Test 3 Final Flashcards
Alveolar pressure equals
atmospheric pressure When…
At rest (before inspiration begins)
Intrapleural pressure is negative When…
At rest (before inspiration begins)
Lung Volume is FRC at…
At Rest (Before Inspiration)
The inspiratory muscles contract and cause the volume of the thorax to increase during…
During Inspiration
Intrapleural pressure becomes more negative during…
During Inspiration
Lung volume increases by one TV during…
During inspiration
Alveolar pressure becomes greater than atmospheric pressure during…
During expiration
Intrapleural pressure returns to its resting value during
a normal (passive) expiration
Sympathetic stimulation and sympathetic agonists dilate the airways via…
β2-receptors, increase the radius, and decrease the resistance to airflow
Laplace’s Law), as shown in the following equation:
P=(2T)/R
P in P=(2T)/R is…
Pressure required to keep alveolus open (dynes/cm2)
Surfactant consists of…
the phospholipid DPPC, other lipids, proteins and carbohydrate. Phospholipid is the major component due to its amphipathic properties
Compliance of the lungs describes?
the distensibility of the lungs and is inversely related to “stiffness”
Mathematically, compliance is
the change in volume for a given change in pressure or C = V/P
“Classically”, an asthma attack begins when an allergen is inhaled. The allergen binds to…
IgE antibodies on MAST CELLS in the lungs.
The most common causes of obstructive lung disease are:
Chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis
Asthma
Some conditions causing restrictive lung disease are:
Interstitial lung disease such as idiopathic pulmonary fibrosis
Obesity
Neuromuscular disease, such as muscular dystrophy or amyotrophic lateral sclerosis
This measurement of respiratory volumes and capacities is important in assessing the severity of a respiratory disease and monitoring improvement or deterioration in a patient’s pulmonary function.
Forced Expiratory Volume 1.0 (FEV1.0)
A healthy adult should be able to expel ______% of the vital capacity in __ second(s)
75-85
1.0
Oxygen is carried in blood in two forms:
- dissolved in plasma (~1.5%)
* bound to hemoglobin (most important; ~98.5%)
Hemoglobin saturation at PO2 40 mmHG
75% 3/4 heme groups filled
Hemoglobin saturation at PO2 25 mmHG
50% 2/4 heme groups filled
Occur when the affinity of hemoglobin for O2 is decreased.
Shifts to the Right
affects of Increases in 2, 3-DPG concentration on hemoglobin dissociation curve.
Shifts to the Right
_________is a decrease in arterial PO2, whereas_________ is delivery to the tissues.
Hypoxemia
hypoxia
occurs when body cells are unable to use O2 even though adequate amounts are delivered. This variety of hypoxia is the consequence of metabolic poisons, such as cyanide.
Histotoxic hypoxia
is indicated by reduced arterial PO2. Possible causes include disordered or abnormal ventilation-perfusion coupling, pulmonary diseases that impair ventilation, and breathing air containing scant amounts of O2.
Hypoxemic hypoxia
ratio is the ratio of alveolar ventilation (V) to pulmonary blood flow
Ventilation-Perfusion Ratio (V/Q Ratio)
If the frequency, tidal volume, and cardiac output are normal, the V/Q ratio is approximately…
0.8
Normal V/Q ratio results in
an arterial PO2 of 100 mmHG, and PCO2 of 40 mmHG
If the airways are completely blocked (e.g., by a piece of food caught in the trachea), then ventilation is zero. If blood flow is normal, then V/Q is zero, which is called a
Shunt
Is primarily responsible for inspiration and generates the basic rhythm for breathing
Medullary Respiratory (Rhythmicity) Center
Dorsal Respiratory Group (DRG)
Inputs information from peripheral chemoreceptors and mechanoreceptors
Cranial Nerve 10 (CN X)
Inputs information from peripheral chemoreceptors
CN IX
Output from the DRG travels via the______ nerve to the diaphragm & external intercostals
phrenic
- is primarily responsible for expiration
- is not active during normal, quiet breathing, when expiration is passive
- is activated (e.g., during exercise) when expiration becomes an active process
Medullary Respiratory Center: Ventral Respiratory Group (VRG)
- is located in the lower pons
- stimulates inspiration, producing deep and prolonged inspiratory gasps (apneusis), followed by occasional brief exhalations
Apneustic Center
- is located in the upper pons
- inhibits inspiration and limits the burst of action potentials in the phrenic nerve
- limits the size of the TV
Pneumotaxic Center
When it comes to breathing, it can temporarily override the brainstem centers
Cerebral Cortex
Chemoreceptors located bilaterally in the ventrolateral medulla.
central chemoreceptors
Chemoreceptors found in the aortic arch and carotid arteries.
peripheral chemoreceptors
Are sensitive to the pH of the CSF
Central Chemoreceptors in the Medulla
Chemoreceptors sensitive to arterial O2
The peripheral chemoreceptors
In order for O2 levels to become a major stimulation for increased ventilation they must drop to at least…
60mmHg
The optimal ration between bicarbonate and CO2 to have a pH of 7.4
20:1
The kidneys regulate pH by:
Secreting H+
Reabsorbing HCO3-
Synthesizing HCO3-
if active this lowers PH
