CARDIOVASCULAR SYSTEM Flashcards
the heart of a healthy adult at rest pumps approximately how many liters of blood
5 liters per minute
the right side of the heart pumps blood to the lungs and back to the left side of the heart through vessels of the
pulmonary circulation
the left side of the heart pumps blood to all other tissues of the body and back to the right side of the heart through vessels of the
systemic circulation
the functions of the heart are
generating blood pressure
routing blood
ensuring one way blood flow
regulating blood supply
the heart is shaped like a
blunt cone
the heart is larger in adults who are
physically active
the heart decreases in size after the age of
65
the blunt rounded part of the heart is called the __
apex
the larger flat part at the opposite end of the heart is called the
base
the heart, trachea, esophagus, and associated structures form a midline partition called the
mediastinum
the heart is surrounded by its own cavity called the
pericardial cavity
the pericardial cavity is formed by the
pericardium
the pericardium consists of two layers
fibrous
serous
the outer layer of the pericardium is called the
fibrous pericardium
the inner layer of the pericardium is the
serous pericardium
the two layers of the serous pericardium are the
parietal
visceral
this layer of the serous pericardium lines the fibrous pericardium
parietal
this layer of the serous pericardium covers the heart’s surface
serous
the pericardial cavity (in the middle of the visceral and parietal) is filled with
pericardial fluid created by the serous pericardium
what is the function of the pericardial fluid
helps reduce friction as the heart moves
a groove called the __ extends around the heart, separating the artia from the ventricles
coronary sulcus
extends inferiorly from the coronary sulcus on the anterior surface of the heart
anterior interventricular sulcus
eds inferiorly from the coronary sulcus on the posterior surface of the heart
posterior interventricular sulcus
these veins carry blood from the body to the right atrium
superior vena cava and inferior vena cava
these veins carry blood from the lungs to the left atrium
four pulmonary veins
these two arteries carry blood away from the ventricles of the heart
great vessels or great arteries
arteries which carry blood into the lungs
right and left pulmonary arteries
arising from the left ventricle, carries blood to the rest of the body
aorta
what are the 4 chambers of the heart
right and left atria
right and left ventricle
these chambers function as reservoirs where blood returning from veins collects before it enters the ventricles
right and left atria
these chambers pump or eject blood into the arteries and force it to flow through the circulatory system
right and left ventricles
receives blood from the superior and inferior vena cava and coronary sulcus
right atrium
receives blood from the 4 pulmonary veins
left atrium
the right and left atrium are separated by the
interatrial septum
pumps blood into the pulmonary trunk ; lungs
right ventricle
pumps blood into the aorta ; other tissues in the body
left ventricle
the right and left ventricle are separated by the
interventricular septum
the one way flow of blood through the heart chambers is maintained by the
heart valves
what are the two types of heart valves
atrioventricular valve
semilunar valve
each ventricle contains cone shaped, muscular pillars called
papillary muscles
two types of atrioventricular valve
tricuspid
bicuspid or mitral
the papillary muscles are attached by thin, strong, connective tissue strings called
chordae tendineae
this type of heart valve is located between each ventricle and its associated great artery
semilunar valve
what are the two types of semilunar valves
pulmonary semilunar valve
aortic semilunar valve
a plate of connective tissue consists mainly of fibrous rings that surround the atrioventricular and semilunar valve and give them solid support
cardiac skeleton or fibrous skeleton
these arteries supply blood to the wall of the heart ; originate from the base of the aorta above the semilunar valves
coronary arteries
types of coronary arteries
left and right coronary arteries
what are the three major branches of the left coronary artery
anterior interventricular
circumflex artery
left marginal artery
these veins drain blood from the cardiac muscle into the coronary sinus
cardiac veins
a large vein located within the coronary sulcus on the posterior aspect of the heart
coronary sinus
what are the layers of the heart wall
epicardium
myocardium
endocardium
layer of the heart which is also called the visceral pericardium, it is the outer surface of the heart
epicardium
the thick middle layer of the heart composed of cardiac muscle cells
myocardium
the smooth inner surface of the heart chambers which allows blood to move easily through the heart
endocardium
the surfaces of the interior walls of the ventricles are modified by ridges and columns of cardiac muscle called
trabeculae carneae
these muscles cells are elongated branching cells that contain one or two centrally located nuclei ; they contain actin and myosin filaments organized to form sacromeres which are joined end to end to form microfibrils
