TISSUE TYPES- EPITHELIA Flashcards
Describe the basic stages of tissue section preparation
1. Tissue collection Fixation (10% formalin and trimming) Dehydration (series of alcohols increasing conc to 100%) Paraffin embedding Sectioning with microtome (3-4 micrometers) Straitening sections on water bath Transferring sections to a slide Staining and cover slipping
What does Haematoxylin stain
(Blue)
Stains mainly genetic material
What does eosin stain
PINK
Stains mainly proteins (mainly cytoplasm)
What are the types of simple epithelium
Simple squamous epithelium
Simple cuboidal epithelium
Simple columnar epithelium
Simple pseudostratifed epithelium
What are the types of Stratified epithelium
Stratified squamous epithelium
Stratified columnar epithelium
Stratified cuboidal epithelium
Transitional epithelium
Where is simple squamous epithelium found
Alveoli Vessels (called endothelium) Body cavities ( called mesothelium)
What does simple squamous epithelium look like and what is it best adapted for. Disadvantage of it
Single thin layer of cells. Cells are very flat
Best suited for passive transport of substances across the cytoplasm.
Provide little protection and thus are not found on surfaces subjected to high stress
Where are simple cuboidal cells found
Thyroid Kidney Lung Ovary Ducts and secretory portions of many glands
Where are simple columnar cells found
Intestine
Female reproductive tract
Many exocrine glands
What do simple cuboidal cells look like and what do they do
Are a single layer of cells
Aren’t as long as simple columnar cells
Usually associated with secretion and /or absorption
What do simmple columnar cells look like and what do they do
A single layer of cells
Are longer than simple cuboidal cells
Usually associated with secretion and / or absorbtion
What does simple pseudostratified epithelium look like and what does it do
Looks like multiple layers of cells but nuclei aren’t in rows
Secretion and movement of particles along tubular organs
Where is simple pseudostratified epithelium found
Trachea
Bronchi
Epididymis
Van deferens
Where is stratified squamous epithelium found
Covers most of the external and some internal body parts
Where are stratified cuboidal and columnar epithelia found
Found in areas of transition between simple and stratified epithelial
Respiratory tract
Ducts of exocrine glands
Where is transitional epithelium found
Only in the urogenital system ( ureter, renal pelvis )
What are endocrine glands
Ductless glands that have no connections o external or internal surfaces
Produce hormones
Are near blood vessels
High diversity of morphology
What are exocrine glands
Glands that secrete its product into a lumen or free space
What specialisations does epithelium have
Basal membrane
Apical modifications
Cell junctions
What are examples of apical modifications
Cilia - movie , long cell processes
Microvilli - no-motile , minute projections found in the epithelia specialised for absorption
Stereocilia - long microvilli
What are the different types of cell junctions
Adherent junctions
Tight junctions
Gap junctions
What are adherent junctions
Anchoring
Cells must bind to each other and to connective tissue to assure tissue cohesion
What are tight junctions
Occluding
Involved in the control of what enters the body
Control diffusion of nutrients from intestinal lumen to blood vessels
Limit the paracellular movement of water
What are gap junctions
Communicating
Cell must communicate with one another
Are aqueous channels allowing smal molecules to pass between two adjacent cells
