Reproductive System

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Reproductive System
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Male Reproductive Anatomy
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• Essential organs
• testes (2) - one of the pair of male gonads that
  produce semen suspended in the scrotum by the
  spermatic cords descend at 7 months in utero
  into the scrotum accompanied by an evagination of
  muscular and connective tissue of the body wall
  that suspend the testes
• Accessory Organs
• Genital ducts send sperm to outside of body
• epididymis (2) - where sperm matures and is
  stored
• vasa deferens (2) - The tube connecting the
  testes with the urethra. The vas deferens is a
  coiled duct that conveys sperm from the
  epididymis to the ejaculatory duct and the
  urethra this is cut during a vasectomy
• ejaculatory duct (2) formed by joining of vas
  deferens and seminal vesicle ends in urethra
• urethra
• Accessory Glands produce secretions that
  nourish, transport and mature sperm
• seminal vesicles (2) - pair of pouchlike glands
  situated on each side of the male urinary bladder
  that secrete seminal fluid and nourish and
  promote the movement of spermatozoa through the
  urethra (60 of semen)
• prostate - surrounds the urethra adds slightly
  acidic, watery, milky secretion to seminal fluid
  (30 of semen)
• bulbourethral (2) secretes alkaline fluid (5
  of semen)
• Supporting structures
• scrotum skin-covered pouch contains testis,
  epididymis and lower spermatic cord
• penis contains urethra penetrating copulatory
  organ
• spermatic cords (2) enclose seminal ducts,
  blood vessels, lymphatics and nerves

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Spermatogenesis
Spermatogonia
mitosis
Primary spermatocytes
meiosis
Secondary spermatocytes
meiosis
Spermatids Spermatozoa (motile)
epididymis
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Spermatogenesis
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• Spermatozoa
• Head contains the 23 chromosomes (genetic
  material) capable of merging with an egg to
  produce a new individual.
• Midpiece connects the head of the sperm to the
  tail. It contains many mitochondria that produce
  ATP. This ATP is used to move the microtubules in
  the tail and create propulsion for the sperm.
  Once in the female system, sperm will "swim" for
  up to 2 days looking for an egg.
• Tail - flagellum with microtubules. The
  microtublues within the tail move past each other
  and move the tail in a whip-like motion. ATP
  provided by the midpiece is required for this
  movement.
• Acrosome - covers the upper portion of the head
  of the sperm. The covering contains enzymes that
  help the sperm penetrate the egg.

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Male Reproductive Cycle

• Organ development in utero testes descend into
  scrotum before birth
• Reproductive function at puberty
• high hormone levels stimulate final stages of
  development
• Sperm production
• Spermatogenesis
• mitosis meiosis
• spermatogonia primary spermatocytes secon
  dary spermatocytes
• meiosis
• spermatids spermatozoa (motile)
• Sperm
• Produced in seminiferous tubules when reach
  puberty
• Spermatids mature to spermatozoa in epididymis
• There are about 200-500 million of those little
  guys in the average amount of semen produced each
  time a man ejaculates.
• It takes 10 weeks for a single soldier to reach
  maturity.
• Mature sperm can live up to 2 weeks in the
  epididymis
• Healthy males produce about 70-150 million sperm
  a day

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• Seminal Fluid (Semen)
• Semen only contains about 10 sperm - the rest
  consists of enzymes, vitamin C, calcium, protein,
  sodium, zinc, citric acid and fructose sugar.
• Produced from 3 glands
• 1. Seminal vesicle 60 of seminal fluid
  produced here 1yellowish fluid rich in
  nutrients
• 2. Prostate (30) spongy, secretes milk,
  alkaline fluid
• 3. Bulbourethral (5) thin, clear mucus that
  neutralizes pH of urine and lubricates
• Healthy males produce about 70-150 million sperm
  a day

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Fertility

• Factors
• sperm count
• sperm size
• sperm shape
• sperm motility
• Infertility caused by antibodies some men make
  against own sperm
• Some things that may reduce sperm number and/or
  quality include
• alcohol, drugs, environmental toxins, including
  pesticides, smoking cigarettes, health problems,
  medicines, radiation treatment and chemotherapy
  for cancer, age
• less than 20 million/mL of semen

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Hypothalamus
GnRH
Pituitary
LH FSH
Testes
Testosterone Sperm

• testosterone develop and maintain secondary sex
  characteristics
• regulate metabolism known as anabolic hormone
• stimulates protein anabolism to promotes bone and
  muscle growth

