Structure and Function of the Human Respiratory System

Structure and Function of the Human Respiratory System

Parts of the Respiratory System

Upper

  • Nasal Cavity- warms and humidifies the inspired air

  • Pharynx- tube that delivers air from mouth to nose to the trachea

  • Larynx- voice box; protects the lower respiratory tract from aspirating food

Lower

  • Trachea- windpipe; connects larynx to bronchi; passage of air

  • Bronchus- tube that connect into each lung

  • Bronchiole- small branches of the bronchial tubes that leads to alveoli

  • Alveoli- air sacs; the site of gas exchange 

  • Lungs- remove oxygen from the air and pass it into the bloodstream- main organ

  • Diaphragm- muscle that helps the lungs to pull air in and push air out

Breathing

  • Physical Act

Respiration

  • More complex process, more on the cellular level

Phases of Respiration

1. Breathing or Ventilation

  • Inspiration and expiration

2. External Respiration

  • Exchange of oxygen and carbon dioxide between the air and blood within the lungs

3. Internal Respiration

  • Exchange of oxygen and carbon dioxide between the blood and blood cells

4. Cellular Respiration

  • Use of oxygen to break down sugar in food-producing energy (ATP) releasing carbon as waste product

Path of Air Inside the Body

Mouth and nose - nasal cavity - pharynx - larynx - trachea - bronchi - bronchioles - alveoli

Inhale

  • Ribs move outward

  • Diaphragm moves downward

  • There is more space in the chest area

  • Air rushes in to fill the space

Exhale

  • Ribs move inward

  • Diaphragm moves upward

  • There is less space in the chest area

  • Because of this pressure, air moves out to fill the space

Gas Exchange

  • Air that enters that alveoli is rich in oxygen while air that leaves is rich in carbon dioxide. Capillaries surround them. These capillaries around the alveoli take in carbon dioxide and give off oxygen. 

Respiratory Diseases

1. Common Colds

Cause: Rhinovirus

Treatment: Adequate rest and water

Symptoms: Sneezing, runny nose, stuffy nose

2.  Influenza

Cause: Viral Infection (myxovirus)

Treatment: Antiviral drugs, vaccination, adequate rest and water

Symptoms: chills, fever, severe headache, muscular pains, runny nose, fatigue

3. Pneumonia 

  • Inflammation of alveoli - filled with pus/fluid

Cause: Bacteria, virus, fungi, protozoan

Treatment: Consult doctor, take prescribed medications

Symptoms: fever, chest pain, difficulty in breathing

4. Tuberculosis

Cause: Bacterial infection (Mycobacterium tuberculosis)

Treatment: Consult doctor, antibiotics for 8 months, multidrug resistance tuberculosis (MDR-TB)

Symptoms: Severe cough, bloody sputum, weight loss, fever, night sweats, loss of appetite, painful coughing, fatigue

5. Asthma

  • Chronic and allergic condition, extra mucus in narrow and swollen airways

Cause: allergies

Treatment: Consult doctor, nebulizer with saline solution, bronchodilator, corticosteroids

Symptoms: Breathing difficulty, wheezing, coughing, chest tightness

6. Bronchitis

  • Inflammation of bronchial tubes

Cause: Viral lung infection, pollutants, smoke

Treatment: adequate rest and water, antibiotics

Symptoms: cough with mucus, soreness in chest, fatigue, headache, body ache, sore throat

7. Emphysema

  • Lack of oxygen supply, affected/damaged alveoli

Cause: Respiratory irritants

Treatment: Bronchodilator, antibiotics, steroid aerosol spray

Symptoms: Cyanosis (bluish discoloration), shortness of breath, chronic coughing, wheezing

8. Chronic Obstructive Pulmonary Disease (COPD)

  • Associated with a group of lung diseases

Cause: Smoking

Treatment: Can be slowed down by antibiotics, no cure

Symptoms: Progressive and long-term obstruction of airflow that makes breathing difficult

9. Lung Cancer

Cause: Long-term exposure to carcinogens, uncontrolled growth of tumors in lungs

Treatment: Surgical removal of damaged part, chemotherapy, radiation

Symptoms: Bloody coughs, mucus production, weight loss, shortness of breath, blocked airways