Cardiovascular system

Question 1

What is the relationship between visceral pericardium and heart? What is the name of the outer wall of heart?

Answer 1

This visceral pericardium is like a blanket that wraps all around the heart now, because it wraps around the heart, it forms the outer walls of the heart.
So the outer wall of the heart is what we call the epicardium.

Question 2

What is the relationship between visceral and parietal layer?

Answer 2

Visceral layer of serous pericardium are route of blood vessels, and they become continuous with parietal pericardium.

Question 3

Which two areas will the visceral and parietal layers meet?

Answer 3

Ascending aorta.

Inferior vena cava and some associated veins

Question 4

Which two areas will the visceral and parietal layers meet?

Answer 4

Ascending aorta.

Inferior vena cava and some associated veins.

Question 5

What are the two types of serous (delicate) pericardium?

Answer 5

Parietal and visceral layer.

Question 6

Does visceral layer cover inner or outer surface of heart?

Answer 6

Outer layer.

Question 7

Where is the pericardial cavity found?

Answer 7

Between 2 serous layers.

Question 8

What is the fibrous (tough) pericardium?

Answer 8

Sac of the fibrous connective tissue that envelopes heart.

Question 9

What does the fibrous pericardium attach to?

Answer 9

Attaches to adventitia (outermost layer of blood vessels) + central tendon of diaphragm + posterior surface of sternum via sternopericardial ligaments.

Question 10

What is the function of fibrous pericardium?

Answer 10

To hold the heart in place and limit extension of heart when heart starts pumping blood out.

Question 11

What is the ability of the fibrous pericardium, when the fluid accumulates slowly and rapidly?

Answer 11

Slow accumulation: Fibrous pericardium has ability to slowly straighten and adapt to changes in in shape, which will occur because of accumulation of this fluid.

Rapid accumulation: Fibrous pericardium doesn’t have elastin in its walls -> therefore it is not able to stretch fast -> thus fluid that accumulates within pericardial cavity will start compressing the heart -> if heart becomes compressed, ventricles start receiving less blood -> thus less amount of blood that gets accumulated in ventricles will result in less amount of blood to be pumped out into lungs and rest of the body -> thus heart will have to start pumping faster to be able to push more blood out of body towards lungs (hypertension = force of blood against artery walls is too high). This is called tachycardia (fast movement of heart).

Question 12

What do the phrenic nerves innervate? What else is located in fibrous pericardium?

Answer 12

Phrenic nerves pass through pericardium and innervate it. Pericardiophrenic vessels are also located in fibrous pericardium.

Question 13

Where is the heart located in the body?

Answer 13

Located left of the body midline; posterior to the sternum in the middle mediastinum.

Question 14

Which side of heart (left or right) is located more anteriorly and posteriorly?

Answer 14

Right side (right atrium and ventricle) is located more anteriorly. 
Left side (left atrium and ventricle) is located more posteriorly.

Question 15

What is the anterior part of the heart dominated by?

Answer 15

Anterior part of the heart is dominated via right ventricle, and also small part of right atrium.

Question 16

What does obtuse separate and what is it formed by? What is the inferior margin formed by?

Answer 16

Obtuse margin, separates anterior part of heart from left pulmonary aspects of heart, and is formed predominantly via left ventricle and left auricle.

Inferior margin is formed via right ventricle and small part of left ventricle.

Question 17

What is the left and right pulmonary surface of heart associated with?

Answer 17

Left pulmonary surface of heart is associated with left lung, but also with left ventricle and left atrium.
Right pulmonary surface is associated with right lung and right atrium.

Question 18

What does the diaphragmatic surface consist of?

Answer 18

Diaphragmatic surface of heart consists of left ventricle, very small part of right ventricle

Question 19

What is the apex of heart formed via?

Answer 19

Apex of heart is formed via left ventricle.

Question 20

What is the base of heart predominantly occupied by?

Answer 20

Base is predominantly occupied by left atrium, but also has small part of right atrium.

Question 21

Outline the full process of oxygen poor blood being delivered from heart to lungs and then to rest of body to supply nutrients.