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Female Reproductive Anatomy
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• Essential Organs
• Ovaries (2) female gonads house ovum (eggs)
• Accessory Organs
• Internal genitals ducts or duct structures that
  extend from ovaries to exterior
• fallopian tubes serve as transport channels for
  ova and as site of fertilization
• uterus
• composed of cervix and the body
• Three layers
• endometrium where embryo attaches, or what
  sloughs off
• myometrium
• peritoneum
• located between rectum and bladder
• position is altered by age, pregnancy
• decreases in size at menopause
• vagina
• hymen mucous membrane bordering vagina in young
  girls
• lining lubricates and stimulates penis
  receptacle for semen
• transports tissue and blood shed during
  menstruation
• External genitals

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Reproductive Cycle

• Ovarian Cycle
• Oocytes at birth meisis halts
• menstruation causes meiosis to resume in several
  oocytes
• meiosis halts until fertilization if not
  fertilized, cell ruptures and is expelled during
  ovulation
• Menstrual Cycle
• Menses
• Postmenstrual phase / Follicular phase
• Ovulation
• Premenstrual phase / Luteal phase

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Menses

• days 1-5 of a new cycle
• endometrial lining sloughs off
• Menarche first menstrual flow
• Amenorrhea lack of menstrual flow

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Postmenstrual / Follicular phase

• time between menses and ovulation (days 6-13)
• FSH and LH are released from the brain and travel
  in the blood to the ovaries.
• The hormones stimulate the growth of about 15-20
  eggs in the ovaries each in its own "shell,"
  called a follicle and production of estrogen
  which changes in appearance, amount and
  consistency of cervical mucus
• High estrogen levels turn off the production of
  FSH
• One follicle in one ovary becomes dominant and
  continues to mature. Others stop growing and die.
  
• The dominant follicle continues to produce
  estrogen.

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Ovulation

• day 14 mature follicle ruptures and expels ovum
  into pelvic cavity
• The rise in estrogen from the dominant follicle
  the amount of LH
• Dominant follicle releases its egg from the ovary
  (ovulation)
• Egg is captured by finger-like projections on the
  end of the fallopian tubes (fimbriae) which sweep
  the egg into the tube.

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Premenstrual / Luteal phase

• time between ovulation and menses (days 15-28)
• The empty follicle develops into a new structure
  called the corpus luteum.
• The corpus luteum secretes progesterone.
• Progesterone prepares the uterus for a fertilized
  egg to implant.
• If intercourse has taken place and a man's sperm
  has fertilized the egg, the fertilized egg
  (embryo) will travel through the fallopian tube
  to implant in the uterus.
• If the egg is not fertilized, it passes through
  the uterus. Not needed to support a pregnancy,
  the lining of the uterus breaks down and sheds,
  and the next menstrual period begins

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Ovarian Follicle Development
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Female Reproductive Hormones
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GnRH FSH stimulate follicle growth LH
stimulates growth of corpus luteum which promotes
estrogen secretion Estrogen - female secondary
sex characteristics, thickens the endometrium,
regulates the menstrual cycle. Progesterone
increases when pregnant, further thickens
endometrium secreted by corpus luteum If no
fertilization -Hormone levels decrease -corpus
luteum breaks down -no more progesterone -endome
trium sloughs off during menstruation
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Fertility

• Birth - approximately 1 million eggs
• Puberty - only about 300,000 remain.
• 300 to 400 will be ovulated during a woman's
  reproductive lifetime. The eggs continue to
  degenerate during pregnancy, with the use of
  birth control pills, and in the presence or
  absence of regular menstrual cycles.
• Factors
• problems with ovulation - Some signs that a woman
  is not ovulating normally include irregular or
  absent menstrual periods.
• blocked fallopian tubes due to pelvic
  inflammatory disease, endometriosis, or surgery
  for an ectopic pregnancy
• physical problems with the uterus
• uterine fibroids
• Risk Factors
• age - about one third of couples in which the
  woman is over 35 have fertility problems
• stress
• poor diet
• athletic training
• being overweight or underweight
• tobacco smoking
• alcohol
• sexually transmitted diseases (STDs)
• health problems that cause hormonal changes

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Menopause

• most women experience this stage after age 40 and
  spend a third of their life in this phase.
• Stages
• Perimenopause
• starts years before your period stops
• ovaries gradually produce less estrogen
• Symptoms during this time include mood swings,
  hot flashes, and loss of sex drive.
• Menopause
• occurs when the ovaries no longer produce an egg
  every month and menstruation stops
• estrogen levels low
• Postmenopause
• lasts years after menopause
• continued decrease in estrogen causes health
  risks

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