Physiology 1 Flashcards
Approximately what percentage of carbon dioxide is carried as bicarbonate?
§ 5%
§ 25%
§ 30%
§ 70%
§ 70%
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
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
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
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
§ -5
Of the following ions, which is the most concentrated in the extracellular environment?
§ Sodium
§ Potassium
§ Chloride
§ Calcium
§ Sodium
Saltatory conduction is characteristic of which part of a typical neuron?
§ Dendrite
§ Nerve cell body
§ Axon hillock
§ Axon
§ Axon
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
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
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
Which of the following is the direction of bipolar lead III?
§ 0 degrees
§ 60 degrees
§ 90 degrees
§ 120 degrees
§ 120 degrees
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
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
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
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
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%