Module #1 - Heart: Anatomy and Function Flashcards
What are the 3 circulation systems of the cardiovascular system?
Pulmonary Circulation
Systemic Circulation
Coronary Circulation
Where is the pulmonary circulation supplied from?
Right side of the heart
Describe Blood flow in the pulmonary circulation (start w/ heart)?
R side of heart –> pulmonary trunk
Pulmonary trunk –> R/L Pulmonary arteries
Pulmonary arteries –> Capillaries surrounding alveoli
Capillaries –> pulmonary veins
Pulmonary veins –> L side of the heart
What is the function of pulmonary circulation?
Deliver blood to lungs for gas exchange
What is the pressure of the pulmonary circulation system compared to systemic pressure?
“Low pressure”
How does the volume of blood pumped per heart beat through the pulmonary circulation compared to systemic circulation?
Same amount of volume
Describe blood flow in the systemic circulation?
L side of the heart –> aorta
Aorta –> major blood vessels of body
Major blood vessels –> capillaries w/in each organ of the body
Capillaries –> venous system
Inferior/superior vena cava –> R side of the heart
What is the function of systemic circulation?
Deliver blood to every region of the body for gas exchange
How does the pressure of the systemic circulation compare to the pulmonary system?
High pressure
What is the function of coronary circulation?
Blood supply to the heart itself
Describe blood flow in the coronary circulation
L side of the heart –> aorta
Aorta –> R/L coronary arteries
R/L Coronaries –> Regional arterial branches
Arterial branches –> Coronary capillaries
Coronary capillaries –> Coronary veins
Coronary veins –> Coronary sinus
What are collateral arteries of the coronary circulation?
Anastomoses –> connections between r/l pathways or 2 branches of R or L coronary artery
What is arteriogenesis?
Collateral growth
When does arteriogenesis occur?
In response to coronary artery obstruction
remodeling allows for new/alternative blood flow pathways to supply myocardium
Describe blood flow through the 4 chambers of the heart
Right atrium –> Tricuspid valve (right AV valve)
Tricuspid valve –> Right ventricle
Right ventricle –> Right semilunar valve (pulmonary semilunar valve)
Lungs –> Left atrium
Left atrium –> Mitral valve (left AV valve)
Mitral valve –> Left ventricle
Left ventricle –> Left semilunar (aortic semilunar valve)
Where does the right atrium get its blood and what kind of blood does it get?
“Low oxygenated blood” from SVC, IVC, Coronary sinus (via coronary gens)
What does the tricuspid valve (right av valve) do?
Regulate blood flow from R atria –> R ventricle
Where does the right ventricle receive its blood and what kind of blood does it receive?
“Low oxygenated” from the R atrium
What is the shape of the right ventricle, and why is it shaped that way?
Triangularly shaped
Functions as “bellow” –> allows pumping of large volume into “low pressure” pulmonary circulation
What does the right semilunar valve do?
Regulate blood flow from right vent rile to pulmonary trunk
Where does the left atrium get its blood from and what kind of blood is it?
“Oxygenated blood” from 4 pulmonary veins (2 from right; 2 from left)
What does the mitral valve (left av valve) do?
Regulated blood flow between left atrium and left ventricle
Where does the left ventricle get its blood and what kind of blood is it?
“Oxygenated blood” from the left atrium
What is the shape of the left ventricle and why is it shaped like that?
“Bullet shaped” –> allows forceful pumping of blood into “high pressure” circulation
What does the left semilunar valve (aortic semilunar valve) do?
Regulates blood flow between left ventricle and aorta
Which phase is systole?
Contraction phase
What happens during systole?
Blood ejected from R/L ventricles into circulation
Which phase is diastole?
Relaxation phase
What happens during diastole?
Blood fills R/L ventricles
Describe what happens during systole during the cardiac cycle
Isovolumetric contraction **first sound
Ventricular ejection
Describe what happens during diastole during the cardiac cycle
Isovolumetric relaxation **second sound
Ventricular filling
Atrial systole
Describe the mechanical events during the cardiac cycle
Atrial kick (atrial systole)
Isovolumetric ventricular contraction
Ventricular ejection
Isovolumetric Relaxation
Ventricular Filling
What happens during Atrial kick?
