Histology Flashcards
Tissues
Groups of cells similar in structure that perform common or related function
Four Basic Tissues
epithelial, connective, muscle, and nervous tissue
Epithelial
a sheet of cells that covers body surfaces or cavities
Two Types of Epithelial
- Covering and lining epithelial
- Glandular epithelia
Glandular Epithelia
Secretory tissue in glands
Functions of Epithelial Tissues
protection, absorption, filtration, excretion, secretion, and sensory reception
Connective Tissue
- mainly helped by extracellular matrix
- connects things and makes up cartilage
- widest range of properties
Epithelial Tissue Charactertistics
Polarity
Specialized contacts
Supported by connective tissues
Avascular, but innervated
Regeneration
Polarity
having a top and bottom
Avascular
without blood supply
Apical side
top ; exposed to cavity
Basal side
inwards to body ; connects to connective tissue
Basal Lamina
connective tissue that connects to bottom of epithelial tissue
Reticular Lamina
- under basal lamina
- consists of collagen fibers
Specialized contacts
- have tight junctions and desmosomes that allow formation of sheets of epithelial tissue
Lack of Desmosomes
causes blisters
Simple Epithelia
a single layer thick
Stratified Epithelia
two or more layers thick and involved in protection (example: skin)
Squamous
flattened and scale like
Cuboidal
box-like, cube
Columnar
tall, column-like
Naming in Stratified Epithelial Cells
In stratified epithelia, shape can vary in each layer, so cell is named according to the shape in apical layer
Simple Squamous
thinnest layer ; makes absorption and secretion fast
Simple Cuboidal
Roughly same size for length and
- Forms walls of smallest ducts of glands and many kidney tubules
Simple Columnar
Single layer of tall, closely packed cells ; involved in absorption and secretion and have cilia
- Found in digestive tract, gallbladder, ducts of some glands, bronchi, and uterine tubes
Pseudostratified columnar epithelium
- respiratory eptihelial
- Cells vary in height and appear to be multi-layered and stratified, but tissue is in fact single-layered simple epithelium