Cardio Mod 1

Question 1

Pulmonary circulation

Answer 1

a. Supplied by right side of the heart
• Pulmonary trunk divides into R/L pulmonary arteries to supply lungs
• Pulmonary capillaries within alveoli
• Pulmonary veins remove blood from pulmonary capillaries and send blood to the left side of the heart

Question 2

Function of pulmonary circulation

Answer 2

• Deliver blood to lungs for gas exchange
• “Low pressure system” compared to systemic
• Volume of blood pumped per heart beat through pulmonary circulation is the same as systemic circulation

Question 3

Systemic circulation

Answer 3

a. Supplied by left side of the heart
• Aorta supplies major blood vessels of the body
• Systemic capillaries within each organ of the body
• Inferior and superior vena cava (IVC and SVC) final venous pathway to return blood to the right side of the heart

Question 4

Systemic circulation function

Answer 4

• Deliver blood to every region of the body for gas exchange
• “High pressure system” compared to pulmonary system
• Volume of blood pumped per heart beat through systemic circulation is the same as pulmonary circulation

Question 5

Coronary Circulation

Answer 5

a. Blood supply to the heart itself
b. Supplied by right/left coronary arteries
• Right and left coronary arteries supply branches to different regions of heart
• Coronary capillaries
• Coronary veins eventually drain into coronary sinus

Question 6

collateral arteries– anastomoses

Answer 6

• Connections between right/left pathways or two branches of right or left coronary artery
• Collateral growth – “arteriogenesis”
(i) Response to coronary artery obstruction
(ii) Remodeling allows for “new or alternative” blood flow pathways to supply myocardium

Question 7

Right atrium

Answer 7

• Receives “low-oxygenated” blood from systemic and coronary circulation
• SVC, IVC and coronary sinus all empty into right atria

Question 8

Tricuspid valve (right AV valve)

Answer 8

• Regulates blood flow from right atria to right ventricle

Question 9

Right ventricle

Answer 9

• Receives “low-oxygenated” blood from right atrium
• Triangular shaped to function like “bellow” to allow pumping large volume of blood into “low pressure” pulmonary circulation
• Pumps blood to pulmonary circulation via pulmonary trunk

Question 10

Right semilunar valve (pulmonary semilunar valve)

Answer 10

• Regulates blood flow between right ventricle and pulmonary trunk

Question 11

Left atrium

Answer 11

• Receives “oxygenated” blood from pulmonary circulation via 4 pulmonary veins (2 from right and 2 from left)

Question 12

Mitral Valve (left AV valve)

Answer 12

• Regulates blood flow between left atrium and left ventricle

Question 13

Left Ventricle

Answer 13

• Receives “oxygenated” blood from left atrium
• “Bullet shaped” to allow forceful pumping of blood into “high pressure” systemic circulation
• Pumps blood to systemic and coronary circulation via aorta

Question 14

Left semilunar (aortic semilunar valve)

Answer 14

• Regulates blood flow between left ventricle and aorta

Question 15

Systole

Answer 15

a. CONTRACTION phase

b. Blood ejected from R/L ventricles into circulation

Question 16

Diastole

Answer 16

a. RELAXATION phase of cardiac chambers,

b. Blood fills R/L ventricles

Question 17

Cardiac Cycle

Answer 17

a. Systole
• Isovolumetric Contraction
• Ventricular ejection

b. Diastole
• Isovolumetric relaxation
• Ventricular filling
• Atrial systole

Question 18

Atrial kick (Atrial systole)

Answer 18

• Atria contract and force additional blood into ventricles
• AV valves– remain open;
• Semilunar valves – remain closed

Question 19

Isovolumetric ventricular contraction (beginning of ventricular systole)

Answer 19

• Ventricles begins to contract causing AV to snap shut (1st heart sound)
• Ventricular pressure increases but semilunar valves remain shut
• All valves shut
• AV valves – snap close (1st heart sound);
• Semilunar valves – remain closed

Question 20

Ventricular Ejection (ventricular systole continues)

Answer 20

• Ventricular pressure eventually exceeds vascular pressure forcing semilunar valves open
• Blood ejects from ventricles
• AV valves – remain closed
• Semilunar valves – push open

