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Anatomy and Physiology

Male reproductive system . Testes

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Anatomy and Physiology

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    1. Anatomy and Physiology April 15th 2010

    3. Male reproductive system Testes – produce sperm and are essential Scrotum Epididymis Vas deferens Seminal vesicles Ejaculatory ducts Prostate Gland Urethra Penis

    4. Male Reproductive System Testes Ovoid glands that are suspended in the scrotum Attached to scrotal tissue and spermatic cords Consist of many lobules (250-300 in each testis) Each lobule contains: Seminiferous Tubules for spermatogenesis Interstitial cells of Leydig that secrete testosterone.

    5. Male Reproductive System The testes are each surrounded by two protective coats (or tunics): Tunica Vaginalis (outer Layer) extension of peritoneum Tunica Albuginea (Inner Layer) extends between each of the lobules

    6. Male Reproductive System Sperm produced in the testes leave via the tubulus rectus that conveys them to a network of tubules on one side of each testis called the rete testis From here the sperm are carried via efferent ducts to the epididymis.

    7. Male Reproductive System 2. Scrotum This literally means "pouch" or "sac" It is a pouch of skin that is incompletely divided into left and right halves. Each half houses one testis. The appearance of the scrotum changes with temperature. Eg. Cold (or sexual arousal) it appears shorter and quite wrinkled, because it is pulled closer to the body for warmth. Eg. Heat, the skin is flaccid (loose) and the testes hang lower in the scrotum to keep them cool.

    8. Male Reproductive System The movement of the scrotum and testes helps to maintain intra scrotal and hence testicular temperature constant @ 93° Movement of the scrotum is achieved by two groups of muscles: Dartos Muscle which is a smooth muscle and causes shrinking of the scrotum Cremaster Muscle with is skeletal muscle and it elevates the testes. It is attached to the internal oblique muscle of the trunk

    9. 3. Epididymis Highly folded duct approx 6m long, for the passage of sperm from the testis to the vas deferens. It has 3 divisions: Head: connected to the testes receiving immature sperm Body Tail: continuous with the vas deferens, contains smooth muscle and during ejaculation, contractions of the smooth muscle expel mature sperm into the vas deferens. Sperm may be stored in the epididymis from 18 hrs - 20 days. During this time the sperm mature, including becoming motile, so they can fertilize an ovum.

    10. Male Reproductive System 4. Vas deferens Short, fairly straight tube approx 45 cm long. Ascends from the scrotum into the abdomen and passes over the bladder. Tube cut in vasectomy doesn’t effect erection or performance Vas deferens stores the sperm. sperm are mature & motile the local accumulation of CO2 from the normal metabolism of the sperm causes the pH to become acidic. under these conditions sperm lose their motility on ejaculation, the alkaline seminal fluid will counteract the low pH and the sperm will become motile again. At the posterior wall of the bladder the tubes expand to form "ampulla of the vas deferens" and join a duct from the seminal vesicles to form the "ejaculatory duct".At the posterior wall of the bladder the tubes expand to form "ampulla of the vas deferens" and join a duct from the seminal vesicles to form the "ejaculatory duct".

    11. Male Reproductive System 5. Seminal Vesicles 2 glands behind prostate gland, size & shape of finger, secretes viscous fluid = 60-70% of seminal fluid (nourish & energize sperm) Also secrete fructose, citric acid, amino acids and Prostaglandins.

    12. Male Reproductive System 6. Ejaculatory ducts Short tubes that descend through the prostate gland and terminate in the urethra. Formed by the union of the vas deferens and seminal vesicle ducts

    13. Male Reproductive System 7. Prostate gland Chestnut-sized gland below bladder. Surrounds the ejaculatory duct and part of the urethra. Secretes a thin liquid that is milky, alkaline and constitutes 30% of the seminal fluid volume Responsible for raising the pH of the female vagina. Provides lubrication during coitus 7. 5. Cowper’s Glands below prostate, 2 pea-sized glands connect to urethra by ducts; secrete thick, clear mucus before ejaculation (at tip of penis) alkaline to protect sperm from acidic vagina. Fluid has sperm! (Sperm in urethra > PREGNANT!!)

    14. Male Reproductive System 8. Urethra Tube 18-20 cm long. Conveys urine and sperm (at different times). Three regions of urethra Contains glands which secrete mucus to aid lubrication during intercourse.

