Male Reproductive System Lecture 23 PDF

 THEME 5: ALL SYSTEMS GO, PART 2 Week 1: Digestive System Week 2: Urinary and Male Repro. Systems Week 3: Female Repro. and Conception/Preg. Week 4: Final Exams!  SPOILER ALERT! Obj. 1: Take tour of male reproductive system Obj. 2: Differentiate ducts from accessory gland...

 THEME 5: ALL SYSTEMS GO, PART 2 Week 1: Digestive System Week 2: Urinary and Male Repro. Systems Week 3: Female Repro. and Conception/Preg. Week 4: Final Exams!  SPOILER ALERT! Obj. 1: Take tour of male reproductive system Obj. 2: Differentiate ducts from accessory glands Obj. 3: Examine the output: semen and sperm  MALE REPRODUCTIVE SYSTEM Functions 1. Form specialized cells for sexual reproduction (gametes) 2. Bring gametes together (copulation) 3. Combine genetic info through fertilization 4. Support development of fetus (gestation) and birth of baby (parturition) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  MALE REPRODUCTIVE SYSTEM Structures Testes: sperm-producing male gonads Scrotum: hold the testes Sperm is delivered to body through system of ducts: 1. Epididymis 2. Ductus deferens 3. Ejaculatory duct 4. Urethra Accessory sex glands: seminal glands, prostate, and bulbo-urethral glands Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  MALE REPRODUCTIVE SYSTEM Ureter Peritoneum Ducts: Ejaculatory duct Ductus (vas) deferens Ampulla of Urinary Urethra ductus deferens Rectum bladder Epididymis Accessory glands: Pubis Seminal gland (vesicle) Prostate Penis: Bulbo-urethral gland Corpus cavernosum Corpus spongiosum Urogenital diaphragm Glans penis Anus Prepuce (foreskin) Testis External urethral orifice Scrotum Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved SCROTUM AND TESTES Urinary bladder Superficial inguinal ring (end of inguinal canal) Testicular artery Spermatic cord Ductus (vas) deferens Penis Autonomic nerve fibers Pampiniform Septum of scrotum venous plexus Epididymis Cremaster muscle Tunica vaginalis External spermatic (from peritoneum) fascia Tunica albuginea Superficial fascia of testis Scrotum containing dartos muscle Internal spermatic Skin fascia Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  SCROTUM AND TESTES Scrotum: Sac of skin and superficial fascia Temperature? Urinary bladder 3°C lower than core Necessary for sperm production Spermatic cord: encloses nerve fibers, Spermatic cord blood vessels, and lymphatics Midline septum divides scrotum Septum of scrotum When cold, testes are pulled closer Cremaster muscle to warm body wall External spermatic fascia Cremaster muscles: Superficial fascia Scrotum skeletal muscle elevate testes containing dartos muscle Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Dartos muscle: SCROTUM AND TESTES Blood supply Testicular arteries from abdominal aorta Pampiniform venous plexus surrounds each testicular artery Absorb heat from testicular arteries Testes: Testicular artery Each surrounded by two tunics: Ductus (vas) deferens Tunica vaginalis: Autonomic outer layer nerve fibers derived from peritoneum Pampiniform venous plexus Epididymis Tunica albuginea: inner layer Tunica vaginalis forms fibrous capsule (from peritoneum) Tunica albuginea Inside testes ~250 lobules, of testis each containing one to four Internal spermatic Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved seminiferous tubules fascia Spermatic cord Blood vessels and nerves Ductus deferens Epididymis Testis Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Spermatic cord Blood vessels and nerves 6. Ductus (vas) deferens Head of epididymis Testis 1. Seminiferous Tubules: 3. Efferent ductule sperm production Lobule 2. Straight tubule Septum Tunica albuginea Tunica vaginalis 4. Duct of epididymis 5. Tail of epididymis Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Seminiferous tubules inside testis Save It Fo r La b ! Sperm Sustentocytes: Surround, support, and nourish developing sperm Spermatogenic cells: In tubule epithelium Sperm-forming cells; surrounded by sustentocytes Interstitial endocrine cells: In connective tissue between tubules Secrete testosterone Myoid cells: Smooth muscle–like cells that surround seminiferous tubules (a) Seminiferous tubule Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Seminiferous tubules inside testis Spermatogenic cells: In tubule epithelium Sperm-forming cells; surrounded by sustentocytes (b) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  MALE REPRODUCTIVE SYSTEM Ureter Peritoneum Ducts: Ejaculatory duct Ductus (vas) deferens Ampulla of Urinary ductus deferens Rectum bladder Urethra Accessory glands: Epididymis Pubis Seminal gland (vesicle) Prostate Penis: Bulbo-urethral gland Corpus cavernosum Corpus spongiosum Urogenital diaphragm Glans penis Anus Prepuce (foreskin) Testis External urethral Scrotum orifice Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Who Let the Sperm Out?! DUCT SYSTEM Spermatic cord Epididymis: Blood vessels sperm mature and nerves Head: efferent ductules Ductus (vas) deferens empty to highly-coiled duct of the epididymis Head of epididymis Testis Efferent ductule The seminiferous Body and Tail: tubules are the sites where sperm are made. rest of epididymis Rete testis Lobule ~ 6 m (20 ft) Straight tubule Septum Tunica Pseudostratified epithelial Body of epididymis albuginea cells of duct mucosa w/ Tunica vaginalis microvilli (stereocilia) Duct of epididymis Cavity of tunica Tail of epididymis vaginalis Large surface area absorption of excess fluid Copyright © 2019, 2016, 2013 Pearson Education, (a) Inc. All Rights Reserved  DUCT SYSTEM Who Let the Sperm Out?! Spermatic cord Nonmotile sperm enter Blood vessels and nerves Pass through takes ~ 20 days Ductus (vas) deferens Finally gain ability Testis to swim Head of epididymis Efferent ductule The seminiferous tubules are the sites where sperm are Can be stored made. Rete testis several months Lobule Straight tubule Septum Ejaculation: Tunica Body of epididymis albuginea epididymis contracts, Tunica expelling sperm into ductus vaginalis Duct of epididymis deferens Cavity of tunica Tail of epididymis vaginalis Copyright © 2019, 2016, 2013 Pearson Education, (a) Inc. All Rights Reserved DUCTUS DEFERENS AND EJACULATORY DUCT Ureter Peritoneum Ducts: Ejaculatory duct Ductus (vas) deferens Ampulla of Urinary ductus deferens Urethra bladder Epididymis Pubis Ductus deferens ~ 45 cm long Joins duct of seminal vesicle to form ejaculatory duct Smooth muscle in duct walls Vasectomy: cutting Copyright © and ligating 2019, 2016, ductus 2013 Pearson deferens Education, Inc. All Rights Reserved Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved DUCTUS DEFERENS AND EJACULATORY DUCT Ureter Peritoneum Ducts: Ejaculatory duct Ductus (vas) deferens Ampulla of Urinary ductus deferens Urethra bladder Epididymis Pubis Ductus deferens ~ 45 cm long Joins duct of seminal vesicle to form ejaculatory duct Smooth muscle in duct walls Vasectomy: cutting Copyright © and ligating 2019, 2016, ductus 2013 Pearson deferens Education, Inc. All Rights Reserved  URETHRA Ureter Peritoneum Ducts: Ejaculatory duct Ductus (vas) deferens Ampulla of ductus deferens Urinary bladder Urethra Epididymis Pubis Urine and semen (at different times) Three regions Prostatic urethra: surrounded by prostate Intermediate part: in urogenital diaphragm Spongy urethra: runs through penis Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  The _______ urethra runs through the penis and opens to the outside at the external uretheral orifice. a) membranous b) spongy c) penile d) prostatic © 2019 Pearson Education, Inc.  MALE REPRODUCTIVE SYSTEM Ureter Peritoneum Ducts: Ejaculatory duct Ductus (vas) deferens Ampulla of Urinary Urethra ductus deferens Rectum bladder Epididymis Accessory glands: Pubis Seminal gland (vesicle) Prostate Penis: Bulbo-urethral gland Corpus cavernosum Corpus spongiosum Urogenital diaphragm Glans penis Anus Prepuce (foreskin) Testis Scrotum External urethral orifice Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  PENIS Male Copulatory Organ Root and shaft ends in glans penis Prepuce (foreskin): Urogenital diaphragm covers glans Root of penis Bulb of penis Crus of penis Circumcision: surgical removal of foreskin Corpora cavernosa Body of penis Corpus spongiosum 60% of males in U.S. only 15% in rest of Glans penis world Prepuce (foreskin) Dorsal vessels Corpora cavernosa and nerves Spongy urethra (a) Posterior view showing longitudinal Tunica albuginea of Studies show 60% (frontal) section of the penis Deep arteries erectile bodies Corpus spongiosum reduction in HIV risk and reduced risk for (b) Cross section of the penis with dorsal surface other reproductive Copyright © 2019, 2016, 2013 Pearson Education, at top Inc. All Rights Reserved PENIS: CROSS SECTION - Vascular spaces - Smooth muscle - Spongy network of connective tissue - Three cylindrical bodies of erectile tissue Corpus spongiosum (1): surrounds urethra expands to form glans and bulb Corpora cavernosa (2): paired dorsal erectile bodies Corpora cavernosa Dorsal vessels and nerves Spongy urethra Tunica albuginea of erectile bodies Deep arteries Corpus Copyright © 2019, 2016, 2013 Pearson spongiosum Education, Inc. All Rights Reserved MALE PERINEUM Penis Scrotum Pubic symphysis Ischial tuberosity Anus Coccyx Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  MALE REPRODUCTIVE SYSTEM Ureter Peritoneum Ducts: Ejaculatory duct Ampulla of ductus deferens Ductus (vas) deferens Urinary Accessory glands: Rectum bladder Urethra Epididymis Seminal gland (vesicle) Pubis Prostate Penis: Corpus cavernosum Bulbo-urethral gland Corpus spongiosum Urogenital diaphragm Glans penis Anus Prepuce (foreskin) Testis External urethral Scrotum orifice Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  ACCESSORY GLANDS Ducts: Ejaculatory duct Urethra Seminal gland (vesicle) Prostate Bulbo-urethral gland Has smooth muscle; contracts during ejaculation Produces viscous alkaline fluid Fructose, citric acid, coagulating