The normal pacemaker of the human heart is the remnant [derivative] of:
1. chordate tendinae
2. bundle of His
3. conus arteriosus
4. sinus venosus

The chamber with the thickest musculature in the human heart would be:

The correct path of circulation of the blood in the human heart is represented by:

Sympathetic stimulation would lead to:
1. increased heart rate.
2. increased stroke volume.
3. vasoconstriction in visceral blood vessels.
4. all of the above.

The innermost layer of blood vessel walls made up of one layer of endothelium and in direct contact with the blood is:

Blood vessels have smooth muscles in their walls that are innervated by:
1. myelinated motor neurons.
2. unmyelinated sympathetic neurons.
3. unmyelinated motor neurons.
4. unmyelinated parasympathetic neurons.

The build-up of fats, cholesterol and other substances in and on the artery walls is known as:

The smoothness of endothelium is a very important factor that prevents thrombus formation. The endothelial cells:
1. increase cardiac output.
2. decrease heart rate.
3. inhibit platelet aggregation and control blood vessel diameter.
4. nourish the cells in the outer half of the blood vessel wall.

Capillary walls are different from the walls of veins and arteries as they are composed of:
1. endothelium only.
2. endothelium and smooth muscle.
3. a tunica interna and a tunica media.
4. smooth muscle and elastic connective tissue.

The right ventricle pumps the blood into the pulmonary trunk that next enters the:
1. pulmonary veins.
2. left and right pulmonary arteries.
3. pulmonary capillaries.
4. left atrium