Question 21

Isovolumetric Relaxation (Diastole begins – “early” diastole)

Answer 21

• At start of isovolumetric relaxation ventricular pressure falls below arterial pressure forcing semilunar valves (aortic and pulmonary valves) to snap shut (2nd heart sound)
• All valves shut
• AV valves – remain closed
• Semilunar valves – snap shut – second heart sound
• NOTE: back pressure in aorta forces blood to flow into coronary arteries
• At end of this phase venous blood continues to return to heart, atrial pressure increases which then forces AV valves open (allowing the next phase to begin)

Question 22

Ventricular Filling (Diastole continues – ‘late” diastole)

Answer 22

• Ventricles passively fill with blood
• AV valves – remain open
• Semilunar valves – remain closed

Question 23

Duration of the Cardiac Cycle

Answer 23

• Resting heart rate of 70 bpm = 0.8 sec/beat

(i) Systolic = 0.3 sec/beat
(ii) Diastolic = 0.5 sec/beat

• Exercising heart rate of 180 bpm = 0.33 sec/beat

(i) Systolic = 0.2 sec/beat
(ii) Diastolic = 0.13 sec/beat

Question 24

First Heart sound – S1 (“lub”)

Answer 24

• AV valves snap shut during the beginning of ventricular systole (isovolumetric ventricular contraction)

Question 25

Second Heart sound - S2 (“dub”)

Answer 25

• Semilunar valves snap shut at the transition between ventricular systole and early diastole (isovolumetric ventricular relaxation)

Question 26

Third Heart sound - S3

Answer 26

* **may not be heard * Commonly heard in children/young individuals * Vibration of ventricular walls from rush of blood into ventricles during rapid filling

Question 27

Splitting of second heart sound

Answer 27

* Delayed interval between aortic and pulmonary semilunar valves shutting allows reduplication of sound (physiological splitting) * Common during inspiration – right pulmonary valve delayed * May occur in various pathologies

Question 28

Murmurs

Answer 28

(i) abnormal sounds heard over heart (ii) turbulent blood flow causes abnormal sound (iii) classic cardiac murmurs = valve disease 1. stenosis – opening of valve is narrowed 2. regurgitation/insufficiency – valve mechanically incompetent allows “back flow”

Question 29

Bruit

Answer 29

(i) abnormal sounds heard throughout vascular system | (ii) turbulent blood flow causes abnormal sound

Question 30

Calculating Target HR

Answer 30

a. Traditional Method • MHR x chosen % = THR b. Heart Rate Reserve Method (Karvonen formula) • [(MHR – RHR)] x chosen % + RHR = THR

Question 31

How to Estimate Max HR

Answer 31

* 220 –age = MHR | * 208 – (0.7 x age) = MHR

Question 32

Stroke Volume

Answer 32

1. Average resting SV = 70 ml, Elite athlete = 90-100 ml 2. “Maximum” SV during exercise = up to 150-200 ml in elite athletes 3. What happens to resting and maximum SV after aerobic training? a. Both increase

Question 33

Cardiac Output

Answer 33

1. CO = SV x HR 2. Average CO at rest = 5 L/min 3. “Maximum” CO during exercise = 20-30 L/min 4. What happens to resting CO after aerobic training? DOES NOT CHANGE = 5 L/min

Question 34

Ejection Fraction

Answer 34

1. EF = percentage of the blood that is ejected from the ventricle • The proportion of the blood pumped out of the left ventricle with each beat. 2. Calculated by dividing the SV by the EDV (end diastolic volume) a. EF = SV / EDV 3. Normal Left ventricular EF (LVEF) at rest ranges 55-68% 4. Normal right ventricular EF (RVEF) is slightly less

Question 35

Clinical Base Lines for Ejection Fraction

Answer 35

5. Clinical base lines (guideline vary from source to source) a. 50-70% considered “normal” (many sources 55-70%) b. 40-50% below normal c. < 35-40% diagnostic and increased “at risk” arrythmia 6. During exercise EF can increase (approx 5-15% above resting value)