1. Reproductive System Objectives:
12.0 Identify structures and functions of the reproductive system
12.1 Differentiating between male and female reproductive systems
12.3 Identifying disorders of the reproductive system Examples: endometriosis, sexually transmitted diseases, prostate cancer

2. Preassessment Quiz What is a male sex cell called?
What is the male primary sex organ?
What do the primary sex organs do?
Name 2 internal male accessory organs.
Name 2 external male accessory organs.
What is a female sex cell called?
What is the female primary sex organ?
Name 2 internal female accessory organs.
Name 2 external female accessory organs.

3. Organs of the Male Reproductive System
Label and color Figure 19.1

4. 1. Testes
Enclosed in a tough, white, fibrous capsule (tunica albuginea) within the scrotum (2.)
Connective tissue thickens along inferior border of capsule and projects into testis, dividing it into 250 lobules
Each lobule contains 1-4 highly convoluted seminiferous tubules.

5. Testes, continued…..
Seminiferous tubules join in a complex network called the rete testis.
Ducts branching off the rete testis join a single, convoluted tube called the epididymis (3.)
Once the epididymis straightens, it becomes the vas deferens (4.)

6. Structure of the Testes, continued…..
What does spermatogenic mean?
Inside the seminiferous tubules:
Spermatogenic cells (specialized epithelial cells) line the walls.
They form sperm cells that collect in the lumen of the tubule.
Between the tubules are interstitial cells (“cells of Leydig”), which produce male sex hormones.

8. Testicular Cancer
Arises from the epithelial cells of the seminiferous tubules. (What are the names of these cells?)
Signs:
Painless swelling of the testis
Scrotal mass attached to the testis
Treatments:
Surgical removal of testis
Radiation and/or chemotherapy

9. Formation of Sperm Cells
Where are they formed???
Males produce sperm cells continually throughout their reproductive lives.
They collect in the lumen and pass to the epididymis, where they mature and accumulate.

10. Formation of Sperm Cells, continued…..
3 main parts:
Head
Mainly a nucleus containing 23 chromosomes
Acrosome – a projection at the end of the head that contains enzymes to assist in penetrating an egg
Midpiece - contains many mitochondria
Tail - flagella; function????

11. Spermatogenesis
Mitosis vs. meisosis

12. Spermatogenesis, continued…..

13. Male Internal Accessory Organs
Epididymis
Vas deferens
Seminal vesicle
Prostate gland
Bulbourethral glands
Semen (*)

14. 3. Epididymis
Convoluted tube that is connected to ducts within the testis, emerges from the top of the testis, descends along the posterior surface of the testis, and ascends to become the vas deferens.
Immature, nonmotile sperm mature as they are moved through the epididymis.

15. 4. Vas deferens Travels from epididymis to just behind the bladder
Unites with the duct of a seminal vesicle (5) to form an ejaculatory duct (6)
Ejaculatory duct passes through the prostate gland (7) and empties into the urethra (8)

16. 5. Seminal vesicle
Convoluted sac-like structure attached to the vas deferens near the base of the urinary bladder
Secretes:
a slightly alkaline fluid to regulate pH of tubular contents
fructose to provide energy to sperm cells
prostaglandins to stimulate muscular contractions in female reproductive organs to help move sperm cells

17. 7. Prostate Gland
Chestnut-shaped structure that surrounds proximal portion of urethra
Ducts open into urethra
Secretes thin, milky, alkaline fluid
Neutralizes acidic fluid containing sperm cells
Neutralizes acidic vaginal secretions
Enhances motility of sperm cells

18. 10. Bulbourethral Glands AKA, Cowper’s glands
Located inferiorly to the prostate gland, within muscle fibers of external urethral sphincter
Secretes mucuslike fluid to lubricate the end of the penis for sexual intercourse
(As always, females do most of the work of producing lubricating fluid. :)

19. Semen The fluid the male urethra releases during ejaculation
Consists of:
Sperm cells
Secretions of the seminal vesicles, prostate gland, and bulbourethral glands
About 120 million sperm cells/mL semen
2-5 mL semen released at a time

20. Enlarged Prostate Gland
Where is the prostate gland located???
So, what would happen if the prostate gland became enlarged?
Testing for prostate cancer:
Rectal exam
PSA (prostate-specific antigen) blood test to check for a cell surface protein found on prostate cells
Ultrasound

