Reproductive System rev 12-12

1
Reproductive System rev 12-12

• The term genitalia refers to male and female
  reproductive organs.
• Male Reproductive System Anatomy
• The scrotal sac contains 2 testes which produce
  sperm (the male reproductive cells).
• The process of sperm formation is called
  spermatogenesis.

2

• The testes are located outside of the body
  because sperm need lower temperatures to survive.
• Sperm production takes place in the seminiferous
  tubules of the testes
• In between the seminiferous tubules are
  interstitial cells which produce testosterone,
  the male hormone.
• Many seminiferous tubules join to become the
  epididymus which is located at the rear of the
  testes. Sperm are stored here and maturation
  also occurs.

3

• Sperm enter the vas deferens or ductus deferens
  (the sperm duct) which passes through an opening
  in the wall of the body called the inguinal
  canal.
• The ability of newly formed sperm to swim
  develops in the epididymis and the vas deferens.
• Sperm continue their maturation here.
• A vasectomy ties off the vas deferens so sperm
  are no longer available for fertilization.

4

• The vas deferens connects to the ejaculatory duct
  after it merges with the seminal vesicle duct.
• When the male ejaculates semen, rhythmic
  contractions of smooth muscle propel the sperm
  through the ejaculatory duct and then through the
  urethra.
• The penis is the male organ of sexual
  intercourse. It contains erectile tissue that
  fills with blood and causes the erection during
  sexual stimulation.

5

• Glands which help sperm survive
• Seminal vesicles produce seminal fluid which is a
  watery mixture containing fructose, which
  provides energy for the sperm, and prostaglandins
  which are thought to induce muscle contractions
  in the female reproductive system that help sperm
  travel more effectively.
• Prostate gland surrounds the urethra and
  produces an alkaline fluid which is added to the
  seminal fluid. This raises the pH of the vagina
  to a more optimal pH for sperm survival.
• Typical size of prostate gland is about that of a
  kiwi fruit
• Cowpers or bulbourethral glands secrete mucus
  into the urethra during sexual arousal. This
  provides lubrication for intercourse and washes
  away traces of acidic urine before the sperm
  arrive.

6

• Meiosis
• Purpose produces sperm and eggs with half the
  number of chromosomes (23) of somatic cells.
  (Cells with ½ the chromosomes are called haploid
  cells.)
• Sperm formation and maturation takes about 9-10
  weeks. Sertoli cells surround and nourish the
  growing sperm cells.
• Egg maturation and release takes about 14 days
  and occurs once per month

7

• Cell division terminology
• Gamete sperm or egg produced by meiosis
• Diploid describes the normal number of
  chromosomes in any cell
• Haploid cell which contain 23 chromosomes (1/2
  the normal amount)

8

• Sperm
• consist of 3 major parts a head, midpiece, and a
  tail.
• The head contains the nucleus and 1/2 of the
  chromosome number of the parent.
• Acrosome covers the head. This is a cap
  containing enzymes that help the sperm penetrate
  the egg
• The midpiece contains mitochondria and ATP.
  These produce the energy to power the tail.
• The tail propels the sperm.

9
Regulation of Male Reproductive Activity

• Hormones
• Testosterone
• Source Leydig cells in seminiferous tubules
• Function controls growth and function of male
  reproductive tissues, stimulates aggression and
  sexual behavior, and secondary sexual
  characteristics
• Within testes, testosterone determines the rate
  of sperm formation
• GnRH Gonadotropin-releasing hormone from the
  hypothalamus stimulates the anterior pituitary
  gland to release LH and FSH
• LH stimulates production of testosterone
• FSH may enhance sperm formation by stimulating
  Sertoli cells

10
The Female Reproductive System

• Anatomy
• The external female genitalia or vulva
• the Mons Pubis, a fatty, rounded tissue area,
  covers the pubic symphysis. It becomes covered
  with hair during puberty.
• The Labia Majora are 2 elongated, pigmented, hair
  covered, fat padded skin folds which surround and
  enclose the Labia Minora.

11

• The Labia Minora are 2 smaller, highly vascular,
  hair free folds.
• The Clitoris is a small organ partly enclosed by
  the labia minora. It is composed of erectile
  tissue and is highly sensitive.
• The Urethral opening lies between the clitoris
  and the vaginal opening.

