Occular (w/ lens) Nosepiece Objective lens Course focus Fine focus Stage Stage clip adjustment knobs Iris control Light source condenser Stage clip Arm base
Rules for microscope use 1.ALWAYS carry with two hands; one on base, one on arm 2.ALWAYS begin and end with the low power lens in place 3.ALWAYS begin and end with the stage completely lowered 4.NEVER use course focus with the high power lens
Plasma Membrane nucleus Cytoplasm 3 MAIN PARTS OF THE CELL VISIBLE WITH THE MICROSCOPE
Histology: the study of tissues Tissue = a group of cells performing related functions and the material around/between them Matrix Fibers Ground substance
Epithelial Tissues Characteristics (partial list) Very cellular (E.T. has very little matrix) Covers/lines surfaces Has a distinct top and bottom (polarity) –Top surface = apical surface –Bottom surface = basal surface Basal surface is held in place/fused to another material by a basement membrane
3 common shapes Amount of cytoplasm related to cell’s ability to be active and perform work squamous cuboidalcolumnar
Simple Squamous: Simple = 1 layer Squamous = flattened 1 layer of flattened cells Thin “quick and easy to pass through” Involved with diffusion and filtration Example locations: –lungs, kidneys, capillaries, serous membranes Key visual characteristic is a flattened nucleus pressed/compressed against the adjacent tissue. Plasma membrane unlikely to be seen
Simple Cuboidal cuboidal = “cube” shaped 1 layer of ‘square’ cells Absorption and secretion Layer thing enough to readily pass through E.g., Kidneys, glands Key visual characteristic is a round nucleus, usually located near the center of cell Cell about as wide as it is tall. Apical surface sometimes appears rounded
Simple columnar columnar = tall and narrow 1 layer of tall, thin cells Absorption and secretion Layer thing enough to readily pass through Goblet cells = produce mucus (mucin) E.g., stomach and intestines Key visual characteristic is an elongated nucleus located in the basal half of the cell.
Finding Simple Columnar in Small Intestine the red line represents the location of the E.T.
Psuedostratified cilliated columnar 1 layer of tall, irregular cells Goblet cells mucus Cilia = ‘hairs’ that move to sweep mucus away E.g. trachea, bronchi, nasal cavity Tissue cleans air as it passes through respiratory tract Key visual characteristic is cilia –It is the only tissue we look at that has cilia
Psuedostratified Ciliated Columnar in Trachea: E.T. is located at red line
Stratified squamous stratified = more than one layer of cells Many layers of cells, upper cells flattened Thick layer Protective, relatively difficult to pass through Skin, oral cavity, vagina, pharynx, tongue Visual feature is a thick tissue with thin apical layers. Many layers of nuclei between apical surface and basal surface
Connective Tissues Most connective tissue has widely spaced cells with lots of matrix in between –Matrix = fibers + ground substance
Areolar Connective Tissue STRUCTURE Cells = fibroblasts Produce proteins fibers Fibers –Collagen: strong, but inelastic –Elastic: weak, but elastic –Both fibers widely spaced and oriented in many directions Function: provides a supportive layer that loosely binds structures together