Respiratory System Anatomy Quiz

The Respiratory System

• The respiratory system is responsible for taking in oxygen and removing carbon dioxide from the body.
• It consists of major components, including the upper and lower respiratory tracts.

Upper Respiratory Tract

• Nose and Nasal Cavity:
  • Function: The primary entry point for air; filters, warms, and moistens the air before it reaches the lungs. Hairs and mucus trap dust, pollen, and other particles.
• Pharynx (Throat):
  • Function: Serves as a passageway for air from the nasal cavity to the larynx and for food from the mouth to the esophagus.
• Larynx (Voice Box):
  • Function: Connects the pharynx to the trachea and contains the vocal cords, which produce sound. The epiglottis prevents food from entering the trachea during swallowing.
• Trachea (Windpipe):
  • Function: A tube that conducts air from the larynx into the bronchi.
• Bronchi:
  • Function: The trachea divides into two main bronchi (left and right) that enter the lungs. The bronchi continue to branch into smaller tubes called bronchioles, lined with ciliated epithelium and mucus to trap particles and move them away from the lungs.
• Bronchioles:
  • Function: Smaller airways that lead from the bronchi to the alveoli.
• Alveoli:
  • Function: Tiny air sacs where gas exchange occurs. Oxygen diffuses into the blood, and carbon dioxide diffuses out into the alveoli to be exhaled. They have thin walls to facilitate gas exchange. They are surrounded by capillaries.
• Lungs:
  • Function: Main organs of the respiratory system where gas exchange occurs.

Lower Respiratory Tract

• Pleura:

  • Function: A double-layered membrane surrounding each lung, whose fluid reduces friction during breathing.

• Intercostal Muscles:

  • Function: Muscles located between the ribs that assist with expanding and contracting the chest cavity during breathing.

• Diaphragm:

  • Function: A dome-shaped muscle that contracts and moves downward to increase thoracic cavity volume for inhalation and relaxes to decrease the volume allowing exhalation.

Additional Structures and Functions

• Cilia and Mucus:

  • Function: Cilia are tiny hair-like structures lining the respiratory tract, especially in the nasal cavity, trachea, and bronchi. They move rhythmically to sweep mucus and trapped particles out of the airways. Mucus is produced by goblet cells and mucous glands in the respiratory tract and traps dust, microbes, and other particles.

• Processes of Breathing:

  • Inhalation/inspiration: The diaphragm contracts and moves downward, intercostal muscles contract, lifting the ribcage. This increases the volume of the thoracic cavity, and decreases the pressure, drawing air into the lungs.
  • Exhalation/expiration: The diaphragm relaxes and moves upward, the intercostal muscles relax, and the ribcage moves inward and downward. This decreases the volume of the thoracic cavity, increasing the pressure inside, which pushes air out of the lungs.

• Gas Exchange:

  • External respiration: Gas exchange occurs in the alveoli and involves the diffusion of oxygen into the blood from inhaled air, and carbon dioxide from the blood to the alveoli to be exhaled. Internal respiration involves the exchange of oxygen and carbon dioxide in the systemic capillaries, where oxygen diffuses into tissues, and carbon dioxide diffuses from tissues into the blood.

• Respiration:

  • Occurs at the systemic capillaries where oxygen diffuses from the blood to the tissues, and carbon dioxide diffuses from the tissues to the blood.

• Transport of Gases:

  • Oxygen Transport: Most oxygen is transported by binding to hemoglobin in red blood cells, forming oxyhemoglobin.
  • Carbon Dioxide Transport: Carbon dioxide is transported in three ways: dissolved in plasma, bound to hemoglobin (forming carbaminohemoglobin); and as bicarbonate ions (HCO3-).

• Respiratory Regulation:

  • Respiratory Centre: Located in the brainstem (medulla oblongata and pons), controls breathing rate and depth.
  • Chemoreceptors: Located in the carotid and aortic bodies, detect changes in blood pH, CO2 and O2 levels, and send signals to the respiratory center to adjust breathing.

• Respiration Disorders:

  • Hypoxia: Insufficient oxygen in tissues.
  • Hypercapnia: Excess carbon dioxide in the bloodstream.
  • Chronic Obstructive Pulmonary Disease (COPD): Group of lung diseases, including emphysema and chronic bronchitis, characterized by obstructed airflow.
  • Asthma: Episodes of airway constriction, inflammation, and increased mucus production.
  • Pulmonary Fibrosis: Condition where lung tissue becomes scarred and stiff, making breathing difficult.
  • Pneumonia: Infection that inflames the air sacs in the lungs filling with fluid or pus, leading to difficult breathing.
  • Laryngitis: Inflammation of the larynx, often causing hoarseness or loss of voice.
  • Sinusitis: Inflammation of the sinuses, causing nasal congestion, facial pain and pressure, discharge.

• Additional Structures:

  • Sinuses: Air-filled spaces in the bones of the face.
  • Laryngeal Cartilages: Include thyroid cartilage (Adam's apple).
  • Respiratory Membrane: Barrier between alveolar air and blood capillaries.
  • Surfactant: A lipoprotein substance that reduces surface tension in the alveoli, preventing their collapse.
  • Alveolar Macrophages: Immune cells in the alveoli that engulf and destroy foreign particles.

• Respiratory Volumes and Capacities:

• Tidal Volume (TV): Amount of air inhaled or exhaled during a normal breath.

• Inspiratory Reserve Volume (IRV): Additional air that can be inhaled after a normal inhalation.

• Expiratory Reserve Volume (ERV): Additional air that can be exhaled after a normal exhalation.

• Residual Volume (RV): Amount of air remaining in the lungs after a maximal exhalation.

• Vital Capacity (VC): Total amount of air that can be exhaled after a maximal inhalation (TV + IRV + ERV).

• Total Lung Capacity (TLC): Total volume of the lungs (VC + RV).