EKG FINAL!!!!!!!! Flashcards
Concoctions that are necessary for cardiac cellular function include?
Electrolyte balance, pH balance, and temperature balance
The cellular substrates are?
Oxygen, water, and carbohydrates
What are the two main coronary arteries
Left and right coronary arteries
Where is the left coronary artery located
Divides into the left anterior descending artery and the circumflex branch, supplies blood to the heart ventricles and the left atrium
Where is the right coronary artery located
Divides into the right posterior descending artery and a large marginal branch, supplies blood to the heart ventricles, right atrium, and the SA node
An inflammation of the serious pericardium
Pericarditis
Fine cords of dense connective tissue that attach to papillary muscles in the wall of the ventricles
Chordae Tendineae
The smooth outer surface of the heart
Epicardium
The thick layer of the heart composed primarily of cardiac muscle cells and responsible for the hearts ability to contract
Myocardium
The innermost layer of the heart; composed of thin connective tissue
Endocardium
Closed two-layer sac that surrounds the heart
Pericardium
Separates the upper chambers of the heart
Interatrial septum
Separates the lower chambers of the heart
Interventricular septum
The semilunar valve located between the right ventricle and the pulmonary artery. It has three cusps
Pulmonic valve
Has two cusps and is located between the left atrium and left ventricle
Bicuspid (mitral) valve
The semilunar valve located between the left ventricle and the trunk of the aorta. Has three cusps
Aortic valve
Has three cusps and is located between the right atrium and the right ventricle
Tricuspid valve
Allow for the exchange of oxygen nutrients, and waste products between the blood and body tissue
Capillaries
Convey blood back to the heart and operate under low pressure
Veins
Convey blood from the heart out to the rest of the body
Arteries
Brings oxygenated blood to the left atrium from the lungs
Pulmonary veins
Drains blood from the head and neck
Superior vena cava
Collects blood from the rest of the body
Inferior vena cava
A short trunk that serves to receive deoxygenated blood from the veins of the myocardium
Coronary sinus
Movement through a course that leads back to the initial point
Circulation
When blood leaves the heart through the right ventricle and travels into the pulmonary artery to the lungs and back through the pulmonary veins to the left atrium
Pulmonary circulation
Refers to the gas exchange within the alveolar capillary membranes I. The lung
Tissue perfusion
The process by which oxygenated blood is distributed throughout the heart muscle
Coronary circulation
The circulation of blood as it leaves the left ventricle and travels through the arteries, capillaries, and veins of the entire body system and back to the primary receptacle of the heart
Systemic circulation
The innermost layer of the arterial wall and consists of endothelium and an inner elastic membrane
Tunica intima
The middle layer of the arterial wall and consists of smooth muscle cells
Tunica media
The outermost layer of the arterial wall and is composed of various connective tissue
Tunica adventitia
Responsible for preparation of the body for physical activity. Increases heart rate, increases contractility, and vasoconstriction
Sympathetic nervous system
Regulates the calmer functions, decreases heart rate, and vasodilation
Parasympathetic nervous system
Regulates functions of the body that are involuntary, or not under conscious control
Autonomic nervous system
What decreases peripheral vascular resistance
Vasodilation
What increases vascular resistance
Vasoconstriction
The actual time sequence between ventricular contraction and ventricular relaxation
Cardiac cycle
Cardiac output formula
Stroke volume x heart rate
What is the primary neurotransmitter for the sympathetic nervous system
Norepinephrine
The pressure in the ventricles at the end of diastole
Preload
The resistance against which the heart must pump
Afterload
The volume of blood pumped out of one ventricle of the heart in a single contraction
Stroke volume
The number of contractions per minute of the heart
Heart rate
The amount of blood pumped by the left ventricle in one minute
Cardiac output
Average amount of blood per beat in stroke volume
70cc
The more the myocardial fibers are stretched, up to a certain point, the more forceful the subsequent contractions will be
Starling’s law of the heart
How are the ions situated in the resting state
Potassium (K) concentration is greater inside and sodium (Na) is greater outside
Depolarization the ions are
Sodium rushes into the cell changing the interior to positive
Similar to ventricular tachycardia, morphology of QRS complexes show variations in width and shape
Torsades De Pointes
What is the landmark feature in a pacemaker rhythm
Spike
Dual chamber pacemakers
AV sequential pacemakers
T wave is below the line
Inverted T wave
ST is above the line
ST elevation
What causes P waves
Hyperkalemia and depolarization of the atrium
Stage of cell in which cardiac cell cannot spontaneously depolarize
Absolute refractory period
The period when repolarization is almost complete and cardiac cell can be stimulated to contract prematurely if the stimulus is much stronger than normal
Relative refractory period
Intrinsic firing rate of the SA node
60-100
Intrinsic firing rate of AV node
40-60
Intrinsic firing rate of the perkinje network
20-40
Distribute electrical impulse throughout the atria and transmit the impulse from the SA node to the AV node
Internodal tracts
Two main branches, the right bundle branch and the left bundle branch, conduct electrical activity from the bundle of his down to the Purkinje network
Bundle branches
The region where the AV node joins the bundle of his
AV junction
Referred to as the primary pacemaker of the heart because it normally depolarizes more rapidly than any other part of the conduction system
SA node
Carry electrical impulse directly to ventricular muscle cells
Purkinje network
Potassium ions can diffuse through the membrane more rapidly than sodium ions by the mechanism of transport called the
Sodium- potassium exchange pump
Three major cations that affect cardiac function are
Potassium, sodium, calcium, and magnesium
Primary cardiac cell characteristics
Automaticity, excitability, conductivity, contractility
The medium bundle of the hearts conduction system that leads to the AV node
Wenckebach’s bundle
The posterior internodal tract bundle of muscle fibers connecting the SA node to the AV node
Thorel’s pathway
Tiny squares on graph paper =
0.04 sec
15 larger boxes =
3 seconds
30 large boxes =
6 seconds
Normal PRI =
.12 to .20 seconds
Normal QRS =
.08 to .12
Best lead to get visual from
Lead 2
ST segment depression
Ischemia and acute coronary syndrome
What can increase peripheral vascular resistance
Hypertension
Inadequate cardiac output can be caused by
Congestive heart failure, myocardial infarction, or shock
When a stimulus is strong enough for cardiac cells to reach the threshold, all cells will respond and
Contract
The ability of cardiac cells to respond to an electrical impulse
Excitability
The ability of cardiac cells to receive an electrical stimulus and then transmit it to other cardiac cells
Conductivity
The ability of cardiac pacemaker cells to generate their own electrical impulses spontaneously without external stimulation
Automaticity
The ability of cardiac cells to shorten and cause cardiac muscle contraction in response to an electrical impulse
Contractility
The correct order of occurrence of primary cardiac cell action
Automaticity, excitability, conductivity, and contractility
The major electrolytes that affect cardiac function are
Potassium, sodium, and calcium
The internodal pathway includes the
Wenckebach’s bundle, Thorel’s bundle, and the Bachmann’s bundle
Represents ventricular depolarization
QRS complex
Represents depolarization if the right and left atria
P wave
Represents ventricular repolarization
T wave
The time interval during which ventricles are depolarized and ventricular repolarization begins
PR interval
The main coronary arteries arise from
The trunk go the aorta
The great coronary vein is also known as
Coronary sinus