APCVS Chapter 29: Respiratory System

Course Information

• Course: APCVS
• Week: 4
• Chapter: 29

Respiratory System Objectives

• Explain the purpose and function of the respiratory system
• List and explain the structures and functions of respiratory organs
• Identify and discuss common respiratory disorders

Respiratory System Overview

• Actions of inhalation and exhalation achieved by alternating contraction and relaxation of respiratory muscles
• Diaphragm
• Muscles attached to ribs (intercostal muscles)
• Muscles of the neck

Organs of the Upper Respiratory Tract

• Nose
• Paranasal sinuses
• Pharynx (throat)
• Larynx (voicebox)

Organs of the Lower Respiratory Tract

• Trachea (splits into two main branches called bronchi)
• Tiny branches of bronchi called bronchioles
• Lungs

Respiratory System Details

• Nose: warms, moisturizes and filters air
• Pharynx: throat
• Larynx: voice box; epiglottis protects larynx from food during swallowing
• Trachea: windpipe; "C" shaped cartilage keeps the tube open
• Bronchi: two main branches into lungs; "C" shaped cartilage keeps tube open
• Bronchioles: tiny branches of bronchi; "C" shaped cartilage keeps the tube open
• Alveoli: tiny air sacs where gas exchange occurs

Important Structures

• Nasal cavity
• Pharynx
• Larynx
• Trachea
• Lungs
• Bronchi
• Bronchioles
• Alveoli
• Diaphragm

Pharynx/Tonsils

• Pharynx
• Pharyngeal tonsils (adenoids)
• Palatine tonsils
• Lingual tonsils
• Part of immune system, help in infection control

Larynx

• Also known as voice box
• Muscular, cartilaginous structure lined with mucous membrane
• Epiglottis: flap that covers the larynx to prevent food from entering when swallowing

Trachea

• Also known as windpipe
• Extends from larynx to bronchi in chest cavity
• C-shaped rings of cartilage protect structure and shape of trachea

Bronchi

• Two main branches (right and left bronchus) from trachea that extend into lungs
• After entering lungs, bronchi subdivide into the bronchial tree, which continues to branch into smaller and smaller branches

Bronchioles

• Smallest components of the bronchial tree
• Thin layer of epithelium and smooth muscle
• Terminate at alveoli in the lungs

Alveoli

• Small air sacs that support networks of capillaries
• Where gas exchange of oxygen occurs

Organs of the Respiratory System (Lungs)

• Lungs
• Hilum: wedge-shaped area on central portion of lung where bronchus, arteries, veins, and nerves enter/exit lung
• Pleura: thin sheets of epithelium; covers outside of lungs (visceral pleura) and inside of thoracic cavity (parietal pleura)

Basic Anatomy

• Right lung: 3 lobes
• Left lung: 2 lobes
• Due to the heart
• Lungs sit on top of the diaphragm

Basic Lung Anatomy

• Apex: narrow, upper part of each lung, under the collarbone
• Base: broad, lower part of each lung, rests on the diaphragm

Basic Lung Anatomy (Pleura)

• Pleura: moist, smooth, slippery membrane that lines chest cavity and covers the outer surface of the lungs
• Reduces friction between the lungs and chest wall during breathing
• Parietal and visceral pleura must slide against each other with every breath; fluid reduces friction

Mechanism of Breathing

• Ventilation: movement of air to and from the lungs
• Two processes of ventilation
  • Inhalation: active
  • Exhalation: passive but can be active

Transport of O2 and CO2

• Hemoglobin (Hgb): protein in RBC
• Carries O2 from lungs to body cells
• Oxyhemoglobin: carries CO2 from body back to lungs
• Carboxyhemoglobin

Respiration

• Receptors influencing respiration
  • Chemoreceptors: respond to changes in carbon dioxide, oxygen, and blood acid levels; located in carotid and aortic bodies
  • Pulmonary stretch receptors: respond to stretch in lungs, protecting respiratory organs from overinflation

Test Your Knowledge (Matching)

• Matching diseases with definitions (Sinus, Pharynx, Larynx, Trachea, Bronchi, Bronchioles)

Specific Diseases

• Sinusitis, Rhinitis, Pharyngitis, Laryngitis, Asthma, COPD, Common Cold/Flu, Lung Cancer, Legionnaires, Pulmonary Embolism, Tuberculosis, Pneumonia, Pneumothorax, Pleuris

Additional Information

• Video on Respiration, Asthma and COPD

Details on Specific Diseases (Examples)

• Pneumonia: variation in severity; caused by bacteria, virus, fungus, or chemical irritants. Signs/Symptoms: fever, sweating, chills; cough with thick, sticky fluid; chest pain; shortness of breath. Treatment: rest, fluid, antibiotics
• Lung Cancer: number one cause of death for men and women; smoking is major risk factor; main types include small cell and non-small cell; treatment includes surgery, chemotherapy, and radiation

Bronchitis

• Membrane inflammation in bronchial passages with swelling and mucous accumulation
• Acute bronchitis lasts less than six weeks; Chronic bronchitis frequently recurs for more than two years and is a form of COPD

Emphysema

• Alveoli burst, body heals the rupture with scar tissue
• Air spaces enlarge but are less functional

Abbreviations

• List of common respiratory abbreviations and their definitions (COPD, TB, SOB, CO2, O2, CPR, PFT, ABG, URI)