Histology

• What is histology?

  Histology is the study of biological tissues.
• What defines a tissue?

  A tissue is a collection of one or more cell types working together for a common purpose.
• Why is an understanding of histology essential for healthcare professionals?

  It is essential because they often participate in taking biopsies (tissue samples).
• What are tissues considered in relation to organs?

  Tissues are the building blocks of organs.
• What are the four major types of tissue in the human body?

  • Epithelial: Secretion, protection, and absorption
  • Connective: Support, binding, transport, and protection
  • Muscle: Movement
  • Nervous: Coordination
• What does this presentation focus on regarding tissues?

  This presentation focuses entirely on epithelial tissues.
• Where are epithelial tissues found?

  Epithelial tissues are found resting on a structure called the basement membrane.
• What is the composition of the basement membrane?

  The basement membrane is composed of peptidoglycan (proteins and sugars).
• What are the two major categories of epithelial tissue?

  The two major categories are simple epithelia and stratified epithelia.
• What characterizes simple epithelia?

  Simple epithelia consist of a single layer of cells resting on a basement membrane.
• How are stratified epithelia structured?

  Stratified epithelia consist of multiple layers of cells stacked on top of each other like layers of bricks in a brick wall.
• What does the term "squamous" refer to in histology?

  The term squamous means resembling a "fish scale," indicating that these cell types are thin and flat.
• Where is simple squamous epithelium typically found?

  Simple squamous epithelium is found in places where thin membranes are necessary, such as in the diffusion of gases.
• What property of squamous epithelial cells is exploited in the alveolar sacs of the lungs?

  Squamous epithelial cells are incredibly thin and relatively elastic.
• What type of epithelial cells predominantly compose the alveolar walls of the lungs?

  Simple squamous epithelial cells
• What surrounds each alveolar air sac in the lungs?

  A dense network of blood capillaries
• What happens to oxygen during inspiration in the alveoli?

  It diffuses rapidly across the alveolar and capillary walls into the blood
• What occurs to carbon dioxide during respiration in the lungs?

  It diffuses from the blood across the capillary and alveolar walls
• What is the inner layer of each artery and vein called?

  The endothelium
• How do squamous epithelial cells in blood vessels affect blood flow?

  They ensure that resistance to blood flow is minimal
• What is the function of the elastic nature of squamous cells in blood vessels?

  It allows blood vessels to dilate and constrict
• What chemical do squamous cells produce to help regulate blood flow?

  Nitric Oxide (NO)
• What are capillaries known for in the human body?

  They are the smallest blood vessels
• What is the primary function of capillaries?

  To ensure blood is delivered to the proximity of all cells and tissues
• What is each capillary formed from?

  A rolled-up tube of simple squamous epithelial cells
• What happens when blood is forced into a capillary?

  Fluid is driven out through slits between adjacent squamous epithelial cells
• What is the fluid that collects in the tiny spaces surrounding the cells of the body called?

  Tissue fluid or interstitial fluid
• What type of epithelial cells line fluid-producing membranes throughout the body?

  Simple squamous epithelial cells
• How does the squamous layer appear when examined from the surface?

  It resembles "crazy paving"
• What is the thin watery fluid secreted by the squamous layer called?

  Serous fluid
• Where is the peritoneum located?

  It lines the abdominopelvic cavity
• What is the function of the serous fluid produced by the peritoneum?

  To lubricate the surface of the internal viscera
• What is the condition called when the peritoneum becomes infected?

  Peritonitis
• What is the outer layer of the gut called?

  The serosa
• What does the serosa produce?

  A lubricating serous fluid
• What is the primary function of the pericardium?

  To protect the heart and anchor it in position
• What type of epithelium lines the pericardial sac?

  Simple squamous epithelium
• What is the fluid produced by the parietal pericardium called?

  Pericardial fluid
• What are the two serous membranes surrounding the lungs called?

  The pleural membranes
• What is the function of pleural fluid?

  To adhere the outer surface of the lungs to the inner chest wall