Answer
The four major types of tissues are epithelium, connective tissue , muscle and nerve tissue.
Muscle and nerve tissue are excitable tissues, that is, they conduct and respond to electrical stimuli( action potentials ), while epithelia and connective tissue do not. Also, in general, muscle and nerve fibers tend to be more elongated then those of epithelia and connective tissues. Epithelia are usually found as linings of cavities and tubes, and sometimes as coverings, for example, the epidermis. Connective tissue, on the other hand, is not usually found near the surface , although there are exceptions to these rules( hair, and nails). In general, epithelium tends to be avascular, while there is usually a rich vascular network associated with connective tissue.
There are three very different types of muscle cells --skeletal, cardiac and smooth. Skeletal and cardiac muscle cells are striated, while smooth muscle fibers are small, spindle-shaped, and non-striated. Neurons have long specialized shapes to facilitate the reception and conduction of stimuli and action
potentials.
Work Step by Step
Epithelium covers, protects and facilitates absorption and exchange of substances between cells and the ECF and cytosol. Connective tissue provides strength and form,structure and support. It also supports other tissues with nutrients and facilitates the excretion of waste and toxins. Blood is a form of connective tissue. Connective tissue has much matrix and few cells while epithelium consists of many layers of cells with sparse matrix.
Muscles provide the motive power for organisms by generating ATP powered contractions that pump blood around the organism and make changes of locations and posture possible.
