PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART A 16 The Reproductive System

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Reproductive System  Function -  To produce and nuture sex cells and transport them to sites of fertilization

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of the Reproductive System  Gonads—primary sex organs  Testes in males  Ovaries in females  Gonads produce gametes (sex cells) and secrete hormones  Sperm—male gametes  Ova (eggs)—female gametes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Male Reproductive System Overview  Primary Sex Organs = Testes  Accessory Sex Organs  Internal and External Organs and Glands  Duct system  Epididymis  Ductus (vas) deferens  Urethra

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Male Reproductive System Overview  Accessory organs  Seminal vesicles  Prostate  Bulbourethral glands  External genitalia  Penis  Scrotum

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Male Reproductive System Figure 16.2a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Male Reproductive System Figure 16.2b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Testes  Oval structures inside the sac-like scrotum separated by a septum  Contain seminiferous tubules  Cross-section contains  Spermatogenic cells - make sperm  Interstitial (between tubule) cells - make hormones (testosterone)  Sperm

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Testes Figure 16.1

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Testes  Seminiferous tubules unite to form ducts to the epididymis  Tightly coiled structures  Function as sperm-forming factories

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Testes Figure 16.1

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis  Sperm are made by spermatogenic cells in the lumen of the seminiferous tubules  Mature in the epididymis  Tad-pole shaped

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of a Mature Sperm Cell  The only human flagellated cell  Head  Contains DNA  Acrosome—“helmet” on the nucleus  Breaks down and releases enzymes to help the sperm penetrate an egg  Midpiece  Wrapped by mitochondria for ATP generation

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structure of a Sperm Figure 16.5b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structure of a Sperm Figure 16.5a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis  Production of sperm cells  Begins at puberty and continues throughout life  Occurs in the seminiferous tubules

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis  Spermatogonia (stem cells) undergo rapid mitosis to produce more stem cells before puberty  Follicle-stimulating hormone (FSH) modifies spermatogonia division  Primary Spermatocyte - form during early development  Secondary Spermatocytes - form during puberty  Spermatids - mature into sperm cells

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis (Overview) Figure 16.3

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis Figure 16.3 (1 of 2)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis Figure 16.3 (2 of 2)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermatogenesis  Primary spermatocytes undergo meiosis  One primary spermatocyte produces four haploid spermatids  Spermatids—23 chromosomes (half as much material as other body cells)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Human Life Cycle  Union of a sperm (23 chromosomes) with an egg (23 chromosomes) creates a zygote (2n or 46 chromosomes)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Human Life Cycle Figure 16.4

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Spermiogenesis  Late spermatids are produced with distinct regions  Head  Midpiece  Tail  Sperm cells result after maturing of spermatids  Spermatogenesis (entire process, including spermiogenesis) takes 64 to 72 days

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Internal Accessory Organs  Sperm cells move to epididymis via rhythmic peristalsis  Sperm cells do not “swim” until after ejaculation

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

Duct System  Epididymis  Ductus (vas) deferens  Urethra

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Epididymis  Comma-shaped, tightly coiled threadlike tube  6 meters long!  Becomes the vas deferens  Functions to mature spermatids and store sperm cells (at least 20 days)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Epididymis Figure 16.1

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ductus Deferens (Vas Deferens)  45 cm long  Carries sperm from the epididymis to the ejaculatory duct  Moves sperm by peristalsis

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ductus Deferens (Vas Deferens) Figure 16.1

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Ejaculatory Duct  Passes through the prostate and empties into the urethra

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Urethra  Extends from the base of the urinary bladder to the tip of the penis  Carries both urine and sperm  Sperm enters from the ejaculatory duct

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Urethra Figure 16.2b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Accessory Organs  Seminal vesicles  Prostate  Bulbourethral (Cowper’s) glands

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Seminal Vesicles  Located at the base of the bladder  Produces a thick, alkaline, yellowish secretion  60% of semen  Fructose (sugar)  Vitamin C  Prostaglandins - stimulate contractions in female to move sperm  Neutralizes the pH in the vagina

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Accessory Organs Figure 16.2b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Prostate  Encircles the upper part of the urethra  Secretes an alkaline milky fluid  Helps to activate sperm  Can enlarge with age - PSA levels increase  Cancer?

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Prostate Figure 16.2a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

Bulbourethral Glands - “Cowper’s Gland”  Pea-sized gland inferior to the prostate  Produces a thick, clear mucus  Cleanses the urethra of acidic urine  Serves as a lubricant during sexual intercourse

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Bulbourethral Glands - “Cowper’s Gland” Figure 16.2a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Semen  Mixture of sperm and accessory gland secretions  pH 7.5  Semen inhibits bacteria

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings External Genitalia  Scrotum  Penis

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings External Genitalia Figure 16.2a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings External Genitalia  Scrotum  Divided sac of skin outside the abdomen  Maintains testes at 3°C lower than normal body temperature to protect sperm viability

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings External Genitalia  Penis  Delivers sperm into the female reproductive tract  Regions of the penis  Shaft  Glans penis (enlarged tip)  Prepuce (foreskin)  Folded cuff of skin around proximal end  Often removed by circumcision

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings External Genitalia Figure 16.2a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings External Genitalia  Internally there are three areas of spongy erectile tissue around the urethra  Erections occur when this erectile tissue fills with blood during sexual excitement

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Erections, Orgasm, Ejaculation, Testosterone  Read pg  Complete the fill in the blank worksheet