Physiology 1 Flashcards by Donald Lester

Approximately what percentage of carbon dioxide is carried as bicarbonate?

§ 5%

§ 25%

§ 30%

§ 70%

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Which center is primarily responsible for establishing the ramp signal during normal breathing?

§ Dorsal respiratory center

§ Pneumotaxic center

§ Ventral respiratory center

§ Carotid body

§ Dorsal respiratory center

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The Va/Q ratio is zero (0) under which of the following conditions?

§ Va= infinity, but Q = 0

§ Va= infinity, but Q = 1

§ Va= 0, but perfusion >0

§ Va >0, but Q = 0

§ Va= 0, but perfusion >0

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Respiratory alkalosis due to a decrease in carbon dioxide concentration caused by hyperventilation is compensated for by which of the following mechanisms?

§ Increased ventilation rate

§ Decreased ventilation rate

§ Renal excretion of bicarbonate ion

§ Renal addition of new bicarbonate ion to extracellular fluid

§ Renal excretion of bicarbonate ion

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Two dogs are used in a study to test the effects of a drug that causes hypertension as a possible side effect. In one of the dogs the baroreceptor feedback system has been inactivated. In the dog with intact feedback system the arterial pressure increases from 100 to 110. In the dog with the inactivated control system, the pressure increases from 100 to 160. What is the effectiveness with which the baroreceptor system controls increases in blood pressure?

§ -1

§ -2

§ -4

§ -5

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Of the following ions, which is the most concentrated in the extracellular environment?

§ Sodium

§ Potassium

§ Chloride

§ Calcium

§ Sodium

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Saltatory conduction is characteristic of which part of a typical neuron?

§ Dendrite

§ Nerve cell body

§ Axon hillock

§ Axon

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Which of the following sarcomeric bands does not undergo a change in length during the contraction of a skeletal muscle?

§ A band

§ H band

§ I band

§ J band

§ Sgt Pepper’s Lonely Heart’s Club Band

§ A band

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Which of the following characteristics would be true of cardiac muscle cells but not skeletal muscle fibers?

§ Cells have the sarcomeric banded pattern

§ Cells utilize T tubules

§ Cells are mononucleated

§ Cells utilize ryanodine channels

§ Cells are mononucleated

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Phase 4 of the cardiac muscle action potential is the resting phase. Which of the following cardiac tissues will depolarize fastest during this phase and eventually reach threshold?

§ SA node

§ AV node

§ Purkinje fibers

§ Ventricular myocytes

§ SA node

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Which of the following is the direction of bipolar lead III?

§ 0 degrees

§ 60 degrees

§ 90 degrees

§ 120 degrees

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Which of the following heart activities is represented in the attached ECG? Needs Image

§ Sinus tachycardia

§ Sinus bradycardia

§ Complete AV block

§ Incomplete second degree block with dropped beats

§ Complete AV block

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Which of the following heart activities is represented in the attached ECG (Lead I)? Needs Image

§ Sinus tachycardia

§ Sinus bradycardia

§ Complete AV block

§ Incomplete second degree block with dropped beats

§ Sinus tachycardia

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84% of the blood volume is in the systemic circulation. Of this, 64% is in which of the following vessels?

§ Capillaries

§ Systemic arteries

§ Veins

§ Arterioles

§ Veins

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What is the volume of venous return when the mean systemic filling pressure is 7 mm Hg, and the right atrial pressure is 0 mm Hg, and the resistance to venous return is 1.4 mm Hg/L/min?

§ 4 liters/min

§ 5 liters/min

§ 9.8 liters/min

§ 7 liters/min

§ 5 liters/min

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If the end-diastolic volume is 120 mL, and the end-systolic volume is 50 mL, what is the approximate value of the ejection fraction?

§ 42%

§ 60%

§ 214%

§ 240%

§ 60%

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Approximately what percentage of total cardiac output is received by the kidneys?

§ 15%

§ 22%

§ 34%

§ 47%

§ 22%

Which of the following, in liters/day, represents the GFR in the average adult human?

§ 3

§ 125

§ 180

§ 360

§ 180

Aldosterone is an important regulator of sodium reabsorption and potassium secretion; one of its main targets is…?

§ Podocyte

§ Principal cells

§ Intercalated cells

§ Cells of macula densa

§ Principal cells

Which of the following plays a major role in stimulating potassium excretion by the kidney tubules?

§ Aldosterone

§ Angiotensin II

§ Sodium ion

§ PTH

§ Aldosterone

Vital capacity does not include which of the following volumes?

§ Inspiratory reserve

§ Expiratory reserve

§ Residual

§ Tidal

§ Residual

Baroreceptors are a type of stretch receptor located in the arterial walls of the carotid system. They sense an increase in arterial pressure. Which of the following statements might best describe the purpose of these receptors?

§ They act as part of a positive feedback system that results in blood vessel dilation and an increase in heart pumping capacity.

