Respiratory System Purpose, Pathway and Problems

Human Respiratory System Purpose:  Exchanges gases between air and blood:  Takes in oxygen from environment  Diffuses O 2 to blood (for cellular respiration).  CO 2 diffuses into lungs  Releases carbon dioxide into env. (waste from cellular respiration).

Blood Transports Gases Between Lungs and Tissues

Human Respiratory System Pathway: u Nasal cavity u Pharynx (Throat) u Larynx (Voice Box) u Trachea (Windpipe) u Bronchi u Bronchioles u Alveoli (Site of gas exchange) Exhaled air follows reverse pathway.

Pathway 1. Nasal cavity:  Air enters nostrils  Filtered by hairs (cilia)  Warmed/humidified

Pathway 2. Pharynx (Throat): Intersection where pathway for air and food cross.

Pathway 3. Larynx (Voice Box): Contains muscular tissue (vocal cords) that vibrate from passing air.

4. Trachea (Windpipe):  Connects larynx to bronchi  Rings of cartilage maintain shape

5. Bronchi:  Connects trachea to lungs

6. Bronchioles:  Connect bronchi to alveoli  Located within the lungs  Lined with mucus  Lined with cilia

7. Alveoli:  Air sacs within the lung  300,000,000 in a person  Elastic walls lined with blood vessels  Site of O 2 and CO 2 diffusion

Breathing: Inhalation: Inhalation:  Diaphragm (muscle) contracts  Chest cavity expands  Air rushes in u Exhalation: u Diaphragm relaxes u Chest cavity contracts u Air rushes out

Diseases of the Respiratory System Respiratory rate: 10 to 14 inhalations/minute. Respiratory rate: 10 to 14 inhalations/minute. In one day, an average human: In one day, an average human:  Breathes 20,000 times  Inhales 35 pounds of air Most of us breathe in air that is heavily contaminated with solid particles, ozone, sulfur oxide, carbon monoxide, nitrogen oxides, and many other damaging chemicals. Most of us breathe in air that is heavily contaminated with solid particles, ozone, sulfur oxide, carbon monoxide, nitrogen oxides, and many other damaging chemicals. Breathing contaminated air can cause a number of diseases including asthma, bronchitis, emphysema, and lung cancer Breathing contaminated air can cause a number of diseases including asthma, bronchitis, emphysema, and lung cancer

Diseases of the Respiratory System Asthma: Condition in which breathing is impaired by constriction of bronchi and bronchioles, cough, and thick mucus secretions. The severity and incidence of asthma has risen dramatically in recent years, especially in children. May be fatal if not treated. Asthma: Condition in which breathing is impaired by constriction of bronchi and bronchioles, cough, and thick mucus secretions. The severity and incidence of asthma has risen dramatically in recent years, especially in children. May be fatal if not treated. Causes: Attacks may be precipitated by inhalation of allergens (e.g.: pollen, cats, and cockroach proteins), pollutants, infection, or emotional stress. Treatment: Alleviates symptoms (e.g.: immuno-suppressors, bronchodilators), but is not a cure.

Diseases of the Respiratory System Bronchitis: Inflammation of the mucous membranes of the bronchi. May present with cough, fever, chest or back pain, and fatigue. Bronchitis: Inflammation of the mucous membranes of the bronchi. May present with cough, fever, chest or back pain, and fatigue. Causes: Associated with smoking, pollution, and bacterial or viral infections. Pneumonia: Acute inflammation of the lungs. Symptoms include high fever, chills, headache, cough, and chest pain. Pneumonia: Acute inflammation of the lungs. Symptoms include high fever, chills, headache, cough, and chest pain. Causes: Bacterial, fungal, or viral infections. Treatment: Antibiotics or other antimicrobials.

Diseases of the Respiratory System Cigarette smoke is one of the worse air pollutants. Cigarette smoke is one of the worse air pollutants.  Over 1 million people start smoking every year.  Kills about 350,000 people every year in U.S.  Contains 4000 different chemicals.  Each cigarette smoked subtracts about 5 minutes from life expectancy.  Cigarette smoke paralyzes cilia in airways, preventing them from removing debris and from protecting delicate alveoli.  Frequent coughing is the only way airways can clean themselves.  Cigarette smoke also causes fetal damage, which can result in miscarriage, premature birth, low birth weight, and poor development.

Diseases of the Respiratory System Emphysema: Permanent and irreversible destruction of alveolar walls, resulting in loss of lung elasticity and gas exchange surface. Emphysema: Permanent and irreversible destruction of alveolar walls, resulting in loss of lung elasticity and gas exchange surface. Symptoms include shortness of breath, difficulty exhaling, cough, weakness, anxiety, confusion, heart failure, lung edema (swelling), and respiratory failure. Causes: Smoking, pollution, old age, and infections. Treatment: Oxygen to help breathing. No cure.

Diseases of the Respiratory System Lung Cancer: Cancerous growth that invades and destroys lung tissue. Very high fatality rate. Lung Cancer: Cancerous growth that invades and destroys lung tissue. Very high fatality rate. Symptoms include bloody sputum, persistent cough, difficulty breathing, chest pain, and repeated attacks of bronchitis or pneumonia. Causes: Smoking (50% of all cases) and pollution (radon, asbestos). Smokers are 10 times more likely to develop lung cancer than nonsmokers. Treatment: Surgery is most effective, but only 50% of all lung cancers are operable by time of detection. Other treatments include radiation and chemotherapy.