Pharynx, Larynx and Trachea (L3) 2012

Pharynx Epithelium Pharynx = nasopharynx +oropharynx +laryngopharynx Part of respiratory and digestive systems Epithelium Either unkeratinized stratified squamous OR Pseudostratified ciliated columnar epithelium and goblet cells

Lamina propria Dense connective tissue with elastic and collagen fibers Mucinous gland, especially around the opening of the Eustachian tube muscularis externa is skeletal muscle and forms the constrictor muscles of the pharynx Contains the tonsils

Tonsils Tonsils consist of a number of lymph follicles All part of the Waldereyers ring Tonsilla lingualis Base of the tongue Smaller and numerous lymphoid follicles Associated with a single crypt Stratified squamous epithelium

Tonsilla palatina (Palatine tonsils) Surface squamous epithelium Part of oral mucosa Folds and forms crypts Often contain bacteria, food particles, mucous (immunity (antigen presentation) + tonsillitis) Lymphoid follicles with connective tissue septa Outer –B lymphocytes Inner-T lymphocytes Deep fibrous capsule –(facilitates tonsillectomy)

Palatine tonsil

Tonsilla pharyngealis (adenoids) Single tonsil Wall of the nasopharynx Ciliated pseudostratified columnar epithelium No crypts Thin capsule Diffuse lymphoid tissue and nodules

Larynx Epithelium Unkeratinized stratified squamous epithelium on the anterior and upper part of the posterior surface of the epiglottis as well as the vocal cords Pseudostratified columnar epithelium containing cilia and goblet cells on the inferior part of the posterior surface of the epiglottis and the walls of the larynx

Skeletal muscle layer (swallowing) Cartilaginous skeleton of hyaline or elastic cartilage that keeps tube open

Trachea Mucosa Pseudostratified columnar cells with cilia Serous cells Kulchitsky cells (part of diffuse neuroendocrine system) Stem cells able to divide and replace other cells Lamina propria Loose highly vascular supporting tissue Submucosa Mixed seromucinous glands Submucosa merges with perichondrium of the underlying hyaline cartilage rings (C-shaped)