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Epithelium
Topic(s): 7 to 8 Histology I
Term | Definition |
---|---|
7. Epithelial Cells: Function (5) | Selective Diffusion Sensory Secretory Absorption Protection |
7. Origin of Epithelium (plus examples) | a. Ectoderm (ECG) Epidermis Cornea Glands b. Mesoderm (MERK) Mesothelium & Endothelium Reproductive tract (F&M) Kidneys c. Endoderm (PAIL) Pancreas Alimentary Canal Intestine Liver |
7. Vascularisation of Epithelium - Blood - Nervous - Intercell Communication | Blood: Avascular (except frog and rabbit) Nerves: Free nerve ending (associated cells) Intercell communication: Glycolex of adj. cells. Tightly packed |
7.1 Absorptive Epithelium (Features and examples) | Brush border: Kidneys Cuticular border: Intestine Microvilli on border (incr. SA absorption) |
7.1 Pigmented Epithelium (Feature and examples) | Melamosomes present Under LM; appear brown Under e- microscope: e- dense bodies eg. In the eye |
7.1 Primary Sensory Epithelium (Features and example) | Receptor Axon/Associated cells Transmit impulses Rods & Cones Olefactory cells |
7.1 Secondary Sensory Epithelium (Features and examples) | Modified cells (covering epithelium) Pass the sensory path onto dendrites Flask/Spindle shaped eg. Hair cells Gustatory cells (tongue) |
8 Describe Epithelial Polarity. | The base and apical borders of the epithelial cell differ (Assymetrical) At base: Basal Lamina At apex: Brush Border/Cuticle Border (cilliated) |
8 The three types of stratification. | 1. Simple Stratified Epithelium: - Simple squamous - Simple cuboidal - Simple Columnar 2. Pseudostratified: - Pseudostratified columnar epithelium - Transitionary epithelium |
8 The three types of stratification (cntd) | 3. Stratified Epithelium - Stratified squamous - Stratified Cuboidal - Stratified Columnar |
8 Describe the three strafications | 1. Simple: 1 row of cells 2. Pseudostratified: 1 row of cells; Though nuclei appear on different levels 3. Stratified: Multiple rows of cells. |