Transcript Cytology
Cytology I. Introduction A. Definition B. History 1. Microscopes The advantage of a microscope magnification and resolution; Magnification to enlarge; Resolution to clearly distinguish two objects or clarity a. In the 16th century, Galileo used simple pieces of glass to visualize and describe the eye of an insect. b. In the 17th century, van Leeuwenhoek ground glass to visualize the structure of cells like bacteria and sperm. c. Robert Hooke used ground glass to visualize cork structure and coined the term “cellulae” or cell. 2. Cell Theory a. In the 19th century Schleiden and Schwann said i. Cells are the smallest functional units of life and ii. All living things are made up of cells. b. Later in the 19th century Virchow and Pasteur added iii. Cells only arise from pre-existing cells. II. Cytological Tools A. Microscopes 1. Light a. Function i. Bright Field iii. Phase Contrast b. Types ii. Dark Field iv. Confocal 2. Electron i. Transmission a. Function b. Types iii. Environmental TEM/SEM ii. Scanning B. Stains 1. Vital Stains are mainly from various plant pigments. for Contrast 2. Antibody Stains are more specific and are made by exposing antigen to some host animal. More Contrast III. Basic Cell Design A. Strategies 1. Prokaryotes a. Cell Size Limits Surface to Volume Ratio Figure 4.2 Figure 4.3 b. Characteristics Figure 4.6 2. Eukaryotes a. Representative Animal Cell Figure 4.7 b. Representative Plant Cell Figure 4.8 B. Parts 1. Cell Membrane a. Molecular Structure Which molecule would act as an impermeable barrier? Which molecule would act as a cellular label or antenna? Which molecule(s) would act as a transporter? Which molecule(s) would act to stiffen the membrane? Figure 4.4 b. Functions i. Membrane Protein Functions Figure 4.5 ii. Passive Transport Requirements = With a Concentration Gradient, Small Molecules, Requires No Energy Expenditure, and Relatively Non-polar Mechanisms = Simple Diffusion, Facilitated Diffusion, and Osmosis Page 92 Osmosis movement of a solvent (usually H2O) across a semi-permeable membrane Figure 5.13 iii. Active Transport Requirements = Uses Energy, Protein Channel, Large Molecules, and Goes against the Concentration Gradient Mechanisms = Molecular, Figure 5.14 Mechanisms = Bulk, Figure 5.15 If the arrowheads were reversed could you tell the difference? Mechanisms= or Cell-Mediated Figure 5.16 2. Cytosol = Cell Sap a. Consistency like thickening Jell-O b. Molecular Make-up 92% is water, 7% protein, and the rest is gases, salts, lipids, and the like dissolved in the water 3. Organelles = Cell Machinery a. Membrane Bound i. Nucleus = the keeper of the plans Chromatin, nucleolus, nuclear envelope, & pores, Figure 4.9 ii. Endomembrane System = rER, sER, and Golgi Figure 4.12 iii. House cleaners Lysosome or Peroxisome iv. Energy Transformers = the Chloroplast and the Mitochondria Figure 4.15 Figure 4.14 v. Vacuoles = Cell storage sites Animal Types = Food (sugars, lipids, etc), or Contractile (water storage) Plant Types = Central (water storage), Amyloplasts (store starch), and Chromoplasts (store Pigments) b. Non-Membrane Bound i. Cytoskeleton Figure 4.16 & 17 & 18 ii. Ribosomes Figure 4.19 iii. Centrioles C. Cellular Specializations 1. Microvilli short non-moving membrane extensions (orange area) to increase cell’s overall surface area 2. Cilia = longer moving internal cellular extensions from a basal to move something across the cell surface 3. Flagella = longest moving internal cellular extensions from a basal body to move the entire cell Figure 4.20 4. Intercellular Junctions Figure 4.21 a. Plants Always think function? b. Animals Figure 4.23 D. Extracellular Matrix & Interactions Figure 4.22 Always think function?