1. Connective tissue
2. Muscle tissue
3. Epithelial tissue
4. Nervous tissue
The connective tissue in animals is separated by non-living material. The connective tissue binds and supports body parts, protects, fills spaces, stores fat and transports materials. The structure of a loose connective tissue and dense connective tissue has three types of fibres. The first one is the collagen fibres which provide strength and flexibility and is the existing protein in animal bodies. The second one is elastic fibres which provide elasticity and when stretched, they return to their original shape. The third one is the reticular fibres which are small and branched and they ...view middle of the document...
A smooth muscle is involuntary which surrounds the gut and moves food through the digestive tract. It is surrounded by thee blood vessels where it controls the blood where some blood vessels are contracted while others are filled as there is not enough blood to fill all the vessels. The skeletal muscle is voluntary where the cells are very long, extending the length of the actual muscle. And the cardiac muscle is found in the heart and is striated and branched.
The epithelial tissue in animals is the tissue that covers the outside surfaces and inside cavities and organs as well as glands which also have epithelial tissue. The epithelia tissue forms boundaries in which the substances move into or out of the body through the epithelial tissue. For example in the kidney tubules the cells lining are epithelial tissue in which one is attached which is called the basal surface and the other surface which is called apical is free. The apical surface of epithelial tissue cells may have tiny projections which are called microvilli and increase the surface area such as for absorption. The epithelial tissue may have cilia which can be seen on the cells lining the trachea. Their function in the trachea is to move mucus and particles up towards the mouth where it will be swallowed, keeping the trachea clear from foreign particles. The main function of the epithelial tissue is for;
The epithelial tissue forms the skin of animals and vertebrates have keratin in their skin cells which makes them resistant to water loss. The ciliated epithelium lines the respiratory tract and the cilia on these cells get rid of the impurities toward the throat. Absorption is a important function of the epithelial tissue such as in the gut which is lined with epithelial tissue and absorbs nutrients from food and in the lungs the epithelial tissue functions to absorb oxygen. Secretion is also important, in the glandular epithelium it secretes chemicals, in the endocrine glands it secrete hormones directly into extracellular area and in the exocrine glands secretion often happens through DUCTS ; and they secrete things such as mucus, saliva, wax and milk. The shape of the epithelial cells are flat, cube-shaped or elongated.
The nervous tissue in an animal responds to stimuli and transmits impulses from part of the body part to...