TOPIC 7 Flashcards
respiration
the exchange of oxygen and carbon dioxide during cellular metabolism
what are the three steps in the process of oxygenation?
ventilation, perfusion, and diffusion
ventilation
the process of moving gases into and out of the lungs
perfusion
the ability of the cardiovascular system to pump oxygenates blood to the tissues and return deoxygenated blood to the lungs
diffusion
exchange of respiratory gases in the alveoli and capillaries
inspiration
an active process, stimulated by chemical receptors in the aorta.
expiration
a passive process that depends on the elastic recoil properties of the lungs, requiring little or no muscle work.
surfactant
a chemical produced in the lungs to maintain the surface tension of the alveoli and keep them from collapsing.
atelectasis
a collapse of the alveoli that prevents normal exchange of oxygen and carbon dioxide. (collapsed lung)
compliance
the ability of the lungs to distend or expand in response to increased interalveolar pressure.
when does compliance of the lungs decrease?
in diseases such as pulmonary edema, interstitial and pleural fibrosis, and congenital or traumatic structural abnormalities such as kyphosis or fractured ribs.
airway resistance
the increase in pressure that occurs as the diameter of the airways decreases from mouth/nose to alveoli.
increased vs decreased airway resistance
increased: bronchoconstriction
decreases: bronchdilation
prolonged use of accessory muscles….
does not promote effective ventilation and causes fatigue.
where do you see the use of accessory muscles in a patient
During assessment observe for elevation of the patient’s clavicles during inspiration, which can indicate ventilatory fatigue, air hunger, or decreased lung expansion.
tidal volume
is the amount of air exhaled following a normal inspiration.
residual volume
is the amount of air left in the alveoli after a full expiration.
forced vital capacity
the maximum amount of air that can be removed from the lungs during forced expiration
blood moves to and from the ______ for gas exchange
alveloar capillary
What affects the rate of diffusion?
thickness of membrane (increased. thickness takes gases longer to transfer across the membrane)
Three things influence the capacity of the blood to carry oxygen:
-the amount of dissolved oxygen in the plasma,
-the amount of hemoglobin,
-the ability of hemoglobin to bind with oxygen.
hemoglobin
which is a carrier for oxygen and carbon dioxide, transports most oxygen (approximately 97%).
neural regulation includes…
central nervous system control of respiratory rate, depth, and rhythm.
what does the cerebral cortex regulate?
the voluntary control of respiration by delivering impulses to the respiratory motor neurons by way of the spinal cord.
chemical regulation maintains…
the appropriate rate and depth of respirations based on changes in carbon dioxide (CO2), oxygen (O2), and hydrogen ion (H+) concentrations (pH) in the blood.
what are factors that decrease the oxygen carrying capacity of the blood
anemia and inhalation of toxic substances (CO)
what can cause hypovolemia and why?
shock and severe dehydration because extracellular fluid loss and reduces circulating blood volume
decreased circulating blood volume causes
hypoxia to the body
the HR increases to increase volume of blood being returned to the heart (increasing CO)
With the decline of the concentration of inspired oxygen…
the oxygen-carrying capacity of the blood decreases.
anemia
(e.g., a lower-than-normal hemoglobin level) is a result of decreased hemoglobin production, increased red blood cell destruction, and/or blood loss.
hypoventilation
Alveolar ventilation inadequate to meet the body’s oxygen demand or to eliminate sufficient carbon dioxide
signs and symptoms of hypoventilation
mental status changes, dysrhythmias, and potential cardiac arrest
hyperventilation
Ventilation in excess of that required to eliminate carbon dioxide produced by cellular metabolism
what can induce hyperventilation
Severe anxiety, infection, drugs, or an acid-base imbalance
signs and symptoms of hyperventilation
rapid respirations, sighing breaths, numbness and tingling of hands/feet, light-headedness, and loss of consciousness
hypoxia
Inadequate tissue oxygenation at the cellular level
Causes of hypoxia include
(1) a decreased hemoglobin level and lowered oxygen-carrying capacity of the blood
(2) a diminished concentration of inspired oxygen, which occurs at high altitudes
(3) the inability of the tissues to extract oxygen from the blood, as with cyanide poisoning
(4) decreased diffusion of oxygen from the alveoli to the blood, as in pneumonia
(5) poor tissue perfusion with oxygenated blood, as with shock; and
(6) impaired ventilation, as with multiple rib fractures or chest trauma.
The clinical signs and symptoms of hypoxia include
apprehension, restlessness, inability to concentrate, decreased level of consciousness, dizziness, and behavioral changes.
hypoxemia
Refers to a decrease in the amount of arterial oxygen.
cyanosis
Blue discoloration of the skin and mucous membranes caused by the presence of desaturated hemoglobin in capillaries, is a late sign of hypoxia.
Central cyanosis
observed in the tongue, soft palate, and conjunctiva of the eye where blood flow is high, indicates hypoxemia.
Peripheral cyanosis
seen in the extremities, nail beds, and earlobes, is often a result of vasoconstriction and stagnant blood flow.