Chapter 22 - Respiratory System Flashcards
Respiration - major function
To supply O2 to tissues and remove CO2 from body
Pulmonary ventilation
(breathing)-
movement of air into and out
of lungs
External respiration
O2 and CO2
exchange between lungs and blood
Circulatory System
Transport-O2 and CO2 in blood
Internal respiration-O2 and CO2
exchange between systemic blood
vessels and tissues
Conducting zone
conduits to gas exchange sites
Respiratory zone
site of gas exchange
The Nose
Provides an airway for respiration
Moistens and warms entering air
Filters and cleans inspired air
Resonating chamber for speech
Houses olfactory receptors
Isthmus of fauces
Part of OroPharynx
opening to oral cavity
Respiratory Membrane
Alveolar and capillary walls and their fused basement membranes
~0.5- m-thick; gas exchange across membrane by simple diffusion
Cells of Alveolar Walls
Single layer of squamous epithelium (type I alveolar cells)
Scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins
Pulmonary circulation
(low pressure, high volume)
Pulmonary arteries deliver systemic venous blood to lungs for oxygenation
Pulmonary veins carry oxygenated blood from respiratory zones to heart
Bronchial arteries
provide oxygenated blood to lung tissue
Part of systemic circulation (high pressure, low volume)
Supply all lung tissue except alveoli
Pulmonary veins carry most venous blood back to heart
Pleurae
thin, double-layered serosa; divides thoracic cavity into two pleural compartments and mediastinum
Pleural fluid fills pleural cavity
Provides lubrication and surface tension assists in expansion and recoil
Atmospheric pressure (Patm)
Pressure exerted by air on the body
760 mm Hg at sea level = 1 atmosphere
Respiratory pressures are relative to Patm
Intrapulmonary (intra-alveolar) pressure (Ppul)
pressure in alveoli
Fluctuates with breathing
Always eventually equalizes with Patm
Intrapleural pressure (Pip)
Pressure in pleural cavity
Fluctuates with breathing
Always a negative pressure (
Atelectasis
(lung collapse) due to plugged bronchioles - collapse of alveoli
Inhalation
Diagphragm contracts intercostal muscles contract Lungs expand Volume Changes Pressure changes Gases flow to equalize pressure change
Boyle’s Law
Relationship between pressure and volume of a gas
Gases fill container; if container size reduced increased pressure
Forced Inspiration
During exercise - accessory muscles (scalenes, sternocleidomastoid, pectoralis minor) further increase in thoracic cage size