Exam 5 (Ch 35- Oxygenation) Flashcards
Oxygenation
Refers to how well the cells, tissues, and organs of the body are supplied with oxygen.
The musculoskeletal and neurological systems
Regulate the movement of air into and out of the lungs
The lungs oxygenate the ____
blood
The heart circulates the blood throughout the body and back to the ____
lungs
The pulmonary system has two major components:
the airway and the lungs
The airway consists of the
nasal passages, mouth, pharynx, larynx, trachea, bronchi, and bronchioles.
Airway structures do the following:
- Moisten the air
- Warm the air
- Filter the air
A moist mucous membrane lining adds
water to inhaled air
Blood flowing through the vascular airway walls transfers
body heat to the inhaled air
Specialized cells in the lining of the airways secrete
sticky mucus to trap foreign particles
Cilia
tiny hairlike projections from the walls of the airways
Cilia move rhythmically to
sweep trapped debris up and out of the airway
Upper airway, located above the larynx, includes:
the nasal passages, mouth, and pharynx
The pharynx (throat) contains the
openings to the esophagus and trachea
The trachea lies just in front of
the esophagus
The epiglottis is
a small flap of tissue superior to the larynx
The epiglottis closes off the
trachea during swallowing so that food and fluids do not enter the lower airway.
It opens during breathing to allow air to move through the airway.
The lower airway, located below the larynx, includes
the trachea, bronchi, and bronchioles.
The lower airway is considered
sterile
The trachea, sometimes called the windpipe, extends from
the larynx to where it divides to form the right and left mainstem bronchi
As the airways branch and become smaller, they have
progressively thinner and less cartilage, until it disappears completely in the smaller bronchioles
The walls of the bronchi and bronchioles contain layers of
smooth muscles
Bronchospasm
Spasm of smooth muscles of the bronchi and bronchioles.
Narrow the airways and obstructs airflow
The lungs are
soft, spongy, cone-shaped organs.
Mediastinum
Separates the lungs.
Contains the heart and great vessels.
The right lung has ___ lobes
3
The left lung has ____ lobes
2
Apex
The upper portion of each lung; extends upward above the clavicle
Base
The lower portion of each lung; rests on the diaphragm
The lungs are composed of millions of
Alveoli
Alveoli
Tiny air sacs with thin walls surrounded by a fine network of capillaries.
Gases (oxygen and carbon dioxide) easily pass back and forth between the ___ and ____.
Alveoli & capillaries
Alveoli are composed of two types of cells:
Type I alveolar cells
Type II alveolar cells
Type I alveolar cells are the
gas exchange cells
Type II alveolar cells produce
surfactant
Surfactant
A lipoprotein that lowers the surface tension within alveoli to allow them to inflate during breathing.
Two major processes occur in the pulmonary system:
ventilation and respiration
Ventilation
the movement of air into and out of the lungs through the act of breathing
Respiration
The exchange of the gases oxygen and carbon dioxide in the lungs
Oxygenation of the blood, and ultimately of organs and tissues, depends on adequate _____.
Ventilation
Inhalation
Expansion of the chest cavity and lungs, which creates negative pressure inside the lungs; this causes air to be drawn in through the nose or mouth and airways.
Diaphragm
the major muscle of breathing; when it contracts with each inhalation, the chest cavity is pulled downward, pulling the lung bases downward with it.
Intercostal muscles
small muscles around the ribs that contract on inhalation and pull the ribs outward, slightly expanding the chest cavity and lungs.
Pleural membrane
covering that adheres to the lungs so that they can expand
Lung expansion creates _____ ______ and draws air in through the only opening to the outside, the trachea.
negative pressure
Exhalation
Diaphragm and intercostal muscles relax, allowing the chest and lungs to return to their normal resting size.
The reduction in size causes the pressure inside the chest and lungs to rise above atmospheric pressure, so air flows out of the lungs.
