Oxygenation & Perfusion Flashcards

Comprehensive vocabulary flashcards covering the anatomy, physiology, assessment, diagnostic testing, pharmacology, and clinical nursing interventions for oxygenation and perfusion.

Oxygenation:

The process of providing life-sustaining oxygen to the body's cells.

Factors essential to normal functioning of the respiratory system:

• integrity of the airway system to transport air to and from the lungs

• properly functioning alveolar system in the lungs

  • to oxygenate venous blood

  • to remove carbon dioxide from the blood

• properly functioning cardiovascular system and blood supply

  • to carry nutrients and waste to and from body cells

Airway:

• pathway for the transport and exchange of oxygen and carbon dioxide

• lined with mucus, which traps cells, particles, and infectious debris

  • also helps to protect the underlying tissues from irritation and infection

• begins at the nose and ends at the terminal bronchioles

  • divides into upper and lower airways

Functions of the Upper Airway:

warm, filter, and humidify inspired air

Components of the upper airways:

• nose

• pharynx

• larynx

• epiglottis

Function of the Lower Airway (Tracheobronchial Tree):

conduction of air, mucociliary clearance, and production of pulmonary surfactant

Components of the lower airway (tracheobronchial tree):

• trachea

• right and left main stem bronchi

• segmental bronchi

• terminal bronchioles

Cilia:

• microscopic hair-like projections that propel trapped material and accompanying mucus toward the upper airway so they can be removed by coughing

• removal is facilitated when mucus is watery in consistency

• an adequate fluid intake is necessary for ciliary action and to produce watery mucus

Lungs:

main organs of respiration

located within the thoracic cavity on the right and left sides

extend from the base of the diaphragm to the apex above the first rib

How many lobes does each lung have?

• the right lung has 3 lobes

• the left lung has 2 lobes

How is each lobe divided?

each lobe is subdivided into segments and lobules

• the main bronchus branches to each lung from the trachea

• the bronchus subdivides into bronchioles

What are the lungs composed of?

the lungs are composed of elastic tissue

What is the function of surfactant?

it reduces surface tension between alveoli, preventing their collapse

• when surfactant production is reduced, the lung becomes stiff and the alveoli collapse

Pleura:

serous membrane lining the lungs and thoracic cavity

• visceral pleura-covers the lungs

• parietal-covers the thoracic activity

Pleural Space:

• lies between the two layers

• pleural fluid between the membranes acts as a lubricant and as an adhesive agent to hold the lungs in an expanded position

What is intrapleural pressure, and what is its funtion?

it’s the negative (subatmospheric) pressure within the pleural space that helps keep the lungs expanded and prevents collapse

Alveoli

Small clusters of air sacs situated at the end of the terminal bronchioles where pulmonary gas exchange occurs.

Surfactant

A substance produced in the lungs that reduces the surface tension of the fluid lining the alveoli, preventing their collapse.

Intrapleural Pressure

The subatmospheric (negative) pressure present within the pleural space that acts adhesively to keep the lungs expanded.

Gas Exchange:

the intake of oxygen and the release of carbon dioxide

• this is made possible by pulmonary ventilation, respiration, and perfusion

Pulmonary Ventilation

The mechanical movement of air into and out of the lungs, comprising active inspiration and passive expiration.

Inspiration:

the active phase, involves movement of muscles and the thorax to bring air into the lungs

Expiration:

the passive phase, is the movement of air out of the lungs

Respiration

The process of gas exchange between atmospheric air in the alveoli and blood in the pulmonary capillaries via diffusion.

Perfusion

The process by which oxygenated capillary blood passes through body tissues.

