Question

Explain animal tissues and the types of tissue?

Answer 1

Animal Tissues There are four types of tissues found in animals: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. In this lab you will learn the major characteristics of each tissue and examine various types of each tissue under the microscope.

I. Epithelial Tissue Epithelial tissues line body surfaces and cavities, as well as form glands. The cells of the tissue are closely connected to each other via cellular junctions and because epithelium is found on the edges of organs, it has two distinct surfaces. The apical surface is exposed to the body cavity or exterior, while the basal surface is adjacent to the underlying tissue (see the figure below). Epithelia contain no blood vessels (they are non-vascular) and are dependent upon the underlying connective tissue for nutrients.Epithelial cells can be one of three shapes: squamous (flattened), cuboidal, or columnar. If the epithelium consists of one cell layer it is called simple epithelium. Stratified epithelium has more than one layer.

II. Connective Tissue Connective tissues vary widely in their form and function, but they are all characterized by the presence of extracellular matrix. The extracellular matrix is nonliving material composed of protein fibers and ground substance. The protein fibers are composed of collagen (which gives strength) or elastin (which gives flexibility). The number and type of fibers differs between the various types of connective tissue. The ground substance fills the spaces between the cells and the fibers. It contains interstitial fluid (tissue fluid) and large polysacchar

III. Muscle Tissue Muscle tissue is specialized for contraction. The cells are elongated, and are also known as muscle fibers. They contain the contractile proteins actin and myosin, which interact to shorten and elongate the cells. There are three different types of muscle tissue: skeletal, cardiac, and smooth. Examine each type of tissue using the muscle composite slide. (*The skeletal and smooth muscle are shown as part of organs, so they are not the only tissue present)

IV. Nervous Tissue Nervous tissue is specialized for communication and composes the brain, spinal cord, and peripheral nerves. The tissue consists of two major cell types: neurons and glial cells. Neurons communicate with each other via electrical and chemical signals. They have nucleated cell bodies and two types of elongated cellular processes: dendrites – which receive signals, and axons – which send signals.