NURSING ANM AND GNM

Detailed explanation-1: -The tympanic membrane is derived from the invagination and meeting of the first pharyngeal groove (cleft) with the first pharyngeal pouch, and as such, it is comprised of two germ layers (ectoderm and endoderm).

Detailed explanation-2: -The inner mucosal layer of the tympanic membrane is derived from the endoderm of the first pharyngeal pouch. The mucous membrane is composed of a non-keratinized squamous epithelium that is continuous with the lining of the tympanic cavity.

Detailed explanation-3: -The tympanic membrane is comprised of three layers of tissue: the outer cutaneous layer, the fibrous middle layer, and a layer of mucous membrane on its innermost surface. The membrane is held in place by a thick ring of cartilage, a tough but flexible kind of tissue.

Detailed explanation-4: -The external ear develops from the first two pharyngeal arches, which begin forming six hillocks of His in the five weeks of development. The first three hillocks originate from the first pharyngeal arch and fuse together to form the tragus, helix, and cymba conchae.