Before you go on to read about the histology of penguins, read the following discussion of cell types. There are four types of tissue in penguins. There is nervous tissue, muscle , epithelial tissue, and connective tissue . Everything that is natural to the penguin, i.e. that which is created by the penguin, is composed of one or more of these types of tissue. Cells are classified as any of the above depending on their location and characteristics.
Muscle is divided into skeletal , cardiac , and smooth .
Skeletal muscle most often attaches to the skeleton and helps the penguin perform voluntary movements like walking, swimming, and vocalizing. Cardiac muscle is the muscle found in the penguin heart. Smooth muscle is the muscle that lines portions of the digestive system. They create movement, whether voluntary or involuntary. The other two tissue types are less obvious.