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By L. Chenor. Bradley University. 2018.

With a low regional V˙ A/Q˙ ratio order 100mg epivir-hbv free shipping symptoms 10 days post ovulation, there is remember that epivir-hbv 100mg fast delivery symptoms enlarged spleen, in healthy individuals, there is some de- Normal Local low VA/Q Local high VA/Q PAO2 = 102 mm Hg PAO2 < Normal PAO2 > Normal PACO2 = 40 mm Hg PACO2 > Normal PACO2 < Normal FIGURE 20. Airway obstruc- tion (middle panel) causes a low regional ventila- tion-perfusion (V˙ A/Q) ratio. A partially blocked˙ airway causes this region to be underventilated relative to blood flow. A low regional V˙ A/Q ratio causes˙ venous admixture and will increase the physio- logical shunt. A partially obstructed pulmonary arteriole (right panel) will cause an abnormally high V˙ A/Q ratio in a lung region. Restricted˙ PO = 40 mm Hg PO = 40 mm Hg blood flow causes this region to be overventi- 2 2 PO2 = 40 mm Hg lated relative to blood flow, which leads to an in- PCO2 = 46 mm Hg PCO2 = 46 mm Hg PCO2 = 46 mm Hg crease in physiological dead space. The primary function of the bronchial Anatomic Anatomic circulation is to nourish the walls of the conducting airways and surrounding tissues by distributing blood to the sup- Low V˙A/Qratio˙ Alveolar porting structures of the lungs. Under normal conditions, the bronchial circulation does not supply blood to the ter- Physiological shunt (calculated Physiological dead space (calculated minal respiratory units (respiratory bronchioles, alveolar total “wasted blood”) total “wasted air”) ducts, and alveoli); they receive their blood from the pul- monary circulation. Venous return from the bronchial cir- culation is by two routes: bronchial veins and pulmonary gree of physiological dead space as well as physiological veins. About half of the bronchial blood flow returns to the shunt in the lungs. The remainder returns through small shunt and a low regional V˙ A/Q˙ ratio. In healthy individuals, bronchopulmonary anastomoses into the pulmonary veins. It is important to remember that any giogenesis, the formation of new vessels. This is extremely deviation of V˙ A/Q˙ ratio from the ideal condition (0. When a clot or embolus obstructs pul- shunt is that it always leads to venous admixture and re- monary blood flow, the adjacent parenchyma is kept alive duces the amount of oxygen carried in the systemic blood. REVIEW QUESTIONS DIRECTIONS: Each of the numbered (C) Compliance (A) Zone 1 items or incomplete statements in this (D) Flow per minute (B) Zone 2 section is followed by an answer or by (E) Capillary blood volume (C) Zone 3 completions of the statement. The effect of gravity on the (D) Zone 4 ONE lettered answer or completion that is pulmonary circulation in an upright 6. Which of the following best the middle of the lung (A) Zone 1 characterizes the pulmonary (B) Capillary pressure to be greater at (B) Zone 2 circulation? Which of the following best (C) Low Low Low High the lung characterizes alveolar ventilation (D) High Low High High (D) Lower vascular resistance at the apex and blood flow at the base, (E) High Low Low High of the lung compared with the base compared with the apex, of the 2. Pulmonary vascular resistance is (E) Venous pressure to be greater than lungs of a healthy standing decreased alveolar pressure at the apex person? A patient lying on his back and Ventilation- (B) By breathing low oxygen breathing normally has a mean left Ventilation Blood flow perfusion ratio (C) At high lung volumes atrial pressure of 7 cm H2O; a mean (A) Higher Higher Lower (D) With increased pulmonary arterial pulmonary arterial pressure of 15 cm (B) Lower Higher Higher pressure H2O; a cardiac output of 4 L/min; and (C) Lower Lower Lower 3. In healthy individuals, the pulmonary an anteroposterior chest depth of 15 (D) Higher Lower Higher and systemic circulations have the same cm, measured at the xiphoid process. The regional changes seen in (B) Vascular resistance which of the following conditions? The apex of the lungs of a 21-year-old SUGGESTED READING perfusion ratios affect gas tensions in subject is 20 cm above the heart. Oxford, UK: But- (D) Highest at apex Lowest at base monary vascular resistance of 4 mm terworth-Heinemann, 2000. Baltimore: Lippin- output of 5 L/min and mean driving pressure for moving cott Williams & Wilkins, 1998. Pulmonary blood flow limits the transfer of O2 and CO2 in decreases the ability of the blood to carry O2. Diffusing capacity depends on the diffusion properties of HCO in the plasma. Hypoxemia is an abnormally low PO2 or oxygen content in of hemoglobin loaded with oxygen.

