M1 Introduction to Histology

• Histology


  deals with the study of normal tissues
• Pathology


  study of abnormal tissue
• Abnormal Tissues


  tissues with altered structure and functions of body, organs, tissues, and cells
• Tissues

  - od french = tussu = weave fabric strands

  - group of cells that have similar structure and intercellular materials interrelated to perform a specific function
• Cytology


  study of cells
• Cells


  basic unit of life that composed all the living things
• Mitosis


  division of a cell into two daughter cells that are genetically identical to the parent cell
• Meiosis


  division of germ cells which results in four daughter cell which are not identical to the parent cell
• Anton Van Leeuwenhoek (16th century)


  - he used a handheld microscope

  - he was the first person to observe and describe living cells
• Robert Hooke (17th century)


  - observed a slice of cork under a microscope

  - here he discovered many small compartments like honey comb structures which he describes as cells

  - his discovery served as a foundation of the cell theory
• Marcello Malpighi


  - first one to describe true units forming animal tissues using simple lenses

  - true father of histology
• Anton Van Leeuwenhoek


  - develop compound lenses

  - 1st describe nucleus while examining RBC of salmon

  - discovered protozoa, bacteria, muscles, nerves, etc.
• Robert brown


  - introduced nucleus (17th century)

  - noticed small dense centers in plant cells but function is yet unknown
• Marie Francois Bichat


  - termed tissues as textures

  - tissues: different group of cells
• Matthias Schleiden


  proposed cell theory for plants
• Theodor Schwann


  - animals are made of cells

  - discovered cells that form sheath surrounding nerve
• Friedrich Gustav Jacob Henle


  published 1st human histology
• Max Schultze


  1st describe cells as mass of nucleated protoplasm
• Rudolf Virchow


  - fundamental Law of Biology or Law of Virchow

  - described human body as "cell state"

  - all diseases involves changes in normal cells
• 19th century


  microtome, fixing, embedding, & staining techniques
• Gross Anatomy


  Study of structures that can be seen with the naked eye
• Organology


  study of group of tissues arranged in pattern of a particular organ
• 3 elements that composed human body

  - cells

  - intercellular substances

  - body fluid-blood and lymphs
• Eukaryotic Cells

  - true nucleus

  - nuclear envelope is present

  - with histones

  - numerous membrane limited organelles
• Prokaryotic Cells

  - no true nucleus

  - nuclear envelope is absent

  - membrane limited organelles usually absent
• Irritability


  - physiologic property of protoplasm

  - respond to stimulus

  - expression of life that disappear upon cell death
• Contractility


  - physiologic properties of protoplasm

  - changing shapes (muscle fiber)
• Conductivity


  - physiologic properties of protoplasm

  - transmit electrical impulse (nerve cells)
• Respiration


  - physiologic properties of protoplasm

  - food substances & O2 interact chemically to produce H2O and CO2
• Absorption/ Endocytosis


  - physiologic properties of protoplasm

  - inhibition of dissolved substances

  - Pinocytosis - cell drinking

  - Phagocytosis - cell eating
• Exocytosis


  - physiologic properties of protoplasm

  - exclusion of waste products by the cell

  - secretion hormones/digestive enzymes (insulin)

  - excretion- exclusion of waste products of metabolism (urine)
• Growth and Reproduction


  - physiologic properties of protoplasm

  - increase number of cells
• Vacuoles/Vesicles


  storage cavities which expels waste and water from cell pigment
• Lipid droplet

  triglyceride storagesite and hormone precursor
• Glycogen Granules

  energy source of organisms once converted to glucose
• Pigment granule

  1. exogenous

  2. endogenous

  - hemoglobine

  - hemosiderin

  - lipofuscin
• Secretory granules


  chief cells of stomach and salivary glands
• Mucigen droplets


  - rich in mucoproteins

  - precursor of mucin which forms mucus upon hydration