(ORAL HISTO)1and2

Cards (168)

  • Embryology is the science that deals with the study of the anatomical & functional development of the individual species.
  • Kaspar Wolff observed in a chick embryo that the individual species arose from gradual enfolding & differentiation of an unorganized tissue into organs.
  • Kaspar Wolff proposed that both parents contribute to the structure of the baby.
  • Von Baer discovered the mammalian ovum & established the law that all embryos came from 3 germ layers.
  • The human body is composed of cells, intercellular substance & fluid.
  • A cell is the smallest living unit of the body capable of independent existence.
  • A cell is composed of nucleus & cytoplasm.
  • Intercellular substance is the product of the cells and surrounds the cells, providing nutrition, taking up waste products, and providing shape to the body.
  • Intercellular substance may be as hard as bone, cartilage or cementum of teeth.
  • Fluid contains blood & lymph, and circulates in vessels throughout the body.
  • Fluid also includes the tissue fluid which surrounds each cell & fiber of the body.
  • The life of all the cells is limited.
  • Important structures of a cell include the cell nucleus, ribosomes, Golgi complex, lysosomes, nuclear membrane, cell cytoplasm, endoplasmic reticulum, mitochondria, peroxisomes, centrioles or diplosomes, and cytoskeleton.
  • The cell nucleus is responsible for the metabolism, growth & reproduction of the cell and is present in all the cells of the body except for mature red blood cells & blood platelets.
  • Ribosomes may exist singly, or in clusters called polyribosomes, or on the surface of rough endoplasmic reticulum.
  • The Golgi complex shows various forms but the most common is in the form of plates or lamellae or plates may dilate to bowl-shaped structure (cisternae).
  • Lysosomes are small membrane covered bodies present in all cells except the RBC and are more active in macrophages & leukocytes.
  • The nuclear membrane that surrounds the nucleus is similar to plasma membrane and consists of 2 phospholipid layers.
  • Cell Cytoplasm contains structures essential for creation & absorption of cell products.
  • The cytosol present in cytoplasm contains the organelles & solutes.
  • Lysosomes are small membrane covered bodies present in all cells except the RBC and are more active in macrophages & leukocytes.
  • The cytosol present in cytoplasm contains the organelles & solutes.
  • Endoplasmic reticulum consists of minute fluid containing membrane bound tubules known as canaliculi cisternae or vesicies which may form a network (reticulum) or may be in the form of granules (when free are known as ribosomes or polysomes).
  • Mitochondria are membrane-covered organelles present in all cells & lie free in the cytoplasm.
  • Peroxisomes perform lipid metabolism and chemical detoxification.
  • Centrioles or diplosomes are located close to the nucleus in a specialized area of the cytoplasm known as centrosome or cell center.
  • The cytoskeleton is a group of fibrous proteins that provide structural support for cells.
  • Filaments are minute threadlike bodies of different lengths & circumferences.
  • In epithelial cells, the threadlike structures are called tonofilaments; of fibroblast, cytoplasmic fibril; of nerve cells, neurofilaments; and of muscles, myofilaments.
  • Fundamental Tissues: Epithelium, Connective, Nervous, Muscular, and Human Tissues.
  • Epithelium gives rise to organs such as glandular organs (pancreas, liver, thyroid gland & salivary gland) and dental organ.
  • Types of Epithelium include Simple (squamous, cuboidal, columnar), Pseudostratified columnar (composed of single layer of columnar cells arranged in a way that the epithelium appears to have several layers of cells, caused by difference in location of nuclei), and Stratified (consist of 2 or 3 more layers of cells).
  • Connective tissue types include Fibrous tissue in lamina propria (less dense in lamina propria of skin & mucosa), Areolar tissue (has small amount of cells, loose & thin network of fibrous intercellular substance held together by large amount of amorphous substance), Fat tissue, Hemopoietic tissue, Cartilage, and Bone.
  • Nervous tissue is composed of nerve cells called neuron capable of reacting to stimuli (irritability) & transmission of excitation or nerve impulse.
  • Central nervous system includes brain & spinal cord.
  • Peripheral nervous system includes nerves of various organs of the body.
  • Smooth muscle tissue is characterized by the cytoplasm of the muscle appearing clear (walls of intestine, walls of blood vessel, &roots of hair).
  • Striated muscle tissue is characterized by the cytoplasm having cross striations.
  • Involuntary muscle tissue is also known as cardiac muscle.
  • Voluntary muscle tissue is also known as skeletal muscle.