heart lecture

Question 1

Where does the heart lay in the body

Answer 1

• Rests on the diaphragm
• 2/3 of the heart lies to the left of the midline
• located within the mediastinum

Question 2

What is in the mediastinum

Answer 2

heart
ascending aorta
SVC
trachea
main stem bronchi
esophagus

Question 3

When does the mediastinum look bigger

Answer 3

on inspiration

Question 4

What is cardiothoracic ratio

Answer 4

widest part of heart and widest part of ribs should be less than 50%
- otherwise congestive heart failure

Question 5

What is in the thoracic cavity

Answer 5

2 pleural cavities and mediastinum

Question 6

What is the pericardium

Answer 6

layer surrounding the heart
keeps heart in the right position

Question 7

2 layers of the pericardium

Answer 7

fibrous pericardium
- stabilizing position of heart and prevents overstretching
serous pericardium
thin more delicate layer
- parietal and visceral layer reduces friction

Question 8

3 layers of heart wall

Answer 8

1. epicardium: viseral layer of pericardium
2. myocardium: striated muscle 95% of heart wall
3. endocardium: smooth inner layer

Question 9

When do you see the left atrium

Answer 9

in a lateral
only see left auricle in PA/AP

Question 10

What is the coronary sinus

Answer 10

enlarged vein that empties venous blood into right atrium

Question 11

What is an auricle

Answer 11

ear like appendage on anterior surface of each atrium
increases capacity of atria

Question 12

Where does the right atrium recieve blood from

Answer 12

SVC & IVC and coronary sinus

Question 13

What is the fossa ovalis

Answer 13

remnant of foramen ovale (opening between right and left ventricle in fetus)

Question 14

What is the trabeculae carnae

Answer 14

form papillary muscles

Question 15

What are the cordae tendinae

Answer 15

stops cuspid valves from flipping in on themselves
attaches to papillary muscles

Question 16

What/Where is pulmonary valve

Answer 16

from right ventricle to pulmonary trunk
located on superior right ventricle

Question 17

Where does left atrium recieve blood from

Answer 17

4 pulmonary veins (oxygenated blood)
contains mitral valve

Question 18

Left ventricle

Answer 18

2-3x thicker than right ventricle because it pumps blood to the whole body
contains aortic valve

Question 19

What is the most ant/post structures of the heart

Answer 19

Ant: Right ventricle
Post: Left atrium

Question 20

How much of the heart touches the sternum

Answer 20

1/3
if larger:RV enlargement

Question 21

Most superior valves of the heart

Answer 21

Pulmonary & aortic

Question 22

Which way do the cusps of Mitral and tricuspid valves go

Answer 22

Project into ventricles
When antria contracts ventricles and chordae tendinaea are relaxed and blood goes from high to low pressure

Question 23

What do the valves do in ventricle contraction

Answer 23

pressure increases
mitral and tri valve close

Question 24

Pathologies of valves

Answer 24

• stenosis: narrowing
• insufficient: failure to close

Question 25

What is the afterload pressure of pulmonary artery

Answer 25

20

Question 26

What is the afterload pressure of aorta

Answer 26

80

Question 27

What is PFO

Answer 27

patent foramen ovale - foramen ovale didnt close - foramen ovale is the opening between atria that closes at birth

Question 28

What is ductus arteriosis

Answer 28

between pulmonary trunk and distal part of aortic arch closes at birth and becomes ligament arteriosum

Question 29

what happens if ductus arteriosus or foramen ovale are open at birth

Answer 29

need a left to right shunt pulmonary hypertension

Question 30

During CPR what part of the heart is pressed on most

Answer 30

right ventricle

Question 31

What are the contractile fibers of the heart

Answer 31

working fibers that contract 99% of cardiac cells

Question 32

Autoryhtmic fibers

Answer 32

-produce their own rythm - make up SA/AV node -1% of cardiac cells

Question 33

what/where is the SA node

Answer 33

- sinoatrial node - pace maker that sets rythm at 100bpm - 70-75bpm during rest - made of autorythmic fibers - located in right atrial wall near opening of SVC**

Question 34

What happens when SA node fails

Answer 34

AV node takes over slower (brachycardic heart rate)

Question 35

What/Where is AV node

Answer 35

- located in interarterial septum superior to the ventricles (near centre of the heart) - slows the speed of the action potentials

Question 36

Order of cardiac cycle and EKG

Answer 36

P wave: atrial depolarization - atrial contraction PR segment: AV nodal delay QRS complex: ventricular depolarization and atrial repolarization ST segment: ventricle contraction and emptying T wave: ventricle repolarization TP interval: ventricles are relaxing and filling

Question 37

How long is the average cardiac cycle

Answer 37

0.8seconds

Question 38

What percent of blood passively flows from atria to ventricles

Answer 38

70% (105ml)

Question 39

What happens duribg atrial systole

Answer 39

blood flow from body to atria from ventricles (diastole) - AV Valves are open SL valves are closed - atrial systole pushes rest of blood into ventricles

Question 40

What happens during ventricle systole

Answer 40

ventricular depolarization

Question 41

What is stroke volume

Answer 41

SV= EDV(end diastic volume) - end systolic volume 130-60ml =70ml

Question 42

What is ejection fraction

Answer 42

stroke volume/end diastic volume(100)

Question 43

What is cardiac output

Answer 43

HR x SV = 75 x 70

Question 44

3 factors affecting stroke volume

Answer 44

1. preload 2. contractility 3. afterload

Question 45

What is the afterload of right and left ventricle

Answer 45

Right: pulmonary trunk 20mmHg Left: aorta 80mmHg

Question 46

What is afterload

Answer 46

Pressure required to eject blood to aorta and pulmonary trunk

Question 47

Where is the caridac centre in the brain

Answer 47

medulla oblongata, contains the cardiovascular centre

Question 48

Carotid sinus

Answer 48

contains chemo and baroreceptors