cardiac muscle cells
these are responsible for muscle contraction and their organization gives cardiac muscle a striated appearance
actin and myosin myofilaments
cardiac muscle relies on __ and __ for contraction
Ca2+ and ATP
cardiac muscle cells are bound end to end and laterally adjacent cell by specialized cell to cell contacts called
intercalated disks
specialized cell membrane structure in the intercalated disks called __ allow cytoplasm to flow freely between cells
gap junctions
action potentials in cardiac muscle exhibit a ___ period
refractory period
what are the three phases of action potentials in cardiac muscle
depolarization phase
plateau phase
repolarization
during this phase, this phase facilitates the sodium to go inside the cell or sodium influx
depolarization phase
during this phase, the action potentials take a longer period because it keeps the calcium channels open
plateau phase
during this phase, the sodium channels are exiting and going outside the cell
repolarization phase
coordinated by specialized cardiac cell muscles in the heart wall form the
conduction system of the heart
the conduction system of the heart includes the
sinoatrial node
atrioventricular node
atrioventricular bundle
right and left bundle branches
purkinje fibers
this node functions as the heart’s pacemaker and is located in the superior wall of the right atrium and initiates the contraction of the heart ; it also produces action potentials at a faster rate than other areas of the heart and ha a larger number of Ca2+ channels than other cells in the heart
sinoatrial node
located in the lower portion of the right atrium ; the AP from SA node are sent to this node and the AP spread slowly through it
atrioventricular node
AP from the AV node travel to this bundle
atrioventricular bundle
the AV bundle then divides into two branches of conducting tissue called the
left and right bundle branches
these are found at the tips of the left and right bundle branches ; these pass to the apex of the heart then extend to the cardiac muscle of the ventricle wals
purkinje fibers
when action potentials originate in an area of the heart other than the SA node, the result is called an
ectopic beat
ectopic beat may cause very small portions of the heart to contract rapidly and independently of all areas, this condition is called
fibrillation
to stop the process of fibrillation, what is done?
defibrillation wherein electrical shock is applied
used to record electrical events in the heart and not a direct measurement of mechanical events
electrocardiogram
what are the compositions of an ECG
P wave
QRS complex
T wave
this composition of the ECG results from depolarization of the atrial myocardium and precedes the onset of atrial contraction
P wave
this composition of the ECG consists of three individual waves ; results from depolarization of ventricles and precedes ventricular contraction
QRS complex
this composition of the ECG represents the repolarization of the ventricles and precedes ventricular relaxation
T wave
the time between the beginning of the P wave and the QRS complex is called the
PQ interval or PR interval
this interval extends from the beginning of the QRS complex to the end of T wave and represents the length of time required for ventricular repolarization
QT interval
this term refers to the repetitive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction
cardiac cycle
this refers to contraction of the two atria
atrial systole
this refers to the contraction of the two ventricles
ventricular systole
this refers to the relaxation of the two atria
atrial diastole
this refers to the relaxation of the two ventricles
ventricular diastole
when a heart valve does not close completely, this is known as
incompetent valve
abnormal heart sounds are called __ and a result of faulty valves
murmurs
when the opening of a valve is narrowed or __, a swishing sound precedes closure
stenosed
is the volume of blood pumped by either ventricle of the heart each minute
cardiac output
is the volume of blood pumped per ventricle each time the heart contracts
stroke volume
the number of times the heart contracts each minute
heart rate
refers to mechanisms contained within the heart itself that control cardiac output
intrinsic regulation
the degree to which the ventricular walls are stretched at the end of diastole
preload
the amount of blood that returns to the heart
venous return
the relationship between preload and stroke volume is called
starling’s law of the heart
refers to the pressure against which the ventricles must pump blood
afterload
it is a mechanism of the nervous system that plays an important role in regulating heart function
baroreceptor reflex
are stretch receptors that monitor blood pressure in the aorta and in the wall of the internal carotid arteries which carry blood to the brain
baroreceptors
within the medulla oblongata is a __ which receives and integrates action potentials from the baroreceptors ; it controls the AP frequency
cardioregulatory center