Reproductive System Lecture PDF

Reproductive System Chapter 22  Medical Terminology Amni Andr/o ‐cyesis Episi/o Galact/o Genit/o Gynec/o Hyster/o Lact/o ‐lipsis Nat/o Neo‐ O/o- ‐partum Phall/o Salping/o Semin/I Venere/o Viv/i Reproduc...

Reproductive System Chapter 22  Medical Terminology Amni Andr/o ‐cyesis Episi/o Galact/o Genit/o Gynec/o Hyster/o Lact/o ‐lipsis Nat/o Neo‐ O/o- ‐partum Phall/o Salping/o Semin/I Venere/o Viv/i Reproductive Systems  Sex Organs (Genitalia) 1. Primary (Gonads)  produce germ cells (gametes) and secrete sex hormones – Males = testes  spermatozoa – Females = ovaries  oocytes 2. Secondary (Accessory) – Ducts – store and transport gametes – Accessory Glands – produce substances to protect and facilitate transport of the gametes – Supporting Structures – assist in delivery and joining of gametes and maturation of embryo/fetus Male Reproductive Anatomy  Functions Testes: produce sperm and testosterone Ducts: transport, store and assist in the maturation of sperm Accessory glands: secrete semen – assist in movement of sperm Penis: passageway for ejaculation of semen and excretion of urine Male Reproductive System Structures Structure Classification Testes Gonads Epididymis Duct Ductus (vas) deferens Duct Ejaculatory ducts Duct Urethra Duct Seminal vesicles Accessory Gland Prostate Accessory Gland Bulbourethral glands Accessory Gland Scrotum Supporting Structure (external) Penis Supporting Structure (external)  Using the following diagram identify: – Testes – Scrotum – Ductus (vas) deferens – to the prostate gland – Penis – Urethra NOTE the location of the: – Urinary bladder – Symphysis pubis – Rectum Male Reproductive System Copyright © 2016 by Nelson 9 Education Ltd. Male Reproductive System Copyright © 2016 by Nelson 10 Education Ltd.  Scrotum Scrotal cavity – Divided by septum to form two sacs – one for each testis – Skin, fascia and smooth muscle – muscle contract and relax in response to external temperature to maintain constant internal temperature for sperm production Scrotal septum  Internal division Scrotal raphe (seam/ridge)  external  Spermatic cord Scrotum and Testes Dartos muscle – In septum & walls – Raises scrotum when contracted (cold) Cremaster muscles – In spermatic cord – Raises testes when contracted (cold) Viable sperm can’t be produced @ 2–3°C below normal body temperature Septum Penis Cremaster – elevates testes Middle septum (internal obliques) of scrotum Dartos – closes scrotal Cremaster muscle space External spermatic fascia Superficial fascia Scrotum containing dartos muscle Skin  Testes Bilobed Sit in Scrotum Divided into lobule by septum – Seminiferous tubules in each lobule – Contain spermatogenic cells producing sperm and Leydig cells secrete testosterone  Using the next image identify Lobules – each divided by a septum Seminiferous tubules in each lobule NOTE: each lobule joins posteriorly to the epididymis  Sagittal Spermatic cord plane Septum dividing Ductus (vas) deferens each lobule posterior anterior Seminiferous tubule Lobule Epididymis (a) Sagittal section of testis showing seminiferous tubules  Testes Contain seminiferous tubules – Sperm production From seminiferous tubules – connect to: Straight tubules to Rete testis Identify each on the next image Sperm leaves testes posterior through Efferent ductules to the epididymis  Spermatic cord Blood vessels and nerves Ductus (vas) deferens Head of epididymis Seminiferous Efferent ductule tubule Rete testis Lobule Straight tubule Body of epididymis Duct of epididymis Tail of epididymis (a)  Using the image follow the pathway of sperm from the seminiferous tubules to the epididymis posterior Anterior  Pathway of sperm: Pathway of sperm – Seminiferous tubules – location of sperm development – Straight tubules – Rete testis – Efferent ductules – Epididymis – Vas deferens – Ejaculatory duct – Urethra  Spermatic ducts Epididymis Ductus Deferens (Vas Deferens) Ejaculatory Ducts From the epididymis sperm