    15. Male Reproductive System 9. Penis Copulatory organ of the external genitalia. Contains 3 compartments of erectile tissue which are covered by a loose layer of skin. Two "corpora cavernosa" One "corpus spongiosum" which lies ventrally in the penis and houses the spongy urethra. Expands at the end of the penis into the "glans penis". When aroused, inc. blood into penis, these compartments fill and expand Leads to erect penis – compression of vessels prevents blood flow out. aroused, ?blood into penis, vessels expand, corpora cavernosa & corpus spongiosum fill & expand > penis erect compression of vessels prevents blood flow out of penis; Engorgement;aroused, ?blood into penis, vessels expand, corpora cavernosa & corpus spongiosum fill & expand > penis erect compression of vessels prevents blood flow out of penis; Engorgement;

    17. Male Reproductive System 9. Penis continued Erectile tissue is sponge-like containing venous sinuses surrounded by arteries and veins. Upon sexual stimulation, the arteries dilate and the spaces (or caverns) fill with blood. As they fill, the erectile tissue becomes rigid and the penis becomes erect. Two main functions of the penis: Removal of urine via the urethra Receipt and ejection of sperm and seminal fluid during copulation, again via the urethra.

    18. Male Reproductive System In uncircumcised males there is a structure that covers the end of the glans penis called the "prepuce or foreskin". Its proposed functions include protection, lubrication of glans, part of sexual pleasure system.

    21. Male Anatomy & Physiology Factors effecting size: heredity, vasocongestion, cold air or water, fear, anxiety (penis draws closer to body & smaller size) Erection – urethra/urinary duct closes so semen passes through (ejaculation) Erection not always because of sexual excitement REM sleep (dreaming)

    22. Myths Penis Size: related to masculinity, aggression, ability to “perform”, sexual attractiveness, virility. Size of shoe predictive of penis size (not research based!). Size not related to ability to have sexual intercourse or pleasure partner. Small flaccid penis enlarges more with erection than larger flaccid penis.

    23. The Ejaculate Ejaculate volume is about 3 ml and ranges from 2 to 6 ml. pH is 7.5, slightly basic to neutralize the acidity of the urethra and the vagina Of the 3 ml of an ejaculate About 0.2 ml, originates from the Cowper's gland About 0.5 ml from the prostate gland about 2 ml is secreted from the seminal vesicles

    24. Reproductive Process Semen production Seminal Fluid - ejaculated liquid with sperm Function: nourish sperm, hospitable environment, transportation of sperm Semen is combo of: seminal vesicle fld., prostate gland fld., sperm mixed in the urethra during ejaculation. Is thick & sticky (clotting factor in fluid) Keeps the sperm together during transport then liquefies so sperm can swim out. Color varies: opalescent (milky white), yellowish or grayish as ejaculate, then becomes clear as it liquefies. 1 tsp. (2-6 Milliliters) semen ejaculated = 200>500 million sperm

    25. Review: Journey of the Sperm

    35. The Process Orgasm: Intense, pleasurable physical sensations & general release of tension accompanying ejaculation. Does not always occur with ejaculation Ejaculation not always occur with orgasm Refractory Period - no erections/orgasms for varying time factors = age, environment, individual few minutes to few days - maybe chemical effects in brain After orgasm > blood flow ? , erection ?, “Blue Balls” Intense arousal without orgasm > heaviness felt in testes. Not as painful as implied. If discomfort continues - masturbation > ejaculate for release.

    36. More info When seminal vesicles are full, feedback signals to ?sperm (inhibin) production. Extra sperm die and are absorbed by body

    37. Female Reproductive Anatomy

    38. Female Reproductive System

    39. Female Reproductive System Internal Ovaries Fallopian tubes Uterus Cervix Vagina External genitalia performing a variety of secretory functions Bartholin's glands Skene’s glands Mammary glands Menstrual cycle

    40. Female Reproductive System Ovaries The female gonads or sex glands 2 almond sized glands, either side of uterus They develop & expel 1 ovum/mth A woman is born with about 400,000 immature eggs called follicles During a lifetime a woman releases about 400 to 500 fully matured eggs for fertilization The follicles in the ovaries produce the female sex hormones, progesterone and estrogen These hormones prepare the uterus for implantation of the fertilized egg

    41. Ovaries Each ovary is held in place by 3 ligaments: Broad ligament: suspends ovaries between the uterus & pelvic wall Ovarian ligament: attaches ovaries to the uterus Suspensory ligament: attaches ovaries to the pelvic wall These ligaments work with the Round and Uterosacral ligaments to suspend female reproductive system in the lower abdomen Significantly different from males where all structures hang These ligaments work with the Round and Uterosacral ligaments to suspend female reproductive system in the lower abdomen Significantly different from males where all structures hang

    42. These ligaments work with the Round and Uterosacral ligaments to suspend female reproductive system in the lower abdomen Significantly different from males where all structures hang

    43. Ovaries Each ovary is covered by 3 layers of epithelial cells – each with different functions: Nurture developing follicles, secrete hormones, blood vessels and muscles.

