cardiovascular ch 31 lewis Flashcards
cusps of the mitral and tricuspid valves are attached to thin strands of fibrous tissue ca
chordae tendineae
are anchored in the papillary muscles of the ventricles. This support system prevents the eversion of the leaflets into the atria during ventricular contraction.
Chordae function
prevent blood from regurgitating into the ventricles at the end of each ventricular contraction.
pulmonic and aortic valves (also known as semilunar valves)
, the coronary circulation
myocardium has its own blood supply aka
diastole (relaxation of the myocardium).
Blood flow into the 2 major coronary arteries occurs primarily during
the left anterior descending artery and left circumflex artery.
left coronary artery arises from the aorta and divides into 2 main branches:
arteries supply the left atrium, left ventricle, interventricular septum, and part of the right ventricle.
left coronary artery arises from the aorta divides into the left anterior descending artery and left circumflex artery.
the right atrium, right ventricle, and part of the posterior wall of the left ventricle
right coronary artery also arises from the aorta, and its branches supply
right coronary artery. For this reason, blockage of this artery often causes serious defects in cardiac conduction.
. In 90% of people, the atrioventricular (AV) node and the bundle of His receive blood supply from the
coronary sinus (a large channel), which empties into the right atrium near the entrance of the inferior vena cava.1
Most of the blood from the coronary system drains into the
- of the SA node
- represents depolarization of the atria
the P wave, begins with the firing
- depolarization from the AV node throughout the ventricles
- time between the beginning of the P wave and the beginning of the QRS wave..
QRS complex represents
repolarization of the ventricles
T wave represents
A large U wave may occur with hypokalemia.
U wave, if seen, may represent repolarization of the Purkinje fibers.
is the amount of blood pumped by each ventricle in 1 minute.
Cardiac output (CO)
amount of blood ejected from the ventricle
stroke volume
heartbeat
heart rate
is the amount of blood pumped by each ventricle in 1 minute.
Cardiac output (CO)
of 4 to 8 L/min
For the normal adult at rest, CO is maintained in the range
is the CO divided by the body surface area (BSA)
Cardiac index (CI)
CI is 2.8 to 4.2 L per minute per meter squared (L/min/m2).3
Cardiac index (CI) range
by the autonomic nervous system, can reach as high as 180 beats/min for short periods without harmful effects.
HR, which is controlled primarily (affect Cardiac Output)
there is less time for diastolic filling and perfusion of the coronary arteries
rapid HRs, effect
are preload, contractility, and afterload.
factors affecting Stroke Volume
rapid HR or hypovolemia reduces ventricular filling during diastole.
Preload is decreased when a
by epinephrine and norepinephrine released by the sympathetic nervous system
Contractility can be increased
is the peripheral resistance against which the left ventricle must pump
Afterload
the size of the ventricle, wall tension, and arterial
Afterload depends on
cardiovascular system must respond to many situations in health and illness (e.g., exercise, stress, hypovolemia). The ability to respond to these demands by altering CO is termed
cardiac reserve.
are the arteries, veins, and capillaries
3 major types of blood vessels
, arterioles, capillaries, venules, and veins, and then back to the right side of the heart.
Blood circulates from the left side of the heart into arteries
serve as the major control of arterial BP and distribution of blood flow
Arterioles
maintains hemostasis, promotes blood flow, and, under normal conditions, inhibits blood coagulation.
endothelium (innermost lining of artery)
is a low-pressure, high-volume system
venous system
at intervals to maintain the blood flow toward the heart and to prevent backward flow.
larger veins have semilunar valves
arterial flow, compression of veins by skeletal muscles, changes in thoracic and abdominal pressures, and right atrial pressure.
amount of blood in the venous system is affected
which returns blood to the heart from the head, neck, and arms, and the inferior vena cava, which returns blood to the heart from the lower part of the body.
largest veins are the superior vena cava,
collect blood from the capillary beds and channel it to the larger veins.
Venules
the sympathetic nervous system and parasympathetic nervous system
autonomic nervous system consists of
effect is mediated by specific sites in the heart called beta (β)-adrenergic receptors, which are receptors for norepinephrine and epinephrine.
beta (β)-adrenergic receptors
by decreasing the impulses from the SA node and thus con
parasympathetic system (mediated by the vagus nerve) slows the HR
beta (β)-adrenergic receptors, which are receptors for norepinephrine and epinephrine.
beta (β)-adrenergic receptors
slows the HR by decreasing the impulses from the SA node and thus conduction through the AV node.
parasympathetic system (mediated by the vagus nerve)
results in vasoconstriction.
Stimulation of α1-adrenergic receptors
causes vasodilation
Decreased stimulation to α1-adrenergic receptors
are sensitive to stretch or pressure within the arterial system
Baroreceptors in the aortic arch and carotid sinus (at the origin of the internal carotid artery)
in the aortic and carotid bodies and the medulla. They can cause changes in respiratory rate and BP in response to increased arterial CO2 pressure (hypercapnia) and, to a lesser degree, decreased plasma pH (acidosis) and arterial O2 pressure (hypoxia)
Chemoreceptors are found
is the force opposing the movement of blood.
SVR
We can assess SBP and pulse using a
Doppler ultrasonic flowmeter.
to the average pressure within the arterial system that is felt by organs in the body
mean arterial pressure (MAP). The MAP refers
With increased age, the amount of collagen in the heart increases and elastin decreases
Age-related changes in the cardiovascular system
(decrease in BP of at least 20 mm Hg that occurs within 75 minutes after eating)
Postprandial hypotension
may be a symptom of peripheral vascular disease and/or a side effect of some drugs used to treat CVD (e.g., β-blockers, diuretics)
Erectile dysfunction (ED)
can identify conduction problems, dysrhythmias, position of heart, cardiac hypertrophy, pericarditis, myocardial ischemia or infarction, pacemaker activity, and effectiveness of drug therapy at one point in time.
A resting 12-lead ECG
