1. Reproductive System
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2. 21.1 The male reproductive system
Male genital tract
Includes structures in fig and Table 21.1 on the following slides
Sperm produced by seminiferous tubules of testes
Undergo maturation in the epididymis
Maturation involves gaining of motility
The Acrosome is “the cap” portion of the sperm that contains the enzymes needed to penetrate the egg.
Sperm pass through vas deferens where products are secreted by glands that contribute to semen
Prostate
Bulbourethral glands
Seminal vesicles
Semen is alkaline and contains fructose and prostaglandins

3. The male reproductive system
Fig. 21.1

4. Male reproductive organs
Table 21.1

5. The male reproductive system cont’d.
Orgasm in males
Penis is the organ of sexual intercourse
Glans is covered by prepuce (foreskin)
Circumcision removes foreskin
Composed of 3 bodies of erectile tissue
Erection-arteries leading into erectile tissue relax, venous drainage is compressed- erectile tissue fills with blood
Erectile dysfunction-erectile tissue fails to fill enough to compress venous drainage
Drugs like Viagra increase penile blood flow
Height of excitation- increased heart rate and respiratory rate, smooth muscle contractions propel semen through urethra
Males have refractory period after orgasm

6. The male reproductive system cont’d.
Male gonads, the testes
Develop in the abdomen, migrate to scrotum
Crypt orchidism-failure of testes to migrate-infertility
Extra-abdominal location allows thermoregulation
Spermatogenesis requires lower temperatures
Seminiferous tubules
Located within lobules of testes
Site of spermatogenesis-newly formed cells move away from outer walls into lumen and undergo meiosis
Sperm structure- refer to fig on following slide
Sertoli cells- nourish developing sperm
Interstitial cells- between tubules, secrete testosterone

7. Testis and sperm
Fig 21.3

8. The male reproductive system cont’d.
Hormonal regulation in males
Gonadotropin releasing hormone from the hypothalamus causes the anterior pituitary to release FSH and LH
FSH targets seminiferous tubules- stimulates sperm production
LH stimulates interstitial cells of the testes to produce testosterone
All are regulated by negative feedback
Testosterone is responsible for male secondary sex characteristics

9. Hormonal control of the testes
Fig. 21.4

10. 21.2 Female reproductive system
The genital tract
Ovaries are within the abdominal cavity
Eggs- ovulated from the surface of the ovary
Oviducts extend from the ovaries to the uterus
Not directly attached to ovaries
Ends of oviducts have fimbriae- sweep the ovulated eggs into the opening of the oviduct
Egg migrates along oviduct propelled by cilia
If not fertilized, only is viable for 24 hours
Fertilization occurs midway through oviduct
Zygote enters the uterus, implants in the uterine wall (endometrium)
Uterus is a thick-walled muscular organ
Neck of the uterus (cervix) leads into the vagina

11. The female reproductive tract
Fig. 21.5

12. Female reproductive organs
Table 21.2

13. Female reproductive system cont’d.
External genitals
Collectively called the vulva
Labia majora- outer skin folds
Labia minora- inner skin folds
Glans clitoris- composed of erectile tissue like the penis
Cleft between labia minora contains the urethra and vestibule of the vagina
Vagina may be partially closed by the hymen
Note that in the female the reproductive and urinary systems are entirely separate, unlike males

14. External genitals of the female
Fig. 21.6

15. Female reproductive system cont’d.
Orgasm in females
Labia minora, vaginal walls,clitoris become engorged
Erection of nipples
Secretion of vaginal fluids, mucus for lubrication
Vagina is the organ of intercourse,clitoris plays an important role in excitation and orgasm
Height of excitation- increased heart rate, blood pressure, and smooth muscle contractions
Females have no refractory period following orgasm

16. 21.3 Female hormone levels The ovarian cycle
Many follicles in the cortex of ovary
Each contains an oocyte
A female is born with about 2 million follicles, but they decrease in number to about 400,000 by puberty
Only about 400 mature throughout life, 1 per month during reproductive years
Ovarian cycle consists a sequence of changes
Primary follicles develop into secondary follicles
Secondary follicles develop into vesicular follicles
Vesicular follicle is fluid filled, bulges on ovarian surface