Two phases of pulmonary ventilation:

inspiration (inhalation) and expiration (exhalation)

During Inspiration:

• the diaphragm contracts and descends (lengthening the thoracic cavity)

• the external intercostal muscle contract (lifting the ribs upward and outward)

• the sternum is pushed forward, enlarging the chest from front to back

• the combination of an increased lung volume and decreased intrapulmonic pressure allows atmospheric air to move from an area of greater pressure (outside air) into an area of lesser pressure (within the lungs)

During Expiration:

• the diaphragm relaxes and moves up

• the ribs move down

• the sternum drops back into position

• there is a decreased volume in the lungs and an increase in intrapulmonic pressure

• as a result, air in the lungs moves from an area of lesser pressure to one of lesser pressure and is expired

Factors Affecting Pulmonary Ventilation:

• condition of the respiratory muscles

• lung compliance

• airway resistance

How the condition of the respiratory muscles affects pulmonary ventilation:

• weak muscles lead to less effective inhalation and exhalation

• the accessory muscles of the abdomen, neck, and back are used to maintain respiratory movements at times when breathing is difficult

• these muscles are used to facilitate breathing; the movement is called retraction

Retractions:

retractions are inward pulling of the chest tissues during breathing, often indicating increased work of breathing

How lung compliance affects pulmonary ventilation:

• low compliance means the lungs are stiff and require more effort to inhale

• the ability of the lungs to adequately fill with air during inhalation is achieved by the normal elasticity of lung tissue, aided by the presence of surfactant

• emphysema, a chronic lung condition, and the normal changes associated with aging are examples of conditions that result in decreased elasticity of lung tissue, which, in turn, decreases compliance

How does surfactant affect lung compliance?

surfactant reduces surface tension in the alveoli, helping them remain open and making lung expansion easier

What can cause airway resistance to increase?

• foreign substances (food, coin, toys, or by liquids)

• secretions (excessive or thickened secretions)

• tissues (tumors or edema of the respiratory tract)

• a decrease in the size of air passages resulting from constriction or poor neck positioning can also impede respiration

• bronchial constriction in asthma is an example of airway resistance related to a decrease in the size of air passages

  • e.g., bronchial constriction in asthma

Lung Compliance

The ease with which the lungs can be inflated, determined by lung tissue elasticity and surfactant presence.

Airway Resistance

Any impediment or obstruction met by air as it travels through the respiratory tract, caused by foreign objects, secretions, tumors, edema, or bronchoconstriction.

Which respiratory organ is the site of gas exchange?

alveoli

Where does gas exchange occur in the respiratory system?

at the alveolar-capillary membrane, where the alveoli meet the surrounding blood capillaries

Diffusion

The passive movement of gas molecules from an area of higher concentration or pressure to an area of lower concentration or pressure.

How do oxygen and carbon dioxide move during gas exchange?

• Oxygen (O2) move from the alveoli into the blood

• carbon dioxide (CO2) moves from the blood into the alveoli to be exhaled

Factors Affecting Diffusion:

• changes in the surface area available

• thickening of the alveolar-capillary membrane

• partial pressure, or pressure resulting from any gas in a mixture depending on its concentration

How do the changes in the surface area available affect diffusion?

• removal of a lung or the presence of a disease that destroys lung tissue can decrease the surface area available (e.g., lung disease)

• incomplete lung expansion or the collapse of alveoli (atelectasis) prevents pressure changes and the exchange of gas by diffusion in the lungs

• conditions that predispose a patient to atelectasis are obstructions of the airway by foreign bodies, mucus, airway constriction, external compression by tumors or enlarged blood vessels, and immobility

Atelectasis

Incomplete expansion or collapse of lung alveoli, which hinders normal pressure changes and respiratory gas exchange.

How does the thickening of the alveolar-capillary membrane affect diffusion?

from diseases such as pneumonia or pulmonary edema, makes diffusion more difficult

How does partial pressure, or pressure resulting from any gas in a mixture depending on its concentration affect diffusion?

