Bio 208 Chapter 42 HW

How much more blood does the heart move in a minute when stimulated compared to at rest?

25200 At rest, 5040 mL of blood is moved per minute. When the heart is stimulated, 30240 mL of blood is moved per minute. To calculate how much more blood is moved per minute during stimulation: 30240−5040=25200mL

Calculate the volume of blood moved per minute by a heart that has been stimulated by epinephine.

30240 The heart rate at rest is 72 beats per minute. Stimulation with epinephrine doubles the heart rate to 144 beats per minute. The blood volume moved per beat at rest is 70 mL. Stimulation with epinephrine triples the volume moved per beat to 210 mL. The total volume moved per minute when the heart is stimulated is: 144beats1min×210mL1beat=30240mL/min

What is the percent increase in blood flow due to stimulation?

500 To find the percent increase, compare the increase to the value at rest: A fraction. In the numerator, 25200 is a value of a volume increase due to the stimulation. In the denominator, 5040 is a value of a volume at rest. This fraction amounts to 5. To transform this value into percent, two places are added after the dot. The result is 500 percent increase. A 500% increase means that 5 times more blood is pumped when the heart is stimulated by epinephrine than when it is at rest.

Calculate the volume of blood moved per minute by a heart at rest.

5040 mL The total volume of blood moved in one minute by a resting heart = the number of beats in a minute x the volume of blood moved per beat 72beats1min×70mL1beat=5040mL/min

When athletes exercise, what is the primary physiological variable responsible for their sustained increase in ventilation rate?

Increased blood P(CO2)

What is the function of a circulatory system?

It brings a transport liquid into close contact with all cells in the body. This transport liquid exchanges gases, nutrients, and wastes with the cells in the body.

What is the function of the left ventricle?

It pumps oxygenated blood around the body via the systemic circulation. The left ventricle receives oxygenated blood from the lungs and pumps it to the rest of the body.

People who produce very little saliva often have more cavities. What is the best explanation for this?

Since saliva normally helps neutralize acid and replace minerals on teeth, a lack of saliva leads to more cavities.

Which event occurs first during atrial and ventricular diastole?

The atria and ventricles are relaxed, and blood flows into the atria. Diastole is the relaxation phase of the cardiac cycle during which the chambers of the heart are relaxed and blood can enter them passively.

Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to the rest of the body?

The large decrease in blood pressure as blood moves through the lungs may prevent efficient circulation through the rest of the body. The changes in blood pressure as blood moves through the lungs of land-dwelling vertebrates make it necessary to have separate circuits to the lungs and the rest of the body.

Why is breathing more difficult at high altitudes, such as at the top of Mount Everest?

The lower partial pressure of oxygen in the atmosphere reduces the rate of diffusion of oxygen into your body. Correct. Differences in partial pressure of gases drive the rate of diffusion. Lower atmospheric pressure means lower oxygen partial pressure, reducing oxygen uptake.

Which event of the cardiac cycle occurs when systolic blood pressure is measured?

The ventricles contract, carrying blood into the aorta, and blood flows into the relaxed atria. The systolic blood pressure is the peak blood pressure, resulting from contraction of the ventricles.

Which of the following is true? Periodontal disease causes heart disease. Heart disease is caused by the presence of bacteria in the blood. There is a correlation between periodontal disease and heart disease. Heart disease causes periodontal disease.

There is a correlation between periodontal disease and heart disease.

Which of the following statements about blood circulation in the body is true?

Valves prevent the backflow of blood into the atria and ventricles. Valves are flaps of tissue that close when the ventricles contract to prevent the backflow of blood into the atria and also when the ventricles relax to prevent the backflow of blood from exiting vessels to the ventricles.

Why does the post-Medieval skull in the video have such bad teeth?

Diets during this time period were high in sugar.

By picking up hydrogen ions, hemoglobin prevents the blood from becoming too _____.

acidic If not carried by hemoglobin, hydrogen ions would reduce the pH, or increase the acidity, of the blood.

What is the direct cause of demineralization of the enamel on teeth?

acids produced by bacteria

Most carbon dioxide is carried from the body tissues to the lungs _____

as bicarbonate ions (HCO3 -) Most carbon dioxide released from body tissues combines with water to form carbonic acid, which then breaks up into hydrogen and bicarbonate ions.

Which of the following can increase your risk of atherosclerosis?

avoiding exercise

In the blood most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues _____.

combined with hemoglobin In the blood most oxygen is transported attached to hemoglobin.

True or false? The circulatory systems of land-dwelling vertebrates are composed of two pumping circuits: the systemic circulation, which is a lower-pressure circuit to the lung, and the pulmonary circulation, which is a higher-pressure circuit to the rest of the body.

false The pulmonary circulation is the lower-pressure circuit to the lung, whereas the systemic circulation is the higher-pressure circuit to the rest of the body.

From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.

inferior vena cava Blood enters the inferior vena cava from the capillaries of the abdominal organs and hind limbs.

Voice sounds are produced by the ____

larynx The larynx houses the vocal cords.

From the pulmonary veins, blood flows to the _____.

left atrium Blood enters the left atrium via the pulmonary veins.

The primary functions of the _____ are to warm, filter, and humidify air.

nasal cavity The functions of the nasal cavity are to warm, filter, and humidify air.

What is the direct cause of gum disease?

plaque formed by bacteria

Together, the respiratory and circulatory systems function to ____________.

provide oxygen to your tissues and remove carbon dioxide from your body Aerobically active tissues require oxygen to carry out metabolism and must get rid of the waste product, carbon dioxide.

Blood returns to the heart via the _____.

pulmonary veins Pulmonary veins carry oxygenated blood from the lungs to the left atrium.

From the superior vena cava, blood flows to the _____.

right atrium Blood enters the right atrium from the superior and inferior venae cavae.

During athletic training, the oxygen−hemoglobin dissociation curve

shifts to the right, unloading more oxygen to tissues

Dentists sometimes give a patient antibiotics after a teeth-cleaning procedure, especially if the patient is older or has heart disease. What is the best explanation for this?

Antibiotics help kill the bacteria that move from the mouth to the bloodstream, and prevent the bacteria from contributing to atherosclerosis.

What might be a consequence of global warming for fishes living in a pond?

As the planets warms, aquatic habitats such as a pond will contain less dissolved oxygen, reducing the ability of fishes to acquire oxygen for their respiratory needs. Correct. This is predicted to be a significant stressor for fishes in some habitats as the planet warms.