Review Questions

Why are open circulatory systems advantageous to some animals?

1. They use less metabolic energy.
2. They help the animal move faster.
3. They do not need a heart.
4. They help large insects develop.

Some animals use diffusion instead of a circulatory system. Examples include:

1. birds and jellyfish
2. flatworms and arthropods
3. mollusks and jellyfish
4. none of the above

Blood flow that is directed through the lungs and back to the heart is called ________.

1. unidirectional circulation
2. gill circulation
3. pulmonary circulation
4. pulmocutaneous circulation

White blood cells:

1. can be classified as granulocytes or agranulocytes
2. defend the body against bacteria and viruses
3. are also called leucocytes
4. all of the above

Platelet plug formation occurs at which point?

1. when large megakaryocytes break up into thousands of smaller fragments
2. when platelets are dispersed through the bloodstream
3. when platelets are attracted to a site of blood vessel damage
4. none of the above

In humans, the plasma comprises what percentage of the blood?

1. 45 percent
2. 55 percent
3. 25 percent
4. 90 percent

The red blood cells of birds differ from mammalian red blood cells because:

1. they are white and have nuclei
2. they do not have nuclei
3. they have nuclei
4. they fight disease

The heart’s internal pacemaker beats by:

1. an internal implant that sends an electrical impulse through the heart
2. the excitation of cardiac muscle cells at the sinoatrial node followed by the atrioventricular node
3. the excitation of cardiac muscle cells at the atrioventricular node followed by the sinoatrial node
4. the action of the sinus

During the systolic phase of the cardiac cycle, the heart is ________.

1. contracting
2. relaxing
3. contracting and relaxing
4. filling with blood

Cardiomyocytes are similar to skeletal muscle because:

1. they beat involuntarily
2. they are used for weight lifting
3. they pulse rhythmically
4. they are striated

How do arteries differ from veins?

1. Arteries have thicker smooth muscle layers to accommodate the changes in pressure from the heart.
2. Arteries carry blood.
3. Arteries have thinner smooth muscle layers and valves and move blood by the action of skeletal muscle.
4. Arteries are thin walled and are used for gas exchange.

High blood pressure would be a result of ________.

1. a high cardiac output and high peripheral resistance
2. a high cardiac output and low peripheral resistance
3. a low cardiac output and high peripheral resistance
4. a low cardiac output and low peripheral resistance