EX 36 Pre-Lab Lecture

Anatomy of the Respiratory System

Learning Objectives

• Major Functions of the Respiratory System

  • Supplies body cells with oxygen (O2)

  • Disposes of carbon dioxide (CO2)

• Key Terminology

  • Pulmonary Ventilation: Movement of air in and out of the lungs.

  • External Respiration: Gas exchange between air in the lungs and blood.

  • Internal Respiration: Gas exchange between blood and body cells.

• Zones of the Respiratory System

  • Conducting Zone: Includes the pathways for air to enter (nose, trachea) but does not participate in gas exchange.

  • Respiratory Zone: Where gas exchange occurs (respiratory bronchioles and alveoli).

• Serous Membrane

  • Name: Pleura

  • Structure: Consists of parietal pleura (lines thoracic cavity) and visceral pleura (covers lungs).

• Histology of Structures

  • Trachea: Lined with pseudostratified ciliated columnar epithelium, aids in filtering air.

  • Lung Tissue: Composed of alveoli surrounded by capillaries, facilitating gas exchange.

The Respiratory System

• Main Functions:

  • Supplies organs with O2 and disposes of CO2.

  • Involves pulmonary ventilation, external respiration, transport of respiratory gases, and internal respiration.

Upper Respiratory Structures

Table 36.1 Structures and Functions

Pharynx

• Majors Divisions:

  • Nasopharynx: Air passage, lined with pseudostratified ciliated epithelium.

  • Oropharynx: Air and food passage, lined with stratified squamous epithelium.

  • Laryngopharynx: Connects to larynx and esophagus, participates in passage of air and food.

  • Pharyngotympanic Tube: Connects nasopharynx to middle ear, equalizes pressure.

  • Paranasal Sinuses: Infoldings of nasal cavity, lined by epithelium, act as resonance chambers.

Lower Respiratory Structures

The Larynx

• Tube connecting laryngopharynx and trachea, made of cartilages including:

  • Thyroid Cartilage: Framework of larynx, known as Adam’s apple.

  • Cricoid Cartilage: Ring of cartilage below thyroid cartilage; connects to trachea.

  • Arytenoid Cartilages: Pyramid-shaped, anchor vocal cords.

  • Epiglottis: Elastic cartilage flap preventing food from entering trachea during swallowing.

  • Vocal Folds: True vocal cords that vibrate for sound.

  • Vestibular Folds: False vocal cords, protect vocal folds.

Bronchial Tree

• Branching Structure:

• Primary Bronchi: Right and left primary bronchi enter lungs.

• Secondary (Lobar) Bronchi: Branch into lobes of the lungs.

• Tertiary (Segmental) Bronchi: Further divisions into bronchopulmonary segments.

• Bronchioles: Smaller branches leading to alveolar ducts.

• Terminal Bronchioles: Last portion of conducting zone, lead into respiratory bronchioles.

• Respiratory Bronchioles: First area where gas exchange occurs.

The Lungs

• Right Lung:

  • Comprises 3 lobes (Superior, Middle, Inferior).

  • Has horizontal and oblique fissures.

• Left Lung:

  • Comprised of 2 lobes (Superior, Inferior).

  • Has 1 oblique fissure and a cardiac notch for heart accommodation.

The Pleurae

• Function: Serous membranes surrounding lungs.

  • Parietal Pleura: Lines thoracic cavity.

  • Visceral Pleura: Covers the lung surfaces.

  • Pleural Cavity: Space between pleurae filled with pleural fluid to reduce friction.

Histological Structures

Trachea and Bronchioles

• Trachea: C-shaped rings of cartilage; lined with ciliated pseudostratified columnar epithelium.

• Bronchioles: Walls made of smooth muscle and simple columnar or cuboidal epithelium without cartilage.

Activities for Learning

• Activity 1: Identify respiratory system organs using various models.

• Activity 3: Examine prepared tissue slides of trachea and lung, including identifying alveoli and pathologies.