3 Control of Cardiac output/Congenital Heart Self study Questions

Question 1

The Frank Starling curve is sometimes plotted as stroke volume vs venous pressure or stroke volume vs end diastolic volume.

What is the relationship between central venous pressure (CVP) and EDV?

Answer 1

An increased central venous pressure will lead to increased filling of the ventricles in diastole (therefor increased EDV)

Question 2

What is the physiological range for central venous pressure?

Answer 2

Central venous pressure is usually measured in cmH20 and should be less than 8cmH20

Question 3

What factors can increase or decrease CVP?

Answer 3

• Increased circulating volume can increase CVP
• CVP will be increased if something obstructs the heart form filling or if the heart is unable to pump out sufficient blood and there is ‘backlog’
• Reduced circulating volume can decrease CVP

Question 4

How will the left ventricle respond if more blood is driven into it from the pulmonary circulation?

Answer 4

If more blood returns to the ventricle it will pump more out

Question 5

What mechanism ensures that the right and left side of the heart pump the same amount of blood per minute?

Answer 5

The Frank-Sterling mechanism ensures that the left and right side of the heart maintain the same output

Question 6

In what direction will blood flow through a ventricular septal defect, assuming there are no other abnormalities?

Answer 6

Blood will flow from the left to the right because the pressure on the left side will be higher

Question 7

Is a ventricular septal defect cyanotic?

Answer 7

No but is bad

Question 8

What is coarctaion of the aorta?

Answer 8

Narrowing of the aorta at the point where the ligamentum arteriosum forms

Question 9

What is the ligamentum arteriosum?

Answer 9

A small ligament that is the remnant of the ductus arteriosus

Question 10

What would you expect the femoral pulse to be like in a patient with coarctation of the aorta?

Answer 10

The femoral pulses will be weak and there will be a delay between the radial and femoral pulses

Question 11

What are the group of cardiac defects known as tetralogy of Fallot?

Answer 11

Ventricular septal defect, over-riding aorta, pulmonary valve stenosis, hypertrophy of the right ventricle

Question 12

Is tetralogy of fallot cyanotic?

Answer 12

Infants with tetralogy of fallot become cyanotic because there is mixing of deoxygenated blood returning from the body with oxygenated blood being pumped out to the systemic circulation

Question 13

Describe the transposition of the great arteries?

Answer 13

Basically the aorta and pulmonary artery have swapped places, so deoxygenated blood returning to the right side of the heart is pumped back around the systemic circulation, and oxygenated blood returning from the lungs is pumped back to the lungs, have two circulation working independently

Question 14

Is transposition of the great arties compatible with life after birth?

Answer 14

No, either need to maintain specific shunts., ductus arteriosus and foramen ovale and have corrective surgery

Question 15

Name some genetic defects or syndromes associated with cardiovascular defects?

Answer 15

marfans, turner syndrome, trisomy 21

Question 16

What does the Ductus Arteriosus do?

Answer 16

Connects the pulmonary artery to the aorta, leads to blood ejected from the right ventricle bypassing the lungs and going directly into the systemic circulation