Answer 21

Poor oxygen blood from superior vena cava flows into right atrium -> this blood will come down to right ventricle -> blood will pump into pulmonary trunk via pulmonary vessels. In this case the pulmonary artery will leave the heart and get into lungs for oxygenation. Oxygen rich blood will return back to heart via pulmonary veins -> pulmonary veins will pass down into left ventricle and then it will be pushed into aorta -> via branches of aorta, blood will flow to whole body and supply oxygen and nutrients.

Question 22

What is the epicardium supply myocardium?

Answer 22

The epicardium contains blood vessels, but also lymphatics and nerves, and these supply myocardium.

Question 23

Which is the thickest of three walls, and what is its role?

Answer 23

Myocardium.
Myocardium is responsible for pumping blood, for pumping action of heart.
This is the reason why it has a lot of cardiac muscle, that is having different fibre orientation.

Question 24

What does the different fibre orientation of cardiac muscle facilitate?

Answer 24

It facilitates compression that this layer requires in order to pump large volumes of blood out of heart.

Question 25

What is the epicardium supply myocardium?

Answer 25

The epicardium contains blood vessels, but also lymphatics and nerves, and these supply myocardium.

Question 26

Which is the thickest of three walls, and what is its role?

Answer 26

Myocardium.
Myocardium is responsible for pumping blood, for pumping action of heart.
This is the reason why it has a lot of cardiac muscle, that is having different fibre orientation.

Question 27

What does the different fibre orientation of cardiac muscle facilitate?

Answer 27

What does the different fibre orientation of cardiac muscle facilitate?

Question 28

What is the innermost layer of the heart wall called? What surfaces of the heart does it form?

Answer 28

Endocardium.

It forms external surfaces of valves of heart.

Question 29

Explain the full process of blood circulation when it is poor in oxygen, to how it supplies to organs of rest of body.

Answer 29

During pulmonary circulation, blood poor in oxygen arrives into heart from superior vena cava -> which drains structures, tissues and organs above diaphragm. Also blood gets into right atrium via inferior vena cava, which drains structures, organs and tissues below diaphragm.

Oxygen poor blood arrives via these blood vessels into right atrium -> then to right ventricle -> oxygen poor blood flows into pulmonary trunk -> to pulmonary artery -> goes to lung for oxygenation.

Once blood becomes oxygen rich, it comes back into heart via pulmonary veins -> to left atrium -> blood will get down into left ventricle -> ascending part of aorta -> by branch it will go to rest of the body.

Question 30

What is sinus venarum?

Answer 30

Sinus venarum is nothing but space where blood flows from superior vena cava to inferior vena cava.

Question 31

What is the boundary between pectinate muscle and sinus venarum called?

Answer 31

Crista terminalis.

Question 32

How is the fossa ovalis formed?

Answer 32

During embryonic development, foetus is within placenta and shunts blood from right atrium to left atrium, because during embryonic development, it goes from right to left atrium via the foramen, which after birth closes and creates fossa ovalis.

Question 33

Right atrium receives blood from _____ sinus. What is the role of ___ sinus?

Answer 33

Coronary sinus.
Coronary sinus collects oxygen poor blood from heart via cardiac veins, and anterior cardiac veins drain the walls of heart.

Question 34

Where is the SA node found?

Answer 34

Right atrium around entry point of superior vena cava is SA node (this is pacemaker of cell), and very important during conduction of heart.

Question 35

Where is the atrioventricular node found?

Answer 35

Atrioventricular node is located between beginning of right ventricle, and it slows down conduction of the heart.

Question 36

Via which valve does oxygen poor blood flow into right ventricle and from right atrium into right ventricle? What abilities do these valves have?

Answer 36

Oxygen poor blood will flow into right ventricle, and this happens via passing of tricuspid valve. Tricuspid valve has ability to control when blood will flow from right atrium to ventricle.

The movement of oxygen poor blood from right atrium into right ventricle happens via right atrioventricular valve.
This valve is important coz it has ability to control when blood will flow from right atrium to right ventricle.

