Term
| What is Fick's Law of Diffusion? |
|
Definition
| the diffusion of a gas is directly proportional to the concentration gradient of the gas and the surface area of the pulmonary caplillary bed available for diffusion |
|
|
Term
| What is the purpose of the cartillagenous rings in the first four generations of airways? |
|
Definition
| they are exposed to thoracic pressures, and the rings prevent airway collapse |
|
|
Term
| What is the terminal respiratory unit composed of? |
|
Definition
| type I alveolar pneumocytes, interstitial tissue, and capillary endothelial cells |
|
|
Term
|
Definition
| the total pressure is the sum of the the partial pressures of the individual gases in the atmosphere |
|
|
Term
| What is the fraction of oxygen in the atmosphere? Of nitrogen? |
|
Definition
21% 79% water vapor and co2 are small enough to be considered 0 |
|
|
Term
| What is the respiratory quotient? |
|
Definition
CO2 production/ O2 consumption normally 0.8 |
|
|
Term
| What is the equation for the alveolar partial pressure of oxygen? |
|
Definition
PAO2=PIO2-PACO2[FIO2+(1-FIO2)/R] PAO2(CO2)= alveolar partial pressure O2 (CO2) PIO2= inspired partial pressure O2 FIO2=fraction O2 in inspired air R=respiratory quotient |
|
|
Term
| What is it called when a small amount of venous blood bypasses pulmonary capillaries and enters the arterial circulation without being exposed to alveoli and becoming oxygenated? |
|
Definition
|
|
Term
| What is the alveolar-arterial gradient? What is a normal value? |
|
Definition
the difference between the calculated PAO2 (alveolar) and the measured PaO2 (arterial) 7-10 mmHg |
|
|
Term
What is a normal PAO2 at sea level? What is a normal PaO2? |
|
Definition
|
|
Term
| What is the normal PaCO2? What is the formula? |
|
Definition
35-45 mm Hg PaCO2= CO2 production x 0.863 / alveolar ventilation |
|
|
Term
| How much oxygen is dissolved in plasma? |
|
Definition
| related to its partial pressure and its solubility constant (0.0031) |
|
|
Term
| When fully saturated, how much oxygen can 1 gram of hemoglobin carry? |
|
Definition
|
|
Term
| What two major factors determine the amount of oxygen actually delivered to tissues? |
|
Definition
| the arterial oxygen content and the cardiac output |
|
|
Term
| What is the formula for minute ventilation? |
|
Definition
| the tidal volume times the frequency of breathing |
|
|
Term
|
Definition
| the amount of gas inspired each breath |
|
|
Term
| What is the dead space volume? |
|
Definition
| the portion of each tidal volume that ventilates only the conducting airways which never reaches the alveoli (about 150 ml) |
|
|
Term
| What is the ratio of FEV1 to FVC (amount expired in one second to the forced vital capacity) a measure of? |
|
Definition
|
|
Term
| What is the average alveolar oxygen partial pressure? |
|
Definition
|
|
Term
|
Definition
| a hemoglobin with it's iron oxidized by nitriles or sulfonamides and is incapable of binding oxygen |
|
|
Term
| Which way does an increase in temperature shift the hemoglobin curve? |
|
Definition
|
|
Term
| Which way does an increase in pH shift the hemoglobin curve? |
|
Definition
|
|
Term
| Which way does an increase in the concentration of 2,3 DPG shift the hemoglobin curve? |
|
Definition
|
|
Term
| What does Henry's law state? |
|
Definition
| as the cells release CO2 and the PCO2 begins to rise, the amount of CO2 dissolved in venous capillary blood increases proportionally and the plasma and erythrocyte CO2 concentrations increase |
|
|
Term
| What is the Hamburger shift? |
|
Definition
| moves chloride ion into the erythrocyte in exchange for the bicarbonate |
|
|
Term
| What is the Haldane effect? |
|
Definition
| the binding of CO2 in the tissues facilitates the release of O2 |
|
|
Term
|
Definition
| the amount of air inspired with each normal breath |
|
|
Term
| What is the value of a normal tidal volume? |
|
Definition
|
|
Term
| What is minute ventilation? |
|
Definition
| the amount of air inspired each minute |
|
|
Term
| What is the expired ventilation? |
|
Definition
| the amount of gas exhaled each minute |
|
|
Term
| Why is the minute ventilation slightly greater than the expired ventilation? |
|
Definition
| the ratio of carbon dioide production to oxygen consumption is usually less than one (the respiratory quotient, about 0.8) |