In these cases buy generic epivir-hbv 100mg treatment authorization request, the lever action of the skeletal sys- When all the initial velocity measurements are related to tem order epivir-hbv 100mg online medications and side effects, not the length-tension relationship, is of primary im- each corresponding afterload lifted, an inverse relationship portance in determining the maximal force the muscle can known as the force-velocity curve is obtained. Cardiac muscle, however, normally works at lengths steeper at low forces. When the measurements are made on significantly less than optimal for force production, but its a fully activated muscle, the force-velocity curve defines passive length-tension curve is shifted to shorter lengths the upper limits of the muscle’s isotonic capability. The length-tension relationship is, there- tice, a completely unloaded contraction is very difficult to fore, very important when considering the ability of cardiac arrange, but mathematical extrapolation provides an accu- muscle to adjust to changes in length (related to the volume rate Vmax value. The role of the length-tension curve in smooth a series of isotonic contractions. The initial velocity points muscle is less clearly understood because of the great di- (A–D) correspond to the contractions shown at the top. For all muscle types, however, the length-tension incomplete stimulation (e. Be- 6 velocities tween these two extremes, work and power output pass 7 8 through a maximum at a point where the force is approxi- mately one-third of its maximal value. The peak of the 3 curve represents the combination of force and velocity at 2 A B C D which the greatest power output is produced; at any after- 1 0 load force greater or smaller than this, less power can be 0 1 2 3 4 produced. It also appears in skeletal muscle that the optimal Time power output occurs under nearly the same conditions at Vmax which muscle efficiency, the amount of power produced 5 for a given metabolic energy input, is greatest. VD In terms of mechanical work, the chemical reactions of 4 muscle are about 20% efficient; the energy from the re- maining 80% of the fuel consumed (ATP) appears as heat. In some forms of locomotion, such as running, the meas- 3 Force-velocity ured efficiency is higher, approaching 40% in some cases. This energy is then partly returned as work 1 during the subsequent contraction. These force-velocity and efficiency relationships are im- 1 portant when endurance is a significant concern. Athletes who are successful in long-term physical activity have Power learned to optimize their power output by “pacing” them- output curve selves and adjusting the velocity of contraction of their muscles to extend the duration of exercise. Such adjust- ments obviously involve compromises, as not all of the 0 many muscles involved in a particular task can be used at 0 1 2 3 optimal loading and rate and subjective factors, such as ex- Afterload force perience and training, enter into performance. Contractions at four different inefficient force-velocity combination to produce the most afterloads (decreasing left to right) are shown in the top graphs. The initial necessarily be of more limited duration than that carried shortening velocity (slope) is measured (VB, VC, VD) and the cor- out under conditions of maximal efficiency. Examples of at- responding force and velocity points plotted on the axes in the tempts at optimal matching of human muscles to varying bottom graph. Note that it reaches a maximum at an afterload of loads can be found in the design of human-powered ma- about one-third of the maximal force. The length-tension curve represents the effect of length on Consideration of the force-velocity relationship of mus- the isometric contraction of skeletal muscle. During iso- cle can provide insight into how it functions as a biological tonic shortening, however, muscle length does change motor, its primary physiological role. The limit of this shortening is represents the maximal rate of crossbridge cycling; it is di- also described by the length-tension curve. For example, a rectly related to the biochemistry of the actin-myosin lightly loaded muscle will shorten farther than one starting ATPase activity in a particular muscle type and can be used from the same length and bearing a heavier load. These relationships are (the afterload) through a distance, the muscle does physi- diagrammed in Figure 9. The rate at which it does this work is its power tal muscle activity, these limits are not usually encountered output (see Figure 9. The factors represented in the because voluntary adjustments of the contracting muscle are force-velocity curve are thus relevant to questions of mus- usually made to accomplish a specific task. At the two extremes of the force-ve- diac muscle, however, such interrelationships between force CHAPTER 9 Skeletal Muscle and Smooth Muscle 163 Triceps Biceps Muscle force is 7 kg 1 kg Hand Hand movement force 7 cm Muscle 1 cm shortening 5 cm 35 cm FIGURE 9. Contraction of the biceps muscle lifts the lower arm (flexion) and elongates the triceps, while contraction of the triceps lowers the arm and hand (exten- sion) and elongates the biceps.

