Reproduction Ch 16

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Reproduction Ch 16

• Male role to produce gametes called spermatoza
  (sex cells)
• Primary organ testes (gonads)
• Accessary organs scrotum, ducts, glands, and
  penis

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Scrotum

• Pouch of skin and fascia
• House the testes
• 3 degrees lower than body temperature for viable
  (live) sperm

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Testes (testicles)

• Paired, oval, each surrounded by 2 tunics
• 1)outer tunic tunica vaginalis
• 2) deeper tunic tunica albuginea (white coat)
• Deeper tunic layer divides the testis into
  compartment (lobules) each containing 1-4
  seminiferous tubules (sperm factories)

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• These tubules converge to form the rete testis
• Sperm leave here to the epididymis
• Leydig cells surround these tubules and produce
  testosterone

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Duct System

• Transport sperm from the body
• Epididymis to ductus deferens (or vas deferens)
  to the urethra

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Epididymis

• 20 foot coiled tube
• Caps the superior portion of the testis
• Receives immature sperm from the seminiferous
  tubules
• Temporary storage site for sperm
• Sperm become motile fertile (about 20 days)

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Ductus deferens (vas deferens)

• It is 18 inches long
• Ascends into pelvic cavity, over bladder, and
  through prostate gland, and merges with the
  urethra
• Transports sperm from epididymis to the urethra
• Vasectomy doctor cuts or cauterizes this tube
  in the scrotum. Sperm cannot reach the body
  exterior

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Urethra

• Terminal (end) portion of the male duct system
• It conveys urine or semen to the tip of the penis

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Accessory organs/glands

• Seminal vesicles, prostate gland, Cowpers gland
• penis

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Seminal vesicles

• Paired glands (2)
• Located at base of bladder
• Produce about 60 of semen volume
• Join ductus deferens right before entering the
  prostate gland
• Contain sugar

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Prostate gland

• Single gland, walnut size
• Encircles the upper part of the urethra just
  below bladder
• Secretion in semen plays a role in activating
  sperm
• Hypertrophy (elderly) strangles the urethra and
  makes urination difficult

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Cowpers glands (bulbourethral)

• Pea sized glands, paired
• Produce clear mucus that neutralizes traces of
  acidic urine in the urethra
• Serves as a lubricant during sexual intercourse

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Penis

• Copulatory organ (delivers sperm into vagina)
• Has an attached root and a free shaft that ends
  in an enlarged tip called glans penis
• Covered by loose skin that slides distally to
  form the foreskin or prepuce, frequently removed
  surgically after birth (circumcision)

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• Internally contains erectile tissue (spongy CT,
  smooth muscle, and vascular spaces)
• Vascular spaces fill with blood causing the penis
  to enlarge and become rigid (erection)
• Impotence failure to attain erection

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Semen

• Milky white fluid mixture of sperm and gland
  secretions
• Provides a transport medium and nutrients
  (fructose) for sperm
• Amount expelled during ejaculation is about 2-6ml
  and 50-100 million sperm in each milliliter

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Male infertility causes

• Anatomical obstructions
• Hormonal imbalances
• Low sperm count
• Environmental effects

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Semen analysis

• Performed because of infertility problems
• Include
• Sperm count
• Sperm motility
• Sperm morphology
• Semen volume
• Semen pH
• Semen fructose content
• Less than 20 million sperm produced per ml makes
  impregnation improbable

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Spermatogenesis

• Production of sperm in the seminiferous tubules
• Begins at puberty and continues throughout life
• Several hundred million sperm produced per day

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Involves meiosis

• Cell division with 2 consecutive divisions
  resulting in
• 4 daughter cells, each with ½ the of
  chromosomes
• 4 sperm cells are made
• Diploid 2n 46
• Haploid n 23 (gametes)
• Sperm (23) Egg (23) zygote (46)

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Spermiogenesis

• Spermatids mature to sperm
• Sperm cell includes acrosome, head (nucleus and
  DNA), midpiece (mitochondria), and tail for
  motility
• Abnormal shape may be due to penicillin,
  tetracycline, radiation, lead, pesticides,
  marijuana, cigarettes, excessive alcohol

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Testosterone (steroid hormone)

• Promotes spermatogenesis
• Causes ducts, glands, penis to grow at puberty
• Causes secondary sex characteristics
• Hair, deepening voice, increase skeletal muscles,
  oilier skin, bones grow and increase in density

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Female

• Ovaries primary reproductive organs
• Produce eggs
• Produce estrogen, progesterone
• Paired, size of almonds
• Contain many tiny saclike structures called
  follicles (that contain immature egg or oocyte)

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Ovulation

• Each month in adult women, one mature follicle
  ejects its oocyte from the ovary
• The ruptured follicle transforms into corpus
  luteum which degenerates

