Question

The layer protecting the underlying tissues against chemical and mechanical stress is made up of :

• A. Pseudostratified epithelium
• B. Stratified squamous keratinized epithelium
• C. Columnar epithelium
• D. Stratified squamous non-keratinized epithelium

Answer 1

The correct option is B Stratified squamous keratinized epithelium

Pseudo-stratified epithelium is a simple epithelium which gives a false impression of stratified epithelium. It is seen in the trachea.

Stratified squamous keratinized epithelium forms the epidermis of the skin. Apical layer of the skin is the stratum corneum which are dehydrated and contain keratin. The presence of keratin on the epithelium of the skin protects the underlying tissue against the chemical (dilute acids and alkalis etc) and mechanical stress (caused by bending or tension etc) surrounding the body.

Columnar epithelium are simple epithelium help in the secretion of mucous in the presence of cilia. They trap foreign particles and move the particles in a specific direction. The non-ciliated columnar epithelium help in secretion and absorption.

Stratified squamous non-keratinized epithelium is present in the surfaces of the inner lining of the buccal cavity, pharynx, oesophagus. They lack keratin, so the inner lining remains moist.