Respiratory System

Introduction Respiratory system composed is of many organs, each with specific functions Lungs enable the body to extract oxygen when inhaling and remove carbon dioxide when exhaling Unwanted particles are removed by the fine hairs in the nose before the particles can enter the body. The mucosal lining of the bronchi also removes unwanted particles. The air is heated in the nose so that it is more compatible with our body temperature.

Structures Respiratory system is like a large inverted tree Large trunk: trachea Two main branches: bronchi Smaller branches: bronchioles Leaves: alveolar sacs (gas exchange)

Diagram of Respiratory System Unwanted particles are removed by the fine hairs in the nose before the particles can enter the body. The mucosal lining of the bronchi also removes unwanted particles. The air is heated in the nose so that it is more compatible with our body temperature.

The Upper Respiratory System Composed of: Nose Pharynx Larynx Nasal cavities

The Upper Respiratory System (Continued) Cavities lined with mucosal lining and cilia Mucous membrane warms and moistens air; Cilia catch dust particles Nose: sense of smell, drainage for tears Pharynx shared with digestive system Larynx: voice box (men protrude—Adam’s apple) Epiglottis covers trachea during swallowing Tonsils: lymphatic tissue; located on pharynx A thin, leaf-shaped cartilaginous structure, the epiglottis, is located at the entrance of the larynx. The epiglottis closes off the trachea automatically when swallowing takes place to keep food, liquid, and saliva from going down the airway and causing choking. Tonsils help the body fight off disease.

Lower Respiratory System Composed of: Trachea Bronchial Tree Bronchi Bronchioles Aveoli Lungs Cilia are microscopic hairlike structures that move unwanted particles upward where the particles are swallowed. Why does the trachea have incomplete rings of cartilage reinforcing it? The cartilage prevents the trachea from collapsing like a folded straw when the neck is bent. There are millions of clusters of microscopic alveolar sacs deep in the lungs.

Lower Respiratory System (Continued) Trachea: windpipe; branches into lungs Trachea lined with mucosal lining (traps airborne particles) and cilia Trachea branches to left and right bronchi  smaller bronchi  smaller bronchioles  alveoli Pleural cavity lines chest cavity & covers lungs

Bronchial Tree Even though the composition of the air taken in during respiration is 79% nitrogen, the body does not use the nitrogen. What happens to the nitrogen? It is expelled into the air along with the carbon dioxide and leftover oxygen molecules.

Lower Respiratory System Facts Right bronchus bigger than left (heart displacement) Diaphragm separates chest cavity from abdominal cavity Lungs—divided into lobes—three on right and two on left When you step outside on a cold winter day, the asthma-like tightening you might feel in your chest is reflex bronchoconstriction. Researchers now believe that one trigger for this protective reflex is cold air hitting the face, before the actual inhalation of cold air. The diaphragm is a large muscle.

Lower Respiratory System (Continued) Right lung: greater capacity Left lung—longer—less capacity Mediastinum: location of heart; separates right and left lung Main function of lungs— breathing—pulmonary ventilation The outer surface of the lungs is covered by moist, smooth, slippery membranes that reduce friction between the lungs and chest wall during breathing.

Respiration Review Inspiration: diaphragm flattens, the intercostals muscles expand, thoracic cavity increases in size Expiration: passive response When a person actively inhales, the increase in the size of the thoracic cavity reduces the pressure inside so that air can enter the lungs. During expiration, the chest relaxes and the thoracic cavity becomes smaller. This causes the pressure within the thoracic cavity to increase and air to leave the lungs.

Breathing Dysfunctions Condition Symptoms Apnea Respiration stops as in heart failure Bradypnea Slow breathing Cyanosis Lack of oxygen causes skin to turn blue gray Dyspnea Labored or difficult breathing Hyperventilation Deep and rapid breathing Hyponea Shallow, inadequate breathing Orthopnea Labored or difficult breathing while lying down Tachypnea Rapid breathing What usually causes hyperventilation? Anxiety and panic are common causes of hyperventilation.

Disorders of the Upper Respiratory System Conditions: caused by genetics, contagious infections, habits (smoking), environmental factors Common condition: respiratory colds, caused by viruses Symptoms: coughing, congestion, sometimes wheezing

Disorders of the Upper Respiratory System (Continued) Flu, influenza: severe type of cold; viral; strain named after region first detected Rhinitis: nasal inflammatory condition caused by colds, flu, allergies Allergies: Most common respiratory problem Remedies: most obtained OTC

Disorders of the Lower Respiratory Tract Pneumonia: Infection Causes acute inflammation Lung airways blocked with thick mucus Causes: bacterial, viral, fungal, chemical, parasitic (rare) Chronic obstructive pulmonary disease (COPD) Involves: Emphysema, chronic bronchitis and asthma Irreversible damage to lungs What is the most common cause of pneumonia? Pneumonia is most commonly caused by bacteria.

Disorders of the Lower Respiratory Tract Acute bronchitis: inflammation of bronchi and trachea, caused by infection; can be chronic Chronic bronchitis: narrows bronchioles; leads to emphysema (smokers) What is the most common cause of pneumonia? Pneumonia is most commonly caused by bacteria.

Conditions of the Respiratory System Condition Definition Pleurisy Inflammation of the lining of the lungs and lung cavities Croup A childhood condition that causes obstruction of the larynx, a barking cough, and noisy breathing Whooping cough Also known as pertussis, this bacterial infection is contagious. It affects the larynx and trachea and produces coughing spasms. Pulmonary edema Caused by fluid filling the respiratory air sacs (alveoli) and bronchioles

Asthma Major childhood respiratory problem In asthma, the muscles around the bronchioles contract, narrowing the air passages so that air cannot be inhaled properly. Worsened by edema and mucus in airway In asthma, the muscles around the bronchioles contract, narrowing the air passages so that air cannot be inhaled properly. What is edema? Edema is an excessive accumulation of serous fluid in the tissue spaces.

Tuberculosis TB: most common bacterial disease affecting pulmonary system Highly contagious infection within the lining of the lungs Immune system weakens, bacteria multiply, symptoms appear High-risk persons: those in confined living space, as in prison

Emergency Disorders of the Lungs Pneumothorax: a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. Pulmonary embolism: embolus blocks pulmonary artery (heart to lungs) How would you characterize pneumothorax? Pneumothorax is a collapse of the alveoli resulting from air escaping into the pleural space. An embolus is a small blood clot.

Emergency Disorders of the Lungs Hemothorax: collapse of lung from blood leaking into pleural space Cancer: persistent hoarseness first sign of laryngeal cancer High risk—smokers—pipe, cigars, cigarettes; chemical (breathed in) with hazardous particles How would you characterize pneumothorax? Pneumothorax is a collapse of the alveoli resulting from air escaping into the pleural space. An embolus is a small blood clot.