|
|
Term
| For each 500 ml air inhaled, about how much remains in the conducting airways and does not take part in gas exchange? |
|
Definition
|
|
Term
| What is physiologic dead space? |
|
Definition
| the sum of the anatomic dead space and the alveolar dead space and constitutes all parts of the tidal volume that do not take part in gas exchange. |
|
|
Term
| How do pulmonary and cardiovascular disease result in increased physiologic dead space? |
|
Definition
| decrease perfusion to alveoli |
|
|
Term
| What is a pulmonary emboli? |
|
Definition
| obstruction of blood flow through pulmonary artery, arterioles and capillaries |
|
|
Term
|
Definition
| destruction of alveolar-capillary membranes. |
|
|
Term
| What is pulmonary fibrosis? |
|
Definition
| vascular tissue replaced with fibrous tissue |
|
|
Term
| What is adult respiratory distress syndrome? |
|
Definition
| acute inflammation of lungs with diffuse areas of altered perfusion and ventilation |
|
|
Term
| What is the Bohr equation to calculate alveolar volume? |
|
Definition
| tidal volume times expired concentration of CO2 = alveolar volume times alveolar concentration of CO2 |
|
|
Term
| What must the PaCO2 be for a diagnosis of hyperventilation? |
|
Definition
|
|
Term
| What does the PaCO2 need to be for a diagnosis of hypoventilation? |
|
Definition
|
|
Term
| What does the pulmonary circulation protect the systemic circulation from? |
|
Definition
| embolization of air, thrombi, amniotic fluid, and fat |
|
|
Term
| What can capillary endothelial cells activate to produce compounds that affect the local circulation, airways and systemic circulation? |
|
Definition
|
|
Term
| What can capillary endothelial cells inactivate to produce compounds that affect the local circulation, airways and systemic circulation? |
|
Definition
| bradykinin, serotonin, prostaglandins E1, 2 and F2 and NE |
|
|
Term
| What can capillary endothelial cells produce during damage that affect the local circulation, airways and systemic circulation? |
|
Definition
| histamine, prostaglandins, and leudotrienes |
|
|
Term
| What percent of the total blood volume is contained in the pulmonary circulation? |
|
Definition
|
|
Term
| What is the driving pressure or perfusion pressure from the left ventricle to the right atrium? |
|
Definition
|
|
Term
| What is the driving or perfusion pressure from the right ventricle to the left atrium? |
|
Definition
|
|
Term
| What percent of the lung's weight is blood? |
|
Definition
|
|
Term
| What are two mechanisms causing a decrease in pulmonary vascular resistance? |
|
Definition
| capillary recruitment and capillary distension |
|
|
Term
| What happens to extra-alveolar vessels during inspiration? |
|
Definition
| there is a decrease in pleural pressure causing an increase in transmural pressure with increases diameter |
|
|
Term
| What happens to the alveolar capillaries during inspiration? |
|
Definition
| the lumen decreases in internal diameter |
|
|
Term
| When is pulmonary vascular resistance the lowest? |
|
Definition
| functional residual capacity |
|
|
Term
| What is the increase in resistance at low lung volumes due to? |
|
Definition
| compression of extra-alveolar vessels by increases in pleural pressure and decreased traction on the vessels by connective tissue |
|
|
Term
| What is the increase in resistance at high lung volumes due to? |
|
Definition
| increased size of alveoli and compression of alveolar capillaries |
|
|
Term
| Name some vasoconstictors |
|
Definition
| serotonin, NE, histamine, thromboxane A2, leukotrienes |
|
|
Term
|
Definition
| adenosine, Ach, PGI2, and isoproterenol and NO |
|
|
Term
| What does global hypoxia cause? |
|
Definition
| generalized pulmonary vasoconstriction leading to a significant rise in pulmonary vascular resistance and pulmonary artery pressure |
|
|
Term
| What factors does fluid flux depend on? |
|
Definition
| hydrostatic pressure, colloid osmotic pressure, alveolar surface tension, capillary permeability, pulmonary edema |
|
|
Term
| What can increase surface tension? |
|
Definition
| damage to type II alveolar pneumocytes decreases surfactant production |
|
|
Term
| What causes decreased colloid osmotic pressure? |
|
Definition