17. Female hormone levels cont’d.
Ovarian cycle con’td.
Oogenesis is initiated as follicle matures
Primary oocyte divides producing one haploid secondary oocyte and one polar body
Vesicular follicle ruptures and releases the secondary oocyte and the polar body both enclosed in a membrane- ovulation
Vesicular follicle turns into a temporary endocrine structure called a corpus luteum (CL) following ovulation
If fertilized in the oviduct, the secondary oocyte then undergoes meiosis II
One egg and a polar body are produced
The fertilized egg contains the diploid number of chromosomes
If no fertilization occurs, the CL degenerates in 10 days

18. Female hormone levels cont’d.
Phases of the ovarian cycle
Follicular phase-FSH stimulates follicle development
Mature follicle begins to produce estrogen
Estrogen feeds back and shuts of FSH-negative feedback
Estrogen spike stimulates the release of a large amount of GnRH from hypothalamus
Leads to an increase in LH production
Induces ovulation at around the 14th day of a 28 day cycle
Luteal phase-LH promotes development of the CL
CL produces progesterone and some estrogen
As progesterone rises it feeds back and shuts off LH-negative feedback
This causes degeneration of the CL

19. Ovarian cycle
Fig. 21.7

20. Hormonal control of the ovaries
Fig. 21.8

21. Female hormone levels cont’d.
The uterine cycle-based on an average 28 day cycle
Days 1-5 menstrual phase
Drop in progesterone causes endometrium to break down and slough off as menstrual flow
Days 6-13 proliferative phase
Increased estrogen production by maturing follicle
Causes proliferation and thickening of the endometrium
Day 14- ovulation occurs
Day secretory phase
Progesterone from the CL maintains the thickened endometrium
Stimulates glandular secretions in endometrium
If fertilization does not occur, the CL breaks down and progesterone decreases brings about the menstrual phase

22. Female hormone levels
Fig. 21.9

23. Ovarian and uterine cycles
Table 21.3

24. Female hormone levels cont’d.
Fertilization and pregnancy
Zygote begins cell divisions while still in the oviduct
Oviduct narrows to slow passage into the uterus
Allows the uterus to be fully in secretory phase to support pregnancy
Implantation occurs when embryo migrates into uterus
Embryo at this stage consists of a ball of cells
Embryo begins to produce human chorionic gonadotropin (HCG)
Has LH-like activity to maintain CL to keep progesterone supply
Trophoblast cells of embryo begin development of the placenta
Will supply fetus with oxygen and nutrients
Placenta will also produce progesterone and estrogen

25. Female hormone levels cont’d.
Pregnancy cont’d.
In summary- a source of progesterone is needed to keep the uterus in secretory phase
Earliest source is CL
To maintain the CL the embryo produces HCG to give the placenta time to develop
Once the placenta is functional, HCG decreases and the CL degenerates
The placenta is now the source of progesterone
Keeps uterus in secretory phase
Suppresses the anterior pituitary so no new follicles form

26. Implantation
Fig

27. Female hormone levels cont’d.
Estrogen and progesterone-both have effects other than those in the ovarian and uterine cycles
Estrogen
Maintains female secondary sex characteristics
Breast development, axillary and pubic hair, subcutaneous fat deposition
Wider pelvis
Progesterone
Also needed for breast development

28. Female hormone levels cont’d.
Menopause
Generally occurs between the ages of 44-55
Ovaries become nonresponsive to GnRH
Perimenopause-time when cycles become irregular
Can last 10 years
Hot flashes, dizziness, headaches, insomnia
Most women experience only mild symptoms or none at all
Hormone replacement therapy
New information suggests that disadvantages outweigh advantages

29. 21.4 Control of reproduction
Birth control methods
Abstinence is the most effective!
Oral contraceptives-contain estrogen and progesterone
Shut down both LH and FSH so no ovulation
Intrauterine device-IUD
Recently new IUD’s have become available
Alter the environment of uterus so implantation does not occur
Barrier methods
Diaphragm- covers the cervix; must be used with spermicide
Condom-also protects against STD’s; male and female versions available
implants and injections-progesterone or combinations of estrogen and progesterone
Function like oral contraceptives but more long term

