Respiratory Anatomy PDF

Respiratory Anatomy PARA 1002 1 Function of Respiratory System Conducts air to the respiratory surfaces O2 and CO2 are exchanged with the blood (circulatory system) Conditions the air (warms, humidifies, cleans) before reaching the respi...

Respiratory Anatomy PARA 1002 1 Function of Respiratory System Conducts air to the respiratory surfaces O2 and CO2 are exchanged with the blood (circulatory system) Conditions the air (warms, humidifies, cleans) before reaching the respiratory tissues Important role in maintenance of body pH Secondary structures for olfaction and vocalization PARA 1002 2 1  Functional Zones Conducting Zone – The various passages that convey air between the external environment and the respiratory surfaces – Structures are lined with epithelial cells that secrete, filter, protect and actively clear debris – Support provided by muscle, bone and cartilage Respiratory Zone – The highly vascularized / perfused region where gas exchange actually takes place – Thin moist membranes and an absence of bony or cartilaginous support structures PARA 1002 3 Structural Divisions Upper Resp. Tract Nasal cavity, oral cavity and pharynx , larynx (boarder) Important for warming and conditioning of air Lower Resp. Tract Trachea, and multiple generations of airways (bronchial tree) Proximal elements are cartilaginous; distal are noncartilaginousPARA 1002 4 2  Upper Respiratory Tract PARA 1002 5 Nasal Cavity The point of entry for external air Projects anteriorly as cartilaginous portion of the nose Extends posteriorly to communicate with the pharynx (respiratory and digestive) Paranasal Sinuses Mucous membrane lined spaces in the skull named for the specific skull bone Ciliated epithelia move mucous from sinuses to nasal cavity through paranasal ducts Humidify/warm air, voice resonance, lighten skull bones PARA 1002 6 3  Nasal Cavity Nasolacrimal Ducts Lead from orbit to the lateral walls of the nasal cavity Tears pass into the nasal cavity from lacrimal glands Auditory (Eustachian) Tubes Connect middle ear with lateral wall of post. pharynx Equalization of air pressure PARA 1002 7 Nasal Cavity PARA 1002 8 4  Nasal Epithelia Respiratory pathways are necessarily exposed to the external environment Epithelial tissues = high turnover (cellular regeneration) Why is this particularly important in this case? Where else are such characteristics desirable? Mucous (specialized cells) is moved posteriorly by cilia (also produced in paranasal sinuses) PARA 1002 9 Functions of the Nasal Cavity Conditioning of Inspired Air Vascular epithelium well suited to warming The moist mucous helps to humidify the incoming air As air moves through the turbinates of the nasal conchae, particles such as dust, smoke, pollen are filtered out and trapped in the mucous Conditioned air ensures that gas exchange is more efficient with respiratory membranes: Warm (body temp.), humid, “clean” PARA 1002 10 5  Functions of the Nasal Cavity Olfaction Nonrespiratory function of the nasal cavity Olfactory receptors on the roof of the nasal cavity Axons from receptors form olfactory nerve branches (CN1) Phonation Air exhaled through the nose lends resonance to the voice How do you sound when you have a cold? PARA 1002 11 Oral Cavity Secondary respiratory passage Clinically important in procedures such as endotracheal intubation (Why the mouth?) Failure of the right and left maxillary bones to fuse embryologically results in a cleft palate Abnormal communication between nasal and oral cavities PARA 1002 12 6  Pharynx (common passageway) Nasopharynx (respiratory role) Continuous with the posterior nasal cavity Mucous (trapped debris) moved posteriorly by cilia Eustachian tubes (to middle ear) located in lateral walls Adenoids (pharyngeal tonsils) on posterior walls Oropharynx (digestive and respiratory role) Region between the soft palate and hyoid bone containing the lingual tonsils and palatine tonsils (What do they do?) Laryngopharynx (distal structure of upper RT) Marks boarder of proximal larynx where air is diverted anteriorly into trachea Hypopharynx? PARA 1002 13 Larynx Adam’s apple Closes glottis during swallowing connection Attachment for vocal cords Located on anterior midline of the neck between C4-C6 Flexible cartilages connected by ligaments and membranes Conducts air, prevents aspiration, vocalizations Rima glottidis - slit between vocal cords (prone to edema / obstruction) PARA 1002 14 7  Lower Respiratory Tract PARA 1002 15 Trachea Maintained by cartilage rings (incomplete posteriorly) Lumen lined with ciliated respiratory epithelium Main conducting tube for air to both lungs Bifurcates into a right and left primary bronchus PARA 1002 16 8  Tracheobronchial Tree Primary Bronchi C-shaped hyaline cartilage maintains airway patency Right 1º bronchus is shorter, larger diameter and more vertical than left (aspirated objects?) Secondary Bronchi (lobar) Connect the 1º bronchi to the lobes of the lung 3 on right and 2 on the left Supported by smaller plates of cartilage PARA 1002 17 Tracheobronchial Tree Tertiary Bronchi (segmental) Supply bronchopulmonary segments within each lobe 10 on right / 8 on left Subsegmental Bronchi Last cartilaginous airways Bronchioles Noncartilaginous and > 2 lobes Right lung >> 3 lobes PARA 1002 28 14  Bronchopulmonary Segments Lungs are further divided into bronchopulmonary segments, associated with the tertiary (segmental) bronchi PARA 1002 29 15