Heart

Question 1

Where in the body is the heart located?

Answer 1

Mediastinum (between the lungs, extending from the sternum to vertebral column)
2 / 3rds to left of the body

Question 2

Roughly what size is the heart?

Answer 2

The size of a clenched fist

Question 3

Where is the apex of the heart?

Answer 3

(Bottom) tip of the left ventricle

Question 4

Where is the base of the heart?

Answer 4

Formed by the atria (mainly left)

Question 5

What are sulci?

Answer 5

A series of grooves which mark the external boundaries between chambers of the heart

Question 6

What are the anterior interventricular sulcus?

Answer 6

External boundary between ventricles anteriorly

Question 7

What are the posterior interventricular sulcus?

Answer 7

External boundary between ventricles posteriorly

Question 8

What are the superior chamber/s of the heart?

Answer 8

The right and left atria

Question 9

What are the coronary sulci?

Answer 9

External boundary between atria and ventricles

Question 10

What are the inferior chamber/s of the heart?

Answer 10

The right and left ventricles

Question 11

Which blood vessels enter the right atria?

Answer 11

Superior vena cava
Inferior vena cava
Coronary sinus

Question 12

Which blood vessels exit the right ventricle?

Answer 12

Pulmonary artery

Question 13

Which blood vessels enter the left atria?

Answer 13

4 Pulmonary veins

Question 14

Which blood vessels exit the left ventricle?

Answer 14

Aorta

Question 15

Name the 3 main layers of the heart wall:

Answer 15

Endocardium
Myocardium
Pericardium

Question 16

What is the Endocardium?

Answer 16

Inner endothelial lining, covering valves

Question 17

Which structure makes up 95% of the heart wall?

Answer 17

Myocardium

Question 18

What is the Myocardium?

Answer 18

The muscle layer of the heart wall

Question 19

Why do the atria have less Myocardium tissue than the ventricles?

Answer 19

Because they only have to transport blood a small distance (to the ventricles rather than around the whole body) so less contractive force is required and therefore less muscle

Question 20

How is muscle fibres arranged in Myocardium tissue?

Answer 20

Spirally

Question 21

Why does the left ventricle contain 10-15mm of Myocardium tissue whilst the right ventricle contains less than half at 4 -5mm?

Answer 21

Because the left ventricle supplies the majority of the body via the aorta, the right only supplies the lungs through the pulmonary artery

Question 22

Describe the microscopic structure of Myocardium:

Answer 22

Short, branching fibres
50-100μm long, 14μm diameter
Fibres connected by Desmosomes (intercalated discs)
Gap junctions

Question 23

What is the function of Gap junctions in the Myocardium?

Answer 23

They allow action potentials between fibres to act as a domino effect, causing whole chamber contraction.

Question 24

There is a space in the heart cell wall, between which layers is this gap present?

Answer 24

The Parietal pericardium layer and visceral pericardium layer, a.k.a epicardium

Question 25

What are the 2 parts of the Pericardium?

Answer 25

``` Fibrous pericardium Serous pericardium (epicardium) ```

Question 26

What is the pericardium?

Answer 26

The outermost heart layer, a triple layered sac which protects the heart and holds it in position

Question 27

What is the fibrous pericardium?

Answer 27

Tough, inelastic, dense connective tissue

Question 28

What is the serous pericardium?

Answer 28

A delicate membrane, made of parietal and visceral layers

Question 29

What is the function of the fibrous skeleton?

Answer 29

Prevents over stretching of valves Electrical insulator Point of insertion for cardiac muscle

Question 30

What is the fibrous skeleton?

Answer 30

4 dense connective tissue rings surrounding each valve and are fused

Question 31

Where are atrioventricular valves located?

Answer 31

Between the atrium and their corresponding ventricles

Question 32

Where are semilunar valves located?

Answer 32

Between the ventricles and their corresponding arteries

Question 33

What is the function of the atrioventricular valves?

Answer 33

To control the flow of blood between the ventricles and atria

Question 34

What is the function of the semilunar valves?

Answer 34

To regulate the flow of blood leaving the heart

Question 35

What are the atrioventricular valves called?

Answer 35

Tricuspid valve | Mitral valve

Question 36

Where is the tricuspid valve located?

Answer 36

Between the right atrium and the right ventricle

Question 37

Where is the mitral valve located?

Answer 37

Between the left atrium and the left ventricle

Question 38

When do the atrioventricular valves open and close?

Answer 38

They close during the start of ventricular systole and open during atrial systole

Question 39

Explain the structure of the tricuspid valve?

Answer 39

It consists of three cusps, the anterior, septal and posterior. The base of each cusp is anchored to a fibrous ring that surrounds the orifice

Question 40

Explain the structure of the mitral valve?

Answer 40

It is also called the bicuspid valve as it has two cusps, the anterior and posterior. The base of each cusp is anchored to a fibrous ring that surrounds the orifice

Question 41

What are the chordae tendineae?

Answer 41

Fibrous cords attached to the atrioventricular valves to free the edges of the valve cusps

Question 42

What are the papillary muscles?

Answer 42

Located on the interior surface of the ventricles, they contract during ventricular systole to prevent prolapse of the valve leaflets into the atria

Question 43

How many papillary muscles are there, and where are they located?

Answer 43

5 muscles in total, three in the right ventricle and two in the left ventricle

Question 44

Where are the origins of the coronary arteries?

Answer 44

The aortic sinuses

Question 45

Where is the aortic valve located?

Answer 45

Between the left ventricle and aortic orifice

Question 46

Where is the pulmonary valve located?

Answer 46

Between the right ventricle and the pulmonary orifice

Question 47

What are the coronary arteries?

Answer 47

Supply blood to the heart myocardium tissue

Question 48

What is the function of the Left Main Coronary Artery (LMCA)?

Answer 48

Blood supply to the left side of the heart muscle

Question 49

What is the function of the Right Main Coronary Artery (RMCA)?

Answer 49

Blood supply to the right side of the heart muscle

Question 50

Where do the coronary arteries branch from?

Answer 50

The ascending aorta

Question 51

Where does the Sinoatrial and Atrioventricular nodes receive their blood supply from?

Answer 51

The Right Main Coronary Artery (RMCA)

Question 52

What are the smaller branches of the Right Main Coronary Artery (RMCA)?

Answer 52

Right posterior descending artery | Acute marginal artery

Question 53

What are the smaller branches of the Left Main Coronary Artery (RMCA)?

Answer 53

Left anterior descending artery | Circumflex artery