Chapter 2-Cardiovascular System Flashcards
Define the pericardium
a two-layered sac of tissue enclosing the heart
Define the right atrium
right upper chamber of the heart which receives blood from body
Define left atrium
left upper chamber of heart which receives blood from lungs
Define right ventricle
right lower chamber of heart which pumps blood to lungs
Define left ventricle
left lower chamber of heart which pumps blood through body (biggest, strongest chamber of heart)
Define the interventricular septum
partition or wall (septum) that divides the right and left ventricles
Define the interatrial septum
wall of tissue that separates left an right atrium
Describe the location and function of the endocardium
inner layer of heart that lines chambers and valves, the purkinje fibres are located myocardium above this layer
Describe the location and function of the myocardium
middle, thickest muscular layer responsible for heart contractions
Describe the location and function of the epicardium (also known as the visceral pericarium)
outside, thin layer of heart that contains the coronary arteries (also known as the inner layer of pericardium)
Describe the function and location of the pericardium (made up of visceral and parietal pericardium)
double layer sac that encloses the heart. The inner layer is called the visceral pericardium and the outer layer is the parietal pericardium
Define the tricuspid valve
valve located between right atrium and right ventricle, prevents backflow of blood into right atrium
Define the mitral (bicuspid) valve
valve with two cusps or leaflets located between left atrium and left ventricle, prevents backflow of blood into left atrium
Define chordae tendineae
structures that connect atrioventricular (tricuspid and mitral) valves to papillary muscles that prevent them from opening in wrong direction
define papillary muscles
muscles in ventricles that anchor chordae tendineae and atrioventricular valves
define pulmonary artery
large artery that transports deoxygenated from right ventricle to lungs, only artery carrying deoxygenated blood
define aorta
largest artery of body, transports blood from left ventricle of heart ti entire body
define semilunar valve
valve with half-moon shaped cusps that open and close allowing blood to travel only one way, located in the pulmonary artery and aorta
define aortic semilunar valve
located in aorta that prevents backflow of blood into left ventricles
define pulmonary semilunar valve
valve found in pulmonary artery that prevents backflow of blood into right ventricle during pulmonary circulation
define vena cava
largest vein in body provides pathway for deoxygenated blood to return to heart, upper portion is the superior vena cava transports blood from head, arms, upper body, lower portion (inferior vena cava) transports blood from lower body and legs
define pulmonary circulation
transportation of blood to and from lungs, blood is oxygenated in lungs during pulmonary circulation
define systemic circulation
pathways for pumping blood throughout body and back to heart
define coronary circulation
circulation of blood to and from heart muscles
define stroke volume
volume of blood ejected with each contraction
define cardiac output
volume of blood pumped each minute
what is an average cardiac output
5L per minute
define systole
contraction phase of cardiac cycle, during which heart is pumping blood out to pulmonary (lungs) and systemic (body) circulation
define diastole
phase of cardiac cycle when heart is expanding and refilling, also known as relaxation phase
define automaticity
ability of heart to initiate electrical impulse without stimulation by independent source
define conductivity
ability of heart cells to receive and transmit an electrical impulse
define contractility
ability of heart muscle cells to shorten in response to electrical stimulus
define excitability
ability of heart muscle cells to respond to impulse or stimulus (irritability)
define sympathetic
branch of autonomic nervous system (ANS) that causes increase in heart rate
define parasympathetic
branch of autonomic nervous system (ANS) that helps slow heart rate
define the sinoatrial (SA) node
area of specialized cells in upper right atrium that initiates heartbeat
define Backmann’s bundle
structure that relays electrical impulse from the SA node to the left atrium in normal heart
define atrioventricular (AV) node
delays electrical impulse to allow atria to complete contraction
define bundle of His (atrioventricular or AV bundle)
located next to AV node, provides transfer of electrical impulse from atria to ventricles
define bundle branches
left and right branches of bundle of His conduct impulses down either side of interventricular septum to left and right ventricles
define purkinje fibers
fibers within heart that distribute electrical impulses from cell to cell throughout ventricles
define purkinje network
spreads electrical impulse throughout ventricles by means of purkinje fibers
define polarization
state of cellular rest which inside is negatively charged and outside is positively charged
define depolarization
electrical activation of cells of heart initiates contraction of heart muscle
define repolarization
return of heart muscle cells to resting electrical state, causing heart muscle to relax
define isoelectric line
period when electrical tracing of ECG is at zero or straight line, no positive or negative deflection seen
define interval
period of time between two activities within heart
define segment
portion or part of electrical tracing produced by heart
define complexes
atrial or ventricular contractions as appear on ECG, complete ECG waveforms
define the appearance and activity of a P wave
-upward small curve
-atrial depolarization resulting in atrial contraction
define the appearance and activity of a QRS complex
-Q,R,S waves
-ventricular depolarization and resulting ventricular contract (larger than P wave), atrial repolarization occurs (not seen)
define the appearance and activity of a T wave
-small upward-sloping curve
-ventricular repolarization
define the appearance and activity of a U wave
-upward small curve
-repolarization of Purkinje fibers (not always seen), may be seen in instances of electrolyte imbalance
define the appearance and activity of a PR Interval
-P wave and baseline prior to QRS complex
-beginning of atrial depolarization to beginning of ventricular depolarization
define the appearance and activity of a QT Interval
-QRS complex, ST segment, and T wave
-period of time from start of ventricular depolarization to end of ventricular repolarization
define the appearance and activity of an ST segment
-end of QRS complex to beginning of T wave
-time between ventricular depolarization and beginning of ventricular repolarization
