Lecture Notes: Respiratory System (AT&T's Version 7 Human Anatomy and Physiology Exam)

Overview

• Focus on the respiratory system for the ATIT's version 7 exam.
• Discusses anatomy and physiology of breathing, gas exchange, and respiratory mechanics.

Anatomy of the Respiratory System

Nasal Cavity

• Air enters through the nasal cavity.
• Functions: Warmed, humidified, filtered by mucus and nasal hairs.
• Structures:
  • Nasal hairs (visible)
  • Cilia (microscopic, hair-like structures)

Pharynx and Larynx

• Pharynx: Crossroad for food (esophagus) and air (larynx).
• Larynx: Known as the voice box; pathway for air to trachea.

Trachea

• Cylindrical tube supported by cartilage rings to keep airway open.
• Epiglottis: Prevents food from entering the trachea.
• Splits into primary bronchi (one for each lung).

Lungs

• Right Lung: 3 lobes.
• Left Lung: 2 lobes with cardiac notch (accommodates the heart, smaller than right).

Bronchial Tree

• Primary Bronchi: Split into secondary and tertiary bronchi, then bronchioles.
• Terminal Bronchioles: Lead to respiratory bronchioles and alveolar ducts.

Alveoli

• Located at the end of alveolar ducts.
• Function: Site for gas exchange (oxygen enters, CO2 exits blood).

Zones in the Lungs

Conducting Zone

• Includes structures like trachea, bronchi, terminal bronchioles.
• Function: Conducts air to the respiratory zone without gas exchange.
• Anatomical Dead Space: No gas exchange occurs.

Respiratory Zone

• Includes respiratory bronchioles, alveolar ducts, alveoli.
• Function: Gas exchange occurs here with alveoli being the primary site.

Respiratory and Circulatory System Interaction

• Red blood cells pick up oxygen and remove CO2 via capillaries.

Involuntary Control of Breathing

• Managed by the nervous system using blood pH levels.
• Changes in pH due to CO2 levels influence breathing rate and depth.

Mechanics of Breathing

Inspiration (Inhalation)

• Process: Active, involves diaphragm and external intercostal muscles.
  • Diaphragm contracts and flattens, increasing thoracic cavity volume.
  • Intercostal muscles pull rib cage upward and outward.

Expiration (Exhalation)

• Process: Passive during normal breathing.
  • Diaphragm and intercostal muscles relax, decreasing thoracic cavity volume.
• Forced Expiration: Active during vigorous exercise or coughing.

Perfusion and Ventilation

• Ventilation: Air movement in/out of lungs.
• Perfusion: Blood flow to alveolar capillaries.

Matching Ventilation and Perfusion

• Ideal when matched for optimal gas exchange.

Imbalances

• Hypoventilation: Insufficient ventilation causes increased CO2 and decreased O2 (hypercapnia and hypoxia).
• Hyperventilation: Excessive ventilation causes decreased CO2 and increased O2 (hypocapnia and hyperoxia).

###Good to know What term describes the maximum amount of air a person can expel from their lungs after taking the deepest breath possible? Answer: c. Vital capacity

What role does hemoglobin play in the respiratory system? Answer: b. Transports oxygen in the blood

Which part of the brain regulates the rate and depth of breathing? Answer: b. Medulla oblongata

Which respiratory condition is characterized by inflamed airways and excessive mucus production? Answer: d. Bronchitis

Conclusion

• The respiratory system is crucial for gas exchange and works in conjunction with other body systems.
• Importance of understanding the respiratory system for ATIT's exams.

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