    44. Female Reproductive System Ovaries: Internal Structure The ovary contains many sac-like structures called ovarian follicles Follicle consists of an immature egg (oocyte) surrounded by several follicle cells named according to its stage of development. Follicle cells support/nourish ova, secrete estrogen. Primary Follicle - one layer of follicle cells around ovum Growing Follicle - >1 layer of follicle cells around ovum Graafian Follicle - mature oocyte, follicle cells have a fluid filled space between them Corpus Luteum - follicle cells left behind after the ovum has ruptured at ovulation (makes progesterone)

    45. Female Reproductive System

    46. Female Reproductive System

    47. Female Reproductive System Fallopian Tubes Tubes approx. 10 cm long, 1 cm diameter Receive ruptured oocyte from ovary Fallopian tubes are NOT in direct contact with ovaries When an oocyte is released from the ovary it moves into the peritoneal cavity. It must reach the mouth of the fallopian tube to be fertilized.

    48. Female Reproductive System At ovulation, a current draws the oocyte into the fallopian tube. Finger-like projections called fimbriae Infundibulum: funnel-like structure Narrows into the ampulla Constricts further into isthmus as it enters uterus

    49. Female Reproductive System Fallopian Tubes Provide site for fertilization by sperm, usually upper end 10-11 days for the zygote to drift down the tube Wall of the Fallopian Tubes lined with longitudinal and circular smooth muscle – move oocyte toward uterus some areas are ciliated secrete nutritive substances to nourish oocyte

    50. Female Reproductive System Tubal ligation, commonly knows as "getting your tubes tied," is a surgical sterilization technique for women. This procedure closes the fallopian tubes, and stops the egg from traveling to the uterus from the ovary. It also prevents sperm from reaching the fallopian tube to fertilize an egg. In a tubal ligation, fallopian tubes are cut, burned, or blocked with rings, bands or clips. The surgery is effective immediately. Over 98% effective as birth control. They do not protect against reproductive tract infections, including HIV/AIDS.

    51. Female Reproductive System Uterus Hollow, thick-walled organ – womb Receives, retains and nourishes the fertilized egg Before first pregnancy it is the size and shape of a pear after first child remains a bit larger

    52. Female Reproductive System

    53. Female Reproductive System Wall of the Uterus The uterine wall is highly muscular and consists of 3 layers: Perimetrium - outermost layer (think of perimeter) Myometrium - thick smooth muscle layer, contracts in childbirth Endometrium - mucosal lining, site of implantation for embryo The endometrium receives a rich blood supply from a complex network in the myometrium so that it can respond to hormonal changes in the blood Eg. Pregnancy, stages of menstrual cycle

    54. Female Reproductive System

    55. Female Reproductive System Cervix The cervix connects the uterus to the vagina The cervical opening to the vagina is small This acts as a safety precaution against foreign bodies entering the uterus During childbirth, the cervix dilates to accommodate the passage of the fetus This dilation is a sign that labor has begun

    56. Female Reproductive System Vagina Thin-walled, fibromuscular tube, 8-10 cm long Lies between the bladder and rectum Extends from cervix of uterus to exterior of body Birth canal (and passage for menses) Female copulatory organ Vaginal mucosa has NO glands With the help of two Bartholin’s glands (outside vagina) becomes lubricated during SI

    57. Female Reproductive System Vagina pH of the vagina in menarchal (reproductive) women is acidic Maintained by glycogen stores that are used by resident normal Flora Keeps vagina healthy – parasite free Low pH is hostile to sperm High pH of seminal secretions aid to neutralize the acidic pH of the vagina and enhance survival of sperm.

    58. Female Reproductive System Fornix at proximal end (meets cervix of uterus) there is a fold - this is a potential site for infection in the female reproductive tract.

    59. Female Reproductive System Hymen at distal end (external opening) there may be an extension of the mucosa partly or completely covering the vaginal orifice highly vascular and often bleeds after first sexual intercourse as it is ruptured

    60. Female Reproductive System External Genitalia, collectively called the Vulva: Mons Pubis fatty, rounded area over the pubic area During adolescence sex hormones trigger the growth of pubic hair on the mons pubis

    61. Female Reproductive System Labia Majora 2 fatty skin folds that are homologous with the male scrotum “Outer lips” – darker pigmentation Protective covering Are covered with hair and sebaceous glands Become flaccid with age and after childbirth Swell during intercourse

    62. Female Reproductive System Labia Minora “Inner lips” smaller folds covered with mucosa and richly supplied with sebaceous glands Made up of erectile, connective tissue that darkens and swells during sexual arousal Located inside the labia majora They are more sensitive and responsive to touch than the labia majora The labia minora tightens during intercourse

