Dev anat

• Embryology


  The study of the prenatal development of an organism
• Embryogenesis


  The formation of body structures and organs
• Cell Differentiation


  The result of cells expressing some genes and suppressing others within a common genome
• Cell types in cell differentiation

  • Stem cells
  • Committed cell
  • Specialized cells
• Teratology


  The branch of embryology that deals with the causes and results of abnormal development or congenital malformation
• Congenital malformation or defect


  An abnormality that arises during prenatal development due to hereditary or environment factors
• Types of congenital defects

  • Anomaly
  • Monstrosity
• Mitosis


  The process whereby one cell divides giving rise to 2 daughter cells that are genetically identical to the parent cell
• Stages of Mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Meiosis


  Cell division that results in 2 daughter cells having haploid number of chromosomes (half the number of chromosomes of the parent cell)
• Stages of Meiosis I

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Stages of Meiosis II

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Meiosis I


  The diploid primary germ cell divides into two secondary germ cells that are haploid
• Meiosis II


  The haploid secondary germ cell (which has two chromatids per chromosome) divides into two haploid gametes each having one chromatid per chromosome
• Embryology provides a dynamic perspective on Gross anatomy, clarifies the more complex anatomy of the adult, and helps in understanding congenital abnormalities
• Germ Layer


  A sheet of cells which gives rise to all tissues and organs of the body
• Primary Germ Layers


  • Ectoderm
  • Mesoderm
  • Endoderm
• Ectoderm


  • The outermost germ layer, gives rise to structures such as the epidermis, hair, nails, the lining of the mouth and nostrils, tooth enamel, and the nervous system
• Mesoderm


  • The middle germ layer, gives rise to structures such as muscle, bone, connective tissue, blood vessels, blood cells, the heart, kidneys, gonads
• Endoderm


  • The innermost germ layer, gives rise to structures such as the lining of the digestive tract, the respiratory tract, the liver, pancreas, and thyroid gland
• Nearly all organs in the body are derived from more than 1 germ layer or from different subsets of the same germ layer
• Epithelium


  Tissue composed of a single layer or several layers of cells that rest on a basal lamina and are closely joined together at their lateral surfaces
• Types of Epithelium


  • Simple epithelium
  • Stratified epithelium
  • Pseudostratified
• Mesenchyme


  A group of loosely and irregularly arranged embryonic cells separated by a large volume of extracellular matrix
• Interaction between the epithelium and mesenchyme is essential for normal development of the embryo
• Connective Tissue


  A group of cells which connects and supports other tissues of the body
• Adjectives of Position


  • Caudal
  • Cephalic
  • Cranial
  • Distal
  • Dorsal
  • Frontal
  • Lateral
  • Medial
  • Median
  • Proximal
  • Rostral
  • Sagittal
  • Transverse
  • Ventral
• All vertebrate embryos develop in a sequential manner from a fertilized ovum, share similar structures, and pass through a common stage of development during which they present similar anatomical features
• Structures Common to All Vertebrate Embryos

  • Body
  • Neural tube
  • Gut tube or primitive gut
  • Paraxial or dorsal mesoderm
  • Intermediate mesoderm
  • Lateral mesoderm
  • Notochord
  • Heart
  • Arteries
  • Veins
• Stratum basale - deepest layer of epidermis, contains stem cells that divide to form new keratinocytes
• Epidermis - outermost layer of skin, made up of stratified squamous epithelium