Reproductive System

• Reproductive system

  • The only system that is not essential to the life of the individual
  • Does affect other systems
  • Male and female reproductive organs
  • Produce and store specialized reproductive cells that combine to form new individuals
  • Also secrete hormones that play major roles in maintenance of normal sexual function
• Structures of the Reproductive System

  • Reproductive system
  • Ensures continued existence of human species
  • Reproductive structures
  • Gonads — organs that produce gametes (reproductive cells) and hormones
  • Ducts receive and transport gametes
  • Accessory glands secrete fluids into ducts
  • Perineal structures collectively known as external genitalia
• Structures of the Reproductive System

  • Reproductive tract
  • Includes all chambers and passageways that connect ducts to exterior of body
  • Male and female reproductive systems
  • Functionally different
  • Female produces one gamete per month
  • Retains and nurtures zygote
  • Male produces large quantities of gametes
  • Half a billion sperm per day
• Male reproductive system

  • Testes (male gonads)
  • Secrete male sex hormones (androgens)
  • Produce male gametes (sperm)
• Female reproductive system

  • Ovaries (female gonads)
  • Release one immature gamete (oocyte) per month
  • Produce hormones
  • Uterine tubes
  • Carry oocytes to uterus — if sperm reaches oocyte, fertilization is initiated; oocyte matures into ovum
  • Uterus encloses and supports developing embryo
  • Vagina connects uterus with exterior
• Pathway of sperm

  • are formed in the testis, leave through the epididymis, the ductus deferens and then the ejaculatory duct and the urethra
  • Scrotum: encases testis, to hang outside of body, important for temperature regulation
• Accessory Glands of male reproductive system

  • Seminal gland, Prostate, and Bulbo-urethral gland
  • secrete fluids into the duct system
• Spermatic cords

  • Extend between abdominopelvic cavity and testes
  • Consist of layers of fascia and muscle
  • Enclose ductus deferens, blood vessels, nerves, and lymphatic vessels of testes
  • Each begins at entrance to inguinal canal
  • Passageway through abdominal musculature
  • Descend into scrotum
• blood vessels for testis include:

  • Spermatic Cord:
  • Genitofemoral nerve
  • Deferential artery
  • Ductus deferens
  • Pampiniform plexus
  • Testicular artery
• Scrotum

  • scrotum divided into 2 chamber, each testis lie in it’s own scrotal cavity, lined by serous membrane: tunica vaginalis to reduce friction between opposing surfaces, have parietal and visceral layer
  • temperature regulation is important for sperm production, needs to be at least 1.1 lower than body temperature is why it hangs outside
  • Tunica vaginalis
  • Tunica albuginea: continous with epididymis, has lots of collagen fibers, dense connective tissue, supports blood and lymphatic vessels and efferent ductule
• Testis

  • testis are subdivided into lobules, ~800 slender tightly coiled: Seminiferous tubules, is location for sperm production, complex network
  • Seminiferous tubules connect to straight tubules, has a connective tissue capsule that surrounds Seminiferous tubules, loose areolar tissue fills space between tubules where blood vessels and larger interstitial endocrine cells : responsible for the production of androgens dominant testosterone
• Testes produce immobile sperm that are not yet capable of fertilizing an oocyte

  • Other parts of reproductive system are responsible for
  • Functional maturation, nourishment, storage, and transport of sperm
  • Immobile sperm from testes
  • Moved by cilia lining efferent ductules into the epididymis
• Epididymis

  • Start of male reproductive tract, primary location for storage of sperm
  • Coiled tube almost 7 m long
  • Bound to posterior border of each testis
  • Has head, body, and tail
• Ductus deferens (vas deferens)

  • 40–45 cm long
  • Part of spermatic cord
  • Begins at tail of epididymis and ascends through inguinal canal
  • Curves inferiorly along urinary bladder
  • Toward prostate and seminal glands
  • Lumen enlarges into ampulla of ductus deferens
  • Wall contains thick layer of smooth muscle
• Male urethra

  • Used by urinary and reproductive systems
  • sharing urethra for sperm: minimizing acidity is important
  • Extends 18–20 cm from urinary bladder to tip of penis
  • Divided into three regions
  • Prostatic
  • Membranous
  • Spongy
• Anatomy of the Ductus Deferens and Accessory Glands

  • Ductus deferens coming down to Ampulla of ductus deferens passing by seminal glands to the Ejaculatory duct then onto Bulbo-urethral glands
  • Seminal gland: tubular foiled and folded compact, produces majority of seminal fluid
• Prostate

  • Small, muscular organ (about 4 cm in diameter)
  • Encircles proximal portion of urethra
  • Below urinary bladder
  • Consists of 30–50 compound tubulo-alveolar gland
  • Surrounded by smooth muscle fibers
• Prostatic fluid

  • Slightly acidic
  • Forms about 25% of semen volume
  • Ejected into prostatic urethra
  • By peristalsis of prostate wall

  § Prostatitis: can obstruct urethra from prostate to outer penis

  – Prostatic inflammation 

  – Can occur at any age

  • Most commonly afflicts older men
• Penis

  • Root of penis
  • Fixed portion that attaches penis to body wall
  • Attachment occurs inferior to pubic symphysis
  • Body of penis (shaft)
  • Tubular, movable portion of penis
  • Glans penis (head)
  • Expanded distal end of penis that surrounds external urethral orifice
• Dermis of penis

  • Contains a layer of smooth muscle
  • A continuation of dartos muscle
  • Underlying areolar tissue
  • Allows skin to move freely
  • Subcutaneous layer
  • Contains superficial arteries, veins, and lymphatic vessels
• Female reproductive system

