7 structure of the heart

Question 1

Where does the heart lie?

Answer 1

behind the sternum in the mediastinum. behind ribs 2-5.

Question 2

Where is the apex of the heart located?

Answer 2

Behind the 5th rib along the midclavicular line

Question 3

What protects the heart?

Answer 3

• ribs
• sternum
• fibrous periacardum

Question 4

What is the job of the fibrous pericardium

Answer 4

• tough unstretchy bag that stops the heart from over filling
• attached to the diaphragm and fused to the great vessels
• to anchor the heart in place

Question 5

What is the structure of the fibrous pericardium?

Answer 5

• visceral and parietal pericardium
• parietal attached to the fibrous
• FP made of dense CT
• visceral (epicardium) attached to the heart wall
• serous fluid between the membranes makes movement frictionless
• gap between membranes = parietal cavity

Question 6

What are the layers of the heart wall?

Answer 6

• epicardium/visceral pericardium
• myocardium
• endocardium

Question 7

What does the epicardium contain?

Answer 7

lots of fat and blood vessels

Question 8

What does the myocardium contain?

Answer 8

Lots of muscle - very thick layer

Question 9

What does the endocardium consist of?

Answer 9

simple squamous endothelial cells for a smooth interior of the heart wall

Question 10

What is another name for the visceral pericardium?

Answer 10

Epicardium

Question 11

What is the name of the gap between the visceral and parietal pericardium?

Answer 11

Parietal cavity filled with serous fluid so two pericardial layers can glide on each other with no friction

Question 12

Where is the bi cuspid valve?

Answer 12

between the left ventricle and atria

Question 13

Where are the mitral valves?

Answer 13

between the ventricles and atria

Question 14

Where are the semilunar valves?

Answer 14

Between the ventricles and aorta/pulmonary artery

Question 15

Where are the atrioventricular valves?

Answer 15

where do you think, stupid?

Question 16

Where is the tricuspid valve?

Answer 16

between the right ventricle and atrium

Question 17

Talk about the action of the AV valves…

Answer 17

• conncted to papillary muscles by chordae tendinae
• as atria fills and pressure builds they open into ventricles
• as ventricles fill and pressure builds they are pushed back up and try to open into the atria causing eversion
• papillary muscles tense up and pull chordae tendinae tight preventing them from doing this

Question 18

Whats eversion?

Answer 18

Flow of blood back into the atria due to backwards valves

Question 19

Action of the semilunar valves:

Answer 19

• pushed open when ventricular pressure exceed aortic pressure
• during diastole they are pushed shut by blood pooling in the cusps

Question 20

How are the coronary vessels fed?

Answer 20

• when systole the semilunar valves cover the entrance to them
• during diastole blood pooled on the cusp flows into the vessels to feed heart
• better this way coz otherwise vessels would be all squeezed up

Question 21

What are the coronary vessels?

Answer 21

LCA 
-anterior inter ventricular vessel
-circumflex 
RCA
-posterior interventricular vessel 
-marginal

Question 22

Which artery does the anterior interventricular vessel come off

Answer 22

LCA

Question 23

Which artery does the posterior interventricular vessel come off

Answer 23

RCA

Question 24

Where is the circumflex

Answer 24

vessel that wraps from the front of the hear round the back around aorta

Question 25

Where do the coronary vessels drain to?

Answer 25

either into the coronary sinus and into the right atria or straight into the right atria

Question 26

What happens if one of the coronary vessels is damaged?

Answer 26

Theres an anastamoses between the anterior and posterior interventricular vessel so they can share blood. otherwise tissue death and potential heart failure

Question 27

How much blood per minute do the coronary vessels get?

Answer 27

250ml

Question 28

What is the anterioventricular artery also known as?

Answer 28

The descending artery

Question 29

What does the conducting system of he heart consist of?

Answer 29

Non contractile elements such as AVN SAN and bundle of his

-However they are adjacent to cells that do contract

Question 30

Talk about contraction of the heart

Answer 30

• when one cell contracts all the cells around it do too so can cause contraction from a specific point
• starts at SAN –> spreads through atria but conat conduct through fibrous skeleton
• must continue through the AVN and down the R and L bundles of his to the apex

Question 31

Foetal adaptations in circulatory system:

Answer 31

• Ductous venosus
• Ductus artereosis
• Foreman ovale

Question 32

Flow of blood through the foetus:

Answer 32

• in through umbilical vein from placenta (o2 rich ish)
• either through the liver or ductous venousus to inferior vena cava (bringing blood from the legs to the heart) - into the heart where it all mixes through DA and FO
• out of the heart to body/lungs - some to feet and bladder but most back to placenta

Question 33

Where is the Foreman ovale?

Answer 33

hole between right and left atria

Question 34

Where is the ductous arteriosis?

Answer 34

linking pulmonary trunk to the aorta

Question 35

What happens to the foreman ovale after birth

Answer 35

-left atrial pressure increases and causes it to slam shut producing the fossa ovale

Question 36

What happens to the ductus venosus after birth?

Answer 36

it doesn’t get blood from the umbilical vein anymore so it shrivels up and becomes ligamentum venosum

Question 37

What happens to the ductous arteriosis after birth?

Answer 37

the baby takes its first breath which expands the lungs causing the pressure in them to drop. this draws more oxygenated blood up towards them causing it to constrict and become ligamentum arteriosum