| systemic inflammatory syndrome, nephrotic syndrome, liver failure, burns and severe malnutrition |
|
|
Term
| What is Fick's law which describes diffusion of oxygen and CO2 across the alveolar-capillary membrane? |
|
Definition
| Vgas= (AxD(P1-P2))/thickness |
|
|
Term
| What is used to measure the diffusion capacity? |
|
Definition
|
|
Term
| What part of the lung recieves the most ventilation? |
|
Definition
|
|
Term
| In what order does the lung fill? |
|
Definition
| sub-apical alveoli, mid-thorax, base |
|
|
Term
| Where is the initial pulmonary lesion of TB? |
|
Definition
| in the periphery of the mid-lung fields |
|
|
Term
| Where do TB and fungi grow best? |
|
Definition
| apex due to their high oxygen requirements for growth |
|
|
Term
| What is alpha-1-antitrypsin deficiency? |
|
Definition
| a metabolic disease where protease inhibitors are deficient. failure to inhibit proteases released by blood born white blood cells leads to destruction of lung parenchyma |
|
|
Term
|
Definition
| a mismatching of ventilation and perfusion |
|
|
Term
| What is the distribution of ventilation to the alveolus dependent upon? |
|
Definition
| compliance of the alveolus and the resistance of the conducting airway |
|
|
Term
| What are three factors increasing airway resistance? |
|
Definition
| bronchiospasm and airway collapse; airway secretions; peribronchial edema or fibrosis |
|
|
Term
| What happens if the V/Q ratio is less than 1? |
|
Definition
| will lower the oxygen content and raise the carbon dioxide content of blood coming from units with these ratios |
|
|
Term
| What happens if the V/Q ratio is greater than 1? |
|
Definition
| will raise the oxygen content and lower the carbon dioxide content of blood coming from units with these ratios |
|
|
Term
| What is the formula for the O2 content of the blood? |
|
Definition
| =(Hgb x 1.34) x % saturation + (PO2 x 0.0031) |
|
|
Term
| Above what partial pressure is hemoglobin almost totally saturated? |
|
Definition
|
|
Term
| What is the P50 and its value? |
|
Definition
the oxygen partial pressure when hemoglobin is 50% saturated with oxygen 28 mmHg |
|
|
Term
What partial pressure defines arterial hypoxemia? Respiratory failure? |
|
Definition
|
|
Term
| Where is mixed venous oxygen measured? |
|
Definition
|
|
Term
| What is the formula for oxygen delivery? |
|
Definition
| = oxygen content x cardiac output x 10 |
|
|
Term
What is the normal level for indexed oxygen delivery? What is the critical level? |
|
Definition
500-600 ml per minute 400 ml per minute |
|
|
Term
| What is the alveolar-arterial oxygen difference? |
|
Definition
| the difference between the calculated alveolar PO2 and the directly measure arterial PO2. a measure of the adequacy of gas exchange in the lungs |
|
|
Term
| What should the physician evaluate in a patient with hypoxemia? |
|
Definition
the alveolar arterial oxygen difference the response to supplemental oxygen |
|
|
Term
| If hypoxemic patients have normal alveolar-arterial oxygen difference, what are some physiologic causes? |
|
Definition
high altitude low oxygen concentration in inspired gas alveolar hypoventilation |
|
|
Term
| If hypoxemic patients have increased alveolar-arterial oxygen difference, what are some physiologic causes? |
|
Definition
diffusion abnormalities ventilation perfusion imbalance shunting |
|
|
Term
| What are some causes for alveolar hypoventilation? |
|
Definition
decreased tidal volume decreased respiratory rate increase in dead space increase in CO2 production without a corresponding increase in minute ventilation |
|
|
Term
| What is an intrapulmonary shunt? |
|
Definition
| occurs in an area of the lung that is totally non-ventilated but is well perfused, will have a V/Q ratio of zero |
|
|
Term
| What does an intrapulmonary shunt result from? |
|
Definition
alveoli that are filled with fluid complete obstruction of an airway total collapse of alveoli (atelectasis) |
|
|
Term
| What is the pressure in the pleural space relative to atmospheric pressure? |
|
Definition
|
|
Term
|
Definition
| a larger lung colume at any given change in pressure during deflation, due to airway closure and trapping of air during expiration |
|
|
Term
| What molecule is responsible for lowering surface tension within the alveoli? |
|
Definition
| dipalmitoylphosphatidylcholine |
|
|