21. Treatment Options for Enlarged Prostate Gland
Surgical removal of prostate
Radiation
Microwave energy delivered through a probe inserted into the urethra or rectum
Freeze tumor with liquid nitrogen delivered by a probe through the skin
Others

22. Male External Accessory Organs
Scrotum
Penis

23. 2. Scrotum 1.Pouch of skin that houses the testes
2. Medial septum divides it into 2 chambers
3. Protects and aids in temperature regulation of the testes

24. 11. Penis Conveys urine and semen through the urethra to the outside
The body (shaft) has 3 columns of erectile tissue:
A pair of dorsally located corpora cavernosa (12)
A single, ventral corpus spongiosum (13)

25. 11. Penis, continued….. Corpus spongiosum: Glans penis
Urethra passes through it
Enlarges at distal end to form the glans penis (14)
Glans penis
Covers the ends of the corpora cavernosa
Bears urethral opening (orifice)
Contains sensory receptors
Prepuce (15) – fold of skin that covers the glans penis; removed in circumcision

26. Erection, Orgasm, and Ejaculation
Sexual stimulation leads to parasympathetic nerve impulses from the spinal cord to release NO, a vasodilator.
Arteries leading to the penis dilate.
Pressure from arterial blood filling the vascular spaces of erectile tissue compress the penis veins.
Venous blood cannot flow out of the penis, erectile tissue fills, and an erection is produced.

27. Erection, Orgasm, and Ejaculation, continued…..
Emission and ejaculation accompany male orgasm.
Emission: the movement of sperm cells from the testes and secretions from the prostate gland and seminal vesicles into the urethra.
Ejaculation: the process of forcing semen through the urethra to the outside

28. Erection, Orgasm, and Ejaculation, continued…..
Emission and ejaculation events occur so that:
Fluid from bulbourethral glands is expelled first
Fluid from the prostate gland is released next
Then sperm cells
Lastly, fluid from the seminal vesicles

29. Erection, Orgasm, and Ejaculation, continued…..
Following ejaculation:
Arteries that supply erectile tissue contract,
Veins of the penis “drain” the spaces of the erectile tissue,
Penis returns to flaccid state

30. Hormonal Control of Male Reproductive Functions
Hormones are secreted by:
Hypothalamus
Anterior pituitary gland
Testes
Functions:
Development of sperm cells
Development of secondary sex characteristics

31. Hypothalamic and Pituitary Hormones
Hypothalamus secretes gonadotropin-releasing hormone (GnRH) to anterior pituitary gland
In response, anterior pituitary gland secretes gonadotropins:
Luteinizing hormone (LH)
Follicle-stimulating hormone (FSH), aka interstitial cell-stimulating hormone (ICSH)

32. Hypothalamic and Pituitary Hormones, continued…..
FSH (ICSH) promotes development of ___________.
Testicular interstitial cells secrete male sex hormones.
LH stimulates supporting cells of seminiferous tubules to respond to testosterone.
Testicular interstitial cells

33. Hypothalamic and Pituitary Hormones, continued…..
FSH + testosterone + supporting cells stimulate spermatogenic cells to give rise to ______________.
Supporting cells secrete inhibin, a hormone which inhibits the anterior pituitary gland, preventing secretion of FSH.
Sperm cells

34. Male Sex Hormones Called “Androgens” (???) Where are they produced?
Most in testicular interstitial cells, but small amounts in adrenal cortex
What is the main male sex hormone?
Testosterone production begins before birth, continues a few weeks after, and then ceases until puberty.

35. Actions of Testosterone
Stimulates enlargement of testes and male accessory organs
Stimulates development of male secondary sex characteristics:
Increased growth of body hair
Enlargement of the larynx and thickening of the vocal cords
Thickening of the skin
Muscle growth, widening of shoulders, narrowing of waist
Thickening and strengthening of bones

36. Actions of Testosterone, continued…..
Increases rate of cellular metabolism
Increases rate of RBC production

37. Regulation of Male Sex Hormones
More testosterone = more developed secondary sex characteristics
Increased levels of testosterone inhibit the hypothalamus.
What effects would inhibition of the hypothalamus have?

38. Organs of the Female Reproductive System
Label Figure 19.7

39. 1. Ovaries Ovarian tissues are subdivided:
Inner medulla
Outer ______
Ovarian cortex appears granular due to tiny masses of cells called ovarian follicles (19).