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Duct system

• Uterine tubes (fallopian tubes) 4 inches by 1 cm
• Receive ovulated oocyte and provide site where
  fertilization occurs
• Not directly connected with ovary

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Uterus (womb)

• Hollow, thick-walled organ that will receive,
  retain, and nourish a fertilized egg
• It is pear size
• Uterine organ consists of a fundus (superior
  region), body (major portion), isthmus (narrow
  bottom region) and the cervix (neck of uterus)

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Uterine Wall

• 1) Perimetrium outermost, serous layer
• 2) Myometrium middle, smooth muscle (contracts)
• 3) Endometrium inner, simple columnar, site of
  implantation

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Vagina

• From cervix to exterior
• Birth canal passageway for baby and for
  menstrual flow
• pH 3.5 4.0 (helps keep free of infection)
• Hymen fold of mucous membrane partly closing
  the vagina orifice. Ruptured during sexual
  intercourse, pelvic exam, tampon insertion, and
  some sports

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Female External genitalia

• Labia majora homologue to the scrotum, contain
  hair follicles, enclose and protect minora
• Labia minora hair free folds, encloses the
  vestibule
• Vestibule region contains clitoris, urethra,
  vaginal openings, and mucus glands
• Clitoris small structure composed of erectile
  tissue and nerve endings (homologue to penis)

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Total supply of eggs in female

• 700,000
• Release time span from puberty (age 14 about 50
  years)
• Oogenesis production of oocyte
• Eggs wait about 11-14 years to 50 years to
  complete meiosis
• Products of oogenesis 1 egg and 3 polar bodies

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Females release about

• 400 500 eggs in a lifetime
• Female orgasm is not required for conception
  (fertilization)

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Ovarian Cycle (3 phases)

• (1) follicle phase (days 1-10) several follicles
  begin to mature
• Produce estrogen (usually 1 egg/mth)
• (2) ovulatory phase (days 11-14) primary oocyte
  completes meiosis I ovulation occurs and expels
  secondary oocyte into peritoneal cavity

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• More than 1 egg expelled multiple births
• (3) luteal phase (days 15-28) ruptured follicle
  converted to corpus luteum
• Produces estrogen and progesterone

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Uterine (menstral) cycle

• Corresponds to ovarian cycle
• Series of cyclic changes that the uterine
  endometrium goes through each month responding to
  hormone levels
• If egg is NOT fertilized, inner layer of
  endometrium detaches and is accompanied by
  bleeding for 3-5 days

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• As new follicles mature, estrogen increases, and
  endometrium repairs and readies for implantation
  again
• Progesterone helps regulate uterine cycle

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Estrogen

• Promotes follicle growth
• Promotes secondary sex characteristics
• Breast development, pelvic widening, fat deposits
  on hips, pubic and axillary hair

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Menopause

• Cease of ovulation and menses about age 46 54
• Decrease estrogen levels dry vagina, increase
  in infections, thinning of skin, loss of bone
  mass, and slow increase in cholesterol

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Pap smear

• Diagnostic test for cervical cancer by looking at
  cells from the cervix under a microscope
• Risk factors for cervical cancer
• STDs
• Multiple pregnancies
• Multiple sexual partners
• unknown

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Gardisil

• Vaccine given to young women to help prevent
  one-two types of papiloma virus that are known to
  cause cervical cancer
• This vaccine does not prevent all types of
  cervical cancer

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Dysmenorrhea

• Painful menstruation (cramping)

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Amenorrhea

• Absence of menstrual flow

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Hysterectomy

• Surgical removal of the uterus
• Performed either through the abdominal wall or
  through the vagina

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STDs or VD

• VD venereal disease
• Infectious diseases spread through sexual contact

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Gonorrhea

• Caused by bacteria called Neisseria gonorrhoeae
• Symptoms male urethritis, painful urination,
  discharge from penis
• Female none sometimes, lower abdominal
  discomfort vaginal discharge, abnormal uterine
  bleeding

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• If untreated
• Male can get urethral constriction
• Female can get pelvic inflammatory disease (PID)
  and sterility
• Treat with penicillin

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Syphilis

• Bacteria called Treponema pallidum
• Infects lymph and blood stream
• 2-4 weeks get a chancre red, painless lesion at
  site of invasion which ulcerates than heals
• If untreated secondary signs (about 6 wks) skin
  rash, fever, joint pain, anemia, and sometimes
  hair loss

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• Tertiary stage destructive lesions of Central
  Nervous System, blood vessels, bones, and skin
• Treat with penicillin

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Chlamydia

• Bacteria Chlamydia trachomatis
• Most common STD
• Urethritis, vaginal discharge, abdominal or
  testicular pain, painful intercourse, irregular
  menses, and may cause sterility in women
• Treat with tetracycline

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Genital herpes

• Virus Herpes simplex II
• Causes blister-like lesions on reproductive
  organs
• May increase cervical cancer
• ¼ - 1/3 of adult Americans harbor this virus