Chapter 16: The Reproductive SystemStudents will be able to understand the male reproductive and female reproductive systems

The Reproductive SystemGeneral Information1. Divided into male and female2. Both systems contain gonads or primary sex organsProduce gametes

I. Male Reproductive AnatomyA. Primary reproductive organs are the testes (male gonads)Have both exocrine (sperm-production) and endocrine (testosterone-production) functionB. Secondary reproductive organs are those used for storage and movement of sperm 1. Ducts and Tubules2. Also called accessory reproductive structures

Testes

Mammal Testes

I. Male Reproductive AnatomyC. Testes1. Are approximately 4 cm long2. Are approximately 2.5 cm wide3. The tunica albuginea, (a fibrous connective tissue), surrounds the testes4. The septa are extensions of the tunica albuginea that divide the testes into lobulesa. Lobules contain 1-4 tightly coiled seminiferous tubulesSeminiferous tubules form the sperm

Tunica Albuginea Cross Section

Seminiferous Tubules

Seminiferous tubules Cross Section

I. Male Reproductive AnatomyC. TestesInterstitial cells, lie in the soft connective tissue surrounding the seminiferous tubules, which produce androgens (i.e. testosterone)5. The rete testis are tubules the sperm move into after production6. Sperm move through the rete testis into the first duct or storage unita. Lies along the external surface of the testes

Testicular Cross Section with Spermatocytes (spermatogonia)

I. Male Reproductive AnatomyD. Duct System1. Consists of the:a. Epididymisb. Ductus deferensc. Ejaculatory ductd. Urethra

Epididymis

I. Male Reproductive AnatomyD. Duct systema. epididymisLies along the exterior surface of the testesComma-shapedHighly coiledCan be 6 m long (approx. 20 ft)Lies superior to the testes, runs down the posterolateral sideTemporary storage systemTakes 20 days to pass through

I. Male Reproductive AnatomyD. Duct systemb. Ductus DeferensAlso called the vas deferensRuns upward from the epididymisMoves through the inguinal canal into the pelvic cavityArches over the urinary bladder to the prostrate glandThe tube is enclosed by the spermatic cordAlso has blood vessels and nerve bundlesPropels live sperm from storage to the ejaculatory ductVasectomy occurs along this duct (cut and cauterize)

I. Male Reproductive AnatomyD. Duct Systemc. Ejaculatory DuctPasses through the prostate glandMerges with the urethraSmooth walls create peristaltic waves during ejaculationSqueezes sperm forward

I. Male Reproductive AnatomyD. Duct Systemd. UrethraExtends from the base of the bladder to the tip of the penis3 regionsProstatic urethra: surrounded by the prostate glandMembranous urethra: between the prostrate and the base of the penisSpongy urethra: length of the penis

I. Male Reproductive AnatomyE. Accessory glands and semen1. Seminal Vesiclea. Located at the base of the bladderb. Produces 60% of the fluid (by volume) of the semenc. The secretion is rich in sugar (fructose), vitamin C, prostoglandins, etc..Used to nourish spermProvide energy conversion capabilitiesMay play a role in ovulation and corpus luteum functiond. Joins the urethra at the connection with the vas deferens (the combination is called the ejaculatory duct)

Seminal Vesicle

Seminal Vesicle

I. Male Reproductive AnatomyE. Accessory Glands and Semen2. Prostate Glanda. Single gland b. Encircles the urethrac. Secretes a milky white fluid that activates the spermd. Alkaline, which protects the sperm from the acid environment of the vaginal areae. Prostrate glandular secretions is (approximately) 40% of the fluid by volume

Prostate Gland

I. Male Reproductive AnatomyE. Accessory Glands and Semen3. Bulbourethral glandsa. Once called Cowpers glandsb. Are pea-sizedc. Produce a thick clear mucusd. It is the first fluid down the urethra during stimulatione. Used to lubricatef. There is some debate over whether there is sperm leaked into this fluid during stimulation

Cowpers Gland (Bulbourethral glands)

I. Male Reproductive AnatomyE. Accessory Glands and Semen4. Semena. Milky white mixtureb. It is stickyc. Has sperm and other glandular secretions40 to 2.5 million spermd. The liquid is a transport mediume. Has nutrients and chemicals (used to protect sperm)f. The pH is between 7.2 7.8g. Contains seminalplasmin, relaxin, and several enzymesSp helps to coagulate the semen, after 15 minutes becomes liquid again

I. Male Reproductive AnatomyF. External Genitalia1. 2 parts a. The scrotumThe testes hang outside of the male bodySperm are not produced at normal body temperatureThe temperature is about 5 degrees coolerIf the outside temperature cools the testes are pulled toward the body

I. Male Reproductive AnatomyF. External Genetalia1. 2 parts (cont)b. The penisHangs outside of the bodyIs designed to deliver sperm to the female bodyHas a shaftAn enlarged tip (glans penis)A loose skin, that folds to cover the tip, foreskin or prepuceCircumcision is the removal of the foreskinInternally the spongy urethra is surrounded by 3 areas of erectile tissue that fills with blood during stimulation