Atria contract –> force additional blood into ventricles
AV valves = open
Semilunar valves = closed
What happens during isovolumetric ventricular contraction?
Ventricles begin to contract –> AV snap shut (1st sound)
Ventricular pressure increases –> semilunar valves = shut
All valves = shut
What happens during ventricular ejection?
Ventricular pressure exceeds vascular pressure forcing semilunar valves open
Blood ejects from ventricles
AV valves = close
Semilunar valves –> push open
What happens during isovolumetric relaxation (beginning of diastole)?
Ventricular pressure falls below atrial pressure –> semilunar valves snap shut = 2nd heart sound
All valves = shut
@ End of this phase, venous blood returns to heart –> arterial pressures increase –> semilunar valves open = start of next phase
What happens during ventricular filling?
Ventricles passively fill w/ blood
AV valves = open
Semilunar valves = closed
What is the total time of the cardiac cycle (assuming there is a resting heart rate of 70 bpm)?
0.8 sec/beat
** systolic = 0.3 sec/beat; diastolic = 0.5 sec/beat
What is the total time of the cardiac cycle (assuming there is an exercising heart rate of 180 bpm)?
0.33 sec/beat
**systolic = 0.2 sec/beat; diastolic = 0.13 sec/beat
Based on the total time of the cardiac cycle in a resting/exercising heart, what is the increase in HR due to?
Dramatic shortening of the diastolic phase of the cardiac cycle
**ie less time to fil/less time for coronary circulation to occur
What is the first heart sound that is heard and what is causing this sound?
S1 = lub
AV valves snap shut during the beginning of ventricular systole
What is the second heart sound that is heard and what is causing this sound?
S2 = dub
Semilunar valves snap shut @ transition between ventricular systole and early diastole
What is the third heart sound?
S3
Heart in kids/young adults
Vibration of ventricular walls from rush of blood into ventricles during rapid filling
What is splitting of second heart sound?
Delayed interval between aortic/pulmonary semilunar valves –> reduplication of sound (physiological splitting)
When do you heart splitting of the second heart sound?
Common during inspiration –> right pulmonary valve delayed
Hear in various pathologies
What is a heart mumur?
Abnormal sounds heart over heart
What causes a heart murmur?
Turbulent blood flow
Classic cardiac mumurs = valve dz
What happens in stenosis that would cause a heart murmur?
Opening of valve is narrowed
What happens during regurgitation/insufficiency that would cause a heart murmur?
Valve mechanically incompetent –> back flow
What is a bruit?
Abnormal sounds heart throughout vascular system?
What causes a bruit?
Turbulent blood flow
What is resting heart rate (RHR)?
Normal = 70 bpm
What is maximum heart rate (MHR) and how would you figure it out?
Estimate of maximum heart rate
220 - age = MHR
208 - (0.7 x age) = MHR
What is the traditional method for calculating target heart rate (THR)?
MHR x chosen %
What is the Karvonen formula that is used to calculate the heart rate reserve method?
[(MHR – RHR)] x chosen % + RHR
What is the average resting stroke volume?
70 mL
What is the average stroke volume in elite athletes?
90 - 100 mL
What is the maximum SV during exercise in elite athletes?
150 - 200 mL
How do you calculate cardiac output?
CO = SV x HR
What is the average CO @ rest?
5 L/min
What is the maximum CO during exercise?
20 - 30 L/min
What is the ejection fraction (EF)?
% of the blood that is ejected from the ventricle
**proportion of the blood pumped out of the left ventricle w/ each beat
How do you calculate the ejection fraction (EF)
EF = SV / EDV (end diastolic volume)
What is the normal left ventricular EF (LVEF) @ rest?
55 - 68%
What is the normal right ventricular EF (RVEF) @ rest?
slightly less than LVEF
What are the clinical base line for EF?
Normal = 50 (or 55) - 70%
Below Normal = 40 - 50%
Diagnostic/increased risk of arrhythmia = < 35 - 40%
What happens to EF during exercise?
Increase 5 - 15% above resting value