• when oxygen is administered, an increased amount of oxygen is available, resulting in greater diffusion across capillary membranes

• for example, when a person is at higher altitudes or in the presence of toxic fumes, less oxygen is available for diffusion

Perfusion:

the flow of blood through body tissues to deliver oxygen

How does blood flow affect gas exchange?

blood flow through the lungs affects how much oxygen and carbon dioxide can be exchanged

What does oxygenated blood deliver to body tissues?

oxygen for cells to use

Factors affecting perfusion:

• position-sitting, standing, or lying down

  • perfusion is greater in dependent areas

• person’s activity level

  • greater activity results in an increased need for cellular oxygen by the body’s tissues and a subsequent increase in cardiac output (CO) and consequently in increased blood return to the lungs

• adequate blood supply and proper cardiovascular functioning-to carry oxygen and carbon dioxide to and from the lungs

Where is the respiratory center located?

in the medulla in the brainstem, immediately above the spinal cord

What stimulates the respiratory center?

• an increased concentration of carbon dioxide and hydrogen ions

• decreased amount of oxygen in the arterial blood

• chemoreceptors in the aortic arch and carotid bodies are sensitive to the same arterial blood gas levels and blood pressure

Stimulation of the medulla does what?

increases the rate and depth of ventilation (both inspiration and expiration) to blow off carbon dioxide and hydrogen and increase oxygen levels

Hypoxia

A condition in which an inadequate amount of oxygen is available to cellular tissues, commonly caused by hypoventilation.

Hypoventilation:

decreased rate or depth of air movement into the lungs

If a problem exist in ventilation, respiration or perfusion what may occur?

hypoxia

Symptoms of hypoxia:

dyspnea

elevated blood pressure

increased respiratory and pulse rates

pallor

cyanosis

anxiety, restlessness, confusion, and drowsiness

Dyspnea:

difficultly breathing

Chronic hypoxia:

• altered though processes

• headaches

• chest pain

• enlarged heart

• clubbing of the fingers and toes

• anorexia, constipation, decreased urinary output, decreased libido, weakness of extremity muscles, and muscle pain

What is vital for exchanges of gases?

an adequately functioning cardiovascular system

The cardiovascular system is composed of:

the heart and the blood vessels

Three components of ciculation:

• the pump (the heart)

• the pipes (the blood vessels)

• the fluid (the blood)

Atria:

upper chambers that receive blood returning to the heart

Ventricles:

lower chambers that pump blood out of the heart

Arteries and arterioles:

carry blood away from the heart

venules and veins:

return blood toward the heart

heart valves:

maintain one-way blood flow and prevent backflow

four heart valves:

• tricuspid

• mitral

• pulmonary

• aortic

capillaries:

exchange oxygen, carbon dioxide, nutrients, and wastes between blood and body tissues

blood vessel pathway:

arteries → arterioles → capillaries → venules → veins

Oxygen Transport:

• blood is squeezed through the heart and out into the body by contractions starting in the atria, followed by contraction of the ventricles, with a subsequent resting of the heart

• deoxygenated blood is carried from the right side of the heart to the lungs, where oxygen is picked up and carbon dioxide is released, and then returned to the left side of the heart

• this oxygenated blood is pumped out to all other parts of the body and back again

• oxygen is carried predominantly via red blood cells due to binding between the hemoglobin in RBCs and oxygen

• once the blood cells reach the tissues, internal respiration must occur

Deoxygenated blood:

low in oxygen, high in carbon dioxide

Oxygenated blood:

high in oxygen, low in carbon dioxide

Internal Respiration

The exchange of oxygen and carbon dioxide between circulating systemic blood and metabolizing tissue cells.

Sinoatrial (SA) Node

• A specialized mass of cardiac tissue in the upper right atrium acting as the heart's natural pacemaker by initiating electrical impulses at regular intervals.

