Notes on the Respiratory System

RESPIRATORY SYSTEM OVERVIEW

• Definition of Respiration: Process of gas exchange between atmosphere and body cells which includes:

  • Ventilation

  • Gas exchange between blood and lungs

  • Gas transport in the bloodstream

  • Gas exchange between the blood and body cells

• Overall Functions: Provide oxygen to the body and remove carbon dioxide.

STRUCTURES OF THE RESPIRATORY SYSTEM

• Conducting Zone: Filters incoming air through a series of tubes.

• Key Components:

  • Nasal Cavity: Air enters and is filtered.

  • Pharynx: Passageway for food and air; houses tonsils.

  • Larynx: Vocal cords located here; protects airway during swallowing.

  • Trachea: Winds through to the bronchi; lined with cilia and mucus for protection.

  • Bronchial Tree: Branches from trachea into each lung; divided into primary and secondary bronchi.

  • Lungs: Right lung has 3 lobes, left lung has 2 lobes.

ANATOMY OF THE UPPER RESPIRATORY TRACT

• Cribriform Plate: Part of the ethmoid bone, supports olfactory nerve endings.

• Paranasal Sinuses: Air-filled spaces in the skull that lighten the skull and help resonate voice.

MECHANICS OF BREATHING

• Pulmonary Ventilation: Moving air in and out of the lungs, which includes phases of:

  • Inspiration (Inhalation): Initiated by contraction of the diaphragm and intercostal muscles, increasing thoracic cavity size; air flows into lungs due to decreased pressure.

  • Expiration (Exhalation): Primarily a passive process that relies on lung elasticity; involves relaxation of muscles and decreasing volume leading to increased pressure, allowing air to exit.

GAS EXCHANGE AND RESPIRATION

• External Respiration: Exchange of gases between alveoli and pulmonary blood.

• Internal Respiration: Gas exchange between blood and tissues occurs at the systemic capillaries.

• Diffusion Principle: Gases move from areas of higher concentration to lower concentration.

CONTROL OF RESPIRATION

• Factors Influencing Rate and Depth:

  • Physical Factors: Body temperature, exercise, talking, coughing.

  • Chemical Factors: Levels of CO2 and O2 in blood; high CO2 can lead to hyperventilation.

RESPIRATORY TERMS TO KNOW

• Apnea: No airflow for at least 10 seconds.

• Sleep Apnea: Lack of oxygen during sleep due to loss of lung elasticity.

• Dyspnea: Labored breathing.

• Hyperpnea: Deep and faster breathing during exertion.

• Hypoxia: Low oxygen availability to tissues.

DISORDERS OF THE RESPIRATORY SYSTEM

• COPD: Chronic obstructive pulmonary disease; majorly caused by smoking.

• Chronic Bronchitis: Chronic inflammation of lower respiratory passages leading to impaired ventilation and gas exchange.

• Emphysema: Deterioration of alveoli walls; difficulty exhaling.

• Cystic Fibrosis: Genetic disease causing lung infections and mucus build-up.

• Lung Cancer: Abnormal cell growth in air passages.

• Asthma: Chronic lung disease causing airway constriction.

• Tuberculosis: A potentially serious infectious bacterial disease that affects the lungs.

IMPORTANT NOTES

• The diaphragm plays a crucial role in breathing.

• Respiratory structures are lined with mucous membranes to trap particles.

• Alveoli have specialized cells: macrophages that help remove debris and pathogens.

• The pleural membranes enclose the lungs and help cushion them within the thoracic cavity.