Animal Tissues and Organ Systems

Animal tissues are groups of cells that perform a specific function. Some of the main types of animal tissues are:

Epithelial tissueA group of similar specialised cells working together to perform a function.: Epithelial tissue lines the surfaces of organs and body cavities and protects the body from the environment. Epithelial tissue is made up of epithelial cells, which are tightly packed together and have a single layer of cell walls. Epithelial cells also have a basement membrane, which is a thin layer of extracellular matrixUsed in mathematics, this is an arrangement of numbers, symbols, or expressions arranged into rows and columns. that separates the epithelial tissue from the underlying connective tissue. Epithelial tissue can be simple, meaning that it is composed of a single layer of cells, or stratified, meaning that it is composed of multiple layers of cells.

Connective tissue: Connective tissue is a type of tissue that provides support and protection for the body. Connective tissue is made up of cells called connective tissue cells and an extracellular matrix that surrounds the cells. The extracellular matrix is made up of fibers and a ground substance. The fibers in the extracellular matrix include collagenA structural protein in bone and other connective tissues that can retain dietary and environmental isotopes. fibers, elastic fibers, and reticular fibers. The ground substance is a gel-like substance that fills the spaces between the fibers. Connective tissue can be loose or dense, depending on the amount of fibers in the extracellular matrix.

Muscle tissue: Muscle tissue is a type of tissue that is specialized for contraction. There are three types of muscle tissue: skeletal muscle, smooth muscle, and cardiac muscle. Skeletal muscle is a type of muscle tissue that is attached to bones and is responsible for voluntary movement. Skeletal muscle is composed of elongated muscle cells called muscle fibers that are surrounded by a thin layer of connective tissue called the endomysium. Smooth muscle is a type of muscle tissue that is found in the walls of organs such as the intestines and the blood vessels. Smooth muscle is responsible for involuntary movement. Smooth muscle is composed of spindle-shaped muscle cells that are surrounded by a thin layer of connective tissue called the perimysium. Cardiac muscle is a type of muscle tissue that is found in the walls of the heart. Cardiac muscle is responsible for pumping blood throughout the body. Cardiac muscle is a type of muscle tissue that is found in the walls of the heart. Cardiac muscle is responsible for pumping blood throughout the body. Cardiac muscle is composed of elongated muscle cells that are interconnected by intercalated discs. Cardiac muscle has a unique featureA non-portable element of an archaeological site, such as a wall, ditch, or hearth. called myofibrils, which are long, thin structures that are responsible for contraction.