Diversity of Cells Flashcards
What are the 4 basic tissue types?
Epithelium, connective tissue, muscle, and nervous tissue.
What are common features of epithelia?
Adhesion between epithelial cells is strong, thus forming sheets of cells, with a minimum of intercellular space. They are therefore perfect to cover surfaces, line body cavities, line hollow organs and also form many glands. All have, at their basal surface, a layer of extracellular matrix components, called a basal lamina (basement membrane), to which the cells are attached. Vary widely in size, shape, orientation and function. The cells are usually polarized, that is the apical and basal ends of the cell differ.
What are the functions of epithelia?
Mechanical barrier (e.g. skin), chemical barrier (e.g. lining of stomach), absorption (e.g. lining of intestine), secretion (e.g. salivary gland), containment (e.g. lining of urinary bladder), locomotion (by cilia) (e.g. oviduct), minor functions include: sensation (neuroepithelium, e.g. taste buds) and contractility (myoepithelial cells).
What are the 3 cell shapes of epithelium?
Squamous (flattened, like a fish scale), cuboidal (cube shaped), columnar (like a column, relatively tall and thin).
What are the 3 number of layers in epithelium?
‘Simple’ = one layer, ‘stratified’ = two or more layers, ‘pseudostratified’ = tissue appears to have multiple layers, but in fact all cells are in contact with the basal lamina.
What does glandular epithelia produce?
Secretory products, for example: sweat, milk, oil, hormones, mucous, enzymes and others.
Where is the product secreted in the endocrine glands?
Toward the basal end of the cell (end sitting on basal lamina), then distributed by the vascular system throughout the body. Termed ‘ductless’ glands.
Where is the product secreted in the exocrine glands?
Toward the apical end of the cell either into the lumen of an internal space, into a duct, or onto the body surface. Termed ‘ducted’ glands.
What is connective tissue?
Forms the framework of the body, but beyond that it has a dynamic role in the development, growth and homeostasis of tissues, and, via fat, in energy storage.
What are examples of soft connective tissue?
Tendons, ligaments, mesentery, stroma of organs, dermis of the skin, etc
What are examples of hard connective tissue?
Bone and cartilage.
What do many authors consider blood and lymph as?
A specialized form of connective tissue.
How is the type of connective tissue determined?
By the types and relative amounts of the extracellular matrix and cells.
What does the extracellular matrix consist of?
Fibres: collagen, reticular and elastic fibres, Ground substance: an amorphous, space occupying material made of huge unbranched polysaccharide molecules called glycosaminoglycans (GAGs), most of which are bound to protein cores to form glycoproteins, Tissue fluid.
What do the cells consist of?
Fibroblasts: widely distributed cells that produce and maintain the extracellular matrix, Adipose cells: fat cells, found scattered in many connective tissues, but predominant cell in adipose tissue (fat), Osteocytes: cells of bone, Chondrocytes: cells of cartilage.
