respiratory

Hyperventilation and its Effects

  • Hyperventilation involves rapid breathing, which leads to excessive loss of carbon dioxide (
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  • Increased CO₂ loss prevents the formation of carbonic acid and bicarbonate, leading to respiratory alkalosis.

    • Respiratory Alkalosis: Condition where the pH of blood increases due to decreased CO₂ levels.

  • Remedy for hyperventilation includes:

    • Breathing into a paper bag:

    • Helps trap CO₂.

    • Allows inhalation of CO₂, thus regulating blood pH more effectively.

Types of Mammalian Breathing

  • Mammals utilize negative pressure for breathing.

  • Two airflow paths:

    • Nasal Breathing:

    • Air absorption through nostrils leading to pharynx.

    • Benefits:

      • Higher humidity levels, which enhances lung function.

      • Filters pathogens using mucus in the respiratory tract.

    • Mouth Breathing:

    • Air absorption through the mouth leading to the pharynx.

    • Disadvantages include:

      • Reduced moisture retention, making it harder for lungs to function.

      • Increased inhalation of dust and pathogens without filtration.

Anatomy of the Respiratory System

  • Upper Respiratory System: (Nose to larynx)

    • Nostrils → Pharynx → Larynx

    • Larynx:

    • Protects vocal cords.

  • Lower Respiratory System: (Larynx onward)

    • Includes trachea and lungs.

  • Trachea:

    • Composed of cartilage rings that aren't full circles.

    • Functions:

    • Maintains open airway.

    • Allows expansion to facilitate breathing.

  • Lungs:

    • Five lobes: Three on the right, two on the left (accommodates the heart).

  • Bronchus and Bronchi:

    • Trachea branches into bronchi; further splits into secondary and tertiary bronchi

    • Ends in bronchioles that lead to alveoli (site of gas exchange).

Alveoli and Gas Exchange

  • Gas Exchange: Alveoli are surrounded by pulmonary capillaries.

    • Function:

    • O₂ absorption and CO₂ expulsion occurs here.

    • Oxygenated blood moves to the heart for circulation.

    • Important for supplying oxygen to tissues and organs.

  • Venous returns from tissues brings CO₂ back to the alveoli for exhalation.

Respiratory Physiology

  • Diaphragm Function: Critical muscle in respiration regulation.

  • Types of Respiration:

    • External Respiration:

    • Gas exchange between environment air and alveoli (O₂ enters, CO₂ exits).

    • Internal Respiration:

    • Gas exchange between blood vessels and tissues (O₂ delivered, CO₂ collected).

  • Cellular Respiration:

    • Breaks down glucose in the presence of oxygen, producing CO₂.

    • CO₂ forms bicarbonate in the blood, contributing to blood pH regulation.

Mechanics of Breathing

  • Inspiration:

    • Diaphragm contracts and moves down.

    • Intercostal muscles lift ribs, expanding thoracic cavity, reducing internal lung pressure, allowing air influx.

  • Expiration:

    • Diaphragm relaxes and moves up, causing increased lung pressure and air expulsion.

  • Boyle's Law:

    • States the inverse relationship between pressure and volume.

    • As lung volume increases, pressure decreases, promoting airflow into lungs and vice versa.

Lung Capacity and Volumes

  • Various lung volume measurements include:

    • Tidal Volume (TV): Average of 0.5 liters during normal breathing.

    • Inspiratory Reserve Volume (IRV): Additional volume breathed in during deep inhalation (~3 liters).

    • Expiratory Reserve Volume (ERV): Volume released during deep exhalation (~1 liter).

    • Residual Volume (RV): The remaining air in the lungs (~1.2 liters) that cannot be expelled.

    • Total Lung Capacity (TLC): Sum of TV, IRV, ERV, plus RV, approximately 5.7 liters.

Functions of Coughing and Sneezing

  • Coughing: Clears lower respiratory passages.

  • Sneezing: Clears upper respiratory passages.

  • Hiccup: Sudden contraction of the diaphragm without a defined purpose.

  • Yawning: Potentially increases O₂ intake and changes brain states; can have social mimicry aspects.

Respiratory Diseases

  • Bronchitis: Infection of bronchioles; characterized by a persistent cough and mucus production.

  • Asthma: Inflammation of airways leading to breathing difficulty.

  • Emphysema: Damage to alveoli, reducing gas exchange due to pollutants and smoking.

    • Example case: Emphysema can arise without smoking if exposed to secondhand smoke or pollution.

  • Upper Respiratory Infections (e.g., influenza, colds): Caused by viruses affecting upper respiratory passages.

  • Pneumonia: Caused by various pathogens; leads to mucus production in alveoli affecting gas exchange.

  • Tuberculosis: Caused by Mycobacterium tuberculosis, leading to damaged lung tissue and compromised gas exchange.

Summary of Key Processes

  • Understand the difference in pressure that drives inspiration and expiration.

  • Recognize the significance of Boyle's Law in respiratory function.

  • Distinguish between external and internal respiration processes.

  • Note the roles of various lung capacities and their clinical relevance.