goes through ductus deferens to ejaculatory ducts – Urethra  Epididymis Posterior border of testes – Head, body and tail – Sperm maturation (10-14 days) and storage (months) – Sperm mobility develops – Recycles damaged/aging spermatozoa – Propels sperm Ductus (vas) Deferens Passes through the inguinal canal then around to posterior urinary bladder Transports sperm during sexual arousal – Smooth muscle - peristalsis Can store for several months – reabsorb non-ejaculated sperm Vasectomy  Sagittal plane Urinary bladder Ductus (vas) deferens End of ductus deferens Start of ductus deferens Urethra Ejaculatory duct Body of penis Epididymis Testis Scrotum Sagittal section Urinary bladder Superficial inguinal ring (end of inguinal canal) Ductus (vas) deferens Penis  Ejaculatory Duct Formed by the union of the ductus deferens and the seminal vesicles Carries sperm to the urethra Passes through prostate gland to the urethra Male Reproductive Ducts ductus/vas deferens joins Vas Deferens with seminal vesicle to form ejaculatory duct Epididymis Testes Scrotum  Urethra Urinary bladder, through prostate to tip of penis Review notes in the urinary system  Accessory glands: Seminal vesicles Prostate Bulbourethral glands  Seminal Vesicles Between bladder and rectum Secrete solution that – Is Alkaline: help neutralize and protect sperm from the acidic male urethra (from urine) – Has high concentration of fructose: ATP production by sperm – Prostaglandins – sperm mobility; contract smooth muscle in penis and female reproductive tract – Fibrinogen – clotting proteins to thicken sperm  Prostate Gland Inferior to bladder Surrounds prostatic urethra and ejaculatory duct Increases in size throughout life Secretes prostatic fluid (slightly acidic; pH 6.5) that contains: – Citric acid – energy – Proteases: such as prostate- specific antigen (PSA) which liquefies the sperm and increases their motility  Bulbourethral Glands Paired Inferior to the prostate on either side of the urethra Erect penis stimulates the release of an alkaline substance into urethra (neutralize prior to ejaculation) and mucus to lubricate the end of the penis for intercourse  Penis Root Medial/anterior to scrotum Three parts: 1. Root – attachment; inferior to pubic symphysis 2. Body/Shaft – 3 pieces of erectile tissue 2 corpora cavernosa 1 corpus spongiosum Contains urethra 3. Glans – distal expanded portion Prepuce (foreskin) covers glans  Erection Limp penis = arteries are vasoconstricted Arousal  parasympathetic impulses: – Smooth muscle relaxes as nitric oxide vasodilates arteries Increases flow – Blood sinuses expand in erectile tissue which compresses veins Slows drainage  Ejaculation Sympathetic input  strong smooth muscle peristaltic contractions all along ducts – Inhibits micturition reflex Pre-ejaculation (emission)  weak peristalsis Sympathetic input constricts arteries and muscles, decompressing veins  drainage of blood  Spermatogenesis Seminiferous tubules Contain spermatogenic cells “Sertoli cells” producing sperm and Leydig cells secrete testosterone Spermatogonia (diploid) undergo meiosis – primary spermatocytes, – secondary spermatocytes (haploid), spermatids (23 chromosomes) – and finally spermatozoa “sperm” – maturation is completed in the epididymis  Sertoli Cells Stimulate spermatogenesis (meiosis) in response to which hormone? (FSH) Support, protect and nourish spermatogenic cells Phagocytosis of degenerating cells Secrete fluid for sperm transport Leydig Cells External to seminiferous tubules Produce testosterone in response luteinizing hormone  Sperm – the End Result of Spermatogenesis ~300 million haploid (n) sperm cells / spermatozoa are produced daily – compare to females Head: contains the nuclear material (DNA) Acrosome: a vesicle containing enzymes – Help sperm cell penetrate a secondary oocyte (egg cell) Tail subdivided into four parts: – Neck – Middle piece: contains mitochondria – Principal piece (longest) – End piece (tapers) Female