Term
| What is the central inspiratory activity integrator? |
|
Definition
| postulated group of cells located within the medullary reticular formation that collects a background amount of pro-inspiratory information, these neurons stimulate the dorsal respiratory group of neurons |
|
|
Term
| What is the dorsal respiratory group? |
|
Definition
| associated with inspiration, demonstrate a rhythmic change in membrane potential that is modified by other input. generates efferent information that activates the muscles of inspiration. |
|
|
Term
| What is the ventral respiratory group? |
|
Definition
| the rostral and caudal sections are associated with expiration and the intermediate with inspiration. primarily involved with expiration, especially when forced expiration is required |
|
|
Term
| What is the role of the intermediate section of the ventral respiratory group? |
|
Definition
| inspiratory, increases the caliber of the airways in the pharynx and larynx during inspiration, also involved in generating the respiratory rhythm |
|
|
Term
| What is the inspiratory cutoff switch? |
|
Definition
| influences the dorsal respiratory group in a negative way, thus inhibiting inspiration and allowing expiration. activated by the ventral respiratory group and the pneumotaxic center within the pons |
|
|
Term
| What is the apneustic center? |
|
Definition
| impinge upon the dorsal respiratory group and stimulate inspiration.. normally held in check by influences from higher centers |
|
|
Term
| What is apneustic breathing characterized by? |
|
Definition
| series of prolonged inspiratory gasps that is ended by a brief and rapid expiratory effort. poor prognostic sign |
|
|
Term
| What is the pneumotaxic center? |
|
Definition
| can inhibit inspiration when stimulated. not required for normal rhythmic breathing, but fine tuning; may be able to influence the tidal volume by terminating inspiration and thus influence the respiratory rate |
|
|
Term
| What controls voluntary breathing? |
|
Definition
|
|
Term
| What are type I cells in the carotid body? |
|
Definition
| glomus cells that are the actual chemoreceptors. respond to a decrease in oxygen by inhibiting K channels which results in membrane depolarization and activation of voltage-gated Ca channels |
|
|
Term
| What are type II cells in the carotid body? |
|
Definition
| similar to glial cells and form a supportive environment for the glomus cells |
|
|
Term
Afferent info from the aortic bodies is carried by what nerve? |
|
Definition
|
|
Term
| Afferent info from the carotid bodies is carried by what nerve? |
|
Definition
|
|
Term
| What are slowly adapting stretch receptors? |
|
Definition
| respond to stretch of the airway muscles, rate of neural firing slowly decays during conditions of constant stimulus |
|
|
Term
| What is the Hering-Breuer reflex? |
|
Definition
| initiates at lung volumes above the normal range and results in a decrease in the tidal volume and a decrease in the frequency of breathing, also stimulates expiration, protecting the lungs from over inflation |
|
|
Term
| What receptors are probably responsible for coughing? |
|
Definition
|
|
Term
| Where are juxtacapillary receptors and what are they innervated by? |
|
Definition
| located both in the alveoli walls near the pulmonary capillaries and airway tissues and are innervated by small unmyelinated C fibers. |
|
|
Term
| What are jextacapillary receptors? |
|
Definition
| respond to both chemical and mechanical stimuli much like the irritant receptors and are rapidly adapting. stimulation results in rapid, shallow breathing, bronchoconstriction and the production of mucus |
|
|
Term
|
Definition
| the patient sits within an air-tight body box that accurately measures a change in pressure with inspiration and expiration. |
|
|
Term
| What is the formula for maximum expiratory flow? |
|
Definition
| Vmax= elastic recoil/ upstream resistance |
|
|
Term
| What does the loop of Henle remove? |
|
Definition
| solute without an appreciable amount of solvent, liquid leaving the loop is relatively dilute |
|
|
Term
| What is the early distal convoluted tubule associated with? |
|
Definition
| Na and Cl reabsorption; also H, K, and ammonia secretion, normally impermeable to water movement |
|
|
Term
