give reasons why the 1)cell lining the blood vessels are simple 2) cells in the skin are many layers 3) cells in the respiratory tract has cilia
Answers
Explanation:
1.) Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membrane. Cell junctions are well employed in epithelial tissues.
2.) The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, and cold.
Skin has three layers:
1 The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone.
2 The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands.
3 The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.
The skin’s color is created by special cells called melanocytes, which produce the pigmen
3.) Cilia are found in the lungs, respiratory tract and middle ear. These cilia have a rhythmic waving or beating motion. They work, for instance, to keep the airways clear of mucus and dirt, allowing us to breathe easily and without irritation.
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