enzyme (vesiculase), and prostaglandins Yellow pigment fluoresces with UV light Comprises 70% volume of semen Duct joinsCopyright ductus deferens © 2019, =Pearson 2016, 2013 ejaculatory duct Education, Inc. All Rights Reserved  ACCESSORY GLANDS Ducts: Ejaculatory duct Urethra Seminal gland (vesicle) Prostate Bulbo-urethral gland Size of peach pit Consists of smooth muscle; contracts during ejaculation Secretes milky, slightly acid fluid Contains citrate, enzymes, and prostate-specific antigen (PSA) Plays a role in sperm activation Makes up one-third of semen volume Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  ACCESSORY GLANDS Ducts: Ejaculatory duct Urethra Seminal gland (vesicle) Prostate Bulbo-urethral gland Pea-sized glands Produce thick, clear mucus during sexual arousal Lubricate glans penis Neutralize traces of acidic urine Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Sperm + SEMEN accessory gland secretions 2–5 ml semen contain 20–150 million sperm/ml Fructose for ATP production, protects and activates sperm, and facilitates sperm movement Alkaline fluid: neutralizes acidity Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  SEMEN Prostaglandins: decrease viscosity of cervix mucus stimulate reverse peristalsis in uterus Hormone relaxin and other enzymes that enhance sperm motility ATP for energy Can suppress female immune response Antibiotic chemicals destroy some bacteria Clotting factors coagulate semen initially, then liquefy it by fibrinolysin so sperm can finish journey Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Which of the following components in semen stimulates the uterus to contract in reverse peristalsis? a) Fructose b) Seminalplasmin c) Alkaline fluid d) Prostaglandins © 2019 Pearson Education, Inc. SPERMATOGENESIS Seminiferous tubules Spermatogonium (stem cell) 2n 2n Basal lamina Type A daughter cell (remains at basal lamina Mitosis as a precursor cell) 2n Growth Type B daughter cell Enters Puberty meiosis I and Meiosis (early spermatogenesis) moves to adluminal 2n Primary compartment spermatocyte Meiosis I completed n n Secondary Spermatogenesis spermatocytes Meiosis II ~90 million / day n n n n Spermatids: Early Late n n n n Spermiogenesis (late spermatogenesis) n n n n Sperm Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved (a) Events of spermatogenesis, showing the relative position of various spermatogenic cells SPERMATOGENESIS Sustentocytes: Nourish spermatogenic cells, get rid of their wastes, and move them through the tubule wall. Are shown below (there are two adjacent sustentocytes with gold cytoplasm). Have their nuclei in the basal compartment. Are joined by tight junctions, which form the blood testis barrier. Spermatogonium 64–72 days (stem cell) Basal lamina in hospitable conditions Basal compartment Type A daughter cell (remains at basal lamina as a precursor cell) Type B daughter cell Primary spermatocyte Unable to swim, Secondary but pressure of testicular fluid spermatocytes Spermatids: Early Late Adluminal compartment n pushes them into epididymis Cytoplasmic bridge Lumen of n n Gain motility seminiferous Sperm tubule and fertilizing power! (b) A portion of the seminiferous tubule wall, showing the spermatogenic cells surrounded by sustentocytes Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Spermiogenesis: Transformation of a Spermatid into a Functional Sperm Approximately 24 days Golgi apparatus Acrosomal Mitochondria vesicle Acrosome Nucleus 1 2 Spermatid Centrioles Microtubules nucleus Midpiece Head (a) 3 Flagellum Excess cytoplasm 4 Tail 5 6 7 (b) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  SPERM Head: genetic region Midpiece Head nucleus helmet-like acrosome with hydrolytic enzymes Midpiece: metabolic region Tail mitochondria produce ATP to move tail Tail: locomotor region flagellum Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  HOMEOSTASIS DISRUPTED Prostate cancer Third most common cause of cancer death in males Affects 1 in 6 men in U.S. Digital exam screening, PSA levels can be checked but have high rate of false positives Treated with surgery, sometimes radiation Metastatic prostate cancer treated with drugs that block testosterone synthesis or action Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved HOMEOSTASIS DISRUPTED Erectile dysfunction Parasympathetic nerves of penis release too little NO Inability to attain erection Affects ~50% of American men over 40 Temporary ED caused by psychological factors, alcohol or drugs (antihypertensives, antidepressants, etc.) Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  HOMEOSTASIS DISRUPTED Erectile dysfunction Chronic ED result of problems with blood vessels (atherosclerosis, varicose veins) or nervous system (stroke, penile nerve damage, multiple sclerosis) Diabetes mellitus is often underlying cause New drugs, sildenafil (Viagra) and others enhance effect of existing NO Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved END OF LECTURE 23