Anatomy of the Reproductive System

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Anatomy of the Reproductive System

• Male Reproductive System

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Reproductive System Introduction

• Primary Sex Organs - Gonads
• Testes male
• Produce sperm male gamete (sex cell)
• Produce testosterone male hormone
• Ovaries female
• Produce Ova/egg female gamete (sex cell)
• Produce estrogen, progesterone female hormone
• Accessory Sex Organs
• Remaining sex organs

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Male Reproductive Organs Figure 16.1

• Testes Male Gonads
• Enclosed in the scrotum
• Suspended outside of the body
• Sperm need to be cooler than body temperature
• Exocrine function Produce sperm
• Seminiferous tubules
• Endocrine function Produce testosterone
• Interstitial cells surrounding the seminiferous
  tubules

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Testes

• Appearance
• Olive-size
• Covered by capsule
• Divided into lobules
• Lobules contain tightly coiled seminiferous
  tubules
• Produce sperm
• Empty sperm into rete testis which empty into the
  epididymis

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Duct System

• Accessory male organs
• Transports sperm from the testes through the
  penis
• Epididymis
• Ductus (vas) deferens,
• Ejaculatory duct
• Urethra
• Prostatic
• Membranous
• Penile

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Epididymis

• Appearance
• Tightly coiled tube 20 feet long
• Location
• Extends from the top of the testis, descends
  along the posterior surface
• Epididymis becomes the ductus/vas deferens as it
  turns up towards the body

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Function of Epididymis

• Passageway for sperm to the ductus/vas deferens
• 20 day journey
• Immature sperm non-motile when entering the
  epididymis
• Allows time for sperm to mature
• Develop flagella
• During sexual stimulation the epididymis ejects
  sperm to ductus deferens

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Ductus (Vas) Deferens Figure 16.2

• Appearance
• Long, winding tube
• Location
• Passes thru the inguinal canal into the abdominal
  cavity
• Arches over the urinary bladder
• Empties into the ejaculatory duct which passes
  through the prostate gland
• Function
• Transport of stored sperm from epididymis by
  peristalsis

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VasectomyFigure T-291

• Small incision into the scrotum cutting through
  the part of the vas deferens in the scrotum
• Sperm are still produced but can no long be
  expelled out of the body

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Spermatic CordFigure 16.1

• Consists of
• Vas deferens
• Nerves
• Blood vessels
• Network of veins surrounding the artery to cool
  the blood flowing into the testes
• Passing through the inguinal canal into the
  abdominopelvic cavity

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Urethra

• Location
• Extends from the base of the urinary bladder to
  the tip of the penis
• Base of the urinary bladder contains the internal
  urethral sphincter
• Last part of the duct system

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Regions of Urethra

• Prostatic urethra
• Passes through the prostrate gland
• Membranous urethra
• Passes through the muscles of the pelvic floor
• Contains external urethral sphincter
• Penile urethra
• Passes through the length of the penis
• Ends at the external urethral orifice

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• Function
• Carries both urine and semen
• Semen
• Sperm and fluids from the accessory glands
• Semen and urine never pass at the same time
• During ejaculation, the internal urinary
  sphincter contracts preventing passage of sperm
  to bladder and passage of urine to urethra

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Seminal Vesicle

• Paired sac-like structures
• Attach to the vas deferens
• Secretes the major portion of the semen seminal
  fluid
• Thick, yellowish
• Fructose - sugar - energy for the sperm
• Other secretions which nourish and activate the
  sperm
• Secretion empties into the ejaculatory ducts

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Prostate Gland

• Appearance
• Single gland chestnut shape
• Ejaculatory duct passes through
• Location
• Surrounds the prostatic urethra
• Function
• Secretes prostatic fluid into the prostatic
  urethra
• Thin, milky, alkaline fluid
• Enhances motility of sperm

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Bulbourethral Glands

• Location - Inferior to the prostate gland
• Appearance
• Very small pea-sized
• Function
• Secretes a clear mucous fluid in response to
  sexual stimulation
• First secretion to pass down the urethra
• Lubricates the end of the penis for sexual
  intercourse
• Cleanse the urethra of traces of acidic urine

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Semen

• Sperm from testes and fluids from seminal
  vesicles, prostate gland and bulbourethral glands
• Functions
• Transport medium
• Contains nutrients for sperm
• Contains chemicals which protect the sperm
• Contains materials which aid in sperm movement
• Alkaline secretion
• Neutralize acid in the male urethra and the
  female vagina
• 2 5 ml (about 1 teaspoon) ejaculated
• 50 130 million sperm per milliliter

