Skeleton System

The stapes bone is found in the human Ear.

It is one of the three tiny bones in the middle ear, collectively known as the ossicles, which transmit sound vibrations from the eardrum to the inner ear.

The smallest bone in mammals is the Stapes. Located in the middle ear, this stirrup-shaped bone plays a crucial role in hearing by transmitting sound vibrations.

The main component of human bone is Calcium.

• Specifically, bones are primarily composed of calcium phosphate, which gives them their hardness and rigidity, providing structural support to the body.

• It is a fibrous structural protein that is also the key component of hair, skin, and the outer layers of many animal structures like horns and hooves, providing strength and protection.

The growth stages divided into

• Anagen,
• Catagen,
• and Telogen

are found in Hair.

These three phases describe the cyclical process of hair growth, regression, and resting, respectively, which occur throughout a person's life.

The structural protein present in rhinoceros horn and in human hair is Keratin.

This tough, fibrous protein provides strength and structure to various epidermal derivatives in animals, including hair, nails, and horns.

1. Epithelium covers most organs and cavities within the body.
2. It also forms a barrier to keep different body systems separate.
3. Epithelial cells form a thin layer of cells known as the endothelium, which is continuous with the inner tissue lining of organs such as the brain, lungs, skin and heart.

The skin, lining of the mouth, lining of blood vessels, lung alveoli, and kidney tubules are all made of epithelial tissue.

More specifically:

1. Skin – Stratified squamous epithelium

2. Lining of the mouth – Stratified squamous epithelium

3. Lining of blood vessels – Simple squamous epithelium (also called endothelium)

4. Lung alveoli – Simple squamous epithelium (for efficient gas exchange)

5. Kidney tubules – Cuboidal epithelium (specifically simple cuboidal epithelium)

• It is a stratified squamous epithelial membrane resting on top of connective tissue.
• The apical surface of this membrane is exposed to the external environment and is covered with dead, keratinized cells that help protect the body from desiccation and pathogens.

• It is produced by specialized cells called melanocytes and absorbs harmful UV radiation, thus protecting underlying tissues from damage.