Respiratory System Anatomy Lecture Notes

Overview of Respiration Processes

• Three main steps in respiration:

  1. Pulmonary Ventilation
     • Airflow: inflow (inhalation) and outflow (exhalation)
     • Exchange of air with the atmosphere and alveoli of lungs
  2. Pulmonary/External Respiration
     • Gas exchange between alveoli and blood
  3. Internal/Tissue Respiration
     • Oxygen enters tissues from blood; carbon dioxide is picked up

• Molecular Level Respiration

  • Aerobic cellular respiration requires oxygen
  • Carbon dioxide is produced as a waste

• Definition of Respiration

  • Continuous exchange of carbon dioxide and oxygen between body and atmosphere
  • Involves breathing, gas exchange in lungs, and in body cells

Anatomy of the Respiratory System

Division of the Respiratory System

• Upper Respiratory Tract

  • Ends at the larynx; does not include the lungs anatomically

• Lower Respiratory Tract

  • Begins at the larynx and includes the lungs

Functional Organization

• Conducting Zone

  • Series of interconnected cavities and tubes
  • Transports air from nose to terminal bronchioles

• Respiratory Zone

  • Where gas exchange occurs
  • Includes alveoli and alveolar ducts

Detailed Anatomy

Nose and Nasal Cavity

• External Structure: Bone, cartilage, skin
• Nasal Septum: Divides the nasal cavity
  • Comprised of septal cartilage, ethmoid bone, and vomer bone
• Nasal Conchae (Turbinates): Superior, middle, inferior
  • Increase surface area, filter air, warm air

Pharynx

• Dual role: respiratory and digestive system
• Tonsils: Part of lymphatic tissue

Larynx (Voice Box)

• Protects the respiratory tract
• Houses the vocal cords
• Key Structures: Thyroid cartilage, epiglottis

Trachea

• Located anterior to the esophagus
• Supported by C-shaped cartilage rings

Bronchial Tree

• Division: Main bronchi -> Lobular bronchi -> Segmental bronchi -> Bronchioles
• Bronchioles: Lack cartilage, contain smooth muscle

Alveoli

• Site of actual gas exchange
• Types of Cells:
  • Type 1: Forms surface area
  • Type 2: Secretes pulmonary surfactant
  • Alveolar Macrophages: Dust cells

Lungs

• Enclosed by pleural membrane
• Right Lung: Larger, three lobes
• Left Lung: Smaller, two lobes, has cardiac notch

Breathing Mechanics

Breathing Process

• Pulmonary Ventilation: Breathing
• Gas Exchange: Alveolar and systemic

Types of Breathing

• Quiet Breathing: Normal breathing
• Forced Breathing: Vigorous activity

Muscles Involved

• Diaphragm: Key muscle
• Others: Sternocleidomastoid, scalene, intercostals

Control of Breathing

Respiratory Centers

• Medullary Respiratory Center:
  • Dorsal (inspiration) and Ventral (rhythm)
• Pontine Respiratory Center:
  • Modifies rhythm

Chemical Regulation

• Chemoreceptors: Sensitive to carbon dioxide levels
  • Central: Medulla
  • Peripheral: Aorta, carotids

Terminology

• Hypercapnia: High CO2
• Hypocapnia: Low CO2
• Hypoxia: Low oxygen at the tissue level

These notes summarize the key concepts of respiratory system anatomy and function, providing a structured guide to the physiological processes involved in human respiration.