12

• Internal female reproductive organs
• Ovaries are the primary reproductive organs.
  They lie near the ends of the fallopian tubes
  (also called oviducts) in the upper pelvic
  cavity. They are held in place by several
  ligaments. Ovaries differentiate from tissues
  which will become the abdominal wall early in
  fetal development.
• The ovaries produce eggs called oocytes at
  regular intervals during the reproductive years.
  Eggs have 1/2 the number of chromosomes as the
  parent.

13

• They also produce the hormones estrogen and
  progesterone
• The distal ends of the fallopian tubes are funnel
  shaped and have fingerlike projections called
  fimbriae. These create waves or currents which
  sweep the egg from the ovary into the pelvic
  cavity into the fallopian tube. They do not
  touch the ovary itself.
• The egg is propelled toward the uterus by the
  cilia on the walls of the fallopian tubes.
• If fertilization by a sperm occurs, it usually
  takes place in the distal third of the fallopian
  tube. Eggs take about 3-4 to 7-10 days to reach
  the uterus.

14

• The uterus is a hollow, pear shaped, muscular
  organ which is located between the bladder and
  the rectum. It will incubate the fertilized
  egg.
• Its narrow, lower end is called the cervix. The
  middle part of the uterus is called the body and
  the upper part is called the fundus.

15

• Uterine layers
• Endometrium inner layer lining of epithelial
  tissue, glands, connective tissue and blood
  vessels
• This is the layer that sloughs off during
  menstrual flow.
• A fertilized egg will implant into this layer.
  After implantation, the endometrium helps form
  the placenta which provides nourishment, waste
  removal, and gas exchange to the fetus.

16

• Myometrium middle, smooth muscle layer, expands
  during pregnancy, constricts during labor
• Perimetrium Outermost layer
• Cervix narrow opening in lower part of uterus
  that permits sperm to enter uterus and allows
  fetus to exit during birth
• joins vagina, a muscular tube that extends from
  cervix to exterior
• serves as birth canal and female organ for
  intercourse.
• Vestibular glands secrete lubricating mucus
• permits passage of menstrual blood to outside

17

• The Breasts are considered to be part of the
  reproductive organs
• are really modified sweat glands which produce
  milk to nourish newborn infants.
• milk production (lactation) is stimulated by
  estrogen and progesterone only when birth has
  actually occurred.
• the nipple is at the center of each breast. It
  contains smooth muscles that can contract and
  cause the nipple to become erect.

18

• Surrounding the nipple is the pigmented areola.
• Internally, the breasts contain mammary glands
  that produce milk.
• The glands consist of many milk producing
  lobules. Contractile cells around each lobule
  allow the milk to be released and ducts deliver
  the milk to the nipple.
• Most of the breast consists of adipose tissue so
  breast size doesnt indicate the potential for
  milk production.

19
Menstrual Cycle

• Each month the ovaries and uterus go through a
  pattern of changes called the menstrual cycle.
• Typically lasts 28 days is controlled by
  hormones
• Menstrual cycles begin at puberty and end at
  menopause
• A complete menstrual cycle consists of 2 linked
  cycles (they both must occur) an ovarian and a
  uterine cycle
• Ovarian cycle (condensed) oocytes mature and are
  released
• Immature follicle develops GnRH, FSH and LH
  increase

20

• Estrogen and progesterone secreted
• Follicle matures now called Graafian follicle
• Increasing estrogen causes surge of LH so that
  ovulation occursthe egg is released (typically
  at the middle of the cycle) and swept toward the
  fallopian tube
• A corpus luteum forms from the ruptured follicle
  site and secretes large amounts of estrogen and
  progesterone to prepare the endometrium for the
  possible pregnancy
• If no pregnancy occurs, estrogen and progesterone
  levels decline and another menstrual cycle
  begins.

21

• If the egg is fertilized, it moves down the
  fallopian tube and implants in the uterine
  endometrium
• The developing embryo secretes its own hormones
  to enable the corpus luteum to continue to
  secrete estrogen and progesterone until the
  placenta develops.
• The placenta will take over the job of secreting
  progesterone and estrogen as well as become a
  nutrient/waste filter between the maternal and
  fetal circulation.

