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Organization of the Respiratory System

• The respiratory system involves structures for ventilation and gas exchange.

• It comprises:

  • Conducting Portion:

  • extends from the nose to larger bronchioles.

  • Respiratory Portion:

  • comprises respiratory bronchioles and alveoli.

Anatomical Divisions

1. Upper Respiratory System:

   • Nose, Nasal Cavity, Sinuses, Pharynx, Larynx.

2. Lower Respiratory System:

   • Trachea, Bronchi, Lungs, Bronchioles, Respiratory bronchioles, Alveoli.

Structures of the Respiratory Tract

• The respiratory mucosa, which lines the conducting portion, is made up of epithelial tissue and lamina propria (connective tissue).

  • Cilia present on epithelial cells help propel mucus towards the pharynx.

  • Mucus traps inhaled debris and microbes. Regardless of size, the larger particles are filtered out first, with smaller particles being engulfed by macrophages in the lungs.

Respiratory Defense System

• The respiratory defense system protects against pathogens and debris.

  • Ciliated cells and mucus play a crucial role in filtering inhaled air.

  • The movement of mucus to the pharynx ensures that debris/trapped pathogens are swallowed and destroyed by stomach acids.

Respiratory Infections and Diseases

• Tuberculosis:

  • Caused by Mycobacterium tuberculosis, which can survive inside macrophages.

  • Recognized as a leading cause of infectious death during pandemics.

• Cystic Fibrosis:

  • Genetic disorder affecting mucus movement and leading to thickening of mucus, creating breathing difficulties.

Functions of the Respiratory Tract Structures

1. Conducting Portion:

   • Air passage, filtration, humidification, and warming of air.

   • Resonates sound and houses olfactory receptors.

2. Respiratory Portion:

   • Gas exchange occurs in alveoli.

Regulation of Respiration

Types of Gas Exchange

• External Respiration:

  • Gas exchange between alveoli and blood.

• Internal Respiration:

  • Gas exchange between the blood and tissues.

Gas Transport

• Transport of oxygen and carbon dioxide via the bloodstream, primarily facilitated by red blood cells.

  • About 98.5% of oxygen is transported bound to hemoglobin forming oxyhemoglobin.

Factors Affecting Respiration

• Increased activity leads to an increased demand for oxygen due to higher metabolic rates.

• Conditions such as hypoxia (low oxygen levels) and hypercapnia (high carbon dioxide levels) can significantly impact respiration.

• Smoking negatively impacts lung function and increases the risk of various respiratory diseases including emphysema and lung cancer.

Definitions

• Hypoxia: Low oxygen levels in tissues.

• Anoxia: No oxygen in tissues, potentially leading to cyanosis (bluish skin).

• Bronchodilation/Constriction: Adjustments in airway resistance to regulate airflow.

Age-Related Changes in Respiration

• Lung tissue elasticity decreases with age, reducing compliance and making it more challenging to breathe effectively.

• Conditions like arthritis can limit rib cage expansion, adversely affecting breathing ability.

Noteworthy Disorders

• Pneumonia: Inflammation in alveoli leading to fluid build-up, restricting airflow and gas exchange.

• Pulmonary Embolism: Blockage in pulmonary arteries, often by blood clots originating from legs.

• Chronic Obstructive Pulmonary Disease (COPD): Encompasses diseases like emphysema and chronic bronchitis that obstruct airflow.

These notes provide a detailed overview of the respiratory system's structure, function, and the significant diseases and conditions affecting respiratory health. The interrelationship between anatomical components, functional mechanics, and impact from various diseases has been emphasized for better understanding.

The respiratory system involves structures for ventilation and gas exchange. It comprises:

• Conducting Portion:

  • Extends from the nose to larger bronchioles, providing a pathway for air passage.

  • Includes structures that filter, humidify, and warm the air before it enters the lungs.

• Respiratory Portion:

  • Comprises respiratory bronchioles and alveoli, where gas exchange occurs.

  • Alveoli are small air sacs that increase the surface area for efficient oxygen and carbon dioxide exchange.

Anatomical Divisions

1. Upper Respiratory System:

   • Nose: The external structure that helps filter and warm air.

   • Nasal Cavity: Contains turbinates that increase surface area and aid in warming and humidifying the air.

   • Sinuses: Air-filled spaces that reduce skull weight and play a role in voice resonance.

   • Pharynx: A muscular tube that connects the nasal cavity to the larynx and esophagus.

   • Larynx: Also known as the voice box, it houses the vocal cords and is responsible for sound production, protecting the trachea against food aspiration.

