7.3 Physiology of the Cardiovascular System

Question 1

Blood pressure is measured as a ratio of what two pressures?

Answer 1

Systolic (ventricular contraction) / diastolic (ventricular relaxation)

Question 2

What is the normal range for blood pressure?

Answer 2

90/60 to 120/80

Question 3

The largest drop in blood pressure occurs in what part of the vasculature?

Answer 3

The arterioles. Capillaries are thin-walled and cannot withstand high pressures.

Question 4

The percentage of hemoglobin molecules carrying oxygen is called oxygen _____.

Answer 4

Saturation

Question 5

Most healthy people have an oxygen saturation level above what percentage?

Answer 5

97%

Question 6

Hemoglobin molecules exhibit what type of binding?

Answer 6

Cooperative binding. Binding a molecule of oxygen increases other subunits’ affinity for oxygen and vice versa.

Question 7

The vast majority of carbon dioxide exists in the blood as what ion?

Answer 7

The bicarbonate ion.

Question 8

When carbon dioxide enters a red blood cell, it encounters this enzyme, which catalyzes the combination reaction between carbon dioxide and water to form carbonic acid.

Answer 8

Carbonic anhydrase. Carbonic acid (a weak acid) will then dissociate into a proton and the bicarbonate anion.

Question 9

Protons can bind to hemoglobin and reduce its affinity for oxygen. This is known as the _____ _____.

Answer 9

Bohr effect

Question 10

What are some causes of a RIGHT shift of the oxyhemoglobin curve? (Hint: greater unloading of oxygen)

Answer 10

1. Increased partial pressure of carbon dioxide
2. Increased concentration of H+ (decreased pH)
3. Increased temperature
4. Increased concentration of 2,3-BPG

Question 11

Does fetal hemoglobin (HbF) or adult hemoglobin (HbA) have a higher affinity for oxygen?

Answer 11

Fetal hemoglobin (HbF)

Question 12

When an individual hyperventilates, this leads to excess carbon dioxide being blown off. The bicarbonate buffer system shifts to the left and pH is increased. This condition is called _____ _____.

Answer 12

Respiratory alkalosis

Question 13

What type of pressure is defined as the force per unit area that the blood exerts against the vessel walls?

Answer 13

Hydrostatic pressure. This pushes fluid out of the bloodstream and into the interstitium through the capillary walls.

Question 14

This type of “sucking” pressure is generated by solutes as they attempt to draw water into the bloodstream.

Answer 14

Osmotic pressure (or oncotic pressure)

Question 15

At the arteriole end of a capillary bed, is the hydrostatic or oncotic pressure greater?

Answer 15

Hydrostatic pressure. There is a net efflux of water from the circulation.

Question 16

At the venule end of a capillary bed, which pressure is greater: oncotic or hydrostatic?

Answer 16

Oncotic pressure. There is a net influx of water from the circulation.

Question 17

The balance of opposing hydrostatic and oncotic pressures is referred to as _____ forces.

Answer 17

Starling

Question 18

Accumulation of excess fluid in the interstitium results in a condition called _____.

Answer 18

Edema

Question 19

Most lymphatic fluid is returned to the central circulatory system by way of a channel called the _____ _____.

Answer 19

Thoracic duct