Chapter 4: The Tissue Level Of Organization Flashcards
Tissue
Group of cells that usually have a common origin in an embryo and function together to carry out specialized activities
Cell Junctions
Contact points between the plasma membranes of tissue cells.
Connexons
Formed by connexins. Tiny fluid filled tunnels formed at gap junctions. Connect neighboring cells.
Lumen
Interior space
Fibroblasts
Connective tissue cells
Avascular
Epithelial tissue that has its own nerve supply
Exchange of Substances in Tissue
Occurs by diffusion between epithelial and connective tissue.
Secretion
Is the production and release of substances such as sweat or enzymes/
Absorption
Is the intake of fluids or other substances such as digested food from the intestinal tract.
Types of Epithelial Tissue: Simple
Simple squamous
Simple Cuboidal
Simple Columnar
Pseudostratified Columnar
Types of Epithelial Tissue: Stratified
Stratified Squamous
Stratified Cuboidal
Stratified Columnar
Transitional
Gland
Consists of epithelium that secretes substances into ducts, or onto a surface.
Eventually into the blood in the absence of ducts.
Tubular Gland
Exocrine Gland with tubular secretory parts
Acinar Gland
Exocrine Gland. Also called: alveolar glands
Rounded secretory portions
Tubuloacinar Gland
Exocrine Gland. Have both tubular and more rounded secretory parts
Connective Tissue Extracellular Matrix
Consists of 2 major elements:
1. Ground substance
2. Fibers
Ground Cells
Component of a connective tissue between the cells and fibers.
Can be: fluid, semi fluid, gelatinous or calcified
Hyaluronic Acid
A viscous slippery substance that binds cells together, lubricates joints and helps maintain the shape of the eyeball.
Chondroitin Sulfate
Provides support and adhesiveness in cartilage, bone, skin and blood vessels.
Dermatan Sulfate
Found in skin, tendons, blood vessels and heart valves.
Keratan Sulfate
Found in bone, cartilage and the cornea of the eye.
Adhesions Proteins
Found in ground substance. Responsible for linking components of the ground substance to one another and to the surface of the cell.
Fibronectin
Main adhesion protein of connective tissue. Binds to both collagen fibers and ground substances linking them together.
Also attached cells to the ground substance.
Elasticity
Ability to return to original shape after being stretched
Stroma
Is the supportive framework of many soft organs like spleen and lymph nodes.
Formed by reticular fibers that are plentiful in reticular connective tissue.
Connective Tissue: General Features
Contains two basics element: Extracellular matrix and cells
Connective Tissue Cells
Embryonic cells called mesenchymal give rise to the cells of CT.
Fibroblasts
Large flat cells with branching processes. Most numerous in CT.
Macrophages
Type of WBC. Two types: fixed and wandering.
Plasma Cells
Or plasmocytes
Most reside in CT, found in GI and resp tract.
Mast Cells
Involved in inflammatory response. Body’s reaction to injury or infection. Can bind to, ingest or kill bacteria.
Adipocytes
Fat cell or adipose cells
Found deep in skin and around organs.
Leukocytes
White blood cells. Found in significant numbers in normal CT.
Embryonic Connective Tissue
Two types: mesenchyme and mucous connective tissue
Mesenchyme
Present in the embryo and fetus.