Sex, Reproduction,

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Sex, Reproduction, Development
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Smoking and PregnancyIn The News
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Types of Reproduction

• Sexual reproduction
• Union of male female gametes (sex cells)
• Each parent supplies half genetic material
• Asexual reproduction
• No union of gametes
• Cloning, unless there is mutation

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Asexual Reproduction

• Occurs in all 3 domains of life
• Disadvantage
• Genetic sameness means less survival with
  changing environments
• Variability only due to mutation
• Advantage
• Individuals can reproduce

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Asexual Reproduction
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Binary Fission

• Dividing of individual into two
• Common in
• Archaea
• Bacteria
• Many protists

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Asexual Reproduction by Spores

• Common in fungi
• Life cycle with sexual asexual stage

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Asexual Reproduction by Budding

• Occurs in sponges, jellyfish anemones

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Asexual Reproduction by Fragmentation

• Occurs in flatworms sea stars
• Fragments regenerate new parts

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Parthenogenesis

• Eggs develop without fertilization
• Some species engage in behaviors simulating mating

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Sexual Reproduction

• Prevalent among most vertebrates
• Common in many invertebrates
• Zygote
• Fusion of haploid egg sperm cells
• Produces diploid cell

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Hermaphrodite

• Both male female in same body
• Some can reproduce by self-fertilization
• Forms of hermaphrodite
• Simultaneous
• Sequential

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Modes of Fertilization

• External Fertilization
• Female sheds eggs
• Male fertilizes eggs after they leave her body

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Modes of Fertilization

• Internal Fertilization
• Male deposits sperm in or near the female
  reproductive tract
• Eggs are fertilized in females body

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Human Reproduction

• Sexual with internal fertilization
• Gonads reproductive organs
• Male testes
• Female ovaries
• Other organs transport receive sex cells
• Accessory glands facilitate reproduction

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Production of Sperm

• Testes
• Housed in scrotum
• Placement allows for development
• Temperature must be lower than body

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Testes Structure

• Composed of seminiferous tubules
• Site of sperm production (spermatogenesis)
• Sperm production triggered by follicle
  stimulating hormone
• Spermatogonia give rise to sperm cells

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Spermatogenesis

• Spermatogonia undergo mitosis
• Some daughter cells undergo meiosis

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Epididymis

• Site of sperm cell storage
• 18 hours to 10 days
• Unused sperm cells are reabsorbed

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Vas Defrens

• Long tube from epididymis thru pelvic cavity
• Loops over urinary bladder
• Delivers sperm to urethra

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Accessory Glands

• Seminal vesicle
• Adds fructose to nourish sperm cells
• Bicarbonate buffers acidity of urethra vagina
• Prostate
• Alkaline fluid
• Bulbourethral glands
• Mucus-like alkaline substance
• Lubricant for sexual intercourse

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Penis

• Cylinders of erectile tissue

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Female Reproductive System

• Vagina
• Accepts penis receives sperm
• External genitals
• Vulva
• Mons pubis
• Labia majora
• Labia minora
• Clitoris
• Erectile tissue

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Ovaries

• Female gonad
• Contain primary oocytes
• Can develop into eggs

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Oogenesis

• One primary oocyte yields in one ovum three
  polar bodies

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Oviducts

• Ovulation mature oocyte is released
• Oocyte enters oviduct
• Oviducts lead to uterus
• Oviduct is site of fertilization

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Uterus

• Cervix lower portion opens to vagina
• Uterus is site of prenatal development
• Endometrium inner lining
• Nourishing layer for embryo
• Shed monthly if no pregnancy occurs

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Reproductive Cycle
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Birth Control Methods
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Birth Control Methods
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Birth Control Methods
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Birth Control Methods
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Birth Control Methods
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Birth Control Methods
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Sexually Transmitted Diseases
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Sexually Transmitted Diseases
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Stages of Human Development

• Zygote fusion of egg sperm
• Embryo
• Morula
• Blastocyst
• Implantation
• Gastrulation
• Neurulation
• Fetus

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Morula

• 1 cell zygote begins to divide rapidly
• Mitosis without growth

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Blastocyst

• Ball of cells
• Portion of interior destined to differentiate
• Cells begin to migrate (morphogenesis)

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Implantation

• Approximately 1 week after fertilization
• Blastocyst secretes enzymes
• Digests portion of endometrial wall
• Nourished by digested uterine cells

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Implantation

• Embryo completes implantation
• Germ layers begin development (first 2)
• Ectoderm
• Endoderm

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From Ovulation to Implantation
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Gastrulation

• Primary germ layers fully formed
• Organs tissues begin development

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Neurulation

• Development of hollow nerve cord
• Neural groove forms

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Embryo at Four Weeks
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Fetus

• All organ systems are formed
• Growth development continues

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Fetus at Five Months
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Human Fetus Near Full Term
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Birth is Initiated by Hormones
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Newborn Physiological Changes

• Obtains oxygen from environment
• Placenta no longer the source of nutrients
• Blood circulation is increased to lungs

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Placental-Fetal circulation
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