§ They act as part of a negative feedback system that results in blood vessel dilation and a decrease in heart pumping capacity.

§ They act as part of a positive feedback system that results in blood vessel constriction and a decrease in heart pumping capacity.

§ They act as part of a negative feedback system that results in blood vessel constriction and an increase in heart pumping capacity.

§ They act as part of a negative feedback system that results in blood vessel dilation and a decrease in heart pumping capacity.

The sodium-potassium ATPase pump is an example of which of the following kinds of transport?

§ Diffusion

§ Primary active transport

§ Secondary active transport

§ Facilitated diffusion

§ Primary active transport

Which of the following types of neurons would transmit an action potential the fastest?

§ Small diameter, non-myelinated

§ Small diameter myelinated

§ Large diameter, myelinated

§ Large diameter, non-myelinated

§ Large diameter, myelinated

Dihydropyridine (DHP) channels are part of which of the following structures? § Sarcoplasmic reticulum § Plasmalemma § T tubules § Z discs

§ T tubules

Which of the following represents the first thing that happens after Ach binds to the ligand-gated channels in the sarcolemma? § An action potential is created on the sarcolemma § Dihydropyridine channels allow entry of calcium ions § An end plate potential is created on the muscle fiber § Ryanodine channels allow calcium to escape into the myoplasm

§ An end plate potential is created on the muscle fiber

The cardiac muscle fast action potential occurs in the atria, ventricles, and conduction system. It is typically divided into 5 phases, numbered from 0 to 4. The resting potential of -85 mV is characteristic of which of the following phases? § Phase 0 § Phase 1 § Phase 2 § Phase 3 § Phase 4

§ Phase 4

In a typical ECG, which of the following waves occurs at the beginning of the contraction of the atria? § T § S § P § Q

§ P

In the typical (average) individual, arterial pressure drops by how much from the time it leaves the left ventricle until it reaches the venous system? § 35 mm Hg § 40 mm Hg § 80 mmHg § 120 mm Hg

§ 120 mm Hg

A systemic vein is about 8 times as distensible as its corresponding artery and has a volume about 3 times as great. How would its compliance compare to that of a corresponding artery? § 8 times as compliant § 3 times as compliant § 24 times as compliant § 2.6 times as compliant

§ 24 times as compliant

The mean circulatory filling pressure is 0 under which of the following conditions? § When blood volume is 5 liters § When blood volume is 4 liters § When blood volume is 6.5 liters § When blood volume is 5.5 liters

§ When blood volume is 4 liters

GFR is determined by the net filtration pressure and the glomerular capillary filtration coefficient. Which of the following factors has the greatest effect on increasing GFR? § Glomerular capillary colloid osmotic pressure § Bowman’s capsule hydrostatic pressure § Bowman’s capsule colloid osmotic pressure § Glomerular hydrostatic pressure

§ Glomerular hydrostatic pressure

Almost 90% of glucose reabsorption occurs in the early proximal tubule. Which of the following mechanisms is responsible for moving glucose from the tubular lumen into the cytoplasmic compartment? § Primary active transport via a glucose ATPase pump § Secondary active transport via a sodium/glucose cotransporter § Secondary active transport via a sodium/glucose antiporter § Diffusion due to concentration differences between tubular fluid and cytoplasm

§ Secondary active transport via a sodium/glucose cotransporter

About two-thirds of filtered electrolytes are reabsorbed in which part of the kidney tubule? § Proximal convoluted tubule § Thin descending loop of Henle § Thick ascending loop of Henle § Distal convoluted tubule

§ Proximal convoluted tubule

Which of the following cells play a major role in the secretion of potassium? § Intercalated cells § Principal cells § Chief cells § Podocytes

§ Principal cells

Which of the following buffer systems is most important in buffering renal tubular fluid? § Phosphate buffer system § Carbonate buffer system § Bicarbonate buffer system § Hemoglobin buffer system

§ Phosphate buffer system

The pressure difference between pleural pressure and alveolar pressure is referred to as: § Atmospheric pressure § Compliance § Thoracic pressure § Transpulmonary pressure

§ Transpulmonary pressure

Humidification of air in the alveoli has which of the following effects on the partial pressures of nitrogen and oxygen in the alveoli? § It increases partial pressures of each of the other gasses. § It decreases the partial pressures of the each of the other gasses. § It has no effect on the partial pressures of each of the other gasses. § It increases the partial pressure of oxygen but decreases the partial pressures of nitrogen in alveolar air.

§ It decreases the partial pressures of the each of the other gasses.

If arterial blood carries 19.4 mL of oxygen per deciliter, and returning venous blood carries 14.4 mL of oxygen per deciliter, the utilization coefficient is approximately…? § 25% § 40% § 50% § 75%

§ 25%

The rate and depth of breathing is mainly controlled through which of the following brain centers? § Dorsal respiratory group § Pneumotaxic center § Ventral respiratory center § Carotid body

§ Pneumotaxic center