30. Control of reproduction cont’d.
Birth control methods cont’d.
Natural family planning (Rhythm Method)
Effectiveness depends upon education and compliance
Generally about 70% effective
Refrain from intercourse approximately 3 days before to 3 days after ovulation
But ovulation is difficult to predict
Birth control methods and efficacies are summarized on the following slide

31. Common birth control methods
Table 21.4

32. Control of reproduction cont’d.
Morning-after pills
Emergency contraception
Taken after intercourse has occurred
Two types, both disrupt uterine environment
Preven- series of progesterone pills; disrupts normal cycle making implantation difficult
RU-486- mifepristone; blocks progesterone receptors in the uterus so that the endometrium is sloughed off

33. Control of reproduction cont’d.
Infertility-failure to conceive after 1 year of unprotected intercourse
15% of couples are infertile
40% due to male, 40% due to female, 20% due to both
Causes
Low sperm count or sperm abnormalities
Sedentary life style, smoking, alcohol consumption all contribute
Body weight in women
Obesity- ovulation failure
Pelvic inflammatory disease in women- blocks oviducts
Endometriosis-uterine tissues outside the uterus; can block oviducts

34. Control of reproduction cont’d.
Assisted reproductive technologies (ART)
Artificial insemination by donor (AID)
Sperm are placed in the vagina
Donor may be the woman’s partner or from another selected individual
Variation- intrauterine insemination (IUI)- uterus is prepared by administration of fertility drugs and sperm are placed directly in the uterus
In vitro fertilization (IVF)
Immature eggs are harvested and maturity occurs in glassware
Sperm are added and fertilization takes place
Embryos are then implanted

35. Control of reproduction cont’d.
ART cont’d.
Gamete intrafallopian transfer (GIFT)
Eggs and sperm are harvested and then placed in the oviducts immediately after they have been combined
Can also wait until zygotes form and then these are placed in the oviducts
1 step procedure
Surrogate mothers
Embryos from a couple are implanted into another woman for development to occur
Intracytoplasmic sperm injection (ICSI)
A single sperm is injected into an egg and then placed in the uterus or oviduct

36. 21.5 Sexually transmitted diseases
AIDS-acquired immunodeficiency syndrome
Caused by HIV (human immunodeficiency virus)
Infects helper T lymphocytes
Helper T’s are necessary for B lymphocytes to make antibodies and for cytotoxic T lymphocytes to kill virus-infected cells
Transmitted by sexual contact including vaginal and anal intercourse, and oral-genital contact
Sharing of hypodermic needles is also a means of transmission
Intrauterine transmission is also possible, as well as infection through breast-feeding
38.6 million adults and 3.2 million children are infected worldwide
Homosexual males are the largest population affected, with heterosexual females showing the greatest rate of increase

37. HIV, the AIDS virus
Fig

38. Sexually transmitted diseases cont’d.
Categories of an HIV infection
Category A stage- helper T cell count is at least 500 per mm3
Immune function is still normal
HIV is replicating rapidly and the helper T population drops rapidly
Some people show mild mononucleosis-like symptoms
HIV test will not yet be positive but the person is contagious
After a period of time, antibodies against HIV begin to appear and a blood test will be positive
As long as the immune system stays ahead of the number of virus-infected cells, the person has an ability to fight off infections

39. Sexually transmitted diseases cont’d.
Categories of HIV infection cont’d.
Category B stage- helper T count is per mm3
Can occur months to years after infection
Swollen lymph nodes, unexplained fever, night sweats, cough, diarrhea
CNS signs also possible- depression, loss of memory
Secondary infections may begin- commonly thrush, shingles, herpes simplex

40. Sexually transmitted diseases cont’d.
Categories of HIV infection cont’d.
Category C- helper T cell count below 200 per mm3
Patient is extremely thin and weak
Opportunistic infections
From decreased immune function
Pneumocystis carinii pneumonia
Mycobacterium avium complex
Toxoplasmosis encephalitis
Kaposi’s sarcoma
Cytomegalovirus
Death results from any of the opportunistic infections

41. Sexually transmitted diseases cont’d.
Treatment for HIV
“Life cycle” of the virus
HIV is a retrovirus-enveloped virus with a spike for attachment
Attaches to a receptor on a helper T cell and enters the cell
Viral genetic material is released along with the enzyme reverse transcriptase-reverse transcription occurs
Directs the synthesis of viral DNA from viral RNA
Integration-viral enzyme integrase inserts the viral DNA into the host cell genome
Directs the synthesis of more viral RNA
Some RNA is used for synthesis of viral proteins, which are cut into small pieces by cleavage
Assembly and budding of new virus particles occurs

