Chapter 15

specialized tissue in the wall of the right atrium the initiates cardiac cycles; the pacemaker

specialized mass of cardiac muscle fibers in the interatrial septum of the heart

group of specialized fibers that conducts impulses from the atrioventricular node to the Purkinje fibers in the ventricular muscle of the heart

specialized muscle fibers that conduct the cardiac impulse from the AV bundle into the ventricular wall

is a recording of the electrical changes in the myocardium during the cardiac cycle

corresponding to depolarization of the atrial fibers that will lead to contraction of the atria

due to depolarization of the ventricular fibers just prior to the contraction of the ventricular walls

an irregular heartbeat

an abnormally slow heart rate or pulse rate

abnormally rapid heartbeat

the normal beating of the heart, as measured by an electrocardiogram (ECG)

is controlled by electrical impulses from the sino-atrial and antrioventriclar nodes

sympathetic branches of the ________ _________ ________ innervate smooth muscle in artery and arteriole walls

baroreceptor reflexes of the medulla oblongata maintain balance between inhibitory effects of the parasympathetic fibers

excess potassium ions alter the usual polarized state of the cardiac muscle fibers

if the potassium concentration drops below normal that heart may develop a potentially life threatening abnormal rhythm

excess calcium ions increases heart action, risking that the heart will undergo a prolonged contraction

low calcium concentration depresses heart action because these ions help initiate muscle contraction

vessel that transports blood from the heart

small branch of an artery that communicates with a capillary network

a small blood vessel that connects an arteriole and a venule

vessel that carries blood from capillaries to a vein

vessel taht carries blood toward the heart

decrease in the diameter of a blood vessel

increase in the diameter of a blood vessel

hydrostatic pressure forces molecules through a membrane

How are gases and nutrients exchanged in the capillaries?

What helps to maintain the osmotic pressure in the capillaries?

Which artery is used to determine the pulse?

volume of blood the ventricle discharges with each heartbeat

the volume of blood per minute that the heart pumps

How is cardiac output calculated?

How does blood volume affect blood pressure?

the sum of the formed elements and plasma volumes in the vascular system

friction between blood and the walls of the blood vessels produces a force calls

tendency for a fluid to resist flowing due to the internal friction of its molecules

amount of blood returning to the ventircles

How is blood pressure controlled?

the relationship between fiber length due to stretching of the cardiac muscle cell just before contraction and force of contraction is called

What is the function of the baroreceptor?

elevated blood pressure

low blood pressure

How is blood moved through the veins?

prevent blood from flowing back and pooling in the lower extremities due to the effects of gravity

the pressure in the right atrium from the veins draining into it

system of blood vessels that carries blood between the heart and the lungs

vessels that conduct blood between the heart and all body tissues except the lungs

What vessels arise from the aortic arch?

What vessels branch from the thoracic aorta?

What vessels branch from the abdominal aorta?

Which veins return blood to the right atrium?

Describe what happens to the CVS during the aging process

severe chest pain due to ischemia (a lack of blood and hence oxygen supply) of the heart muscle

inherited overgrowth of the heart muscle

in which the heart can no longer pump enough blood to the rest of the body