Anatomy

• Embryology


  A branch of anatomy which studies the development of an embryo from the time of fertilization of the ovum to the fetus stage

  
• Embryo


  In humans, it is called an embryo until about eight weeks after fertilization
• Fetus


  A developing human from the embryonic stage until time of birth
• Cell cycle


  1. Mitotic phase

  2. Gaps 1 & 2

  3. Synthetic phase

  
• Interphase


  Cells perform their normal role in the body
• G0 phase


  Cells generally do not undergo mitosis e.g. neuronal cells
• Mitosis


  Cell division that takes place in somatic cells, resulting in the formation of 2 daughter cells identical to the parent cell

  
• Meiosis


  Cell division that takes place in germ cells, the daughter cells have half the chromosome number of the parent cells
• Gametogenesis


  1. Oogenesis (in females)

  2. Spermatogenesis (in males)
• Oogenesis


  The process through which female gametes are formed, continues at puberty and ends at Menopause
• Spermatogenesis


  The process through which male gametes are formed, begins at puberty and continues until death
• Ovarian cycle


  Mature ovum is released during ovulation, controlled by hormones of the hypothalamus and the anterior pituitary

  
• Menstrual cycle


  Cyclical event that occurs within the uterus in tandem with the ovarian cycle, has four phases: menstrual, proliferative, secretory and ischemic

  
• Fertilization


  The union of the male and female gametes to form a zygote
• Zona pellucida


  Barrier surrounding the mature ovum at the time it is 'ovulated'

  
• Capacitation


  Process mature spermatozoa must undergo to fertilize an ovum

  
• Cleavage


  Series of mitotic divisions of the zygote following fertilization, begins simultaneously with the transport of the zygote through the uterine tube

  
• Blastomeres


  Individual cells in the zygote
• Morula


  16-cell stage zygote
• Blastocyst


  Morula that has developed a blastocoele
• Implantation


  Embedding of the zygote into the endometrium of the uterus, begins by the 6th day of development
• Gastrulation


  Formation of the three primary germ layers: ectoderm, mesoderm, and endoderm
• Derivatives of the ectoderm layer

  • Central nervous system
  • Peripheral nervous system
  • Sensory epithelium of the ear, nose and eye
  • Epidermis, hair and nails
  • Subcutaneous, mammary and pituitary gland
  • Enamel of teeth
• Derivatives of the mesoderm

  • Bones
  • Muscles
  • Dermis of Skin
  • Excretory units of the kidneys and gonads
• Derivatives of the endoderm

  • Epithelial lining of the gastrointestinal system
  • Respiratory system
  • Urinary bladder and urethra
  • Tympanic cavity and auditory tube
  • Parenchyme of the tonsils, thyroid, parathyroid, thymus, liver and pancreas
• Derivatives of the neural crest

  • Preaortic ganglion
  • Sympathetic ganglion
  • Organ plexus
  • Developing suprarenal gland
  • Dorsal root ganglion
• Derivatives of the mesoderm

  Bones, muscles, dermis of skin, excretory units of the kidneys and gonads
• Luteal phase


  The final phase of the menstrual cycle, lasting for about 14 days, during which the empty follicle forms the corpus luteum and produces progesterone to maintain the thickened lining of the uterus
• Ovulation


  The phase of the menstrual cycle, lasting for about 24 hours, during which a mature egg is released from the ovary and travels through the fallopian tube
• Follicular phase


  The first phase of the menstrual cycle, lasting for about 14 days and involving the growth of follicles in the ovaries and the production of estrogen
• Menstrual cycle


  A series of hormonal and physical changes that occur in the female reproductive system in preparation for pregnancy, typically lasting for 28 days
• Spongy bone


  The porous, less dense inner layer of bones that provides flexibility, shock absorption, and blood cell production
• Compact bone


  The dense, hard outer layer of bones that provides strength and protection to the body
• The menstrual cycle is regulated by the complex interaction of hormones: luteinizing hormone, follicle-stimulating hormone, and the female sex hormones estrogen and progesterone.
• Luteinizing hormone (LH) stimulates the release of an egg from one of the ovaries at midcycle.
• Follicle-stimulating hormone (FSH) promotes the development of eggs within the ovaries throughout the menstrual cycle.
• Estrogen levels increase during the early part of the menstrual cycle, causing the uterine lining to thicken in anticipation of implantation of a fertilized egg.
• Progesterone levels rise following ovulation and remain elevated until the end of the menstrual cycle.
• Breathing

  1. Air enters through nose or mouth

  2. Travels down throat (pharynx)

  3. Passes through larynx (voice box)

  4. Enters trachea (windpipe)

  5. Trachea branches into two bronchi
• Bronchi


  • Lead to each lung