42. Reproduction of HIV
Fig

43. Sexually transmitted diseases cont’d.
As HIV particles are released, part of the envelope comes from the T cell membrane, and the spike from proteins encoded by viral genes
Drug therapy
Highly active antiretroviral therapy (HAART)
Combination of drugs
Entry inhibitors
Reverse transcriptase inhibitors- like AZT
Integrase inhibitors
Protease inhibitor
Can stop progression of infection for long periods in many cases
No cure, however, because when discontinued the virus progression continues

44. Sexually transmitted diseases cont’d.
Treatments for HIV cont’d.
Vaccines
An effective vaccine should increase B lymphocyte production of antibodies and stimulate cytotoxic T cells
Clinical trials of vaccines have not been successful to date
Some researchers believe a combination of vaccines will be necessary

45. Sexually transmitted diseases cont’d.
Genital herpes- caused by herpes simplex
Type 1 generally causes cold sores while type 2 is associated with genital lesions
Crossover can occur
Begins as a tingling or itching sensation
Followed by development of blisters, swollen lymph nodes, fever, painful urination
When blister rupture, painful ulcers develop
After blisters heal the virus becomes dormant in cell bodies of sensory neurons
Stress, menstruation, sunlight, intercourse all may reactivate the virus
Babies born during an outbreak may be infected

46. Sexually transmitted diseases cont’d.
Genital warts- human papilloma virus
Transvaginal infection possible at birth
Flat, raised warts on genitals
Implicated in cancer of the cervix, vulva, vagina, anus, and penis
No cure
Treatment is by topical therapies or surgery

47. Sexually transmitted diseases cont’d.
Hepatitis infections
Hepatitis B is an STD
Hepatitis A is transmitted by contaminated water
Hepatitis C by exposure to infected person’s blood
Hepatitis B is highly contagious
Only 50% of infected people have symptoms
Fever, headache, nausea, muscle aches, abdominal pain, jaundice
Can lead to liver failure
Vaccination with HBV vaccine can prevent infection

48. Sexually transmitted diseases cont’d.
Chlamydia
Caused by bacterium Chlamydia trachomitis
More new chlamydial infections diagnosed than any other STD
5 times as many women as men are diagnosed
Probably reflects a decrease in males seeking medical attention
Mild lower urinary tract signs are common-painful urination, burning, mucus discharge
Can spread to prostate in men
Can lead to pelvic inflammatory disease in women-infertility
Babies born to infected women may develop pneumonia and ocular infections
Guidelines for testing general population-women up to 24 years old with multiple sex partners, history of unprotected sex, bleeding during pelvic exam
Treatment- antibiotics

49. Chlamydia eye infection
Fig

50. Sexually transmitted diseases cont’d.
Gonorrhea
Caused by bacterium Neisseria gonorrheoae
Males- painful urinations, greenish-yellow discharge
Females-often no symptoms until pelvic inflammatory disease develops
Babies born to infected mothers may develop severe eye infections leading to blindness
All babies delivered vaginally receive prophylactic treatment with ocular anitbiotics or silver nitrate
Treatment for gonorrhea is antibiotic therapy

51. Sexually transmitted diseases cont’d.
Syphilis
Caused by the bacterium Treponema pallidum
3 stages of disease
Primary stage- hard sore called a chancre indicates point of infection
Secondary stage- non-itchy rash, hair loss, gray patches on mucous membranes
Tertiary stage- weakening of arterial walls (aneurysms), psychological disturbances, large ulcers on skin
Congenital syphilis- crosses placenta and causes fetal blindness and malformations
Treatment for syphilis is penicillin

52. Syphilis
Fig

53. Sexually transmitted diseases cont’d.
Bacterial vaginosis
Overgrowth of the bacterium Gardnerella vaginalis
Can be nonsexual in transmission, but is commonly passed by asymptomatic males
Vaginal itching and discharge
Trichomoniasis
Caused by the protozoan Trichomonas vaginalis
Frothy white foul-smelling discharge