| What percent of the entire glomerular filtrate is reabsorbed back into the body? |
|
Definition
|
|
Term
| What does the glomerulus do? |
|
Definition
| forms an ultrafiltrate of plasma free of all formed cells and plasma proteins, produces approximately 187 L of fluid per day |
|
|
Term
| What types of cells make up the cortical collecting tubules and the collecting ducts? |
|
Definition
| principal and intercalated cells |
|
|
Term
| What is the function of the principal cell? |
|
Definition
| reabsorption of sodium, chloride, potassium and water |
|
|
Term
| What is the function of alpha intercalated cells? |
|
Definition
| secrete hydrogen but do not reabsorb sodium, play a significant role in acid-base balance |
|
|
Term
| What is the function of beta intercalated cells? |
|
Definition
| secrete bicarbonate under appropriate conditions, play a role in acid-base balance |
|
|
Term
| What is the function of the proximal convoluted tubule? |
|
Definition
| reabsorbs 2/3 or more of the filtered load of many compounds: Na, Cl water, bicarbonate, glucose, K, phosphate, Ca); secrets H, organic acids, and ammonia |
|
|
Term
| What is the function of the cortical collecting tubule? |
|
Definition
| reabsorbs Na, Cl, water, etc under hormonal control. secrets K, H and ammonia, differential permeability to water and urea in response to hormonal stimulation |
|
|
Term
| What is the function of the collecting duct? |
|
Definition
| area where the final concentration of the urine is decided. the collecting ducts can reabsorb solute and depending upon the nature of hormonal influences, can reabsorb variable amounts of water |
|
|
Term
| Which region of the kidney has high osmotic pressure? |
|
Definition
|
|
Term
| What is the function of peritubular capillaries? |
|
Definition
| return materials to the body which were reabsorbed by the tubules or they can provide materials to the tubules for secretion |
|
|
Term
|
Definition
| specialized peritubular capillary bed which is only associated with juxtamedullary nephrons, characterized by parallel loops and act as a counter-current exchange mechanism which allows the medullary region to remain properly hypertonic which allows the collecting ducts to effectively concentrate the urine |
|
|
Term
|
Definition
| it means that no matter what happens at the glomerulus, it will be compensated for in the tubules; more filtration leads to more reabsorption |
|
|
Term
| What is the filtration pressure equilibrium? |
|
Definition
| the point along the apillary length where the protein concentration in plasma increases and the net hydrostatic pressure decreases to just match the filtration and reabsorptive forces |
|
|
Term
| What is the formula for clearance of a substance? |
|
Definition
| clearance of X = (the urine concentration of X times the urine flow rate)/ the plasma concentration of X |
|
|
Term
|
Definition
| the transport of an osmotically active molecle across a water permeable membrane |
|
|
Term
What decreases phosphate resabsorption? Increases? |
|
Definition
decreases: increased parathyroid hormone, increased ACTH, decreased rate of Na reabsorption increases: vitamin D3, increased plasma Ca |
|
|
Term
|
Definition
| moves aquaporin AQP2 into the apical membrane of the renal collecting duct |
|
|
Term
| How does sodium move across the luminal membrane of the PCT? |
|
Definition
| enters the proximal tubular cell from the ultrafiltrate down its electrochemical potential gradient primarily in connection with cotransport systems |
|
|
Term
| How does sodium move across the basolateral membranes of the proximal convoluted tubule? |
|
Definition
| active transport, must move against both an electrical and a concentration gradient, need a Na/K ATPase |
|
|
Term
| How does chloride move across the luminal membrane of the PCT? |
|
Definition
| moves from the tubular fluid into the cell against an electrical gradient but down its concentration gradient |
|
|
Term
| How does Cl- move across the basolateral membranes of the PCT? |
|
Definition
| Cl- movement from the cell interior into the peritubular fluid involves a favorable electrical gradient and an adverse concentration gradient |
|
|
Term
| What is the luminal membrane of the PCT? |
|
Definition
| separates the interior of the cell from the tubular fluid in the tubular lumen |