I. Male Reproductive AnatomyG. Male reproductive functions1. Spermatogenesisa. The production of sperm via meiosisb. Creates 4 sperm with each meiotic eventEach sperm is haploid (half the chromosomes)Allows for genetic variationc. Spermatogonia are stem cells in the seminiferous tubules which produce more stem cells until puberty and then divide meioticly to form other cells

I. Male Reproductive AnatomyG. Male reproduction functions1. Spermatogenesis (cont)d. The change over occurs due to the hormone, follicle stimulating hormone (FSH)During cell division a stem cell is produced (type A), and a primary spermatocyte (type B)Spermatocytes will then undergo meiosis and produce sperm

I. Male Reproductive AnatomyH. Testosterone Production1. Produced by the interstitial cells2. Most important hormone produced by the testes3. Are activated by the hormone luteinizing hormone (LH)a. Also called interstitial cell stimulating hormone (ICSH)b. Released by the anterior pituitary gland4. Activate other secondary sex characteristicsa. Deeper voice, increased hair growth, enlargement of the skeletal muscles, etc.

II. Female Reproductive systemA. General InformationMore complex than the male reproductive systemMust produce gametesMust nurture and protect developing fetus

II. Female Reproductive systemB. Ovaries1. Primary reproductive organ2. Produce both endocrine products (estrogens and progesterone) and exocrine products (eggs/ova)3. The size of almonds4. Has many sac-like structures called ovarian follicles

Ovaries

Ovaries

Ovarian Follicles

Ovarian Follicles

II. Female Reproductive systemB. Ovaries5. Ovarian follicles carry an immature egg called an oocytea. Surrounded by follicle cellsb. Ova mature over time, the follicle enlarges, becomes fluid filled (central region is called the atrum)The follicle is now called a Graafian or vesicular follicle, containing a mature ova called a secondary oocyteWill be ejected during ovulationThe follicle is now called a corpus luteum

Oocyte

Oocyte

Oocyte development

II. Female Reproductive systemB. Ovaries6. Ovulation occurs approximately every 28 days7. Supported by suspension ligaments8. Anchored to the uterus by ovarian ligaments9. Held in place by peritoneum called the broad ligament

II. Female Reproductive systemC. Duct system1. Uterine tubes 2. Uterus3. Vagina

Uterus

Uterus with Cancerous tumor

II. Female Reproductive systemC. Duct System1. Uterine (Fallopian) Tubesa. The initial part of the duct systemb. Provide a fertilization sitec. Receives the secondary oocyted. The tubes are approximately 10 cm longe. Empty into the super region of the uterusf. The distal end contains infundibulumFunnel shaped, with finger-like projections called fimbriae (surround the ovary)

II. Female Reproductive systemC. Duct systemThe fimbriae create fluid currents to pull the oocytes into the fallopian tubesg. Oocytes are carried toward the uterus by peristalsis and rhythmic beating of ciliah. Oocytes take 3-4 days to reach the uterusi. Oocytes are only viable for 24 hrs after ovulationj. Fertilization usually occurs in the fallopian tubes

II. Female Reproductive systemC. Duct system2. Uterusa. Located in the pelvisb. Between the urinary bladder and rectumc. It is hollowd. Functions to receive, retain and nourish the fertilized egge. Held in place by ligaments (anteriorly-round, posteriorly-uterosacral)

II. Female Reproductive systemC. Duct system2. Uterusf. The major portion of the uterus is called the bodyg. The entrance of the uterine tubes are called fundush. The entrance into the vagina is called the cervixi. The uterine wall is thick and has 3 layersInner (mucosa) layer is the endometriumMiddle (myometrium) layer is thick with smooth muscle, used during deliveryOuter (serous) layer is the perimetrium

II. Female Reproductive systemC. Duct system3. Vaginaa. Thin walled tubeb. It is 3-4 inches longc. Runs from the surface to the cervixd. Called the birth canale. Receives the penisf. A thin membrane (mucosa) closes the distal end, called the hymen

II. Female Reproductive systemD. External Genitalia1. Also called the vulva2. Includes the followinga. Mons Pubisb. Labia Majorac. Vestibuled. Greater Vestibular Glandse. Clitorisf. Perineum

II. Female Reproductive systemD. External Genitaliaa. Mons pubisFatty rounded areaOverlying the pubic symphysisCovered with hair after pubertyb. Labia majoraRuns posteriorly from the mons pubisEncloses two hair free foldsDelicate skin, very sensitive, quickly irritatedLabia minora

II. Female Reproductive systemD. External Genitaliac. VestibuleIs the longitudinal cleft enclosed by the LMajContains the external organs of the urethraContains the external organs of the vaginaCovered by the labia majorad. Greater vestibular glandsFlank the vaginaLubricate the distal end of the vagina

