Lecture PowerPoint to accompany
Inquiry into Life
Twelfth Edition
Sylvia S. Mader
Chapter 21
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
21.1 Male Reproductive System
• Genital Tract
– Sperm are produced by seminiferous tubules of
testes
– Undergo maturation in the epididymis
• Maturation involves gaining of motility
– Sperm pass through vasa deferentia where products
are secreted by glands that contribute to semen
• Seminal vesicles
• Prostate
• Bulbourethral glands
– Semen is alkaline and contains fructose and
prostaglandins
The Male Reproductive System
Penis Anatomy
21.1 Male Reproductive System
• Orgasm in Males
– Sexual excitement increases blood flow to the penis
causing an erection
– Sperm enters the vasa deferentia, glands contribute
secretions to the semen
– Semen is ejaculated
– Ejaculation is followed by a refractory period
– Over 400 million sperm cells may be ejaculated
21.1 Male Reproductive System
• Male Gonads, the Testes
– Produce sperm and hormones
– Located outside of the body cavity
• Internal body temperature is too high for sperm production
– Scrotum helps regulate temperature of the testes
A Testis
• Spermatogenesis occurs
in the seminiferous
tubules
• Sertoli cells support,
nourish, and regulate
spermatogenic cells.
• Interstitial cells produce
testosterone
A Sperm Cell
• Three Main Parts
– Head
• The acrosome contains
enzymes needed to
penetrate an egg
– Middle Piece
• Many mitochondria
– Tail
• Flagellum
21.1 Male Reproductive System
• Hormonal Regulation in Males
– Gonadotropin Releasing Hormone (GnRH) from the
hypothalamus causes the anterior pituitary to release
Follicle-Stimulating Hormone (FSH) and Luteinizing
Hormone (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
Hormonal Control of Testes
21.2 Female Reproductive System
External Genitals of the Female
21.2 Female Reproductive System
• 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
21.3 Female Hormone Levels
Ovarian Cycle
Hormonal Control of the Ovaries
• The hypothalamus,
anterior pituitary and
ovaries all function to
control female
hormone levels. Like
other hormones,
female hormones are
regulated by feedback
mechanisms.
21.3 Female Hormone Levels
• Female cycles are studied based on an average
of 28 days
The Ovarian Cycle
Two Phases
Follicular Phase
Luteal Phase
The Uterine Cycle
Three Phases
Menstruation
Proliferative Phase
Secretory Phase
Ovarian and Uterine Cycles
21.3 Female Hormone Levels
• Menstruation
– Arteries that supply the endometrium (uterine lining)
constrict thereby weakening the capillaries
– The endometrium detaches in random patches
– Tissue, blood, and mucus are lost in the menstrual
flow
– Menstruation lasts 3 - 10 days
21.3 Female Hormone Levels
• Fertilization and Pregnancy
– An embryo begins development in the oviduct
– Implantation occurs when embryo migrates into uterus
– Embryo begins to produce human chorionic
gonadotropin (hCG)
• hCG maintains the corpus luteum to prevent a drop in levels
and estrogen and progesterone
• Pregnancy tests detect hCG
– Later, the placenta will secrete estrogen and
progesterone
– Estrogen and progesterone prevent ovulation and help
to maintain the endometrium
21.3 Female Hormone Levels
• 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
21.3 Female Hormone Levels
• Menopause
– Generally occurs between the ages of 45 - 55
– Ovaries become unresponsive to FSH and LH
– At the onset of menopause, the menstrual cycle
becomes irregular. Other characteristics include hot
flashes, dizziness, headaches, insomnia and
depression.
– Menopause is complete when menstruation has not
occurred for one year
– Hormone replacement therapy has advantages and
disadvantages
21.4 Control of Reproduction
21.4 Control of Reproduction
• Morning-After Pills
– Emergency contraception
– Taken after intercourse has occurred
– Two types, both disrupt uterine environment
• Preven - series of progesterone pills that disrupts normal
cycle making implantation difficult
• RU-486 (mifepristone) - blocks progesterone receptors in the
uterus so that the endometrium is sloughed off
– In 2006, a non-prescription drug was approved by the
United States Food and Drug Administration
21.5 Disorders of the Reproductive
System
• Sexually Transmitted Diseases
21.5 Disorders of the Reproductive
System (STD’s)
• AIDS
– Acquired Immunodeficiency Syndrome
– Caused by HIV (human immunodeficiency virus)
– Transmission
• Sexual Contact
– Vaginal or anal intercourse
– Oral / genital contact
• Intravenous drug use
• Birthing process
• Breast feeding
– Primary host cells are helper T-cells
21.5 Disorders of the Reproductive
System (STD’s)
• Stages of an HIV Infection
– Upon initial infection with HIV, the virus replicates
rapidly in macrophages and CD4+ T cells (helper)
– HIV quickly spreads through lymphatic tissues
– Early symptoms may include fever, chills, aches and
swollen lymph nodes, these symptoms then subside
– Antibodies against HIV appear several weeks after
exposure
• The basis of HIV tests
21.5 Disorders of the Reproductive
System (STD’s)
• Stages of an HIV Infection
– Eventually, the number of CD4+ T cells (helper T cells)
begins to decline
– A person is in the later stages of the disease when
the CD4+ T cell count is 200 cells per mm3 or lower
21.5 Disorders of the Reproductive
System (STD’s)
• Stages of an HIV Infection
– Opportunistic infections that kill most AIDS patients:
• Bacterial pneumonia
• Kaposi’s sarcoma
• Yeast infections
• Pneumonia
• Toxoplasmosis of the brain
Reproduction of the Retrovirus HIV
21.5 Disorders of the Reproductive
System (STD’s)
• Treatments for HIV Infection
– Three Classes of Antiretroviral Drugs
• Reverse transcriptase inhibitors
• Protease inhibitors
• Fusion inhibitors
– Patients are usually given multiple drugs
• Highly active antiretroviral therapy (HAART)
– Antiretroviral drugs slow the progression of AIDS
21.5 Disorders of the Reproductive
System (STD’s)
• Treatments for HIV Infection
– HIV Vaccines
• Obstacles to making an HIV vaccine include:
– There are many strains of HIV
– HIV mutates rapidly
– HIV “hides” inside cells
• Current research includes:
– Recombinant vaccines
» Inserting a piece of DNA encoding an HIV protein into
another organism
– Targeting the gp120 protein
21.5 Disorders of the Reproductive
System (STD’s)
• Genital Herpes
– Two types of Herpes Simplex Virus
• Type 1: Colds sores and blisters (oral)
• Type 2: Genital herpes
• Crossover infections can occur
– Symptoms
• Tingling, itching occur first
• Then blisters appear (2 - 20 days later)
• Fever, painful urination, swollen lymph nodes
– Later, the virus lies dormant
• May be reactivated by environmental factors
– Infection of newborn babies can occur with serious health issues
21.5 Disorders of the Reproductive
System (STD’s)
• Human Papillomaviruses (HPV)
–
–
–
–
Cause genital warts
Newborns can be infected
Some HPV’s can cause cervical cancer
Teenagers who have had multiple sex partners are
particularly susceptible to HPV infection
– No cure, treatments include removal of the warts by
freezing, burning, acids, or lasers.
