Anatomy and Physiology of the Respiratory System

Main Structures:
- Nasal Cavity: Filters, warms, and moistens air.
- Pharynx: Pathway for air and food; aids in vocalization.
- Larynx: Contains vocal cords; protects the trachea against food aspiration.
- Trachea: Windpipe; connects larynx to bronchi; lined with cilia and mucus to trap particles.
- Bronchi: Two main branches from the trachea leading to each lung; further divide into bronchioles.
- Lungs: Pair of organs where gas exchange occurs; contain alveoli (air sacs).
- Alveoli: Tiny sacs where oxygen and carbon dioxide exchange occurs; surrounded by capillaries.
Physiology:
- Function: Provides oxygen to the bloodstream and removes carbon dioxide.
- Surface Area: Large surface area of alveoli maximizes gas exchange efficiency.
- Mucociliary Escalator: Mechanism that moves mucus and trapped particles out of the airways.

Process:
- Occurs in the alveoli; oxygen diffuses from alveoli into the blood, carbon dioxide diffuses from blood into alveoli.
Partial Pressure:
- Gas exchange driven by differences in partial pressure of gases (oxygen and carbon dioxide).
Hemoglobin:
- Protein in red blood cells that binds oxygen; essential for transporting oxygen throughout the body.
Factors Affecting Gas Exchange:
- Surface area, thickness of the alveolar membrane, and partial pressure gradients.

Inspiration:
- Diaphragm contracts, increasing thoracic cavity volume; air is drawn into the lungs.
Expiration:
- Diaphragm relaxes, decreasing thoracic cavity volume; air is pushed out of the lungs.
Accessory Muscles:
- Involved in forced breathing; include intercostal muscles, abdominal muscles.
Respiratory Cycle:
- Regular alternation between inspiration and expiration.

Asthma:
- Chronic inflammatory condition; causes wheezing, shortness of breath due to bronchoconstriction.
Chronic Obstructive Pulmonary Disease (COPD):
- Includes emphysema and chronic bronchitis; characterized by obstructed airflow.
Pneumonia:
- Infection of the lungs; causes inflammation and fluid in alveoli, impairing gas exchange.
Tuberculosis (TB):
- Bacterial infection that primarily affects lungs; can lead to serious complications.
Lung Cancer:
- Abnormal cell growth in lung tissue; often linked to smoking and environmental factors.

Nasal Cavity: Functions to filter, warm, and moisten inhaled air, preparing it for the lungs.
Pharynx: A dual-purpose pathway for both air and food, essential for facilitating vocalization.
Larynx: Houses vocal cords and acts as a barrier to prevent food aspiration into the trachea.
Trachea: Also known as the windpipe, it connects the larynx to the bronchi; lined with cilia and mucus for trapping particles.
Bronchi: Main branches from the trachea, leading to each lung and further subdividing into smaller bronchioles.
Lungs: Essential organs for gas exchange, containing tiny air sacs called alveoli.
Alveoli: Microscopic sacs where the exchange of oxygen and carbon dioxide occurs, surrounded by a network of capillaries.
Function: The respiratory system’s primary role is to supply oxygen to the blood and remove carbon dioxide.
Surface Area: The extensive surface area of alveoli significantly increases the efficiency of gas exchange.
Mucociliary Escalator: A defense mechanism that transports mucus and trapped particles out of the airways.

Process: Takes place in the alveoli where oxygen moves from the alveoli into blood and carbon dioxide moves from blood into alveoli.
Partial Pressure: Gas exchange is influenced by differences in the partial pressures of oxygen and carbon dioxide.
Hemoglobin: A protein in red blood cells critical for oxygen binding and transport throughout the body.
Factors Affecting Gas Exchange: Efficiency affected by the surface area of alveoli, thickness of the alveolar membrane, and the established partial pressure gradients.

Inspiration: Involves the contraction of the diaphragm, increasing thoracic cavity volume to draw air into the lungs.
Expiration: Occurs when the diaphragm relaxes, reducing thoracic cavity volume, thus expelling air from the lungs.
Accessory Muscles: Include intercostal and abdominal muscles, activated during forced breathing efforts.
Respiratory Cycle: The regular pattern of inhalation and exhalation involving coordinated respiratory movements.

Asthma: A chronic condition characterized by inflammation and bronchoconstriction, leading to wheezing and shortness of breath.
Chronic Obstructive Pulmonary Disease (COPD): Encompasses conditions like emphysema and chronic bronchitis marked by airflow obstruction.
Pneumonia: Infection resulting in lung inflammation and fluid accumulation in alveoli, disrupting gas exchange.
Tuberculosis (TB): A severe bacterial infection primarily impacting the lungs, potentially leading to significant health complications.
Lung Cancer: Defined by irregular cell growth in lung tissues, often associated with smoking and other environmental hazards.