Respiratory System

The Respiratory System Nose, pharynx, larynx, trachea, bronchi, & lungs Involved in breathing & gas exchange Brings oxygen to body cells Gets rid of carbon dioxide Works in conjunction with the Circulatory System. If either system fails, body cells begin to die from oxygen starvation & accumulation of CO2

The Nose Air enter the nostrils (external nares) Continues into the nasal cavity, which is divided by a nasal septum. Warms the outside air Moistens air Traps incoming bacteria & foreign debris. Ciliated cells create a current that directs contaminated mucus toward the throat where it is swallowed & digested by stomach juices.

The Pharynx (Throat) Muscular passageway (+/- 13 cm) Common passage for Food & Air Air enters from the nasal cavity & passes through the pharynx to the larynx Contains the tonsils

The Larynx (Voice Box) Routes air & food into the proper channels. Plays a role in speech Consists of 8 rigid hyaline cartilages & a spoon-shaped flap of elastic cartilage (the epiglottis) Epiglottis protects the opening of the larynx Forms a lip over the larynx when swallowing Routes food into the esophagus A cough reflex is triggered when anything other then air enters the larynx Helps prevent contamination of the lungs

The Trachea (Windpipe) Air enters from the larynx Only way air can enter the lungs Lined with ciliated mucus Propel dust & debris away from the lungs to the throat Smoking destroys the cilia Blockage of the trachea or larynx leads to choking

Bronchi & Lungs Bronchi: Lungs: Trachea divides into two tubes leading to the lungs (Right & Left Bronchi) Air entering the bronchi is warm, cleansed of most impurities, & well humidified. Lungs: Divided into lobes (Rt – 3 & Lt – 2 lobes) Primary bronchi subdivide into bronchioles Bronchioles terminate in alveoli air sacs where gas exchange occurs Grape-like sacs Lungs consists of millions of clustered alveoli

The Path of Air Air enters through nose or mouth Flows into the pharynx, past the epiglottis, through the larynx. Travels down the trachea, into the bronchi which connects to the lungs.

Cleaning Air The nasal cavity, trachea, & bronchi are lined with ciliated cells that secrete mucus. Traps foreign matter & moves it back up the throat Can be swallowed or expelled by coughing or sneezing.

Gas Exchange Takes place in the lungs The two bronchi branch into bronchioles that lead to thousands of thin-walled sacs (alveoli) Like sacs of grapes Alveoli exchange O2 & CO2 by diffusion between the air & the blood

Transport of Gases Blood vessels surround the alveoli Oxygen diffuses into the blood vessels The heart pumps the blood to the body cells Body cells use the oxygen for cellular respiration Carbon dioxide diffuses from body cells into the blood Blood carries the CO2 back to the lungs & is released in your exhale.

The Mechanics of Breathing Involves the diaphragm & muscles between the ribs Inhale = diaphragm contracts & flattens, enlarging the chest cavity & drawing air into the lungs Exhale = diaphragm relaxes & the chest cavity volume decreases, forcing most of the air out of the alveoli.

Control of Respiration Involuntary process High levels of CO2 will cause the brain to signal the rib muscles & diaphragm to contract, & you inhale

Factors affecting Respiratory Rate & Depth Physical Factors Talking, coughing, exercise, increased body temperature, etc. Volition (Conscious Control) Singing, swimming underwater, etc. Emotional Factors Fear, crying, laughing, etc. Chemical Factors Levels of CO2 & O2, decrease in blood pH

Intervention of Respiratory Crises: Cardiopulmonary Resuscitation (CPR) Artificial reestablishment of respiration & circulation The A,B,C’s of CPR Airway, breathing, & circulation Heimlich Maneuver The abdominal thrust maneuver used in cases of choking. Elevates the diaphragm, compresses the lungs, & increases air pressure in the bronchial tree.

Respiratory Disorders Cleft Palate Failure of bones forming the palate to fuse medially Breathing, chewing, & speaking problems Emphysema Deterioration of alveoli leading to loss of their elasticity Bronchial Asthma Spasms of smooth muscle in bronchial tubes results in partial closure of air passages.

Respiratory Disorders Pneumonia Acute inflammation or infection of the alveoli Sudden Infant Death Syndrome (SIDS) Possibly triggered by a viral infection of the upper respirator tract Coryza – common cold Caused by viruses Usually no fever

Lung Cancer More people in the United States die from lung cancer than any other type of cancer 28% of all cancer deaths were due to lung cancer Cigarette smoking is the number one cause About 90% of lung cancer deaths in men and almost 80% of lung cancer deaths in women Can also be caused by using other types of tobacco (such as pipes or cigars), secondhand smoke, being exposed to substances such as asbestos or radon at home or work, and family history