22

• Uterine cycle prepares uterus for pregnancy
• Menstrual phase With no pregnancy, days 15,
  estrogen and progesterone decrease, endometrial
  lining degenerates, menstruation occurs
• Proliferative phase days 614, estrogen and
  progesterone increase, endometrial lining begins
  to proliferate
• Ovulation day 14
• Secretory phase corpus luteum produces
  progesterone and estrogen, endometrium continues
  to proliferate, uterine glands mature and produce
  glycogen as a potential energy source for an
  embryo

23
Maintenance of Menstrual Cycle

• Cycles of hormones of pituitary and reproductive
  structures
• Positive feedback
• In proliferative phase, increasing estrogen
  causes surge in LH
• Negative feedback
• In secretory phase, steady levels of estrogen and
  progesterone inhibit LH and FSH release

24
Polycystic ovary syndrome (PCOS)

• common hormonal disorder among women of
  reproductive age.
• The name of the condition comes from the
  appearance of the enlarged ovaries containing
  numerous small cysts in most, but not all, women
  with the disorder
• Ovaries produce excessive amounts of male
  androgens
• Signs and symptoms vary
• Menstrual abnormality.
• Excess androgen. Elevated levels of male hormones
  (androgens) may result in excess facial and body
  hair (hirsutism), adult acne or severe adolescent
  acne, and male-pattern baldness
• Polycystic ovaries. Enlarged ovaries containing
  numerous small cysts

25

• Causes
• Exact cause unknown these factors thought to
  play a role
• Excess insulin.
• Low-grade inflammation.
• Heredity. If your mother or sister has PCOS, you
  might have a greater chance of having it, too.
• Abnormal fetal development. excessive exposure to
  male hormones (androgens) in fetal life may
  prevent genes from working the way they're
  supposed to.
• No specific test to definitively diagnose
  diagnosis is made by exclusion, rule out other
  possible disorders.

26

• Treatment
• treatment focuses on management of individual
  concerns, such as infertility, hirsutism, acne or
  obesity.
• Regulate the menstrual cycle?low-dose birth
  control pills that contain a combination of
  synthetic estrogen and progesterone.
• an oral medication for type 2 diabetes that
  lowers insulin levels. This drug improves
  ovulation and leads to regular menstrual cycles.
• also slows the progression to type 2 diabetes if
  you already have prediabetes and aids in weight
  loss if you also follow a diet and an exercise
  program.

27

• Help you ovulate. If trying to become pregnant,
  you may need medication to help you ovulate.
• Reduce excessive hair growth birth control pills
  to decrease androgen production or medication
  that blocks the effects of androgens on the skin.
  
• SurgeryIf medications don't help you become
  pregnant, an outpatient surgery called
  laparoscopic ovarian drilling is an option for
  some women with PCOS.
• part of the ovaries are destroyed to try to
  restore regular ovulation cycles

28
Infertility Inability to Conceive

• Many causes of infertility
• Number and quality of sperm, pelvic inflammatory
  disease (PID), endometriosis
• Enhancing fertility
• Options artificial insemination, in vitro
  fertilization, GIFT (Gamete intrafallopian
  transfer- no in vitro procedures used harvested
  eggs are mixed with sperm are transferred into
  the fallopian tube to hopefully fertilize an egg
  and implant in the uterus) and
• ZIFT (Zygote intrafallopian transferoocytes
  fertilized in vitro are immediately transferred
  to the fallopian tube with the hopes the zygote
  will implant),
• fertility-enhancing drugs, surrogate mothers

29
Sexually Transmitted Diseases (STDs) Worldwide
Problem

• Bacterial gonorrhea, syphilis, chlamydia
• Viral HIV, hepatitis B, genital herpes, genital
  warts
• Other yeasts (Candida), protozoan (Trichomonas),
  arthropod (pubic lice)
• Prevention
• Strategies choose partner wisely, communicate,
  use suitable barriers, get tested and treated

30

• SyphillisMost people dont notice early
  symptoms. Without treatment, it can lead to
  paralysis, blindness and death. Can be cured
  with antibiotics
• Signs First sign is usually a firm, round,
  painless sore on the genitals or anus.
• The disease spreads through direct contact with
  the sore.
• Later, may see a rash on the soles, palms, or
  other parts of the body as well as swollen
  glands, fever, hair loss or fatigue. In late
  stages, symptoms come from damage to organs such
  as the heart, brain, liver, nerves and eyes.

31

• Gonorrhea spreads easily and can lead to
  infertility. Antibiotics stop the infection
• Symptoms burning during urination and
  discharge. In men, may see penile discharge,
  swollen testicles
• In women vaginal discharge, pelvic pain,
  spotting. Symptoms may be confused with a
  urinary tract or vaginal infection
•   Late in the infection, may see skin rashes or
  spread of the bacteria to the joints and blood.