1.01 - Basic Tissue Types Flashcards
What is the H&E stain and what structures does it stain?
Haemotoxylin and Eosin Stain
Haemotoxylin stains nuclei blue
Eosin stains cytoplasm, collagen pink
What are the four basic types of tissue?
Epithelial
Connective
Muscle
Nervous
What is epithelium?
A group of tissues that cover or line all body cavities, surfaces and tubes and functions as an interface between different biological compartments
What are the functions of the epithelium?
Barrier/Protection/Containment - skin
Secretion - produces substances - breast
Absorption - uptake of substances - small intestine
Excretion - Elimination - kidneys
Diffusion - movement of molecules - lungs
Contractility - have ability to shorten - bladder
Sensation - to perceive, feel - tongue
What are the two broad classifications for epithelia?
Simple - one layer thick
Stratified - two or more layers thick
What terms are used to describe the cellular morphology of epithelium?
Squamous - flattened, scale like
Columnar - column shaped (taller than they are wide)
Cuboidal - cube shaped
What are some special features of epithelial cells?
Cilia Goblet Cells Secretory Granules Microvilli Cell-cell junctions
What subtypes of simple epithelium are there?
Squamous
Cuboidal
Columnar
Pseudostratified
What subtypes of stratified epithelium are there?
Squamous
Cuboidal
Columnar
Transitional
What are epithelial tissues made up of?
Epithelial cells and the underlying basement membrane
Describe the basement membrane
Sheet like arrangement of extracellular matrix proteins (such as collagen) that forms an interface between supporting tissues and epithelial cells. Forms an impenetrable barrier to downward growth of cells but allows flow of nutrients and metabolites to and from the epithelium.
What are some generic features of epithelia
Closely attached cells
Little extracellular matrix
Cell to cell attachments are strong
Usually do not move
What are the type of intercellular junctions?
Occluding Junctions - Tight junctions (zonula occludens)
Adhering Junctions - Desmosome (macula adherens)
- Belt desmosome (zonula adherens)
Communicating junctions - Gap junctions
Describe Tight Junctions
Zonula Occludens
Usually found closest to the free surface of the epithelial cell and prevent materials from intestinal lumen leaking in to the intercellular spaces of the epithelium.
Consists of two closely opposed cytoplasmic membranes without an intervening gap.
Describe Desmosomes
Macula Adherens
Dense regions of attachment between epithelial cells. Contribute to the strong bonds between the cells in the skin.
Consists of two opposing dense plaques on the cytoplasmic membranes