

•Oocytes (egg cell)

•Sperm

ducts to transport gametes from gonads to fertilization

Sexual intercourse, copulation or coitus

puberty external sex characteristics become prominent, reproductive organs become functional, gametes mature and gonads secrete sex hormones

•Puberty starts when hypothalamus release GnRH (gonadotropin-releasing hormone)-stimulates anterior pituitary to secrete FSH (follicle-stimulating hormone) and LH (luteinizing hormone)

•FSH and LH stimulate gonads

between the thighs, •pubic symphysis, ischeal tuberosities, and coccyx

between ischeal tuberosities divides the perineum into two triangles:

•Urogenital triangle: urethral and vaginal orifices and base of the penis and scrotum

•Anal triangle: anus and external anal sphincter

1.Vesicouterine pouch: space between uterus and urinary bladder

2. Rectouterine pouch: space between uterus and rectum

ovaries

accessory sex organs

•Uterine tubes

•Uterus

•Vagina

•Clitoris

•Mammary glands

slightly larger than almond

•Mesovarium: double fold of peritoneum attached to anterior ovary

•Broad ligament: peritoneum anterior of uterus

•Ovarian ligament: anchors to lateral uterus

•Suspensory ligament: attaches lateral ovary to pelvic wall

supplied by an ovarian artery and ovarian vein

germinal epithelium (outer)

tunica albuginea

cortex (ovarian follicles)

inner medulla (blood vessels, lymph vessels, and nerves)

Within ovary’s cortex are thousands of ovarian follicles

A follicle consists of an oocyte surrounded by follicle cells

different types of ovarian follicles, representing a different stage of development

earliest - primary oocyte surrounded by squamous follicle cells

primary oocyte surrounded by cuboidal granulosa cells

• zona pellucida of glygoproteins surrounds the oocyte

primary oocyte, many layers of granulosa cells, and some thecal cells (connective tissue)

fluid filled antrum within granulosa cells

•Corona radiata is innermost layer of granulosa cells that make up the cumulus oophorus surrounding oocyte

secondary oocyte numerous granulosa cells, and a large antrum

•1 each month released

remnants of follicle after oocyte released

•secretes progesterone and estrogen

After corpus luteum breaks down.

white, connective tissue scar that is then reabsorbed

maturation of primary oocyte to a secondary oocyte

During fetal life, oogonia start oogenesis but are arrested as primary oocytes in prophase I

•At birth, ovaries contain about 1.5 million primordial follicles

During childhood, ovaries are inactive and some primordial follicles degenerate, atresia

From puberty to menopause, females show a monthly reproductive cycle

Monthly variations in hormone levels

•Follicular phase Days 1 to 13

•FSH and LH stimulate the dominant follicle to rapidly grow in size

•As antral follicle matures, its oocyte finishes meiosis I, resulting in a secondary oocyte and a polar body (each with 23 chromosomes)

•Ovulation Day 14

•A peak in LH causes mature follicle to release secondary oocyte

•Luteal phase Days 15 to 28

•Granulosa cells of former follicle become corpus luteum

•Secretes progesterone and estrogen for possible pregnancy

•As corpus luteum degenerates (if no fertilization occurs), it’s release of estrogen/progesterone decreases, resulting in menstruation (menses or period); first menstruation is called menarche

it implants in uterine lining and begins development

Pre-embryo releases human chorionic gonadotropin (hCG), which acts on corpus luteum to keep it functional until the placenta can take over hormone production (after about 3 months)

Women nearing menopause

•Estrogen levels drop

•Irregular and/or light periods

a woman has not had a period in one year

•Typically between 45 and 55 years of age

(fallopian tubes) extend from both sides of uterus toward ovaries ciliated columnar epithelium

-secondary oocyte fertilized in lateral part of the uterine tube

• 3 days to travel uterine tube and reach lumen of the uterus

Tubes are 12 cm in length and covered by the mesosalpinx, part of the broad ligament

•Infundibulum: funnel-shaped, fingerlike projections fimbriae

•Ampulla: turns medial, fertilization here

•Isthmus: one-third of uterine tube

•Uterine part: shortest, enter uterus

•Mucosa: ciliated columnar epithelial cells

•Muscularis: inner circular layer and an outer longitudinal layer of smooth muscle