|
|
Term
| What is the peritubular membrane? |
|
Definition
| separate the interior of the cell from the peritubular space |
|
|
Term
| What happens in the ascending limb of the loop of Henle? |
|
Definition
| Na and Cl are passively transported out and water is impermeable |
|
|
Term
| By the time the filtrate reaches the early distal convoluted tubule, is it hyper or hypo tonic with respect to blood plasma? |
|
Definition
|
|
Term
| How do thiazide diuretics work? |
|
Definition
| they specifically inhibit the Na/Cl cotransport system in the early distal convoluted tubule |
|
|
Term
| How does angiotensin II help to balance total body solute? |
|
Definition
| acts as a potent vasoconstrictor affecting the GFR and also directly stimulates aldosterone production, can also increase sodium and water reabsorption by the PCT via Na/H exchange and Na/K ATPase system activity. also induces thirst |
|
|
Term
| How does aldosterone control sodium reabsorption? |
|
Definition
| acts primarily on the cortical collecting tubules and the collecting ducts to increase sodium permeability across the distal luminal cellular membrane, diffuses into the cell across the basolateral membrane and binds to a high affinity mineralocorticoid receptor |
|
|
Term
|
Definition
| dilates the renal vasculature and increases the GFR, acts on the kidney to inhibit the reabsorption of sodium |
|
|
Term
| How does bradykinin, prostaglandin E, and PGI2 affect the renal tubules? |
|
Definition
| inhibits sodium reabsorption |
|
|
Term
| What is an area of automatic K reabsorption? |
|
Definition
|
|
Term
| Which nephron segment controls the circulating plasma K concentration? |
|
Definition
|
|
Term
| How does potassium enter the principal cell? |
|
Definition
| Na/K ATPase system, transports K into the cell |
|
|
Term
| How is bicarbonate reabsorbed? |
|
Definition
| H secretion paired with Na reabsorption, the secreted H spontaneously combines with HCO3 to form H2CO3, carbonic anhydrase quickly catalyzes the dissociation of H2CO3 into CO2 and water, both of which passively diffuse across the luminal membrane into the cell; there is also an antiport system with Cl- |
|
|
Term
| What is the primary regulator of calcium reabsorption/excretion by the kidney? |
|
Definition
|
|
Term
| What is the purpose of countercurrent multiplication? |
|
Definition
| allows the tubule to participate in the process of producting a concentrated urine |
|
|
Term
| Which structures are part of the system which is responsible for the concentration of urine? |
|
Definition
| the loops of Henle, the collecting ducts, and the vasa recta |
|
|
Term
| How does countercurrent multiplication work (4 requirements)? |
|
Definition
1 solute is actively reabsorbed from the ascending limb of the loop 2 the permeability of the ascending limb to solvent is extremely low 3 the solute which is transported out of the ascending limb enters the medullary interstitium and increases the osmolarity within the interstitium (descending limb permeable to solute and solvent, so tubular fluid becomes more concentrated as it flows down the descending limb to equilibrate with the interstitium) 4 the physical length of the loop plays a role in the degree to which the osmotic gradient within the medullary interstitium can rise |
|
|
Term
| Which nephrons function in countercurrent multiplication? |
|
Definition
|
|
Term
| What determines how many cycles of countercurrent multiplication can occur, and therefore determines the degree of solute concentration at the tip of the loop? |
|
Definition
|
|
Term
| What sections of the nephron are significantly involved with the action of ADH? |
|
Definition
| the cortical collecting tubules and the collecting duct |
|
|
Term
| What are the cortical collecting tubules? |
|
Definition
| a connection between the distal tubule and the collecting duct located in the renal cortex |
|
|
Term
| How is urea measured clinically? |
|
Definition
| BUN (blood urea nitrogen) |
|
|
Term
| Which transporter does ADH stimulate? |
|
Definition
|
|
Term
| What is the function of the vasa recta? |
|
Definition
| responsible for removing those materials from the renal medulla that are deposited there by the loop of Henle or the collecting ducts, also responsible for providing oxygen and nutrients |
|
|
