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• Anton van Leeuwenhoek used a single lens to observe
• Robert Hooke used microscopes in science laboratories to visualize very minute objects such as cells and microorganisms
• Microscopes have special components that enable them to achieve high magnification levels
• To transport a microscope, hold the arm with one hand and support the base with the other hand
• Place the microscope at least 6 inches away from the edge of the table
• Before using the microscope, clean the eyepiece, objectives, condenser, and mirror with lens paper or a soft piece of cloth
• Always ensure that the mirror is directed towards the source of light
• Prepare a slide using the letter e and secure it with the stage clips
• Use the coarse adjustment knob to move the objective as close as possible to the slide, then use the fine focus knob for a sharper image
• Sketch the image and adjust the intensity of light
• When removing the slide, ensure the LPO is in viewing position and the objective and stage are as far apart as possible
• Total Magnification = Magnifying power of the eyepiece X Magnifying power of the objective used
• Preparing Microscopic Specimens:

  • Obtain skin cells by scraping the inner cheek
  • Wipe the scrapings on a clean slide and add a drop of methylene blue
  • Place a coverslip on the slide and locate cells using LPO and HPO
• Cell Anatomy Lab Exercise Objectives:

  • Identify different organelles and determine their function
  • Identify major organelles on a specimen
• The Cell's Life Cycle Lab Exercise:

  • Cell life cycle is regulated by stimulation from hormones or growth factors
  • Disruption of the cycle can affect the body's health
  • Most human cells divide 40 to 60 times before dying
• Cell's Life Cycle Phases:

  • Interphase: Cell obtains nutrients to grow
  • Cell division (mitosis): Nucleus divides, hereditary component replicated and distributed to daughter cells
  • Mitosis named by Walther Flemming, cytokinesis follows mitosis
  • Differentiation: Cell becomes specialized
• Epithelial Tissue Lab Exercise
• Mitosis results in the division of a cell's nucleus into two daughter cells
• Mitosis occurs at the same time or just after the last phase of mitosis
• Differentiation is when a cell becomes specialized
• Epithelial tissue forms the outer layer of the body and lines many body cavities for protection
• Connective tissue supports and protects organs and limbs
• Muscle tissue enables various forms of movement, both voluntary and involuntary
• Nerve tissue carries electrical and chemical signals from the brain and central nervous system to the periphery
• Epithelial tissues can be single-layered or multi-layered and have the ability to regenerate
• Types of epithelial tissues include simple, stratified, and pseudostratified
• Simple epithelia are composed of a single layer of cells
• Stratified epithelial tissue is composed of multiple layers
• Pseudostratified epithelium appears stratified but is actually only one layer deep
• Epithelial cells can be ciliated (having cilia) or non-ciliated
• Transitional epithelium can appear to pile up on top of each other in a relaxed, empty bladder
• Different shapes of epithelial cells include squamous, cuboidal, and columnar
• Squamous cells are flat and round, while cuboidal cells are cube-shaped with a central nucleus
• Columnar cells are tall and narrow, with the nucleus located at the base
• Simple squamous epithelium is thin and flat, found in the lining of mouth, lungs, and capillaries
• Simple cuboidal epithelium is cube-like and found in secreting organs like glands and kidney tubules
• Simple columnar epithelium is column-like with nuclei at the base, found in the lining of stomach, intestine, and salivary glands
• Ciliated columnar epithelium contains cilia and is found in the respiratory system and female reproductive tract
• Stratified squamous epithelium provides protection against abrasion and water loss, found in the skin and mucous linings
• Stratified cuboidal epithelium lines excretory ducts and large ducts of excretory glands