Flashcards in Cardiopulmonary III Deck (110):
What is the natural state of the lungs?
What connects the Lungs to the Thoracic cavity?
Adhesive nature of the fluid between the Visceral and Parietal pleura
What formula describes pressure changes in the lungs?
P1V1 = P2V2
If Intra-alveolar volume increases, pressure...
If Intra-alveolar volume decreases, pressure...
Normal breathing is...
Ventilator breathing is...
Negative pressure breathing
Positive pressure breathing
At the point between exhale and inhale, the intrapleural pressure is...
*pulling back at compressed lungs
When does intrapleural pressure become positive?
What are the 3 factors that hinder air passage in breathing?
Alveolar surface tension
What are the 2 receptors that affect bronchial radius?
What does alveolar tension counteract?
Collapsing pressure is inversely proportional to...
What cells make surfactant in the lungs?
Type 2 Alveolar
What is the major component of surfactant?
*62%, and other amphipathic phospholipids
What is the primary function of surfactant?
Decrease surface tension
Higher humidity climates require more or less surfactant?
Large alveoli have _____ collapsing pressures while small alveoli have _____ collapsing pressures.
What is the collapse of alveoli called?
The opposite of stiffness is...
What antibody does allergen bind in the lung?
What does binding induce?
Mast cells release Histamine and Leukotrienes
What do Histamine and Leukotrienes cause?
Contraction smooth muscles in bronchi
Occurs within 1 hour allergen exposure (early phase)
What type of inflammatory cells are preferentially drawn into the lungs in response to an allergic reaction?
4-5 hrs Late phase
There is no genetic component to making IgE antibody associated with asthma.
*can be allergic or non-specific like cold or exercise
The 4 physiological/pathological characteristics of asthma?
Increased responsiveness of trachea/bronchi
What are the 2 most common obstructive lung diseases?
COPD (chronic obstructive pulmonary disease)
What are 2 types of COPD?
What defines an obstructive lung disease?
Difficulty fully exhaling
(air lingers in lungs after full expiration)
What defines a restrictive lung disease?
Cannot fill lungs
*often because of stiffness
What are some conditions causing restrictive lung disease?
What is another way of assessing pulmonary function besides measuring respiratory volumes and capacities using spirometry?
(Forced Expiratory Volume)
What is the normal FEV (1.0)?
75-85% vital capacity exhaled in 1.0 seconds
FEV (1.0) below 75% suggests?
above 85% suggests?
Obstructive (difficulty exhaling)
Restrictive (no air left because difficulty filling lungs)
100% FEV =
FVC - forced vital capacity
By how much does Hemoglobin increase carrying capacity of blood?
How much Oxygen is dissolved in plasma?
How much bound to Hb?
Structure of Hemoglobin.
4 Heme subunits
What is the saturation of Arterial blood?
What is the saturation of Venous blood?
What accounts for the sigmoid shape of the Oxygen-Hemoglobin binding curve?
How does this manifest physiologically?
Easier to pick up Oxygen at lungs and drop off at tissues
Name 5 blood factors that influence Hemoglobin saturation.
What RBC binding factor affecting Hemoglobin saturation with Oxygen is made by RBC's as the break down glucose?
(also 2,3 DPG)
What are the 3 most important factor that influence Hemoglobin saturation?
What shifts the Hemoglobin binding curve to the RIGHT?
(decreases affinity for Oxygen)
What is this known as?
Increase in CO2
decrease in pH (more acidic)
(shifts to the right increase unloading Oxygen in tissues)
How does exercise create the Bohr Effect?
tissues produce more CO2
Unloads Oxygen at tissues
What does an increase of temperature do to the Hemoglobin binding curve?
Shifts to the right
(gives up Oxygen more easily)
What binds to the Beta chains of deoxyhemoglobin and decreases the affinity of hemoglobin for Oxygen?
What blood factor is increased in those that live at high altitude?
*facilitates Oxygen unloading at the tissues
Shifts to the right ____ affinity of hemoglobin for Oxygen.
Shifts to the left _____ affinity of hemoglobin for Oxygen.
What is the affinity Hemoglobin has for Carbon Monoxide compared to Oxygen?
Carbon monoxide binding shifts the curve to the _____, then _____.
Left (increases affinity for remainder oxygen)
A decrease in arterial oxygen is...
A decrease in oxygen delivery to tissues is...
Three things that cause hypoxia:
Decrease Cardiac Output
Decreased Oxygen binding capacity Hb
Decreased arterial Oxygen
What is lack of Hemoglobin (due to RBC or Hb deficiency) called?
What is blockage of blood flow leading to bad delivery of oxygen called?
Ischemic (or stagnant) hypoxia
Lack of Oxygen because cell can't use:
Lack of Oxygen due to... lack of oxygen (pulmonary disease, altitude, etc).
What are the 3 ways Carbon Dioxide is carried in the blood?
Dissolved (small amount)
Carbaninohemoglobin (also small amount)
HCO3- (major form)
How is CO2, in the form of HCO3-, carried through the blood?
Where does rxn take place?
What enzyme converts CO2 + H2O > H2CO3?
