Human Respiratory System Quiz

Respiratory System

• The respiratory system is an intricate system for gas exchange, facilitating oxygen intake and carbon dioxide removal.
• The system includes the conducting airways (nose, mouth, pharynx, larynx, trachea, primary bronchi, and bronchioles), and the respiratory zone where gas exchange occurs, in the alveoli.
• The Anatomy of the thorax includes: The thoracic cage, Thoracic Wall and the Thoracic Cavity. The three internal compartments are the central mediastinum, Left pleural cavity (containing the left lung) and Right pleural cavity (containing the right lung).
• The respiratory system is responsible for ensuring a continuous supply of oxygen to body tissues and removing the waste product carbon dioxide.

Anatomy of the Airways

• Upper Airways: Conducting air, warming, moistening, and filtering it. The upper airways contain the nose, pharynx, and larynx.
  • Mucosal lining filters particulate matter (debris and dust).
  • Warms incoming air.
  • Moistens incoming air.
• Lower Airways: responsible for gas exchange. The lower airways include the trachea, bronchi, and lungs.
  • Trachea: a rigid tube that connects the pharynx to the bronchi.
  • Bronchi: The trachea branches into two bronchi, one for each lung.
  • Lungs: spongy, cone-shaped organs responsible for gas exchange.

Anatomy of the Pharynx

• Connects nasal and oral cavities with the esophagus.
• Contains three parts based on location and function: nasopharynx, oropharynx, and laryngopharynx.
• Each section has a unique epithelial lining reflecting its function as both an airway and digestive tract.
  • Nasopharynx: Pseudostratified ciliated columnar epithelium
  • Oropharynx: Stratified squamous epithelium
  • Laryngopharynx: Stratified squamous epithelium

Paranasal Sinuses

• Hollow air spaces within the skull.
• Located in the frontal, maxillary, sphenoid, and ethmoid bones.
• Continuous with the nasal cavity, enhancing the surface area for warming and moistening the inspired air.

The Larynx

• The larynx, also known as the voicebox, connects the pharynx to the trachea.
• Cartilages that form the larynx (3 Unpaired, and 3 Paired).
  • Thyroid, Cricoid, Epiglottis
  • Arytenoid, Cuneiform, Corinulate

The Trachea

• A flexible tube composed of C-shaped cartilage rings and smooth muscle, providing structure and flexibility.
• Connects the larynx and the bronchi.
• Begins at the level of C6 and bifurcates into the two primary bronchi at the level of T4.

The Ribs

• 12 pairs of ribs form the protective thoracic cage
• 1-7 true ribs, 8-10 false ribs, 11-12 floating ribs
• Differentiate based on attachment to sternum (direct/indirect).
• Have a posterior end with head, neck and tubercle for ligament and vertebra attachment
• Have an anterior end that connects to the sternum via costal cartilages

Thoracic Wall (Muscular Component)

• The thoracic wall comprises three layers of intercostal muscles (External, Internal & Innermost)
• Responsible for breathing movements.
• Supplied by anterior rami of thoracic spinal nerves
• Blood supplied from Intercostal arteries.

Conducting and Respiratory Zones

• The conducting zone brings air to the respiratory zone, where gas exchange occurs.
• Structures in the conducting zone include the nose, mouth, pharynx, larynx, trachea, primary bronchi, bronchioles.
• The respiratory zone consists of the respiratory bronchioles and alveoli.

Alveoli

• Tiny air sacs in the lungs where gas exchange takes place.
• The thin, single-cell-layered structure allows for efficient diffusion of gases across the membrane.

Pulmonary Ventilation

• Mechanics of breathing:
• Pressure difference between atmospheric pressure and intrapulmonary pressure drives air movement.
• Muscles such as the diaphragm and intercostal muscles change lung volume, and thus the pressure gradient, driving air flow.

Physical Aspects of Ventilation

• Compliance: The elasticity of the lung tissue.
• Elasticity: The tendency of the lungs to recoil to their original state.
• Surface tension: The force exerted by the thin fluid lining the alveoli that resists expansion.

Intrapleural pressures

• Fluid between the visceral and parietal pleurae to minimize friction during breathing due to continuous movement between the parietal and visceral
• The intrapleural pressure is normally subatmospheric (-3 to -5mmHg), contributing to maintaining lung expansion.

Pulmonary Function Tests

• Techniques like spirometry assess lung function.
• Various measurements involving measurement of breathing, volume and rate are recorded.

Lung Volumes and Capacities

• Various parameters such as tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume describe lung volumes.
• Different combinations of volumes form lung capacities (e.g., inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity).

Restrictive and Obstructive Pulmonary Disorders

• Restrictive Disorders reduce the vital capacity (e.g., pulmonary fibrosis)
• Obstructive Disorders reduce expiratory flow rates (e.g., asthma, chronic obstructive pulmonary disease). - Spirometry measures parameters like FEV1 to determine if a condition is restrictive or obstructive.

Gas Exchange in the Lungs

• Gas exchange occurs between alveolar air and pulmonary capillaries, driven by partial pressure differences.
• Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli.

Factors Affecting Gas Exchange

• Partial pressures: Drive the diffusion of gases.
• Surface area: Larger surface area increases gas exchange.
• Membrane thickness: Thinner membrane increases rate of diffusion.
• Diffusion constant: Higher values increase gas diffusion rate.

Haemoglobin & Oxygen Transport

• Hemoglobin: A protein in red blood cells that carries oxygen from the lungs to body tissues.
• Factors affecting hemoglobin's affinity for oxygen (e.g., pH, temperature, PCO2, 2,3-BPG).
• Oxygen dissociation curve illustrating how oxygen binding to hemoglobin is affected by these factors.

Effects of Blood PCO2 and pH on Ventilation

• Chemoreceptors: Respond to changes in blood carbon dioxide, oxygen, and pH.
• Hypoventilation: Reduced ventilation leads to increased carbon dioxide, and reduced pH.
• Hyperventilation: Increased ventilation results in decreased carbon dioxide and increased pH.

Mechanisms of CO2 Transport

• Dissolved: A small portion of CO2 is dissolved in plasma.
• Bound to hemoglobin: CO2 combines with hemoglobin (forming carbaminohemoglobin).
• Bicarbonate ion form: CO2 converted to bicarbonate ions in red blood cells for transport.

Acid Production and Regulation

• Body produces significant amounts of H⁺ ions daily.

• Sources like aerobic metabolism, anaerobic glucose metabolism, and amino acid and fatty acid oxidation contribute.

• Buffering systems: Bicarbonate, Phosphate, Protein buffer systems.

• Physiological buffering: Through the lungs (excretion of CO2) and the kidneys (excretion of acids and reabsorption of bases).

Additional Notes

• This is a summary of the comprehensive information provided in the image set, covering various aspects of the respiratory system, including anatomy, physiology, and clinical applications.

Test your knowledge on the human respiratory system and its functions with this comprehensive quiz. Questions cover various aspects such as the conducting zone, anatomical structures, and respiratory mechanics. Perfect for biology students or anyone interested in respiratory health.