Exhalation requires no ___ or ____.
Energy, effort
What factors affect the adequacy of ventilation?
The rate and depth of respirations, lung compliance and elasticity, and airway resistance.
Respiratory rate and depth
Rate is how fast you breathe and depth is how much your lungs expand to take in air.
These processes affect O2 AND CO2 levels in the blood
Hyperventilation
When a person breathes fast and deeply to move a large amount of air through the lungs, causing too much CO2 to be removed by the alveoli.
Mild hyperventilation can occur in response to ____.
hypoxemia
Hypoxemia
A low level of oxygen in the blood.
When blood oxygen is low, ____ increases to draw additional air (and oxygen) into the lungs
ventilation
As ventilation increases, ___ ___ levels fall.
carbon dioxide
Severe hyperventilation is usually triggered by:
Medications, central nervous system abnormalities, high altitude, heat, exercise, panic, fear, or anxiety.
Hypoventilation
When a decreased rate or shallow breathing moves only a small amount of air into and out of the lungs.
Hypoventilation predisposes to the development of _____ because less air (carrying oxygen) reaches the alveoli.
hypoxemia
Hypoxemia can lead to
hypoxia
Hypoxia
An oxygen deficiency in the body tissues
Lung compliance
ease of lung inflation.
Lungs inflate easily because
Of their stretchy elastin fibers, low water content, and low alveolar surface tension.
Lung compliance is reduced by conditions that cause
elastin fibers to be replaced with scar tissue (collagen), increased lung water (edema), or loss of surfactant.
Lung elasticity (or elastic recoil)
refers to the tendency of the elastin fibers to return to their original position away from the chest wall after being stretched
e.g. stretching a rubber band, then letting go of it
Alveoli that have been overstretched, as with emphysema, lose their ___ ___ over time.
elastic recoil.
This loss of elasticity allows the lungs to inflate easily but inhibits deflation, leaving stale air trapped in the alveoli.
Airway resistance
The resistance to airflow within the airways. The larger the diameter of the airway, the more easily air moves through it.
Normally, airway resistance is very low, so it takes little effort to move large volumes of air into and out of the lungs.
Respiration
Gas exchange, the oxygenation of blood and elimination of carbon dioxide in the lungs.
Gas exchange occurs at 2 equally essential levels:
1) at the alveolar-capillary membrane in the lungs (external), and 2) at the capillary-cellular membrane in body tissues (internal)
External respiration (alveolar-capillary gas ex-change)
Occurs in the alveoli of the lungs. O2 diffuses across the alveolar-capillary membrane into the blood of the pulmonary capillaries; CO2 diffuses out of the blood and into the alveoli to be exhaled.
Pleural effusion
fluid in the lungs
Pneumothorax
lung collapse
Asthma
bronhospasms
Hypoxemia
Low blood-oxygen levels.
Occurs when blood is not adequately oxygenated in the alveoli.
Internal respiration (capillary-tissue gas exchange)
Occurs in body organs and tissues.
Oxygen diffuses from the blood through the capillary-cellular membrane into the tissue cells, where it is used for metabolism. From the cells, CO2, a waste product of cellular metabolism, diffuses through the capillary-cellular membrane into the blood, from where it is transported to the lungs and exhaled.
Tissue oxygenation requires both
adequate external respiration and adequate peripheral circulation.
The respiratory centers in the brain stem control ____ using feedback from chemoreceptors and lung receptors.
breathing
Chemoreceptors
Located in the medulla of the brainstem, the carotid arteries, and the aorta detect changes in blood pH, O2, and CO2 levels, and they send messages back to the central respiratory center in the brain stem.
Low blood O2 levels (hypoxemia) stimulate ____ to get more oxygen into the ____.
breathing, lungs
Lung receptors
Located in the lung and chest wall
Sensitive to breathing patters, lung expansion, lung compliance, airway resistance, and respiratory irritants.