1. The Reproductive Systems
Chapter 21
The Reproductive
Systems

2. Common Structures & Functions
Systems adapted for development of sperm or ova followed by successful fertilization, development, and birth of offspring
Sex hormones in both genders important in development of secondary sexual characteristics and normal reproductive system activity

3. Male Reproductive System
Structural plan - organs classified as essential or accessory
Essential organs of reproduction are the gonads (testes), which produce sex cells (sperm or spermatozoa)
Accessory organs of reproduction
Ducts - passageways that carry sperm from testes to exterior
Sex glands - produce protective and nutrient solution for sperm
External genitals

4. Testes Located in scrotum - lower temperature
Covered by tunica albuginea, which divides testis into lobules containing seminiferous tubules
Interstitial cells produce testosterone

5. Testes Spermatogenesis is process of sperm production
Sperm precursor cells called spermatogonia
Meiosis produces primary spermatocyte, which forms four spermatids with 23 chromosomes

6. Testes Spermatozoa - highly specialized cells
Head contains genetic material
Acrosome contains enzymes to assist sperm in penetration of ovum
Mitochondria in midpiece provide energy for movement

7. Testes Production of testosterone by interstitial cells
Testosterone “masculinizes” and promotes development of male accessory organs
Promotes and maintains development of male accessory organs
Stimulates protein anabolism and development of muscle strength

8. Quick Check What is the name of the male gonads?
In what specific structures of the gonad are the sperm produced?
What hormone is produced in the male gonad?

9. Male Reproductive Ducts
Ducts through which sperm pass after exiting testes until they exit from the body
Epididymis - single, coiled tube about 6 m in length; lies along the top and behind the testis in the scrotum
Sperm mature and develop the capacity for motility as they pass through epididymis
Ductus (vas) deferens - receives sperm from the epididymis and transports them from scrotal sac through the abdominal cavity
Passes through inguinal canal
Joins duct of seminal vesicle to form the ejaculatory duct

10. Male Accessory Sex Glands
Accessory, or supportive, sex glands help produce semen: mixture of sperm and secretions of accessory sex glands
Averages 3 to 5 mL per ejaculation
Each milliliter containing about 100 million sperm

11. Male Accessory Sex Glands
Seminal vesicles
Pouchlike glands that produce about 60% of seminal fluid volume
Secretion is yellowish, thick, and rich in fructose to provide energy needed by sperm for motility
Less than 5% of seminal fluid volume

12. Male Accessory Sex Glands
Prostate gland
Shaped like a doughnut and located below bladder
Urethra passes through the gland
Secretion represents % of seminal fluid volume - is thin and milk-colored
Activates sperm and is needed for ongoing sperm motility

13. Male Accessory Sex Glands
Bulbourethral (Cowper’s) glands
Resemble peas in size and shape
Secrete mucus-like fluid constituting less than 5% of seminal fluid volume

14. Male External Genitals
Penis and scrotum called genitalia
Penis has three columns of erectile tissue:
two dorsal columns called corpora cavernosa
one ventral column surrounding urethra called corpus spongiosum
Glans penis covered by foreskin (prepuce)
Surgical removal of foreskin is called circumcision

15. Quick Check What duct leads from the epididymis?
Which organs produce the fluid in semen?
What is the function of erectile tissue?

16. Female Reproductive System
Structural plan—organs classified as essential or accessory
Essential organs are gonads (ovaries), which produce sex cells (ova)
Accessory organs of reproduction
Ducts or modified ducts
Oviducts
Uterus
Vagina
Sex glands - including the breasts
External genitals

17. Ovaries
Paired glands attached to ligaments in pelvic cavity on each side of uterus
Microscopic structure
Ovarian follicles - contain an oocyte, which is an immature sex cell (about 1 million at birth)
About 350 to 500 mature follicles ovulate during the reproductive lifetime of most women - sometimes called graafian follicles
Corpus luteum forms after ovulation

18. Ovaries
Oogenesis - this meiotic cell division produces daughter cells with equal chromosome numbers (23)
Production of estrogen and progesterone
Granulosa cells surrounding the oocyte in the mature and growing follicles produce estrogen
Estrogen causes development and maintenance of secondary sex characteristics
Corpus luteum produces progesterone
Progesterone stimulates secretory activity of uterine epithelium and assists estrogen in initiating menses

19. Quick Check What is the name of the female gonads?
Where are the female gonads located?
What is oogenesis?
What hormones are produced by the female gonads?

20. Female Reproductive Ducts
Uterine (fallopian) tubes (oviducts)
Extend about 10 cm from uterus into abdominal cavity
Expanded distal end surrounded by fimbriae
Mucosal lining of tube is directly continuous with lining of abdominal cavity

21. Female Reproductive Ducts
Uterus - composed of body, fundus, and cervix
Lies in pelvic cavity just behind urinary bladder
Myometrium is muscle layer
Endometrium lost in menstruation
Menopause - end of repetitive menstrual cycles (about 45–50 years of age)

22. Female Reproductive Ducts
Vagina
Distensible tube about 10 cm long
Located between urinary bladder and rectum in the pelvis
Receives penis during sexual intercourse and is birth canal for normal delivery of baby at end of term of pregnancy
Accessory or supportive sex glands

23. Female Accessory Glands
Bartholin’s (greater vestibular) glands
Secrete mucus-like lubricating fluid
Ducts open between labia minora

24. Female Accessory Glands
Breasts
Located over pectoral muscles of thorax
Size determined by fat quantity more than amount of glandular (milk-secreting) tissue
Lactiferous ducts drain at nipple, which is surrounded by pigmented areola
Lymphatic drainage important in spread of cancer cells to other body areas

25. Quick Check What is another name for the uterine tubes?
What three major functions does the uterus perform?
What substance is conducted through lactiferous ducts?

26. Female External Genitals
Vulva includes mons pubis, clitoris, orifice (meatus) of urethra, Bartholin’s gland, vagina, labia minora and majora, and hymen
Perineum—area between vaginal opening and anus
Surgical cut during childbirth called episiotomy

27. Menstrual Cycle
Involves many changes in the uterus, ovaries, vagina, and breasts

28. Menstrual Cycle

29. Summary of Male and Female Reproductive Systems
In men and women the organs of the reproductive system are adapted for the specific sequence of functions that permit development of sperm or ova after the successful fertilization and then the normal development and birth of offspring
The male organs produce, store, and ultimately introduce mature sperm into the female reproductive tract

30. Summary of Male and Female Reproductive Systems
The female system produces ova, receives the sperm, and permits fertilization followed by fetal development and birth, with lactation afterward
Production of sex hormones is required for development of secondary sex characteristics and for normal reproductive functions in both sexes

31. Quick Check Which female structure is made of erectile tissue?
What is another term for menses?
Which hormone reaches a high peak just before ovulation?