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External Genitalia

• Scrotum
• Pouch of skin posterior to the penis containing
  the testes
• Surrounded by muscles (cremaster muscle) to move
  the testes closer or further from the body
• Sperm development requires a temperature of 3
  degrees lower than body temperature
• In cold weather the muscles contract and pull the
  scrotum closer to the body
• In warm weather, the muscles relax and move the
  scrotum further away from body

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Penis

• Erectile tissue
• Spongy tissue that fills with blood causing the
  penis to enlarge and become rigid
• Erection
• To deliver the sperm to the female vagina
• Shaft with an enlarged tip glans penis
• Glans penis is covered by loose skin called the
  prepuce (foreskin)
• Prepuce removed by circumcision
• Contains the external urinary/urethral orifice

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Anatomy of the Reproductive System

• Female Reproductive System

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Female Reproductive System

• Functions
• Produce the female gametes (ova)
• Nurture and protect the developing fetus
• Produce female sex hormones
• Primary reproductive organ Gonad
• Ovaries
• Exocrine function produce eggs/ova
• Endocrine function produce hormones
• Estrogens, progesterone

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Ovary Figure 16.7

• Paired, almond shaped organs
• Contain follicles where the egg develops
• Each follicle contains an immature egg
• Oocyte
• Total supply of eggs are present in the ovary at
  birth
• Mature vesicular follicle is the follicle which
  ruptures in ovulation
• Ovulation mature egg expelled from the follicle

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Corpus Luteum

• Development of the ruptured follicle
• Forms an endocrine gland secreting estrogen
• Continue for about 10 days and then stop if
  fertilization does not occur
• If fertilization does occur it will continue to
  secrete estrogen until the placenta develops to
  take over the secretion
• About 3 months
• Degenerating corpus luteum corpus albicans
  scar

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Ovaries

• Suspended by ligaments
• Broad ligament
• Ovarian ligament
• Function
• Development of egg cells to maturation
• Ovulation of mature egg cell
• Secrete sex hormones

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Uterine Tubes

• Location
• Extend from the ovaries to the uterus
• Appearance
• Muscular tube lined with cilia
• Expands near ovaries to form funnel shaped
  structure called the fimbriae forms currents to
  sweep egg in
• Does not make physical contact with the ovaries

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• Function
• Receive the ovulated egg
• Depends on movements of the fimbriae to create
  currents and guide an ovulated egg into the tube
• Some eggs are lost in the peritoneal cavity and
  might even be fertilized there
• Carry egg (zygote if fertilization occurred) to
  the uterus
• Muscular walls for peristalsis of egg into the
  uterus
• Rhythmic beating of cilia in uterine tubes

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Fertilization

• Fertilization generally occurs in the uterine
  tubes
• Sperm must swim up through the vagina and uterus
  to the fallopian tubes
• In the fallopian tubes, sperm must swim against
  the current of the cilia and peristaltic
  contractions which move the egg toward the uterus

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Uterus

• Hollow, muscular organ
• Fundus, body, cervix
• Cervix - Lower 1/3 of the uterus projecting into
  the vagina
• Function
• Implantation
• Attachment of embryo
• Site of embryo development
• Prepares each month for zygote
• If no fertilization, menstruation occurs

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Layers

• Endometrium - mucus
• Embryo burrows into this lining implantation
• Sloughs off about every 28 days if fertilization
  does not occur
• Myometrium - muscle
• Contracts during childbirth
• Perimetrium
• Outer layer
• Visceral peritoneum

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Vagina

• Muscular tube 3-4 inches long
• Contains ridges which stimulate the penis during
  intercourse
• Acidic
• Protects the vagina but is harmful to sperm
• In adolescents the vagina is more alkaline
• Opening is the vaginal orifice covered by the
  hymen
• Functions
• Transports uterine secretions
• Transports the fetus during childbirth birth
  canal
• Receives the penis during intercourse

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External Genitalia Figure 16.9

• Female reproductive structures external to the
  vagina
• Also called the Vulva
• Mon pubis, labia, clitoris, vestibular glands
• Mons pubis
• Fatty rounded area over the pubic symphysis
• Covered with pubic hair after puberty
• Labia
• Labia majora
• Hair covered skin folds
• Labia minora
• Located between the labia majora
• Hairless

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• Clitoris
• Small projection at anterior end of vulva
• Corresponding to penis of the male
• Hooded by the prepuce
• Contains erectile tissue which becomes swollen
  with blood during sexual excitement
• Vestibular glands
• Produce mucus
• Lubricates distal end of vagina during
  intercourse

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Mammary Glands

• Modified sweat glands
• Divided into lobules
• Alveolar glands produce the milk
• Lactation
• Lactiferous ducts take the milk to the nipple
• Areola
• Pigmented area surrounding the protruding nipple