specialized tissue in the wall of the right atrium the initiates cardiac cycles; the pacemaker
sinoatrial node/ SA node
specialized mass of cardiac muscle fibers in the interatrial septum of the heart
atrioventricular node/ AV node
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
autonomic nervous system
baroreceptor reflexes of the medulla oblongata maintain balance between inhibitory effects of the parasympathetic fibers
cardiac control center
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?
multiply stroke colume in mL by the heartrate in beats per minute
How does blood volume affect blood pressure?
any change in blood volume will directly alter 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?
by mechanisms that regulate cardiac output and peripheral resistance
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?
can detect changes in blood pressure
elevated blood pressure
low blood pressure
How is blood moved through the veins?
skeletal muscle contraction
vasoconstriction of 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
central venous pressure
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?
common carotid artery
left subclavian artery
What vessels branch from the thoracic aorta?
bronchial, pericardial, and esophageal arteries
posterior intercostal arteries
What vessels branch from the abdominal aorta?
inferior mesenteric artery
middle sacral artery
Which veins return blood to the right atrium?
superior and inferior vena cava
Describe what happens to the CVS during the aging process
incidence of disease of the heart and blood vessels increases with age
severe chest pain due to ischemia (a lack of blood and hence oxygen supply) of the heart muscle
inherited overgrowth of the heart muscle
familial hypertrophic cardiomyopathy
in which the heart can no longer pump enough blood to the rest of the body
congestive heart failure CHF