•Serosa: external serous membrane covering uterine tube

pear-shaped, thick-walled, muscular organ within the pelvic cavity

- lumen that is continuous with the uterine tubes superolaterally and to the vagina inferiorly

Normally angled anterosuperiorly across superior surface of urinary bladder, anteverted

If positioned posterosuperiorly (projecting toward the rectum), retroverted

•Site of implantation

•Supports and protects the developing embryo/fetus

•Ejects the fetus during labor

•Fundus: superior

• Body: major

• Isthmus: constricted segment

• Cervix: inferior.cervical canal

-Superior internal os

-Inferior external os, mucus plug

Muscles of the pelvic floor (pelvic diaphragm)

Round ligaments from lateral uterus, through inguinal canal, and attach to labia majora

Transverse cervical ligaments (cardinal ligaments) attach cervix and superior vagina to pelvic wall

Uterosacral ligaments (sacrocervical ligaments) connect inferior portion of uterus to the sacrum

Weakness of this support can result in prolapse, in which the uterus protrudes through the vagina

branches from the internal iliac arteries, supply the uterus

•Perimetrium: outer serosa

• Myometrium: thick, middle smooth muscle hypertrophy & hyperplasia during pregnancy

• Endometrium: mucosa of simple columnar epithelium and underlying lamina propria with uterine glands

-Basal layer of endometrium (deeper layer) undergoes little change during the uterine cycle

-Functional layer of endometrium changes thickness during the uterine cycle and is shed as menses

change in endometrium influenced by estrogen and progesterone

•Menstrual phase: Days 1 to 5—menstrual bleeding

•Proliferative phase: Days 6 to 14—development of endometrium’s functional layer

•Secretory phase: Days 15 to 28—increased vascularization and development of uterine glands (due to high progesterone levels)

connects uterus to outside of the body

wall consists of three tunics: inner mucosa, middle muscularis, and outer adventitia

•The mucosa is a nonkeratinized stratified squamous epithelium with a highly vascular lamina propria

-opening: vaginal orifice

folds of the mucosa form a membranous barrier called the hymen

Erectile bulbs of the vestibule on either side of vaginal orifice increase sensitivity during intercourse

Mons pubis skin and subcutaneous connective tissue anterior to the pubic symphysis

-labia majora folds of skin, hair, containing sebaceous and sweat glands

-labia minora inside no hair; highly vascularized; contain many melanocytes

•hole: vestibule

•Within the vestibule : urethral opening and the vaginal orifice

(glands of Bartholin) secrete mucin to lubricate the vagina

erectile body

•Two small erectile bodies corpora cavernosa form body

superficial region: glans

•prepuce covering

compound tubuloalveolar exocrine gland that produce and secrete milk

nipple contain multiple openings from internal secretory ducts

areola pigmented around nipple

Suspensory ligaments attaching its skin to the deep fascia of the pectoralis major muscle

lobes, then lobules

secretory units alveoli that produce milk

drains into lactiferous ducts

lactiferous sinuses -expansions of the ducts as they approach the nipple

-primary male sex organs - testes

The accessory organs include a complex set of ducts and tubules leading from the testes to the penis

The penis is the organ of copulation

scrotum is a skin-covered sac that cooler environment 2° to 3° Celsius below normal body temperature

The scrotum is homologous to the labia majora

-raphe midline ridge on the scrotum

-dartos muscle smooth muscle wall of the scrotum

originates in inguinal canal, consists of

•Internal spermatic fascia from deep abdominal muscles

•Cremaster muscle and cremasteric fascia

•External spermatic fascia which forms from aponeurosis of external oblique muscle

•Testicular artery: branch of the abdominal aorta

•Pampiniform plexus: a network of veins surrounding the testicular artery

within scrotum

- production of sperm and secretion of androgens, testosterone

covered by a serous membrane tunica vaginalis- outer parietal layer & an inner visceral layer

white fibrous capsule deep to the tunica vaginalis that cover the testis

At the back of the testis mediastinum testis

•Site where blood vessels, lymphatic vessels, and some nerves enter

form walls of septa and lobules

•inside lobule: four convoluted seminiferous tubules

1. Sustentacular cells: (Nondividing)

•Release inhibin when sperm count is high

•blood–testis barrier

2. germ cells (dividing) produce sperm at puberty

•Interstitial cells (interstital space) produce hormones androgens

Spermatogenesis process of sperm development, in the seminiferous tubules of testes