– A vaccine is available, however it offers no protection
to already infected individuals
21.5 Disorders of the Reproductive
System (STD’s)
• Hepatitis B
– Highly contagious
• About 50% of infected people have symptoms that include:
fever, headache, nausea, muscle aches, abdominal pain,
jaundice
• Can lead to liver failure
– Vaccination with HBV vaccine can prevent infection
21.5 Disorders of the Reproductive
System (STD’s)
• 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 and epididymis in men
• Can lead to pelvic inflammatory disease in women
• Babies born to infected women may develop pneumonia and
ocular infections
– Treatment is with antibiotics
21.5 Disorders of the Reproductive
System (STD’s)
• Gonorrhea
– Caused by bacterium Neisseria gonorrheoae
– Males: painful urinations, greenish-yellow discharge
– Females: often no symptoms until pelvic
inflammatory disease develops
– The bacteria can spread to the throat (via oral sex) or
other body parts that may be in contact direct or
indirectly with sexual organs
– Treatment for gonorrhea is antibiotic therapy
21.5 Disorders of the Reproductive
System (STD’s)
• Syphilis
– Caused by the bacterium Treponema pallidum
– Three stages of disease
• Primary stage: hard sore called a chancre at the 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
Syphilis
21.5 Disorders of the Reproductive
System
• In Males
– Erectile Dysfunction (impotence)
• Inability to produce or maintain an erection
• Causes may include diseases, medications,
alcohol consumption, and psychological factors.
• Drugs that increase blood flow to the penis are a
common treatment.
21.5 Disorders of the Reproductive
System (Males)
• Disorders of the Prostate
– Benign Prostatic Hyperplasia (BPH)
• Enlargement of the Prostate
• May constrict the urethra resulting in bladder or kidney
damage
• Treated with medications and/or surgery
– Cancer of the Prostate
• Most common diagnosed cancer in American males
• Treatable if detected early
Benign Prostatic Hyperplasia
21.5 Disorders of the Reproductive
System (Males)
• Testicular Cancer
– Most common cancer in males aged 15 - 35
– Highly treatable if detected early
– Treatments may include surgery, chemotherapy and
radiation
– Self examinations are highly recommended
21.5 Disorders of the Reproductive
System (Females)
• Endometriosis
– Presence of endometrial tissue outside of the uterine
cavity
– Pain, abnormal menstrual cycles and infertility may
result
– Treatments include pain management, drugs, and
surgery
21.5 Disorders of the Reproductive
System (Females)
• Ovarian Cancer
– Typically occurs in women over the age of 40
– 50% five-year survival rate
– Sometimes described as “silent” because obvious
signs or symptoms may not appear until the cancer is
in later stages
– Treatments include surgery, chemotherapy and
radiation
– Women who have not had children are at a higher risk
21.5 Disorders of the Reproductive
System (Females)
• Disorders of Menstruation
– Too little bleeding
• May indicate a problem with the hypothalamus or pituitary
gland
– Too much bleeding
• May be caused by STD’s, medications, or problems with
blood clotting
– Dysmenorrhea (painful menstruation)
• Half of all women may experience this
• May be caused by high level of prostaglandins,
endometriosis, or ovarian cysts
21.5 Disorders of the Reproductive
System (Females)
• Disorders of Menstruation
– Premenstrual Syndrome (PMS)
• Characteristics include mood swings, headaches, joint pains,
digestive upsets, and sore breasts.
21.5 Disorders of the Reproductive
System (Infertility)
• Infertility is the failure to conceive after one year
of regular, 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 is linked to ovulation failure
• Pelvic inflammatory disease in women (blocks oviducts)
• Endometriosis
21.5 Disorders of the Reproductive
System (Infertility)
• Assisted Reproductive Technologies (ART)
– Artificial Insemination by Donor (AID)
• Sperm are placed in the vagina
• Donor may be the woman’s partner or a donor
• 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
– Embryo’s can be tested for genetic diseases
21.5 Disorders of the Reproductive
System (Infertility)
• Assisted Reproductive Technologies (ART)
– 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
– 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