Principles of Cardiac Output Part 2

Question 1

treatment of heart failure

Answer 1

• When 1 side of the heart fails, the other side is strained
• Ultimately, the whole heart will fail
• A seriously weakened, or decompensated, heart is irreparable

Question 2

Management of heart failure

Answer 2

• Diuretics: increase excretion of Na+,H2O by the kidneys
• Blood pressure medications to reduce afterload
• Digitalis: increases heart contractility
• Heart transplant

Question 3

development of the heart

Answer 3

• The human heart is derived from mesoderm
• The heart starts pumping at ~22 days gestation

Question 4

4 primitive heart chambers

Answer 4

• sinus venosus
• atrium
• ventricle
• bulbus cordis

Question 5

sinus venosus

Answer 5

receives all venous blood from the embryo – becomes the smooth-walled portions of the atria, the coronary sinus, and the SA node

Question 6

atrium

Answer 6

becomes the pectinate muscle-ridged parts of the atria

Question 7

Ventricle

Answer 7

the strongest part of the embryonic heart – becomes the left ventricle

Question 8

Bulbus Cordis

Answer 8

has a cranial extension – the truncus arteriosus – becomes the pulmonary trunk, part of the aorta, and most of the right ventricle

Question 9

development of the heart

Answer 9

• over the next 3 weeks, the embryonic heart contorts into a double-sided pump
• after the 2nd month of gestation, the heart makes little changes - mostly, it grows
• at/shortly after birth, both bypasses close and the heart is fully divided into right and left

Question 10

foramen ovale

Answer 10

a hole in the interatrial septum, a bypass for the lungs - becomes the fossa ovalis in adults

Question 11

ductus arteriosus

Answer 11

a shunt between the pulmonary trunk and the aorta, another bypass for the lungs - becomes the ligamentum anteriosum in adults

Question 12

congenital heart defects

Answer 12

• about 40,000 infants are born each year with 1 of 30 different congenital heart defects
• congenital heart defects are the most common birth defect
• some congenital heart defects are traceable to environmental influences/in-utero exposures - others are not

Question 13

2 basic types of congenital heart defects

Answer 13

1. Mixing of O2 rich and O2 poor blood – inadequately oxygenated blood reaches the body’s tissues
   Ex: septal defects, patent ductus arteriosus
2. Narrowed valves/vessels increase the heart’s workload
   Ex: Coarctation of the Aorta - really narrow aorta (heart has to work harder to push blood through)

Question 14

Tetralogy of Fallot (4)

Answer 14

a serious condition in which cyanosis appears within minutes of birth - encompasses both types of defects
1. narrowed pulmonary trunk/pulmonary 2. valve stenosed
3. hypertrophied right ventricle
4. ventricular septal defect
aorta receiving blood from both chambers
Typically, surgeries can correct these congenital defects

Question 15

heart function over the lifespan

Answer 15

• Regular, vigorous exercise enlarges the heart and makes it more efficient and powerful
• Aerobic exercise can clear fatty deposits from blood vessels and slow the development coronary heart disease
• The benefits of exercise persist into old age

Question 16

age related cardiac changes

Answer 16

• Thickening/Stiffening of Valves
• Decline of Cardiac Reserve
• Fibrosis of Cardiac Muscle
• Atherosclerosis

Question 17

Thickening/Stiffening of Valves

Answer 17

Worst where the stress of blood flow is highest – the mitral valve

Question 18

Decline of Cardiac Reserve

Answer 18

• The aging heart is less able to respond to sudden and prolonged stresses
• Max HR decreases as SNS activity becomes less efficient

Question 19

Fibrosis of Cardiac Muscle

Answer 19

• Aged cardiac muscle cells die, get replaced by fibrous tissue
• The heart stiffens and SV decreases
• Nodes fibrose and the risk of arrythmias increases

Question 20

Atherosclerosis

Answer 20

• Worsened by inactivity, smoking, poor diet, and stress
• Leads to CAD and HTN + an increased risk of CVA and MI