Respiratory System nasal cavity Primary Bronchi bronchioles alveoli

Respiratory System: - nasal cavity - Primary Bronchi, bronchioles & alveoli - Cells in alveoli

Organization of the respiratory system • Functions, movement of air (breathing); exchange oxygen for carbon dioxide • Conducting portion and respiratory portion • Conducting: epithelium, cartilage, smooth muscle, bones – Nasal and oral cavities, nasopharynx, larynx, tracea, primary bonchi, secondary bronchi, brondhiles, terminal bronchioles.

Conducting portion • warm air, filter out bacteria, prevent dehydration, immune against infection • Olfactory epithelium

Nasal Cavity • Respiratory epithelium and keratinizing stratifed squamous epithelium • Pseudostratified ciliated epithelium also in the trachea and bronchioles (respiratory ep) – – – Ciliated columnar cells – secretory Ig. A transcytosis Goblet cells Basal cells Brush cells with tall microvilli DNES cells (diffuse neuroendocrine system)

Olfactory epithelium • • • OSNs SCs BC Bowman’s glands Glomeruli (1000 – 1500) around 10, 000 odors

Trachea • Mucosa – respiratory epithelium – Lamina propria, loose fibroelastic tissue, lymph elements, elastic lamina • Submucosa – dense fibro-elastic, mucous and seromucous glands, lymphoid elements, BV • Adventitia – C rings, fibroelastic CT, anchors to various structures

Primary Bronchi - histological structure same as trachea

Intrapulmonary bronchi - adventitia has irregular plates of cartilage - elastic fibers - between lamina propria and submucosa - smooth muscle - form opposing spirals around bronchi - lamina propria with seromucous glands

Bronchioles - ciliated simple columnar, few goblet cells --> simple cuboidal, no goblet cells, yes Clara cells - produce surfactant - contain cytochrome P 450 enzymes - proliferate and can differentiate to epithelial cells Lamina Propria - no glands - surrounded by a loose network of helically oriented smooth muscle cells **no cartilage**

Terminal bronchioles - epithelium is cuboidal ciliated with Clara cells - one or two layers of smooth muscle Respiratory bronchioles - similar to terminal bronchioles - wall has alveolar outpouchings Alveolar Ducts - linear arrangements of alveoli

Alveolar sacs - cluster of alveoli Alveoli - primary structural and functional unit of the respiratory system - allow for gas exchange between air and blood

Cells in alveoli: Type I pneumocytes - simple squamous epithelium - occluding junctions - basal lamina Type II pneumocytes - cuboidal cells - form occluding junctions with type I pneumocytes - contain lamellar bodies with pulmonary surfactant that is secreted by exocytosis Alveolar macrophages - phagocytose dust and bacteria

Continuous capillaries: - endothelial cells without fenestrae - fasciae occludentes Blood-Gas Barrier - surfactant and type I pneumocytes - fused basal laminae - endothelial cells

Digestive System - Oral Cavity Tongue - epidermis, taste cells, glands, muscles Lingual papillae: - filiform - no taste buds - fungiform - dorsal taste buds - foliate - taste buds in neonates, lateral furrows - circumvallate - look like a submerged donut - taste buds on sides

Taste buds - taste pore - nerve fibers form synaptic junctions with type I, type III cells - type IV are basal cells

Glands of the tongue - von Ebner’s glands - serous glands - ducts at the base of circumvallate and folate papillae