2. Lower Respiratory System:

   • Trachea: A sturdy windpipe that carries air to the bronchi, reinforced with C-shaped cartilage to prevent collapse.

   • Bronchi: Two primary branches from the trachea that lead to each lung and further divide into smaller bronchioles.

   • Lungs: Organs that house the bronchi, bronchioles, and alveoli, facilitating gas exchange.

   • Bronchioles: Smaller air passages within the lungs leading to the alveoli.

   • Respiratory Bronchioles: Transition structures where some gas exchange begins.

   • Alveoli: Tiny air sacs where oxygen enters the blood and carbon dioxide is expelled.

Structures of the Respiratory Tract

• The respiratory mucosa, which lines the conducting portion, is made up of epithelial tissue and lamina propria (connective tissue).

• Cilia present on epithelial cells help propel mucus towards the pharynx, facilitating the movement of trapped particles out of the respiratory system.

• Mucus traps inhaled debris and microbes, playing a critical role in protecting lung tissues. Regardless of size, larger particles are filtered out first by the nasal passages, while smaller particles are engulfed by macrophages in the lungs, providing additional defense against respiratory infections.

Respiratory Defense System

• The respiratory defense system protects against pathogens and debris through various mechanisms.

• Ciliated cells and mucus work together to filter inhaled air, preventing harmful substances from reaching the lungs.

• The movement of mucus to the pharynx ensures that debris and trapped pathogens are swallowed and destroyed by stomach acids, effectively clearing the respiratory tract.

Respiratory Infections and Diseases

• Tuberculosis:

  • Caused by Mycobacterium tuberculosis, which can survive inside macrophages.

  • Recognized as a leading cause of infectious death during pandemics due to its contagious nature and potential for latent infection.

• Cystic Fibrosis:

  • Genetic disorder affecting mucus movement and leading to thickening of mucus, creating significant respiratory difficulties and increasing the risk of lung infections.

Functions of the Respiratory Tract Structures

1. Conducting Portion:

   • Provides an air passage, facilitating the filtration, humidification, and warming of incoming air.

   • Contributes to sound resonance and houses olfactory receptors for the sense of smell.

2. Respiratory Portion:

   • Gas exchange occurs in the alveoli, maximizing surface area for oxygen and carbon dioxide exchange to maintain efficient respiratory function.

Regulation of Respiration

Types of Gas Exchange

• External Respiration:

  • Refers to gas exchange between alveoli and blood, where oxygen diffuses into the bloodstream and carbon dioxide is expelled.

• Internal Respiration:

  • Describes gas exchange between the blood and tissues, essential for cellular metabolism.

Gas Transport

• Transport of oxygen and carbon dioxide via the bloodstream is primarily facilitated by red blood cells.

• About 98.5% of oxygen is transported bound to hemoglobin, forming oxyhemoglobin, while carbon dioxide is transported in three forms: dissolved in plasma, bound to hemoglobin, or as bicarbonate ion.

Factors Affecting Respiration

• Increased activity leads to an increased demand for oxygen due to higher metabolic rates and therefore an increased respiratory rate.

• Conditions such as hypoxia (low oxygen levels) and hypercapnia (high carbon dioxide levels) can significantly impact respiration, necessitating compensatory mechanisms.

• Smoking negatively impacts lung function and increases the risk of various respiratory diseases, including emphysema, chronic bronchitis, and lung cancer.

Definitions

• Hypoxia: Low oxygen levels in tissues, impairing cellular function.

• Anoxia: Complete absence of oxygen in tissues, potentially leading to cyanosis (bluish skin).

• Bronchodilation/Constriction: Adjustments in airway resistance to regulate airflow and maintain optimal ventilation efficiency.

Age-Related Changes in Respiration

• Lung tissue elasticity decreases with age, reducing compliance and making it more challenging to breathe effectively.

• Conditions like arthritis can limit rib cage expansion, adversely affecting the ability to breathe deeply.

Noteworthy Disorders

• Pneumonia: Inflammation in alveoli leading to fluid build-up, restricting airflow and gas exchange, resulting in cough and difficulty breathing.

• Pulmonary Embolism: Blockage in pulmonary arteries, often caused by blood clots originating from the legs, potentially leading to respiratory distress and hypoxia.

• Chronic Obstructive Pulmonary Disease (COPD): Encompasses diseases like emphysema and chronic bronchitis that obstruct airflow, resulting in chronic coughing, wheezing, and shortness of breath.

--- These notes provide a detailed overview of the respiratory system's structure, function, and the significant diseases and conditions affecting respiratory health, emphasizing the interrelationship between anatomical components, functional mechanics, and impact from various diseases for a more comprehensive understanding.