Cells of the immune hemostatic plug buy cheap epivir-hbv 100 mg on line medicine jar, which promote wound healing buy 150 mg epivir-hbv with mastercard treatment jellyfish sting, prevent system, the white blood cells, are derived from bone mar- further infection, and promote the development and vascu- row precursors and are delivered to their sites of action by larization of new tissue. When blood is allowed to clot or coagulate, the suspending medium is referred to as serum. Blood Has a Higher Density and Viscosity than Water Blood is normally confined to the circulation, including the heart and the pulmonary and systemic blood vessels. Fresh, anticoagulated blood density of individual blood cells varies according to cell is allowed to settle at room temperature in a graduated cylinder. While blood is only slightly heavier than water, it is cer- tainly much thicker. Blood’s Determination of hematocrit values is a simple and im- viscosity increases as the total number of cells present in- portant screening diagnostic procedure in the evaluation of creases and when the concentration of large molecules hematological disease. At pathologically healthy adults are 47 5% for men and 42 5% for high viscosity, blood flows poorly to the extremities and in- women. Low hematocrit values indicate the presence of anemia, a reduction in the number of circulating erythro- The Erythrocyte Sedimentation Rate cytes. Increased hematocrit levels may likewise indicate a and Hematocrit Are Important serious imbalance in the production and destruction of red Diagnostic Measurements cells. Increased production (or decreased rate of destruc- tion) of erythrocytes results in polycythemia, as reflected Erythrocytes are the red cells of blood. Dehydration, which de- have only a slightly higher density than the suspending creases the water content and, thus, the volume of plasma, plasma, they normally settle out of whole blood very also results in an increase in hematocrit. To determine the erythrocyte sedimentation rate (ESR), anticoagulated blood is placed in a long, thin, grad- uated cylinder (Fig. As the red cells sink, they leave Blood Functions as a Dynamic Tissue behind the less dense leukocytes and platelets in the sus- pending plasma. Erythrocytes in the blood of healthy men While the cellular and plasma components of blood may sediment at a rate of 2 to 8 mm/hr; those in the blood of act alone, they often work in concert to perform their func- healthy women sediment slightly faster (2 to 10 mm/hr). Working together, blood cells and plasma proteins The ESR can be an important diagnostic index, as values play several important roles, including are often significantly elevated during infection, in patients • Transport of substances from one area of the body to with arthritis, and in patients with inflammatory diseases. In another some diseases, such as sickle-cell anemia, polycythemia (ab- • Immunity, the body’s defense against disease normal increase in red cell numbers), and hyperglycemia • Hemostasis, the arrest of bleeding (elevated blood sugar levels), the ESR is slower than normal. Blood carries several important substances Blood cells can be quickly separated from the suspend- from one area of the body to another, including oxygen, ing fluid by simple centrifugation. When anticoagulated carbon dioxide, antibodies, acids and bases, ions, vitamins, blood is placed in a tube that is rotated about a central cofactors, hormones, nutrients, lipids, gases, pigments, point, centrifugal forces pull the blood cells from the sus- minerals, and water. The hematocrit is the portion of the total most important functions of blood, and blood is the pri- blood volume that is made up of red cells. Sub- termined by the centrifugation of small capillary tubes of stances can be transported free in plasma, bound to plasma anticoagulated blood to pack the cells. CHAPTER 11 Blood Components, Immunity, and Hemostasis 193 Oxygen and carbon dioxide are two of the more impor- tant molecules transported by blood. In tissue capillaries, red cells release oxygen, which is then Normal used by respiring tissue cells. By doing so, it maintains Cations Sodium (Na ) 136–145 mEq/L the proper temperature in different organs and tissues, and Potassium (K ) 3. Blood leukocytes are involved in the body’s Copper (Cu2 ) 70–155 g/dL battle against infection by microorganisms. While the skin Hydrogen (H ) 35–45 nmol/L and mucous membranes physically restrict the entry of in- Anions Chloride (Cl ) 95–105 mEq/L fectious agents, microbes constantly penetrate these barri- Bicarbonate (HCO3) 22–26 mEq/L ers and continuously threaten internal infection. In most cases, penetrating microbes are (HPO2 /H PO ) 4 2 4 efficiently eliminated by the sophisticated and elaborate Proteins Total 6–8 g/dL antimicrobial systems of the blood. Bleeding is controlled by the process of he- Fats Cholesterol 150–200 mg/dL Phospholipids 150–220 mg/dL mostasis. Complex and efficient hemostatic mechanisms Triglycerides 35–160 mg/dL have evolved to stop hemorrhage after injury, and their fail- Carbohydrates Glucose 70–110 mg/dL ure can quickly lead to fatal blood loss (exsanguination). Vitamins, Vitamin B 200–800 pg/mL 12 Both physical and cellular mechanisms participate in he- cofactors, and Vitamin A 0. Homeostasis is a steady state that provides Transaminase (SGOT) 9–40 U/mL an optimal internal environment for cell function (see Alkaline phosphatase 20–70 U/L Acid phosphatase 0.

