Respiratory System & Skin Study Guide PDF

DR. Amany Abdelfattah Respiratory system Conducting portion Respiratory portion Nasal cavities, Nasopharynx, Larynx, Respiratory bronchioles Trachea, Bronchi, Bronchioles, Alveolar ducts. Termi...

DR. Amany Abdelfattah Respiratory system Conducting portion Respiratory portion Nasal cavities, Nasopharynx, Larynx, Respiratory bronchioles Trachea, Bronchi, Bronchioles, Alveolar ducts. Terminal bronchioles. Alveoli. Air conduction & conditioning Gas exchange Nasal cavity Divided into: 1. Vestibule: External, dilated part, lined by skin. 2. Respiratory region: The largest part lined by respiratory epithelium. 3. Olfactory region: The roof of the nasal cavities lined with specialized olfactory epithelium (neuroepithelium). Nasopharynx The first part of the pharynx. It is lined by respiratory epithelium. Larynx A short passage for air between the pharynx and the trachea. It has rigid wall due to presence of cartilage (maintain an open airway). Contain vocal cords → important for phonation or sound production.  DR. Amany Abdelfattah Trachea Air tube extend from the larynx to the thorax and serves as a pathway for air. Its wall consists of: 1. Mucosa. 2. Submucosa. 3. Cartilaginous layer. 4. Adventitia. 1. Mucosa: consists of: Epithelium: respiratory epithelium. Lamina propria: loose C.T. Elastic membrane: between the lamina propria & the submucosa. 2. Submucosa: loose C.T contains tracheal glands (mucus & serous glands). 3. Cartilaginous layer: C-shaped rings of hyaline cartilage. Maintain patency of tracheal lumen. The gaps between the free edges are bridged by smooth muscle fibers. 4. Adventitia: C.T. Pulmonary Alveoli Def.: The functional and structural units of the lung. Structure: mainly formed of alveolar epithelium composed of: a) Pneumocytes Type -1 (alveolar cell type I). b) Pneumocytes Type-2 (alveolar cell type II). Pneumocytes Type -1 Pneumocytes Type -2 Percentage 95% of alveolar lining 5% of alveolar lining Shape flat squamous cells Cubical cell with rounded central nuclei Function Provide a very thin Secrete pulmonary surfactant→ membrane through which decrease surface tension →prevent gas exchange takes place. alveolar collapse.  DR. Amany Abdelfattah The Skin The largest organ in the body. Types of Skin: 1. Thick (non-hairy) skin → In palms and soles. 2. Thin (hairy) skin → Covers the rest of body. Thick Skin Structure: I. The Epidermis: Thin superficial layer (epithelium). II. The Dermis: Thick deeper layer (C.T.) I. The Epidermis Formed of stratified squamous Keratinized epithelium Consists of 4 types of cells: a) Keratinocytes (85%) → keratin forming cells b) Melanocytes → melanin forming cells c) Langerhans cells (epidermal macrophages) → phagocytosis d) Merkel's cells → receptors for touch sensation II. The Dermis Formed of white fibrous connective tissue (irregular type). Contain sweat glands Thin Skin Present all over the body except sole & palms. Epidermis is thinner. Contain sweat glands in addition to hair and sebaceous glands.