Respiratory System

Functions of the Respiratory System Brings Oxygen into the blood. Removes Carbon Dioxide from the blood stream. Pulmonary Ventilation: Exchange of air between external environment and the air sacs of the lungs. External Respiration: Exchange of gases between the lungs and the blood stream. Internal Respiration: Exchange of gases between the blood stream and the body cells. Respiration: All three of the above put together.

Functions of the Respiratory System Providing a large area for gas exchange between air and circulating blood. Moving air to an from the gas-exchange surfaces of the lungs. Protecting the respiratory surfaces from dehydration, temperature changes, and defend against infection. Producing sounds permitting speech, singing, and nonverbal auditory communication. Aiding the sense of smell by the olfactory receptors in the nasal cavity.

Organs of the Respiratory System Respiratory Tract- the passageways that carry air to and from the exchange surfaces of the lungs. Upper Respiratory Tract (Conduction Pathway) Nose: Initial receiving chamber for inhaled air. Vestibule: Small chamber of nose (nasal cavity) Nasal Cavity: Larger chamber of nose (nasal cavity) Nasal Septum: Divides the nose (nasal cavity) in half Nasal Conches: 3 boney projection in the nasal cavity that increase airflow. Pharynx: (AKA the throat) Runs from the nasal cavity to the larynx Carries the oxygenated air to the larynx Carries food to the esophagus

Organs of the Respiratory System Cont… Larynx: Connects the pharynx to the trachea Adam’s Apple: Enlargement of Larynx in males. Voice Box: Vocal Cords: are folds of elastic fibers that vibrate when air rushes past them. Doesn’t contain cilia ( why you must clear your throat) Epiglottis: Flap that covers the trachea when you are swallowing food to prevent food from passing into the lungs. When you swallow the Larynx moves up and the Epiglottis moves down. Respiratory Mucosa: A mucous membrane that lines the conducting portion of the respiratory system.

Organs of the Respiratory System Cont.. Trachea: ( 4 ½ inches long) AKA the wind pipe Divides in the thoracic cavity to form the right and left bronchi. Lined with mucous membranes and cilia which are used to move dust particles and bacteria towards the pharynx. Bronchial Tree: Primary Bronchi-Distal end of bronchial tree (where trachea splits in two). Lower Respiratory Tract (Respiratory Portion) Bronchioles-Subdivisions of primary bronchi (more branching) Alveolar Ducts- Smallest tubes of the bronchial tree. Alveoli- Small round sacs at the end of each alveolar ducts. 300-500 million in each lung Location of gas exchange( between blood and the air of the lungs) One cell thick Have the surface area of a tennis court Allow for the diffusion of oxygen and carbon dioxide

The Lungs & Pleural Cavities Two lungs, each divided into lobes. Left Lung- Contains two lobes; superior & inferior. Right Lung- Contains three lobes; superior, middle, inferior. Males have larger lungs v. females Pleural Cavities The space inside of the thoracic cavity that the lungs occupy. Lined by a serous membrane called the pleura. Parietal pleura: Covers the inner surface of the cavity body wall and extend over the diaphragm and mediastinum. Visceral pleura: Covers the outer surface of the lungs. Diaphragm Respiratory muscle that separates the throacic and abdominopelvic cavity. Is responsible for

External Respiration External Respiration: Exchange of gases between the lungs and the blood stream. Events of External Respiration Breathing or the physical movement of air into and out of the lungs Gas exchange between the alveolar space and the capillaries of the alveoli to infuse blood with oxygen and extract carbon dioxide. Transport of oxygen and carbon dioxide.

Pulmonary Ventilation Pulmonary Ventilation: Exchange of air between external environment and the air sacs of the lungs. Respiratory Cycle: A single breath, consists of inhalation and exhalation. Respiratory Rate: The number of breaths per minute Alveolar Ventilation: The movement of air into and out of the alveoli.

Pulmonary Ventilation Pressure and Airflow (Pressure & Volume Relationship) Pressure is the driving force for airflow into and out of the respiratory system. As the diaphragm expands and contracts it changes the volume of the pleural cavity and the lungs which in turn changes the pressure in those spaces and forces air to rush into and out of the lungs using a pressure gradient. As volume increases pressure decreases and volume decreases pressure increases. Air flows from an areas of high pressure to an areas of low pressure. Compliance: Indicates the resilience of the lungs to expand. The lower the compliance the more force needed to fill and empty the lungs The greater the compliance the easier to fill and empty the lungs.

Pulmonary Ventilation Modes of Breathing Quiet Breathing: Inhalation involves muscular contractions but exhalation is passive. Forced Breathing: Both inhalation and exhalation are active involving the diaphragm, accessory muscles, intercostal muscles, and abdominal muscles. Lung Volumes & Capacities Tidal Volume: The amount of air moved into or out of the lungs during a single respiratory cycle. Expiratory Reserve Volume(ERV):During normal, quite respiration the amount of air that could be voluntarily expelled at the end of such a respiratory cycle Inspiratory Reserve Volume (IRV): The amount of air that can be taken in over and above the resting tidal volume. Vital Capacity: The sum of IRV, ERV, and Tidal Volume. The max air that can be moved in and out in a single respiratory cycle. Residual Volume: The amount of air that remains in the lungs after exhalation. Minimal Volume: Amount of air in the lungs after the chest cavity has been penetrated (pneumothorax, collapsed lungs)

Internal Respiration & Gas Exchange Internal Respiration: Exchange of gases between the blood stream and the body cells. During the pulmonary ventilation, the alveoli are supplied with oxygen, and carbon dioxide is removed from the blood stream. Gas exchange occurs between the blood and alveoli. Gas exchange depends on partial pressure and diffusion of molecules between gas and liquid. Partial Pressure: The pressure contributed by a single gas proportional to its relative abundance in air.

Conditions of the Respiratory System Hypoxia: A deficiency in the amount of oxygen being delivered to the tissues of the body (often used in reference to the supply of oxygen to the brain). Pulmonary Embolism: The blockage of a branch of a pulmonary artery that stops blood flow to a group of alveoli. COPD: Chronic Obstructive Pulmonary Disorder, a group of disorders that result in difficulty expelling air from the lungs. Bronchitis: Inflammation of the tissue lining the bronchial tubes.

Conditions of the Respiratory System Asthma: Disorder of respiration(often allergenic), characterized by bronchio-spasm, wheezing, and difficulty in expiration, often accompanied by coughing and a feeling of constriction in the chest. Pneumothroax: Any condition that damages the parietal pleura and allows air into the pleural cavity. Hemothorax: The reduction in lung volume due to the accumultion of blood in the pleural cavity. Hypoxia: Low tissue oxygen levels. Anoxia: Oxygen supply to tissue is cut off.