Question 37

What do the tricuspid valves attach to? What does the contraction and relaxation of this attachment lead to?

Answer 37

The tricuspid valves attach to muscle called papillary muscles. Attachment happens via little fibres, called chordae tendinae.

Contraction of this papillary muscles when heart is in conduction will pull the chordae and close heart valve. Relaxation of these muscles will lose chordae and open heart valve.

Question 38

What is the structure of trabecula carnae?

Answer 38

Irregular small muscle ridges.

Moderator band makes a bridge called Interventricular septum (located b/w right and left ventricles).

Question 39

What ability does moderator band have?

Answer 39

As blood flows from right ventricle, band has ability to prevent extension of right ventricle.

Blood flows from right ventricle into pulmonary trunk via pulmonary valve (semilunar tricuspid). Called semilunar because it doesn’t have chordae tendineae.

Question 40

Why does pulmonary valve have to be small?

Answer 40

Pulmonary valve has to be small so that blood can go straight into pulmonary trunk with no disturbances.

Question 41

In the left atrium, describe the whole process in which oxygen rich blood ends up in left ventricle.

Answer 41

Oxygen rich blood will come to left atrium via pulmonary veins -> blood will pass from atrium -> to left ventricle via left AV valve.

Question 42

Compare the two atria of the heart.

Answer 42

Two atria look similar and have similar demands; used to collect blood returning to heart, and convey blood to ventricles.

Question 43

Compare two ventricles of heart.

Answer 43

Lungs are close to heart. Pulmonary blood vessels are short and wide, meaning right ventricle does not have to work very hard to push blood through pulmonary segway. Thus right ventricle is thin, approx 3-4 mm.

Left ventricle needs 4-6 times more pressure in order to push blood through systemic circuit, thus this is why it has a thicker wall.
So left ventricle has to push blood into aorta, and from aorta, blood goes to whole body. There is also bigger distance b/w aorta and ventricle. So, left ventricle needs to contract more and it needs a thicker wall.

Left ventricular wall has thicker ventricular wall than right one, as it needs to produce more force to push blood from left ventricle into aorta and supply with blood to rest of the body.

Question 44

What is the structure of cardiac skeleton?

Answer 44

Fibrous connective tissue that surround valves. Also forms an interconnection of cardiac skeleton between four valves, happening via left and right fibrous trigone.

Question 45

What are the functions of the cardiac skeleton?

Answer 45

• Keeps orifices of valves open
  
  • Prevents the valves from being overly distended
  • Separates atrial from ventricular musculature
  • Attachment site of valve cusps
  • Attachment of myocardium
  • Forms electrical insulation between atria and ventricles

Question 46

What is the main function of these valves?

Answer 46

To maintain unidirectional blood flow.

Question 47

Between which two structures is the interventricular sulcus located between?

Answer 47

Anterior interventricular sulcus is located b/w right and left ventricle.

Question 48

What is within the anterior sulcus? What is alongside this structure?

Answer 48

Anterior interventricular artery.

Alongside anterior interventricular artery is the great cardiac vein.

Question 49

What structure separates the right and left atrium? What does this structure contain? What is alongside the component of the structure?

Answer 49

Posterior interventricular sulcus separates right and left atrium. It contains posterior interventricular artery.
Alongside posterior interventricular artery, there is a middle cardiac vein.

Question 50

What is the biggest vein of the heart?

Answer 50

Coronary sinus

Question 51

The major blood supply of heart occurs via what?

Answer 51

Coronary arteries (there two; right and left one). 
Then they take blood to ascending aorta.

Question 52

Where do the left and right coronary arteries arise from and at which angles?

Answer 52

Left coronary artery from left aortic sinus. At an acute angle.
Right coronary artery from right aortic sinus. At a right angle.

Question 53

What does the right coronary artery branch into?

Answer 53

Arteriole branches -> that then branch into right marginally artery -> branches posteriorly into posterior descending artery.

Question 54

What is right dominant heart? How many percentage of people are right dominant? What is left dominant heart?

