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EX 36 Pre-Lab Lecture

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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

Structure

Description

Function

External Nose

Visible part, supported by bone and cartilage, nostrils contain air.

Entrance for air into the respiratory system.

Nasal Cavity

Lined with respiratory mucosa, has hard/soft palates.

Filters, warms, and moistens air; resonance for voice.

Nasal Vestibule

Anterior nasal cavity area with glands and hair follicles.

Filters coarse particles.

Nasal Septum

Formed by vomer, ethmoid bone, and cartilage.

Divides nasal cavity into left and right sides.

Nasal Conchae

Superior, middle, and inferior projections from lateral walls.

Increase mucosal surface area for trapping particles.

Posterior Nasal Apertures

Openings at the back of the nasal cavity.

Exit for air into the nasopharynx.

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.