NaimExplain

What are the primary germ layers during embryonic development and what do they ultimately produce? Answer: The ectoderm produces skin, the nervous system, and all tubes opening to the outside. The mesoderm produces muscles and connective tissue. The endoderm produces all internal organs.

How is blood unique among connective tissues? Answer: Blood does not give mechanical support, its matrix is fluid, the cells are loose, the fibers are soluble, it carries nutrients, waste products, and other substances and attaches to several gasses.

What is a simple method of telling the difference between stratified squamous epithelium and transitional epithelium? Answer: Stratified squamous epithelium changes cell shape from the basement membrane to the surface. At the basement membrane the cells tend to be columnar or cuboidal and flatten out as they work their way to the surface. Transitional epithelium has cells that are pretty much the same shape from the basement membrane to the surface. The surface cells are generally the largest cells. The cells change their shape according to the pressure applied.

How is epithelial tissue the opposite of connective tissue? Answer: In epithelial tissue the cells are packed together very tightly. Epithelial tissue is avascular. Epithelial tissue has three cell types that cover or line things and make tubes. Epithelial tissue has no fibers and it tends to be polar. Connective tissue has cells spaced far apart and is highly vascular (except cartilage). The cells of connective tissue vary greatly in shape and size. Connective tissue glues other tissues together and has three fiber types. Connective tissue tends to be nonpolar. Connective tissue has a large amount of ground substance; epithelial tissue does not.

Tendon tears or breaks are difficult to repair both physiologically and surgically. Why? Answer: Tendons are composed of dense regular connective tissue, which consists of densely packed, parallel connective tissue fibers. This type of tissue has relatively few cells and vascular supply is poor; consequently, repair is slow. Because of the structure of the tissue, surgical repair can be compared to attempting to suture two bristle brushes together.

Since mature adipocytes do not divide, how can adults gain weight? Answer: Adipocytes contain a fat-filled vacuole that can fill or empty, causing the cell to gain or lose volume.