Study guide Anatomy and Physiology I Exam IV December 6 2012 The Respiratory System Functional Anatomy of the Respiratory System 1 List the structures and functions of the nose nasal cavity and paranasal sinuses a Nose provides an airway for respiration moistens warms filters and cleans incoming air provides a resonance chamber for speech houses olfactory receptors i Divided into the external nose which is formed by hyaline cartilage and bones of the skull and the nasal cavity which is entirely within the skull b Nasal Cavity consists of two types of epithelium olfactory mucosa and c Paranasal Sinuses within the frontal maxillary sphenoid and ethmoid respiratory mucosa bones i Serve to lighten the skull warm and moisten air and produce mucus 2 Describe the structures of the pharynx larynx and trachea a Pharynx Connects the nasal cavity and mouth superiorly to the larynx and esophagus inferiorly i Nasopharynx serves only as an air passageway and contains the pharyngeal tonsil which traps and destroys airborne pathogens ii Oropharynx air and food passageway that extends inferiorly from the level of the soft palate to the epiglottis iii Laryngopharynx air and food passageway that lies directly posterior to the epiglottis extends to the larynx and is continuous inferiorly with the esophagus b Larynx provides an open airway routes food and air into the proper passageways and produces sound through the vocal cords i Vocal ligaments form the core of mucosal folds the true vocal cords which vibrate as air passes over tehm to produce sound ii The vocal folds and the medial space between them are called the glottis c Trachea windpipe descends from the larynx through the neck into the mediastinum where it terminates at the primary bronchi 3 Explain the structure of the lungs and the vascular and neural networks that supply them a The conducting zone consists of right and left primary bronchi that enter each lung and diverge into secondary bronchi that serve each lobe of the lungs b Secondary bronchi branch into several orders of tertiary bronchi which ultimately branch into bronchioles c As the conducting airways become smaller the supportive cartilage changes in character until it is no longer present in the bronchioles d The respiratory zone begins as the terminal bronchioles feed into respiratory bronchioles that terminate in alveolar ducts within cluster of alveolar sacs which consists of alveoli i The respiratory membrane consists of single layer of squamous epithelium Type I cells surrounded by a basal lamina Interspersed amond the Type I cells are cuboidal Type II cells that secrete surfactant ii iii Alveoli are surrounded by elastic fibers contain open alveolar pores and have alveolar macrophages 4 Discuss the relationship of the pleurae to the lungs and thoracic wall and their functional importance a The lungs occupy all of the thoracic cavity except for the mediastinum each lunch is suspended within its own pleural cavity and connected to the mediastinum by vascular and bronchial attachments called the lung root b Each lobe contains a number of bronchopulmonary segments each served by its own artery vein and tertiary bronchus c Lung tissue consists largely of air spaces with the balance of lung tissue its stroma comprised mostly of elastic connective tissue d There are two circulations that serve the lungs i Pulmonary Network carries systemic blood to the lungs for oxygenation ii Bronchial arteries provide systemic blood to the lung tissue e The lungs are innervated by parasympathetic and sympathetic motor fibers that constrict or dilate the airways as well as visceral sensory fibers f The pleurae form a thin double layered serosea i The parietal pleua covers the thoracic wall superior face of the diaphragm and continues around the heart between the lungs ii The visceral pleura covers the external lung surface following its contours and fissures Mechanics of Breathing 5 Define intrapulmonary and intrapleural pressure a Intrapulmonary the pressure exerted in the alveoli which rises and falls during respiration but always eventually equalizes with atmospheric pressure Intrapleural the pressure in the pleural cavity It also rises and falls during respiration but is always about 4 mmHg less than intrapulmonary pressure 6 Describe pulmonary ventilation and the relationships between pressure and volume b changes as they apply to the lungs a Pulmonary Ventilation breathing is the exchange of air between the atmostphere and the lungs b Boyle s Law Gas will always move from a region of high pressure to a region of low pressure If volume increases in the thoracic cavity due to inhalation the pressure will decrease 7 Identify the events of quiet and forced inspiration and passive and forced expiration a Inspiration i Inspiratory muscle contract 1 Diaphragm descends 2 Rib cage rises b Expiration ii Thoracity cavity volume increases iii Lungs stretched intrpulmonary volume increases iv v Air gases flows into lungs down its pressure gradient until Intrapulmonary pressyre drops to 1 mmHg intrapulmonary pressure is 0 to atmospheric pressure i Inspiratory muscle relax 1 Diaphragm rises 2 Rib cage descends du to recoil of costal cartilages ii Thoracic cavity volume decreases iii Elastic lungs recoil passively intrapulmonary volume decreases iv v Air gases flows out of lungs down its pressure gradient until Intrapulmonary pressure rises to 1 mmHg intrapulmonary pressure is 0 8 Discuss the effects of airway resistance alveolar surface tension and lung compliance on pulmonary ventilation a Airway Resistance friction is the major nonelastic source of resistance to airflow i Flow change in pressure resistance ii Greatest resistance occurs in the medium sized bronchi iii Epinephrine released via Sympathetic Nervous System dilates bronchiole and reduces air resistance b Alveolar Surface Tension determines the attraction of liquid molecules to one another at a liquid gas interface i Surfactant a detergent like complex reduces surface tension and helps keep the alveoli from collapsing c Lung Compiance the ease with which lungs can be expanded i The measure of the change in lung volume that occurs with a given change in transpulmonary pressure ii Two main factors 1 Distensibility 2 Surface tension of the alveoli of the lung tissue and surrounding thoracic cage iii Factors that diminish lung compliances 1 Scar tissue fibrosis diminishes resiliency 2 Mucus which blocks smaller respiratory passages 3 Reduced
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