IV. TISSUES – HISTOLOGY is the study of Tissues
A. Epithelial tissue[endothelium in cardiovascular system]
Very cellular, avascular, protects, sensory, glands, permeability
Examples include the outer layer of the skin (the epidermis), the lining of the digestive and respiratory tracts.
B. Muscle tissue
Capable of contraction
C. Nervous = Neural tissue
Control and communication
D. Connective tissue
Most abundant tissue in the body.
Framework, structural, surrounds, connects, transports, protects, storage.
Examples include bone, cartilage, tendons, ligaments, blood and fat.
Fibroblasts are the most abundant fixed (stationary) connective tissue cells and produce and maintain fibers and ground substance. Other cells could (depending on the type of connective tissue) be adipose cells, osteocytes, chondrocytes, or blood cells.
2. Intercellular matrix
a. Ground substance – fluid to semisolid homogeneous background made by the connective tissue cells
1. Collagen – rope like, strong protein fibers.
2. Elastic – stretchy fibers such as those in the vocal cords.
3. Reticular – short and thin fibers such as those of the spleen, liver and lymph nodes.
E. Membranes are barriers that consist of epithelium and connective tissue – although they are considered to be at the tissue, not organ, level. These barriers cover and/or protect.
1. Mucous Membrane are membranes, moist with mucus, that line cavities such as the oral and nasal cavities.
2. Serous Membranes are permeable membranes that are moist with a watery fluid found lining the thoracic and abdominal cavities.
3. The Cutaneous Membrane is skin.
4. Synovial Membranes line the joint cavities and produce synovial fluid.