Respiratory System Overview

Study Notes

Structure and Function

The respiratory system facilitates gas exchange, bringing oxygen into the body and removing carbon dioxide.
It comprises the nose, pharynx, larynx, trachea, bronchi, and lungs.
The lungs are the primary organs, containing millions of alveoli where gas exchange occurs.

Airflow and Ventilation

Breathing involves inhaling and exhaling air.
Inhalation is an active process; the diaphragm and intercostal muscles contract, expanding the thoracic cavity and decreasing pressure to draw air in.
Exhalation is a passive process; these muscles relax, the thoracic cavity recoils, and pressure increases to force air out.
Lung compliance and elasticity influence the ease of breathing, impacted by factors like lung tissue elasticity and the presence of surface tension.

Gas Exchange

Oxygen diffuses from the alveoli into the capillaries surrounding them.
Carbon dioxide diffuses from the capillaries into the alveoli to be exhaled.
This exchange is facilitated by the high concentration gradient.
Hemoglobin, a protein in red blood cells, binds to oxygen and transports it throughout the body.

Control of Respiration

Respiration is controlled by the autonomic nervous system, specifically the respiratory centers in the brainstem.
Chemoreceptors detect changes in blood oxygen and carbon dioxide levels and adjust breathing rate accordingly.
Higher carbon dioxide levels and lower oxygen levels stimulate the respiratory centers to increase breathing.

Pulmonary Volumes and Capacities

Lung volumes and capacities describe the amount of air moved during breathing.
Tidal volume is the amount of air inhaled and exhaled during a normal breath; inspiratory reserve volume, expiratory reserve volume, and residual volume describe different quantities in lung capacity.
These volumes and capacities can be determined during pulmonary function tests.

Respiratory Disorders

Many conditions can affect the respiratory system.
- Asthma involves airway inflammation and constriction, making breathing difficult.
- Pneumonia is characterized by lung inflammation and fluid buildup, inhibiting gas exchange.
- Chronic Obstructive Pulmonary Disease (COPD) encompasses conditions like chronic bronchitis and emphysema, leading to persistent airflow blockage.
- Cystic fibrosis creates thick mucus that obstructs airways.
- Lung cancer involves uncontrolled cell growth in the lungs.

Factors Influencing Respiration

Physical factors like altitude and temperature can affect gas exchange.
Exercise increases the body's demand for oxygen, resulting in increased breathing rate and depth.
Age, certain medical conditions (like heart disease), obesity, and smoking also have implications for respiratory function.

Protection Mechanisms

The respiratory system has protective mechanisms to filter the air and prevent infection.
- Mucus and cilia line the airways, trapping and removing particles.
- Cough reflex helps expel irritants.
- Immune responses help neutralize pathogens.

Description

Explore the structure and function of the respiratory system, including the process of gas exchange. Understand the mechanics of airflow and how breathing is regulated through inhalation and exhalation. Delve into the role of lungs and the significance of lung compliance.