II. Female Reproductive systemD. External Genitaliae. ClitorisAnterior to the vestibuleIt is hooded by a prepuceComposed of very sensitive tissueBecomes swollen with blood, during stimulationf. PerineumIs the region that includes, the labial folds, the anus, and the ischial tuberositiesDiamond shaped

External Female Genitalia

II. Female Reproductive systemE. Oogenesis1. Development starts while the female is still a fetus2. Oogonia (stem cell) multiply and dividea. Producing primary oocytesb. Surrounded by single layer of follicle cells and are now primary folliclesc. At birth the oogonia no longer existd. At birth women have approximately 2 million primary oocytes

II. Female Reproductive systemE. Oogenesis3. At puberty the anterior pituitary produces FSH4. Stimulates follicle growth5. Ovulation will occur each montha. Ovarian cycleb. At puberty approximately 400,000 oocytes remain and a small number of oocytes are activated each monthc. Only (approx) 500 ova are used in a lifetime

II. Female Reproductive systemE. Oogenesis5. Ovulation will occur each month (cont)a. The follicle grows due to FSH and fluid fills the sacb. The center is the atrumc. The primary oocyte begins meiosisProducing one egg/ova (secondary oocyte) and 3 polar bodiesd. Luteinizing Hormone causes the follicle to rupture the ovary (coronary radiata)e. Sometimes causes pain in the abdomen Mittelschmerz (middle pain)

II. Female Reproductive systemE. Oogenesis6. If the secondary oocyte is penetrated by a sperm it is called an ovum (fertilized egg)

II. Female Reproductive systemF. Uterine (Menstrual) Cycle1. Yes, this is the dreaded PMS!2. Actually it includes the Pre-Menstrual Syndrome3. The uterus is only capable of implantation for a short time each month4. The endometrium responds to hormone changes each montha. Reacts to the production of estrogen and progesterone, which are produced by the ovaries

II. Female Reproductive systemF. Uterine (menstrual) Cycle5. There are 3 stagesa. Days 1-5 Menstrual phaseb. Days 6-14 Proliferative phasec. Days 15-28 Secretory phase

II. Female Reproductive systemF. Uterine (menstrual) Cyclea. Days 1-5 Menstrual phaseThe endometrial lining is sloughed offBecomes detached from the myometriumBleeding occurs for 3 to 5 daysLose approximately 50 to 150 mlAt the end, estrogen is being produced by the ovaries

II. Female Reproductive systemF. Uterine (menstrual) Cycleb. Days 6-14 Proliferative phaseStimulated by rising estrogen levelsThe basal layer of the endometrium regeneratesBlood supply and glands are increasedOvulation occurs at some point between day 10 and day 12, at the latest day 14, in response to the rise in LH in blood stream

II. Female Reproductive systemF. Uterine (menstrual) Cyclec. Days 15-28 Secretory PhaseProgesterone levels in the blood begin to riseCauses the blood supply to the endometrium to increaseEndometrium glands begin producing nutrients into the uterus (anticipating fertilization)If fertilization does occur, the ovum will produce a hormone similar to LH to maintain the endometrium until implantationLH levels begin to decline

II. Female Reproductive systemF. Uterine (menstrual) Cyclec. Days 15 - 28 Secretory PhaseAs the hormones decline (LH and FSH), the blood flow to the endometrium will decreaseThe endometrium cells dieCycles back to the menstrual phase

II. Female Reproductive systemF. Uterine (menstrual) Cycle (cont)6. Menstrual Cycle can varya. Shortest, 21 daysb. Longest (typical), 40 daysc. Longer than 40 days is an indicator of other problems

II. Female Reproductive systemG. Hormone Production by the Ovaries1. Estrogensa. Cause the appearance of secondary sex characteristicsEnlargement of the accessory organs, uterine tubes, uterus, vagina, and external genitalsDevelopment of the breastsAppearance of axillary and pubic hairIncreased deposits of fat beneath the skin, particulary the hips and breastsWidening and lightening of the hipsOnset of the mensus

II. Female Reproductive systemG. Hormone Production by the Ovaries (cont.)2. Progesteronea. Produced by the corpus luteumb. Progesterone is produced as long as LH is presentc. Stops producing progesterone after 10-14 daysd. Helps to maintain the pregnancy, and prepare the breasts for milk production (lactation)Source is now the placenta

II. Female Reproductive systemH. Mammary Glands1. Present in both sexesa. Yes, breast cancer CAN happen in males!2. Stimulated by sex hormones, especially estrogen3. Are modified sex glands4. Contained within the breasta. Darker pigmented area is called the areolaHas large numbers of nerve endings

II. Female Reproductive systemH. Mammary Glands (cont)b. Central protruding area is called the nipple5. Has 15 to 25 lobes, radiating around the nipplea. Lobules contain alveolar glands that produce milk during lactationb. Milk moves into the lactiferous ducts, which open to the surface of the skin

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