40. Ovaries, continued….. Primordial(???) follicles: Form before birth
Found in outer region of cortex
Each contains a SINGLE primary oocyte, surrounded by follicular cells (specialized epithelial cells)
No new primary follicles are formed during life.
Millions of oocytes at birth; 400,00 at puberty; released during reproductive years

41. Oogenesis:
The process of egg cell formation

42. Follicular Maturation

43. Ovulation
The process of releasing a secondary oocyte (18) and its associated polar body from the ovary

44. Female Internal Accessory Organs
Uterine tubes
Uterus
Vagina

45. 2. Uterine Tubes
Opens near the ovaries and travels medially into the uterus
Infundibulum (16): the funnel-shaped end of the uterine tube at the ovary
Fimbriae (3): finger-like projections at the end of the infundibulum

46. Uterine Tubes, continued…..
Oocytes are moved into and along the tubes by:
Ciliated epithelial cells
Peristaltic contractions
Fertilization occurs in the uterine tubes, and the oocyte becomes an egg (ovum)

47. 4. Uterus Hollow, muscular, pear-shaped organ
Located medially in the anterior portion of the pelvic cavity
Body of the uterus (22): upper 2/3
Cervix (5):
lower 1/3
Connects to vagina (6)
Cervical orifice (24): opening from uterus to vagina

48. Uterine Wall Endometrium(20)– mucosal layer
Myometrium(21) - _______ layer
Perimetrium(23) – serosal (thin, watery-filled) layer

49. 6. Vagina
Fibromuscular tube that extends from the uterus to the outside of the body
Located posterior to urinary bladder (11) and urethra (12), and anterior to rectum (14) (see Fig diagram)
Functions:
Conveys uterine secretions
Receives penis during intercourse
Channel for birth

50. Vaginal Wall Inner mucosal layer Middle muscular layer
LACKS mucosal glands
Mucous comes from uterine glands and vestibular glands at mouth of vagina
Middle muscular layer
Mostly smooth muscle (involuntary)
Bulbospongiosus muscle (voluntary) closes off vaginal orifice (7)

51. Vaginal Wall, continued…..
3. Outer fibrous layer
Dense connective tissue
Attaches vagina to surrounding organs
Urethra (13)
Rectum (14)

52. Female External Accessory Organs
Labia majora
Labia minora
Clitoris
Vestibule

53. 9. Labia Majora Enclose and protect other external accessory organs
Correspond to male scrotum
Composed of 2 rounded folds of adipose tissue, smooth muscle, and skin that lie on either side of the other accessory organs
Anterior ends join to form the mons pubis

54. 8. Labia Minora 2 flattened folds that lie between the labia majora
Join with the labia majora posteriorly
Merge anteriorly to form a protective, hoodlike covering around the clitoris

55. 10. Clitoris
Small projection at the anterior end of the vulva (the external accessory organs that surround the vaginal opening)
Corresponds to male penis:
2 columns of erectile tissue (corpora cavernosa)
Glans, erectile tissue at anterior end, contains sensory nerve endings
So what would be its function?

56. Vestibule The space enclosed between the labia minora
Vestibular glands:
2 at the opening of the vagina
Correspond to male bulbourethral glands (FUNCTION?)
Vestibular bulbs:
lie beneath the mucosa of the vestibule on either side
A mass of erectile tissue

57. Erection , Lubrication, and Orgasm
Where is erectile tissue located?
Once these tissues are stimulated, parasympathetic nerve impulses release nitric oxide (a vasodilator).
What effect would a vasodilator have?
If stimulation is sufficient, vestibular glands secrete mucus into the vagina. (WHY??)

58. Erection , Lubrication, and Orgasm, continued…..
The muscles of the perineum (area b/t the anus and external accessory organs) and walls of the uterus and uterine tubes contract rhythmically.
Why would all these areas need to contract?
Contractions help transport sperm to the upper ends of the uterine tubes.

59. Hormonal Control of Female Reproduction Functions
Hormones are secreted by:
Hypothalamus
Anterior pituitary gland
Ovaries
Functions:
Control development and maintenance of female secondary sex characteristics
Maturation of female sex cells
Changes during monthly reproductive cycle
Where are the male hormones secreted?
What are the functions of the male hormones?