Spermatogonia lie near the base of each tubule

•They divide mitotically to produce new spermatogonia

•Some spermatogonia develop into primary spermatocytes

Primary spermatocytes committed to becoming sperm

Primary spermatocytes are diploid (have 46 chromosomes)

undergo meiosis I to form two haploid secondary spermatocytes (have 23 chromosomes)

Secondary spermatocytes complete meiosis II to form spermatids (also haploid)

Spermiogenesis :a spermatid differentiates into a mature spermatozoa

A spermatozoa has an acrosome cap over its nucleus, a midpiece, and a tail

•Rete testis

•Efferent ductules

•Epididymis

•Ductus deferens

•Ejaculatory duct

•Urethra

rete testis receive sperm from seminiferous tubules

•Channels of rete testis merge to form efferent ductules

Efferent ductules connect the rete testis to the epididymis

Situated on the posterosuperior of testes,

•Head

•Body

•Tail

duct of the epididymis

stores sperm cells and assists in their maturation

Sperm leaving the epididymis enter this aka (vas deferens)

•Wall: inner mucosa, middle muscularis, outer adventitia

•Contraction in muscularis propels sperm

travels within the spermatic cord and enters the pelvic cavity through the inguinal canal

As the ductus deferens approaches the prostate gland, it enlarges to form the ampulla

The ampulla of the ductus deferens unites with the proximal portion of the seminal vesicle to form the ejaculatory duct

Ducts conduct sperm and seminal vesicle secretions to the prostatic urethra

semen from both ejaculatory ducts to outside

•Prostatic urethra in prostate gland

•Membranous urethra through urogenital diaphragm

•Spongy urethra through the penis

nourish sperm and neutralize the acidity of vagina

•Seminal vesicles

•Prostate gland

•Bulbourethral glands

posterior of urinary bladder, lateral to the ampulla of the ductus deferens

They are elongated, hollow organs

They secrete a viscous, whitish-yellow, alkaline fluid containing fructose, prostaglandins, and bicarbonate

inferior to the urinary bladder

It secretes directly into the prostatic urethra

Prostatic secretion is slightly acidic and contains mucin, citric acid (nutrient for sperm), seminalplasmin (antibacterial), and prostatic-specific antigen (PSA), an enzyme that helps liquify semen)

pea-shaped, sit in the urogenital diaphragm on either side of the membranous urethra

clear mucin lubricates urethra prior to ejaculation

Seminal fluid from three accessory glands + sperm from the testes = semen

When released : ejaculate

Ejaculate 200 to 500 million sperm

penis and scrotum form the external genitalia

root form bulb and crura of the penis

body (shaft) elongated

The tip glans, which surrounds the external urethral orifice

prepuce foreskin

•Paired corpora cavernosa

•single corpus spongiosum along the midline surrounds the spongy urethra

•The distal end of the corpus spongiosum continues within the glans

The erectile bodies are composed of venous spaces, fill with blood from a central artery to produce an erection

•Parasympathetic innervation is responsible for penile erection

expelling of semen

•Aided by rhythmic contraction of smooth muscle of the urethra

•Sympathetic innervation is responsible for ejaculation

Reproductive systems are nonfunctional until puberty

In females, gamete maturation stops in 40s or 50s with menopause

•Decrease in hormones causes some atrophy of reproductive organs

•Menopause also increases risk of heart disease and osteoporosis

•Some women opt for hormone replacement therapy (HRT) to help ease symptoms of menopause, though there are risks

In males, testosterone declines during their 50s signaling the male climacteric, but gametes are still produced

•Most males experience prostate enlargement

•Many experience erectile dysfunction and impotence

originate from same primordia

•Genetic sex refers to sex chromosomes (XX = female; XY = male) and is determined at conception

•Phenotypic sex: appearance of genitalia

•If the sex-determining region Y (SRY) gene (within testis-determining factor region of Y chromosome) is present, then proteins are made that stimulate production of androgen hormones and male phenotypic development ensues

, intermediate mesoderm gives rise to genital ridges that will form the gonads

•Germ cells migrate from the yolk sac to the genital ridges

Two sets of ducts form:

•Mesonephric ducts male duct system

•Paramesonephric ducts female duct system

•All embryos develop both duct systems but only one remains—the other degenerates