Exam 23: Circulation and Respiration

Scenario Blood flowing away from the heart is under tremendous pressure, able to travel to just about any portion of the body. However, blood pressure drops considerably as it moves away from the heart. When blood finally reaches capillaries, the blood pressure drops to nearly zero. Therefore, when a person is standing, blood returning from the feet is not moved back towards the heart by contractions of the heart. -A scientist claimed that students might get better scores on written exams if they wiggle their legs frequently while taking an exam. This could work (but it is not better than studying)because wiggling legs might ________.

When you hold your breath, which changes in one or more blood gases leads initially to the urge to breathe again?

Which blood vessels have thin, leaky walls?

Which is a characteristic of open circulatory systems but NOT closed circulatory systems?

Veins carry ________.

Scenario Yawning is a reflexive action that is often associated with sleepiness. When a person yawns, the mouth opens, and a longer than normal breath of air is inhaled, followed by a longer than normal exhalation. Hypothesizing that yawning has a regulatory mechanism similar to breathing, scientists conducted an experiment on college students to test the effect of existing carbon dioxide levels on yawning. -Yawning uses the same muscles as regular breathing. When a person exhales to complete a yawn, what happens?

One type of electrical defect in the heart is a delay in the electrical signal from the sinoatrial node to the relay point. Predict the effect of this defect on the cardiac cycle.

Scenario In sickle cell disease (SCD), a mutation in hemoglobin causes deoxygenated hemoglobin to stick together in long chains, which in turn distorts red blood cells into an elongated, sickle (crescent) shape. -Red blood cells with a sickle shape can block circulation in small blood vessels. Which blood vessels are most likely to become blocked by sickle cells?

Examine the structure of blood vessels in the figure. Which vessel has the structure best suited to chemical exchange between the blood and tissues?

Animals such as hydras and jellies can exchange gases directly with the environment by ________.

Scenario Blood flowing away from the heart is under tremendous pressure, able to travel to just about any portion of the body. However, blood pressure drops considerably as it moves away from the heart. When blood finally reaches capillaries, the blood pressure drops to nearly zero. Therefore, when a person is standing, blood returning from the feet is not moved back towards the heart by contractions of the heart. -Because of the changes in blood pressure through the circulatory system, the best way to feel a pulse is by pressing a finger against ________.

Why do cigarette smokers cough more than most people do?

Scenario Yawning is a reflexive action that is often associated with sleepiness. When a person yawns, the mouth opens, and a longer than normal breath of air is inhaled, followed by a longer than normal exhalation. Hypothesizing that yawning has a regulatory mechanism similar to breathing, scientists conducted an experiment on college students to test the effect of existing carbon dioxide levels on yawning. -What finding would be considered support for the hypothesis tested by the scientists?

Blood pressure is lowest in ________.

What can cause anemia?

The figure below is from an experiment on athletes. The "live high, train low" group lived for 18 days in rooms with a simulated altitude of 3,000 m, while training (exercising)at 1,200 m. Use this information and this figure to answer the following questions. -The scientists studied 11 elite runners in this experiment. How does their sample size affect the validity of their study?

Reduced consumption of ________ is associated with increased risk of cardiovascular disease.

Scenario Yawning is a reflexive action that is often associated with sleepiness. When a person yawns, the mouth opens, and a longer than normal breath of air is inhaled, followed by a longer than normal exhalation. Hypothesizing that yawning has a regulatory mechanism similar to breathing, scientists conducted an experiment on college students to test the effect of existing carbon dioxide levels on yawning. -The scientists found that the level of carbon dioxide in the air did not cause college students to yawn more frequently. What other experiment could they conduct to confirm that they should reject the hypothesis that yawning is regulated in the same way as breathing?

Which of these carry(ies)oxygen-poor blood?

Please refer to the following art to answer the following questions. -The one-way flow of blood in veins is maintained by ________.