60. Female Sex Hormones
About age 10, hypothalamus begins secreting GnRH, which stimulates _____________ to release _______ and _______.
Female sex hormones belong to 2 basic groups:
Estrogens (estradiol, estrone, and estriol)
Progesterone

61. Estrogens Produced primarily in the ovaries
Stimulate enlargement of ALL accessory organs
Develop secondary sex characteristics:
Development of breasts and ductile system of mammary glands
Increased deposits of adipose tissue subcutaneously and in breasts, thighs, and buttocks
Increased vascularization of the skin
What are the male secondary sex characteristics?

62. Progesterone Also produced primarily in the ovaries
Promotes changes in the uterus during reproductive cycle
Affects mammary glands
Helps regulate secretion of gonadotropins from _________ gland

63. Female Reproductive Cycle
AKA, menstrual cycle
Regular, recurring changes in the uterine lining
Ovarian cycle: changes in the ovaries (occurs along with menstrual cycle)
Menarche: female’s first menstrual cycle

64. Female Reproductive Cycle, continued…..
Hypothalamus secretes ____________, which stimulates the _________ to secrete _______ and ______.
FSH stimulates maturation of an ovarian follicle.
LH stimulates ovarian cells to produce testosterone, which is used to produce estrogens.

65. Female Reproductive Cycle, continued…..
Follicular cells produce estrogens:
Maintain secondary sex characteristics
Cause uterine lining to thicken
While follicle matures (1st 14 days of cycle), the estrogens secreted INHIBIT release of LH by the anterior pituitary gland.
Once follicle is mature, LH is released.

66. Female Reproductive Cycle, continued…..
The released store of LH weakens and ruptures the bulging follicular wall, releasing the oocyte from the ovary. (What is this step called?)
The “empty follicle” fills with blood, clots, and forms a temporary glandular structure called the “corpus luteum”.
Corpus luteum secretes progesterone and estrogens.

67. Female Reproductive Cycle, continued…..
Corpus luteum secretes progesterone and estrogens:
Progesterone causes the endometrium to become more vascular and glandular.
Estrogens and progesterones inhibit release of LH and FSH from _______, so no new follicles develop while corpus luteum is active.

68. Female Reproductive Cycle, continued…..
If egg is unfertilized, corpus luteum begins to degenerate on about day 24 of cycle, becoming a “corpus albicans”
What would happen to estrogen and progesterone levels when the corpus luteum “dies”?
What do you think is the main source of estrogen and progesterone in a pregnant female?

69. Female Reproductive Cycle, continued…..
In response to decreased levels of estrogen and progesterone, blood vessels in the endometrium constrict:
No more nutrients and oxygen to thickened uterine lining
Tissues die and slough off
Blood escapes from damaged capillaries

70. Female Reproductive Cycle, continued…..
Because estrogen and progesterone levels are low, the hypothalamus and anterior pituitary glands are no longer inhibited, and cycle starts anew.

71. Female Reproductive Cycle, continued…..
Figure 19.13, p.514
Figure 19.13, p.514

72. Menopause The end of monthly cycles
Caused by aging of ovaries which, after about 35 years of cycling, contain too few primary follicles to have one mature each month.
Thus, no ovulation occurs, and blood levels of estrogen and progesterone plummet, causing changes in secondary sex characteristics.

73. Mammary glands
Accessory organs specialized to secrete milk following pregnancy
Contained within the breasts
Mammary glands are composed of lobes, which contain alveolar glands that lead to an alveolar duct, which leads to a lactiferous duct, which leads to a nipple and opens to the outside.
Males have mammary glands which do not develop at puberty. (They lack ovarian hormones.)

74. Critical Thinking
Why must the chromosome number be halved in sperm cells and oocytes?
Sometimes a sperm cell fertilizes a polar body rather than an oocyte. An embryo does not develop, and the fertilized polar body degenerates. Why is a polar body unable to support development of an embryo?

75. Critical Thinking, continued…..
3. Some men are unable to become fathers because their spermatids do not mature into sperm. Injection of their spermatids into their partner’s secondary oocytes sometimes results in conception. A few men have fathered healthy babies this way. Why would this procedure work with spermatids, but not with primary spermatocytes?

77. What is the largest cell in the human body?
What is the smallest cell?