If we were to permit [defendants] to mitigate damages with payments from plaintiff’s insurance buy generic epivir-hbv 150mg on line treatment of pneumonia, plaintiff would be in a position inferior to that of having bought no insurance buy 150mg epivir-hbv overnight delivery treatment trends, because his payment of premiums would have earned no benefit. Defendant should not be able to avoid payment of full compensation for the injury inflicted merely because the victim has had the foresight to provide himself with insurance. When a defendant chooses to introduce such evidence, the plaintiff may introduce evidence of the amounts he or she has paid, for example, 9 “More than a decade may pass before a suit is brought on an incident involving a minor. This further complicates the methods of establishing rates, and is inequitable since the vast majority of medial malpractice committed on infants is detectable within the normal statute of limitations. Although this modifi- cation of the collateral source rule does not specify how the jury should use such evidence, the underlying legislative presumption and the prac- tical effect is that in most cases, the jury sets plaintiff damages at a lower level because of its awareness of plaintiff net collateral source benefits. Other states have altered their collateral source for medical negligence cases to explicitly mandate a deduction of the amount of the collateral sources from the plaintiff’s award. Danzon, The Frequency and Severity of Medical Mal- practice Claims: New Evidence, Law & Contemp. Chapter 2 / Litigation 21 future damages through a “lump sum” judgment, payable at the con- clusion of the trial. Accordingly, they have advocated legislative adoption of a “periodic payment” procedure as a reform measure that would, in these com- mentators’ view, benefit both plaintiffs and defendants. Code § 6-11-3(3) (future damages of more than $150,000 to be paid periodically); Alaska Stat. In addition, they determined that the public interest is served by limiting a defendant’s obligation to those future damages that a plaintiff actually incurs, eliminating windfalls obtained by a plaintiff’s heirs when they inherit a portion of a lump sum judgment that was intended to compensate the injured person for losses he never sustained. As the California Su- preme Court stated when, against constitutional attack, it upheld that state’s periodic payment provision:20 One of the factors which contributed to the high cost of malpractice insurance was the need for insurance companies to retain large reserves to pay out sizeable lump sum awards. The adoption of a periodic payment procedure permits insurers to retain fewer liquid reserves and to increase investments, thereby reducing the costs to insurers and, in turn, to insureds. In addition, the portion of [the periodic payment statute] which provides for the termination of a significant portion of the remaining future damage payments in the event of the plaintiff’s death is obviously related to the goal of reduc- ing insurance costs. HOW THE VARIOUS RULES “FIT” WITHIN THE LEGAL HIERARCHY Notice that most of the rules discussed so far are state statutes or judge-made by courts where the liability disputes arise. Court- or judge- made rules (they are synonymous) are known as common law rules. They are derived from particular factual disputes and, after articulation of them by the court as a guiding principle for future cases, have the force of stare decisis or precedent. Precedent is to be followed by future courts unless it is has outlived its usefulness or no longer makes sense. That decision is made by an intermediate appellate court or the highest court in that state or by the legislature. When the defendant in a profes- sional liability case is the federal government or its employees, or arises under particularly defined circumstances that implicate federal law, 20American Bank & Trust Co. Chapter 2 / Litigation 23 then federal courts decide the dispute according to federal statutes and federal common law. All statutes—federal and state—must be interpreted or applied by courts to particular facts. This naturally gives courts some leeway to clarify the application of the statute and, by so doing, put an additional gloss on its plain language. If a statute is itself a statement of the common law, there is authority that a court can just amend it by inter- preting it in light of changing circumstances and conditions. When statues are amended in ways a legislature does not like, it can “correct” the court’s interpretation by restating or further amending the statute. In interpreting statutes courts must look to pertinent constitutional provisions, the purpose of the statute, how it relates to other statutes that also apply to the dispute, and to canons of statutory interpretation or aids in reading the text and ascertaining whether the enacting body “said what it meant, and meant what it said. A federal statute cannot be invalidated on constitutional grounds except by reference to the US Constitution. A state statute, however, must comply with both the federal and state constitutions as well as with federal statutory law that preempts the field. Although generally a stat- ute found in compliance with the US Constitution also satisfies its cor- responding state constitutional cognate, this is not always so. State constitutions sometimes provide greater protection to their citizens than analogous provisions of the federal constitution. The interplay between the hierarchy of courts and related statutes and constitutional provisions is an important dynamic to keep in mind when playing the litigation game. For example, from 1872 to 1975, California personal injury cases were governed by the rule of con- tributory negligence, a rule that by popular consensus was embodied in a statute unchanged in wording from when originally enacted.