Reproductive System Tortora, Derrickson:Principles of Anatomy and Physiology, 14th EditionAnatomy and Physiology Visual Library  2. Female Reproductive System Two major functions: 1. Produce oocytes (oogenesis) in ovaries 2. Prepare uterus to support embryo during pregnancy  Secondary Organs Internal: – Uterus – Uterine (fallopian) tubes / oviducts – Vagina External: – Vulva (pudendum)  Functions of the Female Reproductive System Structures 1. Ovaries  produce oocytes & hormones – Estrogens, progesterone (& others) 2. Fallopian Tubes  transport 20 oocyte to uterus; normal site of fertilization 3. Uterus  site of implantation of fertilized ovum; development of fetus; labor 4. Vagina  birth canal 5. Mammary Glands  create, secrete, eject milk for post-natal nourishment  Uterine (fallopian) tube Sagittal plane Ovary Uterus Cervix Urinary bladder Pubic symphysis Coccyx Rectum Urethra Anus Vagina Sagittal section  Ovaries Paired & lateral to uterus In “ovarian fossa” inferior to fallopian tubes Retroperitoneal & held in place by three paired ligaments derived from the peritoneum  Fimbriae of uterine tube Fundus of uterus Infundibulum of uterine tube Uterine (fallopian) tube Uterine cavity Ovary Endometrium Ovarian ligament Myometrium Perimetrium Body of uterus Ureter Cervix of uterus Lateral fornix Vagina View Posterior view Histology of Ovary Primary Oocytes Two major regions of the ovary: 1. Cortex (superficial) – contains follicles 2. Medulla (deep) – contains connective tissue, blood vessels, and nerves  What is Happening to the Follicles? Follicle = houses an oocyte during oogenesis; secretes estrogen Pre-birth  oogenesis begins, generating all the primary oocytes a woman will ever have in her life – ~40,000 remain at puberty; ~400 total fully mature until menopause – 10 oocytes (2n) frozen in prophase of meiosis 1  What is Happening to the Follicles? Each month  oogenesis resumes in several 10 oocytes (2n) – Only one will fully mature into a 20 oocyte (n) in a mature follicle Ovulation = expulsion of the 20 oocyte from mature follicle into fossa  fallopian tubes – Corpus luteum = remaining degenerating follicle (secretes hormones critical for maintenance of endometrium)  Uterine tubes/fallopian tubes/oviducts 4 to 5 inches Smooth muscle and cilia =transport oocyte Lipids and glycogen =microvilli 3 segments (identify on next image) 1.Infundibulium (proximal to ovary) Fimbriae (movement brings oocyte into tube) 2. Ampulla = most likely site of fertilization 3. Isthmus – connect to uterus; distal to ovary  3 Segments of Uterine Tubes (Lateral  Medial) 4 to 5 inches Smooth muscle and cilia =transport oocyte 1. Infundibulum  open, funnel- shaped end 2 – Contains fimbriae  pick up the 20 oocyte from ovarian fossa 2. Ampulla  most likely site of 1 3 fertilization; longest region 3. Isthmus  opening to superior/lateral part of uterus  Uterus Implantation of fertilized egg; development of fetus and labor If egg does not implant – inner lining will shed = menstrual flow 3 Regions of Uterus 1. Fundus – dome- shaped superior portion 2. Body – begins inferior to uterine tube openings – Uterine cavity 3. Cervix – narrow, inferior opening into the vagina – Interal Os (orifice) – Cervical Canal – External Os – Fornix  Uterine Wall 1. Perimetrium (serosa): – Visceral peritoneum – Surrounds fundus and body 2. Myometrium: – 3 layers of smooth muscle  oblique, circular, longitudinal – Contractions during labour (which hormone?) 