  • Produces sex hormones and functional gametes
  • Protects and supports developing embryo
  • Nourishes newborn infant
  • Main organs
  • Ovaries
  • Uterine tubes
  • Uterus
  • Vagina
  • External genitalis
• Anatomy of uterus

  • Broad ligament: important structures that suspend the uterus, all enclosed in broad ligament
• Ovaries

  • Small, almond-shaped organs near lateral walls of pelvic cavity
  • Three main functions
  • Production of immature female gametes (oocytes)
  • Secretion of female sex hormones (estrogens andprogesterone)
  • Secretion of inhibin (involved in feedback control of pituitary FSH)
• Structures Stabilizing the Ovary

  • Ovarian ligament
  • Mesovarium
  • Suspensory ligament: extends from the ovaries to the pelvic wall, also contains ovarian artery and vein
  • these vessels connect via ovarian hilum where ovarian attaches to mesovarium
• Relationships between the Ovaries, Uterine Tubes, and Uterus

  • Medulla surrounded by Cortex: gametes produced within cortex
  • visceral peritoneum covers ovaries: overlays Tunica albuginea consists of columnar epithelial cells
  • stroma, interior tissue of ovary
• Uterine tubes

  • Also called fallopian tubes or oviducts
  • Hollow, muscular tubes about 13 cm long
  • Transport oocyte to uterus
  • Infundibulum: funnel on ovaries that gathers up gametes into tube, lined with ciliated columnar epithelium
  • Ampulla: muscular layer middle segment, thickness increases as we get near uterus
  • Isthmus: short segment
  • the oocyte transport involves ciliary movements of ciliated columnar epithelial cells and peristaltic contractions to bring egg to uterus
• Uterus

  • Provides for developing embryo (weeks 1–8) and fetus (week 9 through delivery)
  • Mechanical protection
  • Nutritional support
  • Waste removal
  • Pear-shaped organ
  • 7.5 cm long, 5 cm diameter, weighs 50–100 g
  • Normally bends anteriorly near base (anteflexion)
  • In retroflexion, uterus bends backward
• Suspensory ligaments of uterus

  • Uterosacral ligaments
  • Prevent inferior–anterior movement
  • Round ligaments
  • Restrict posterior movement
  • Extend through very small inguinal canal along with ilioinguinal nerve
  • Cardinal ligaments
  • Prevent inferior movement
• Gross Anatomy of the Uterus

  • Uterine artery and vein: arise from branches of the internal iliac arteries
  • Cervical canal
  • External os of uterus
  • Ovarian artery and vein: come off abdominal aorta
  • body of the uterus is biggest, leading to the Cervix
  • a very vascular structure in order to develop placenta and nourish fetus
• Nerves of uterus

  • Autonomic fibers from hypogastric plexus (sympathetic)
  • Sacral segments S3 and S4 (parasympathetic)
  • Segmental blocks
  • Anesthetic procedures used during labor and delivery
  • Target spinal nerves T10–L1
• Uterine wall

  • Perimetrium
  • Incomplete serous membrane
  • Continuous with peritoneal lining
  • Covers fundus and posterior surface of uterine body and isthmus
  • Myometrium
  • Thick, middle, muscular layer
  • Endometrium
  • Thin, inner, glandular layer
• Myometrium

  • Thickest portion of uterine wall
  • Constitutes almost 90 percent of mass of uterus
  • Smooth muscle is arranged into longitudinal, circular, and oblique layers
  • Provides force to move fetus from uterus into vagina
• Endometrium

  • Contributes about 10 percent of mass of uterus
  • Glandular and vascular tissues support physiological demands of growing fetus
  • Many uterine glands
  • Open onto endometrial surface
  • Extend deep into lamina propria
  • Estrogens
  • Cause uterine glands, blood vessels, and epitheliumto change monthly
• Vagina

  • Elastic, muscular tube
  • Extends between cervix and vestibule
  • 7.5–9 cm long
  • Highly distensible
  • Three functions
  • Passageway for elimination of menstrual fluids
  • Receives sperm during sexual intercourse
  • Forms inferior portion of birth canal
• Vagina

  • Cervix projects into vaginal canal
  • Vaginal fornix
  • Shallow recess surrounding cervical protrusion
  • Lies parallel to
  • Rectum, posteriorly
  • Urethra, anteriorly
• Blood supply of vagina

  • Through vaginal branches of internal iliac (or uterine) arteries and veins

  § Innervation of vagina

  – Hypogastric plexus

  – Sacral nerves S2–S4

  – Branches of pudendal nerve
• Breasts

  • Mammary glands
  • Specialized organs of integumentary system
  • Produce milk (lactation) to nourish infant
  • Controlled by hormones
  • Lie in pectoral adipose tissue
  • Nipple
  • Contains ducts of mammary glands
  • Areola
  • Reddish-brown skin around each nipple
• Mammary glands

  • Consist of lobes
  • Each containing several secretory lobules 
  • Separated by dense connective tissue
  • Mammary gland ducts
  • Leave lobules
  • Converge to form a lactiferous duct in each lobe
  • Lactiferous duct
  • Forms expanded chamber (lactiferous sinus)
  • 15–20 open to each nipple
• Female Reproductive Structures

  • Suspensory ligaments of breast
  • Bands of connective tissue
  • Originate in dermis of overlying skin
  • Areolar tissue separates mammary gland complex from underlying pectoralis muscles
  • Blood supply of mammary glands
  • Branches of internal thoracic artery
• Active mammary gland

  • Tubulo-alveolar gland
  • Consisting of multiple glandular tubes
  • Ending in secretory alveoli
  • Secretory apparatus does not complete development unless pregnancy occurs