• the heart’s natural pacemaker: starts the electrical impulse

Atrioventricular (AV) node:

it delays the electrical impulse so the atria can finish pushing blood into te ventricles before the ventricles contract

Electrical conduction pathway:

SA node → AV node → Bundle of His → bundle branches → Purkinje fibers

Dysrhythmia (Arrhythmia)

A disturbance in the rate, rhythm, or conduction of electrical impulses through the heart.

What can cause Dysrhythmia (Arrhythmia)

• caused by an abnormal rate of electrical impulse generation from the SA node, or from impulses originating from a site or sites other than the SA node

• abnormal conduction of electrical impulses through the heart

Dysrhythmia (Arrhythmia) Occurs With:

• heart disease

• damage to the heart

• certain drugs

• decreased oxygenation to heart tissues

• trauma

Symptoms of Dysrhythmia (Arrhythmia):

• decreased BP

• dizziness/fainting

• palpitations (throbbing)

• weakness

Myocardial Ischemia

A deficiency of blood and oxygen delivery to the heart muscle, most frequently resulting from atherosclerosis.

Atherosclerosis

The accumulation of fatty substances and fibrous plaques in arterial linings, resulting in vessel narrowing and reduced blood flow.

Myocardial Infarction (MI)

The death of myocardial tissue caused by an acute lack of oxygen supply; commonly referred to as a heart attack.

Symptoms of MI:

• chest pain

• anxiety

• nausea/vomiting

• indigestion

• shortness of breath

Risk Factors of MI:

modifiable:

• smoking

• high blood pressure

• high cholesterol

• diabetes

• obesity

• physical inactivity

non-modifiable:

• age (increases with age)

• family history

• male

Heart Failure:

occurs when the heart is unable to pump a sufficient blood supply, resulting in inadequate perfusion and oxygenation of tissues

Heart failure may result from:

• MI

• hypertension

• coronary artery disease

• valvular abnormalities

Symptoms of heart failure:

• shortness of breath

• peripheral edema

• swelling of legs

• fatigue

Chronic Obstructive Pulmonary Disease (COPD)

• progressive lung disease that obstructs airflow and makes breathing difficult

• it include two main conditions: emphysema and chronic bronchitis

  • most individuals with COPD have a combination of both

Primary cause of COPD:

long-term exposure to lung irritants, especially cigarette smoke

Other causes of COPD:

• air pollution

• occupational exposure to dust and chemicals

• secondhand smoke

• rare genetic condition: alpha-1 antitrypsin deficiency

Symptoms of COPD:

• chronic cough

• shortness of breath, especially during physical activity

• wheezing

• fatigue

• frequent respiratory infections

• frequent exacerbations

Risk factors of COPD:

• smoking (main risk factors)

• age (typically 40+)

• environmental and occupational exposure

• genetic predisposition

• history of asthma

Treatment of COPD:

while COPD is not curable, it is manageable

• smoking cessation

• bronchodilators and inhaled corticosteroids

• oxygen therapy (in advanced cases)

• vaccinations (e.g., flu and pneumonia)

• lifestyle changes and exercise

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Asthma

A chronic inflammatory disorder of the airways causing reversible bronchial obstruction, airway hyperresponsiveness, and mucosal edema.

Key symptoms of asthma:

• reversible airway obstruction

• airway hyperresponsiveness

• chronic inflammation

Common symptoms of asthma:

• shortness of breath

• wheezing (especially when exhaling)

• chest tightness or pain

• persistent cough, often worse at night or early morning

• difficultly breathing during exercise or exposure to triggers

Triggers of asthma:

• allergens (pollen, dust mites, pet dander, mold)

• respiratory infections (cold, flu)

• exercise (especially in cold, dry air)

• smoke, pollution, strong odors

• stress and emotional upset

• weather changes

Treatment of asthma:

asthma is not curable, but is manageable

• quick-relief medications (e.g., short-acting bronchodilators)

• long-term control medications (e.g., inhaled cortiosteriods)

• avoidance of triggers

• monitoring with peak flow meters

• asthma action plans for managing flare-ups