3. Endometrium: – Mucus membrane – Implantation site for ovum / attachment site for embryo – Forms the placenta – Sheds each month if fertilization does not occur (menstruation)  Vagina Inferior/anterior from uterus to environment 3-3.5 inches long Functions: – Discharge of menstrual fluid – Receive penis and semen – Birth canal External Genitalia: Vulva/Pudendum Mons Pubis  adipose tissue; cushions pubic symphysis Labia Majora  lateral longitudinal folds of skin – Adipose tissue, oil glands, sweat glands Labia Minora  medial folds of skin – No fat; mostly oil glands  External Genitalia: Vulva/Pudendum Clitoris  erectile tissue – Anterior junction of labia minora forms the prepuce (foreskin) – Exposed part = glans Vestibule  everything between the labia minora – Hymen (covers vaginal orifice if present) – Vaginal orifice – External urethral orifice  Mammary Glands Modified sweat glands that produce milk Function = Lactation – Synthesis, ejection (hormones?) External Structures: – Areola  circular pigment – Nipple  contains duct openings which release milk Internal Structures: – Lobules contain clusters of alveoli (milk-producing glands) Cooper’s Ligaments  support the breast and lobes of mammary glands in conjunction with adipose tissue  Oogenesis Primary oocytes grow during childhood and go through the first meiotic cell division just before ovulation to produce a haploid secondary oocyte The second meiotic cell division, to separate the sister chromatids, does not occur unless that secondary oocyte is fertilized. The Female Reproductive Cycle Ovarian Cycle – development of 20 oocyte Estrogen is low = release of FSH and LH As follicles develop = Increase estrogen Inhibin – stops FSH The Female Reproductive Cycle Uterine (Menstrual) Cycle – monthly preparation of the endometrium to receive and implant a fertilized egg release of 20 oocyte into fallopian tube begins on day 1 of period, and ends the last day before the next period – 24-36 day cycle (28 on average) Key: Ovulation occurs 14 days BEFORE the date of the NEXT period  Hormones of the Reproductive Cycle Follicle-Stimulating Hormone (FSH)  initiates follicular growth and promotes follicular estrogen secretion Luteinizing Hormone (LH)  continues stimulation of follicular maturation/estrogen secretion – **TRIGGERS OVULATION AT MID-CYCLE** – Stimulates estrogen and progesterone secretion from corpus luteum and keeps it alive  Hormones of the Reproductive Cycle Progesterone/estrogen cooperate to: – Prepare/maintain endometrium for implantation – Prepare mammary glands for milk synthesis Estrogen also: – Promotes secondary sex characteristics – Stimulates protein synthesis (lesser extent than androgens) – Lowers blood cholesterol Phases of the Female Reproductive Cycle 1. Menstrual Phase  first 5 days – Day 1 = 1st day of cycle – Part of endometrium is shed (blood/tissue discharge) Due to decline in progesterone/estrogen 2. Pre-Ovulatory (Follicular) Phase  days 6-13 – Group of follicles begins maturation  one outgrows rest (dominant follicle); rest die – Endometrium being repaired (due to estrogen secreted from follicles) Phases of the Female Reproductive Cycle 3. Ovulation  day 14 – High estrogen  Spike in LH production – Spike in LH  rupture of the dominant, mature (graafian) follicle – 20 oocyte released into ovarian fossa 4. Post-Ovulatory (Luteal) Phase  days 15-28 – Time from ovulation to next menstruation – Corpus luteum secretes large amounts of progesterone/estrogen Endometrium thickens in readiness for implantation Fertilization and Implantation vs. Not If no: – Corpus luteum degenerates to corpus albicans after 14 days as LH levels decline – Progesterone/estrogen levels massively decline – Discharge of endometrium (menstruation) and cycle repeats If yes: – Corpus luteum is maintained by human chorionic gonadotropin (hCG) produced by embryo An LH replacement! Continued progesterone/estrogen secretion *Home pregnancy tests  Ovulation Release of follicle into tube menstrual cycle begins day one of period and ends last day before next period 14 days FROM date of next period – E.g., 28 day cycle 28 minus14 =ovulate on day 14 – 30 day cycle – 30 minus 14 =ovulate on day 16  Remember Sperm can survive for 3 -7days …  Fertilization Can occur up to 24 hours after ovulation 1000 of the 300 million sperm get to the ovum – Acrosome secrete enzymes 5 to 7 days to get to the uterus – Zygote doubles in size Hormone levels rise preventing menstruation The end