H2CO3 > H+ + HCO3-
What prevents this from lowering blood pH?
H+ is bound to hemoglobin
What does the Chloride shift do at the tissues?
Binds RBC and kicks HCO3- into plasma
(this maintains osmotic equilibrium)
What does the Chloride shift do at the lung?
Chloride leaves RBC for HCO3- and is converted back to CO2.
What matches to achieve the ideal exchange of Oxygen and Carbon dioxide?
Ventilation - Perfusion Ratio
What is the V/Q ratio if the frequency, tidal volume, and cardiac output are normal?
(4.2 L/min ventilation / 5.5 L/min blood flow)
What could drive the V/Q ratio to zero?
(blockage of airflow in lungs)
What are the normal pressures of Oxygen and Carbon Dioxide in the blood?
100 mm Hg Oxygen
40 mm Hg Carbon dioxide
What could drive the V/Q ratio to infinity?
*no circulatory perfusion by blockage
What are the 3 groups of neurons in the brainstem that control breathing?
Where are they in brainstem?
Medullary respiratory center
1st in Medulla, latter 2 in Pons
What group of nerves is responsible for spontaneous breathing and is perhaps the most important set of nerves we have?
Where is it?
DRG - Dorsal Respiratory Group
What does the DRG (Dorsal Respiratory Group) innervate?
What does the VRG (Ventral Respiratory Group) innervate?
*make up Medullary Respiratory Center
What 2 cranial nerves are the DRG inputs?
What info do they input?
X Vagus - peripheral chemoreceptors and mechanoreceptors
IX Glossopharyngeal - peripheral chemoreceptors
What makes is the output of the DRG?
What does it innervate?
When is the VRG active?
*when passive expiration isn't enough
How much time does the DRG spend in the Active and Inactive states in normal breathing?
2 seconds active (inspiration)
3 seconds inactive (expiration)
What type of inspiration does the Apneustic Center stimulate?
Ispiratory gasps (apneusis)
How does the Apneustic Center affect the Medulla?
Prolongs action potential in Phrenic nerve and contraction of diaphragm
What neuronal center limits the size of the Tidal Volume?
Where is it located?
What neuronal center limits action potentials of the Phrenic nerve?
Hyperventilation causes blood pH to...
Where are the Central and Peripheral Chemoreceptors located?
Central - bilateral ventrolateral Medulla
Peripheral - aortic arch/carotid arteries
What stimuli increase the breathing rate?
A decrease in pH and/or increase in CO2 will stimulate what type of chemoreceptor?
Central or Peripheral
An decrease of Oxygen below 60 mm Hb will stimulate what kind of chemoreceptor?
What is the most potent and closely controlled chemical influencing respiration?
What is its normal range?
40 mm Hg
*controlled to within +/-3 mmHg
What is the main mechanism of control over the effects of CO2?
What is the central Chemoreceptor in the Medulla particularly sensitive to?
CO2 crosses BBB much easier than H+
must breath faster
*H+ acts directly on Medullary receptors
How does CO2 increase H+ in the CSF?
CO2 + H2O > H+ and HCO3-
*via carbonic anhydrase
What type of receptors are sensitive to arterial Oxygen?
*CO2 has much greater effects on these receptors
At what point does dearth of Oxygen become a major stimulus to peripheral chemoreceptors?
60 mmHg or below
What type of chemoreceptors are most important in regulating CO2?
What is the term for the result chemoreceptor adaptation in which Oxygen takes over as the primary chemical regulator?
(often due to pulmonary disease)
Why is gas mixture only slightly enriched with Oxygen in people with Hypoxic Drive?
If it's too high (above 60 mmHg) will slow breathing.
Name 3 non-chemical receptors that also input to the brainstem and regulate breathing?
Lung stretch receptors
Joint and muscle receptors
What is the Herring-Breuer reflex?
Lung stretch reflex
Where are irritant receptors located?
What nerve innervates?
Between epithelial cells lining airways
*restricts and increases breathing rate
What 2 components lead to increased breathing before exercise?
For this class, Acids are...
pH = pKa + log [HCO3-] / [CO2]
*at 20:1 pH = 7.4
What is the normal range of pH in ECF?
What are the 3 lines of defense against increase in H+?
What are the 3 major buffers in the body?
Bicarbonate (and protonated carbonic acid)
What parts of a protein respond to Acidosis?
acidosis: Amine accepts proton
alkalosis: carboxyl releases proton
What effect does hypoventilation have on pH?
What effect does Hyperventilation have on pH?
What are the 3 ways kidneys regulate pH and where does this regulation occur?
Secretes H+ (distal convoluted tubule)
Reabsorbs HCO3- (prox. convoluted tubule)
Synthesizes HCO3- (prox. convoluted tubule)
What is Respiratory Acidosis caused by?
What are its effects in the kidney?
Emphysema (anything can't breath)
Increases secretion of H+
What causes Respiratory Alkalosis?
Effects in kidney?
Decrease secretion H+
What causes Metabolic Acidosis?
Effect on HCO3-?
Production of H+ (ketoacidosis, etc)
*Kidneys secrete H+
What causes Metabolic Alkalosis?
Effect on HCO3-?