    63. Female Reproductive System Clitoris Contains erectile cavernous tissue like the penis Richly supplied with nerves, and so is one of the most sensitive areas for women Engorges with blood upon sexual arousal Housed in a hood of tissue (prepuce) formed by the junction of labia minora Highly sensitive organ composed of nerves, blood vessels, and erectile tissue Key to sexual pleasure for most women

    64. Female Reproductive System Urethra Opening located directly below clitoris Passage of urine Vaginal Opening Opening may be covered by a thin sheath called the hymen Using the presence of an intact hymen for determining virginity is erroneous Some women are born without a hymen The hymen can be perforated by many different events

    65. Female Reproductive System Vestibular Glands Greater vestibular (Bartholin's) 2, posterior, mucous secreting, can plug and make cysts, reservoir for VD Lesser vestibular (Skene's) 2, anterior to opening of the vagina, mucous producing

    68. Female Reproductive System Perinium The muscle and tissue located between the vaginal opening and anal canal It supports and surrounds the lower parts of the urinary and digestive tracts The perinium contains an abundance of nerve endings that make it sensitive to touch An episiotomy is an incision of the perinium used during childbirth for widening the vaginal opening

    69. Female Reproductive System Mammary Glands Present in both sexes but only become functional in women Only of importance functionally after childbirth to produce milk for feeding the baby Each mammary gland is contained within a rounded, skin- covered breast In the centre of each breast is a slightly hollowed area, darker than skin, called the areola, surrounds the central nipple In the areola there are large sebaceous glands that give it a lumpy texture and appearance. Both the areola and nipple are innervated by the autonomic nervous system and become erect by tactile and sexual stimuli (also cold temperatures)

    70. Female Reproductive System Mammary Glands: Internal Structure Each mammary gland is made up or 15-25 lobes that radiate around the nipple Each lobule is connected by lactiferous ducts that open into the nipples (gets milk to nipple) Lobes contain Alveolar Glands produce milk during lactation Lobes are separated by connective tissue and fat There are suspensory ligaments in the connective tissue that attach the breasts to the pectoral muscles of the chest

    73. Reproduction and the Menstrual Cycle

    74. Reproduction and the Menstrual Cycle Structures involved Hypothalamus Pituitary (anterior lobe) [secretes FSH & LH] Ovary [estrogen, progesterone] Uterine lining The average cycle is 28 days in length (range 24-35) Feedback loop of hormones

    76. SEX HORMONES HORMONES PRODUCED IN THE PITUITARY GLAND FSH Follicle stimulating hormone LH Luteinizing hormone - signals ovulation HORMONES PRODUCED BY THE FOLLICLES IN THE OVARIES Estrogen- produced throughout the menstrual cycle Progesterone-produced during second half of cycle Contributes to thickening of the endometrium which is shed during menstrual phase if fertilization does not take place

    78. Reproduction and the Menstrual Cycle 2 main phases: follicular and luteal phase – each 14 days Follicular phase (14 days) Includes menstrual flow phase (5 days) Loss of 25-65 ml of blood average Hypothalamus triggers pituitary to secrete FSH Causes the follicle to develop As follicle develops, starts to produce estrogen Estrogen has three important effects: Inhibits FSH production “we’ve got a follicle and don’t need to produce another one now” causes the endometrium lining to build up Causes the pituitary to secret LH LH surge causes ovulation: marks end of the follicular phase

    80. Reproduction and the Menstrual Cycle As FSH declines, causes the increase in secretion of LH (Luteinizing hormone). Spike in LH causes ovulation to occur After ovulation, in luteal phase After ovulation the follicle is called a corpus luteum Corpus luteum makes progesterone. Progesterone: inhibits pituitary manufacture of LH (and FSH) “We’ve got successful ovulation, don’t need anymore” During the flow phase, there may be depression accompanying the decreased hormone levels Psychological pickup possible during follicular phase, estrogen level is risingDuring the flow phase, there may be depression accompanying the decreased hormone levels Psychological pickup possible during follicular phase, estrogen level is rising

    83. Reproduction and the Menstrual Cycle The egg cell is fertile for about 48 hours after ovulation In general, fertilization occurs 14th and 15th days. Sperm cells are fertile in the reproductive tubes for about 48 hours.

    84. Reproduction and the Menstrual Cycle If pregnancy occurs… Estrogen and progesterone stay high FSH and LH stay low, the endometrium continues to grow Corpus luteum grows and dominates the ovary Most birth control pills contain the combination of the hormones estrogen and progesterone to prevent ovulation: inhibits FSH and LH

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