Cardio Anatomy

Question 1

Describe the basic anatomy of the heart

Answer 1

R atrium, L atrium, R ventricle, L ventricle

Question 2

What are the names of each of the cardiac valves and where are they located?

Answer 2

• Tricuspid, (3) - between R atrium and R ventricle
• Mitral, (also known as bicuspid 2) -between L atrium and L ventricle
• Aortic (3) - between L ventricle and aorta
• Pulmonary valve (3) - between R ventricle and pulmonary artery

Question 3

What arteries supply the heart?

Answer 3

The coronary arteries supply the heart with blood, they are epicardial

Question 4

What supplies the coronary arteries with blood?

Answer 4

The aortic sinuses supply the coronary arteries with blood.
When the heart is relaxed (diastole) back flow of blood fills these small openings behind the R and L flaps of the aortic valve allowing blood to enter the coronary arteries.

Question 5

What causes a MI?

Answer 5

Blockage of a coronary artery

Question 6

Where can an apex beat be heard?

Answer 6

5th intercostal space along the mid-clavicular line

Question 7

What do the papillary muscles of the ventricle attach to?

Answer 7

The papillary muscles of the ventricle attach to the artioventricular valves (tricuspid and mitral) via chordae tendee (or heart strings), this allows the valve to close

Question 8

What is pericardial space?

Answer 8

Pericardial space is potential space between pericardial layers, it is filled by pericardial fluid which lubricates the layers reducing friction. Mesothelial cells produce pericardial fluid.

Question 9

What is a Pericardial effusion?

Answer 9

Pericardial effusion ("fluid around the heart") is an abnormal accumulation of fluid in the pericardial cavity. 
The heart cannot stretch fast enough to accomodate fluid and fluid accumulation leads to an increased intrapericardial pressure. This is compression is known as Cardiac tamponade. (it often occurs after chest trauma-distended neck veins and muffled heart sounds-Emergency Thoracotomy)

Question 10

Which side of the heart is thicker and more muscular and why?

Answer 10

The left side because this side pumps blood to the rest of the body via the aorta.

Question 11

How many veins drain into the L atria.

Answer 11

4 pulmonary veins drain oxygenated blood from the lungs into the L atrium

Question 12

Whats is a) regurgitation b)stenosis

Answer 12

a) regurgitation, this is when a valve is leaky so some blood drains back after the valve has been closed
b) stenosis, this is narrowing of a valve and means that a lower volume of blood can pass through the valve during systole

Question 13

What does the coronary sinus do and where is it located?

Answer 13

the coronary sinus drains blood from the heart muscle into the right atrium

Question 14

What supplies the R atrium with blood?

Answer 14

IVC, SVC and coronary sinus

Question 15

Describe the route of blood through the heart beginning in the IVC

Answer 15

1) The IVC drains de oxygenated blood into the R atrium along with the SVC and coronary sinus
2) The blood passes through the tricuspid valve into the R ventricle
3) Blood passes through the pulmonary valve into the pulmonary artery to the lungs
4) Four pulmonary veins deliver oxygenated blood into the left atrium
5) Blood passes from the L atrium to the L ventricle through the bicuspid/mitral valve
6) Blood passes to the aorta through the aortic valve to the body

Question 16

Describe the layers of the heart wall

Answer 16

• the epicardium (external layer), thin layer of endothelium overlying a thin layer of connective tissue, provides a smooth lining and is continuous with the endothelial lining of the large blood vessels
• the myocardium (middle layer), comprised of cardiac muscle tissue, responsible for pumping
• the endocardium (inner layer), thin delicate connective tissue

Question 17

Explain the changes of texture in the R atrium

Answer 17

The right atrium has a smooth portion from the sinus venosus and trabeculated (from original atrium). The crista terminalis seperates these areas.

Question 18

What is the fossa ovalus?

Answer 18

The fossa ovalus is a depression in the wall of the R atrium. It is the remnant of a thin fibrous sheet that covered the foramen ovale during fetal development.

Question 19

What separates the the smooth and trabeculated sections of the R atrium

Answer 19

The crista terminalis separates the the smooth and trabeculated sections of the R atrium

Question 20

What are intercalated discs?

Answer 20

Cardiac muscle cells cross and link at intercalated discs

Question 21

Describe the most common anatomy of coronary arteries

Answer 21

2 main coronary arteries, R and L.
L main arteries branches into left anterior descending (LAD) and circumflex (Cx)
R artery branches into the posterolateral and posterior descending arteries (70% of population)

Question 22

Describe the anatomy of the LAD

Answer 22

The LAD is a branch of the left coronary artery, it runs in the anterior inter ventricular groove. The LAD gives off septal and diagonal branches to the septum and left ventricular myocardium

Question 23

Describe the anatomy of the circumflex

Answer 23

The Cx runs in the left atrioventricular groove. The Cx gives off obtuse marginal branches to the posterolateral LV wall.
-In 10% of people the Cx provides the posterior descending artery (PDA)

Question 24

Describe the anatomy of the Right coronary artery, what does it supply?

Answer 24

the RCA runs in the right atrioventricular groove.

The RCA usually supplies the sinus node, AV node, and branches to the right ventricle wall

Question 25

Describe the anatomy of the posterior descending artery

Answer 25

The PDA runs in the posterior inter ventricular groove and supplies the inferior septum and Left ventricle

Question 26

What is cardiac dominance?

Answer 26

Dominance refers to the artery (RCA, or Cx) that supplies the posterior descending artery
(70% of the population are R dominant as PDA comes from the Right coronary artery, this is important as the PDA supplies the L ventricle.)
20% are co-dominant as both RCA and Cx supply the PDA
10% are left dominant as Cx supplies the PDA

Question 27

Are most coronary arteries functional end arteries?

Answer 27

Unless collateral supply has developed coronary arteries are functional end, this means they re soley responsible for blood supply to a section of the heart. Therefore if the artery is blocked the tissue may die.

Question 28

What is the mediastinum?

Answer 28

The space between the two pleural cavities and the lungs.
It is divided into the superior mediastinum and the inferior mediastinum.
inferior mediastinum - anterior, middle, posterior
The heart is located in the middle mediastinum.

Question 29

Note the surface markings of the heart. At what position are the following normally found?

a) right border of the heart
b) the apex of the heart

Answer 29

a) right border of the heart - right sternal edge

b) the apex of the heart - 5th intercostal space, mid-clavicular line.

Question 30

Where would you expect to find the

(a) sinoartial node (b) atrioventricular node?

Answer 30

SA node - A ‘long’ crescent shaped area in the crista terminalis at the superior border of the right atrium (the crista terminalis is where the smooth and trabeculated parts of the right venous chamber meet.
AV node - small nodule just above the septal cusp of the tricuspid valve in the inter-atrial septum.

Question 31

How is the heart innervated?

Answer 31

The heart has a rich sympathetic and parasympathetic supply.

• Sympathetic innervate the whole heart and release norepinephrine (receptors are B-adrenergic). The hormone epinephrine, from the adrenal medulla, binds to the same receptors as norepinephrine and exerts the same action
• Parasympathetic terminate mainly on atria cells and release acetylcholine (receptors are muscarinic)