Answer 54

Right dominant heart = Posterior interventricular artery branches into right coronary artery.
80-85% are right dominant.
Left dominant heart = posterior interventricular artery = branch of circumflex artery.

Question 55

What does the left coronary artery branch into?

Answer 55

The left coronary artery branches into left anterior descending branch or anterior interventricular artery, also it branches into left circumflex branch.

Question 56

Which areas does the right coronary artery supply blood with?

Answer 56

• Right atrium
  
  • Right ventricle
  • Posterobasal wall of left ventricle
  • Interatrial septum
  • Sino-atrial and atrioventricular nodes
  • Posterior 1/3 of interventricular septum (in right dominant)

Question 57

What are the two branches of the left coronary artery? What areas do these branches supply blood to?

Answer 57

Circumflex artery:
Supplies blood to left atrium, parts of left ventricle and also one third of the Interventricular septum.

Anterior interventricular artery:
Supplies blood to apex of heart, anterior wall of left ventricle, anterior 2/3 of interventricular septum and bundle branches of conducting system.

Question 58

What does the small cardiac vein run alongside? And what drains into it?

Answer 58

Small cardiac vein runs alongside right coronal artery and sometimes right marginal vein drain into it.
When right marginal vein does not drain into small cardiac vein, it will drain into right atrium.

Question 59

Where does an anterior vein directly drain into?

Answer 59

Anterior veins do not drain into the coronary sinus, but drain directly into right atrium.

Question 60

Where do small, middle and great cardiac veins drain into?

Answer 60

Small, middle and great cardiac veins all drain into the coronary sinus. Coronary sinus collects blood from all other veins and then it will take these blood into right atrium of heart. And then from their blood will get into right ventricle, pulmonary back to lungs and then left atrium and left ventricle into aorta.

Question 61

What is the heartbeat initiated? What is its function?

Answer 61

Sinoatrial node.
Pumping blood out the cells of SA node. It will act as pacemaker and arhythmic centre that establishes the pace for this cardiac activity comes from SA node. Then via parasympathetic innervations -> SA node will initiate pulses -> then impulses will travel from SA node into AV node -> AV slows down conduction of impulses, as impulses travel from atria to ventricles -> it will provide some sort of delay b/w activation and contractions of the ventricles.

Question 62

What is the heartbeat initiated? What is its function?

Answer 62

Sinoatrial node.
Pumping blood out the cells of SA node. It will act as pacemaker and arhythmic centre that establishes the pace for this cardiac activity comes from SA node.

Question 63

Describe how ventricular contractions are achieved via the sinoatrial node?

Answer 63

Pumping blood out the cells of SA node. It will act as pacemaker and arhythmic centre that establishes the pace for this cardiac activity comes from SA node.
Then via parasympathetic innervations -> SA node will initiate pulses -> then impulses will travel from SA node into AV node -> AV slows down conduction of impulses, as impulses travel from atria to ventricles -> it will provide some sort of delay b/w activation and contractions of the ventricles. From AV node, it will pass into AV bundle -> Via opening in fibrous skeleton, it allows AV node to communicate with other parts of conducting system, as it will transfer signals down into the left and right branches (called purkinje fibres) -> these activate contractions of ventricles.

Question 64

What is the full process of diastole and systole in the heart?

Answer 64

B. When heart starts moving at the beginning of diastole, pulmonary and aortic valves close -> there is no blood that will go from ventricles into major blood vessels. AV nodes are also closed -> so blood cannot go from atrium to ventricle.
C. AV valves open (this happens early during diastolic) -> then blood flows into ventricles. Pulmonary and aortic valves are closed, so blood is accumulated into ventricles, but cannot get into pulmonary trunk and aorta.
D. Not all of blood flows from artery into ventricles. But, atria contracts -> remaining blood flows into ventricles again, the semi-lunar valved are closed.
E. Atrioventricular valves will close, semi lunar valves will open. Very soon the systole will start.
Aortic and pulmonary valves will open and allow blood to flow into blood vessels.