APCVS Week 4: Respiratory System Overview

Course Information

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

Objectives

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

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 Respiratory System: Upper Respiratory Tract

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

Organs of the Respiratory System: Lower Respiratory Tract

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

Respiratory System: Specific Structures

• Nose: warms, moisturizes, and filters air
• Pharynx: throat
• Epiglottis: protects larynx from food during swallowing
• Trachea: "C" shaped cartilage keeps the tube open
• Bronchi: "C" shaped cartilage keeps the tube open
• Bronchioles: "C" shaped cartilage keeps the tube open
• Alveoli: gas exchange in these tiny air sacs

Respiration Video

The Sinuses

• Air pockets within the bony skull
• Frontal sinus
• Ethmoid sinus
• Sphenoid sinus
• Maxillary sinus

Nose

• Organ of smell
• Component of respiration and voice
• Warms inhaled air
• Filters the air (traps dust, pollen, and other foreign matter)
• Moisturizes air (tears drain into the nasal cavity)

Important Structures of the Respiratory System

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

Pharynx/Tonsils

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

Larynx

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

Trachea

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

Bronchi

• Two main branches (right and left bronchus) from trachea that extend into lungs
• Subdivide into bronchial tree which continues to branch into smaller branches

Bronchioles

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

Alveoli

• Small air sacs that support a network of capillaries where oxygen exchange takes place

Organs of the Respiratory System

• Lungs
• Hilum (wedge-shaped area on central portion of each lung where primary bronchus, arteries, veins, and nerves enter and exit)
• Pleura (thin sheets of epithelium covering the outside of lungs and inside of the thoracic cavity)

Basic Anatomy

• Right lung: 3 lobes
• Left lung: 2 lobes
• Lungs sit on top of diaphragm
• Due to the heart, parts of lungs are situated differently in the chest to allow for the heart’s location

Basic Lung Anatomy

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

Basic Lung Anatomy: Pleura

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

Mechanism of Breathing

• Ventilation: movement of air to and from the lungs
• Inhalation: active process
• Exhalation: passive but can be active
• Nervous system and respiratory muscles

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, preventing overinflation

Test Your Knowledge (Matching)

• Answers for Matching questions (page 24&25)

Diseases and Conditions (Specific respiratory diseases and infections)

• Sinusitis: Infection/inflammation of the air spaces (sinuses) in the skull
• Rhinitis: inflammation of the nasal mucous membranes (common cold, hay fever)
• Pharyngitis: inflammation of the throat (usually viral or bacterial)
• Laryngitis: inflammation of the larynx/vocal cords (often from overuse)
• Asthma: Chronic inflammatory disease of the bronchi (irritants trigger swelling)
• COPD: chronic/progressive obstruction of airflow (most often smoking related)
• Bronchitis: inflammation of the bronchial tubes (usually acute or chronic)
• Emphysema: alveoli burst, body heals with scar tissue that enlarges air spaces, but leads to less functional air sacs.
• Cold/Flu: viral infection of upper respiratory tract
• Lung Cancer: number one cause of death in the US. Smoking is the number one risk factor
• Legionnaires: bacteria from water sources
• Pulmonary Embolism: blood clot that travels to the lungs
• Tuberculosis: bacterial infection in lungs that takes months of antibiotics to treat
• Pneumonia: fluid accumulation in lungs (bacterial, viral, fungus or chemical)
• Pneumothorax: air in the chest cavity caused by a punctured lung, which collapses a lobe of the lung.
• Pleurisy: inflammation of the parietal pleura leading to difficulty breathing and stabbing pain

Video(s)

• Asthma and COPD video
• Respiration video

Basic Information

• Normal breathing rate for healthy adults (15-20 breaths/minute)
• Terminology for fast (tachypnea) and slow (bradypnea) breathing
• Other related terms
• Abbreviations
• Answers to abbreviations