Week 1: Module 1 Pt. 1

Question 1

What is the pulmonary circuit?

Answer 1

Right side of the heart, carries deoxygenated blood towards lungs for gas exchange and then back to the heart.

Question 2

What is the systemic circuit?

Answer 2

Left side of the heart, carries oxygenated blood to all tissues and then back to the heart.

Question 3

Where is the heart located?

Answer 3

In the mediastinum, between the 2nd and 5th ribs between the lungs.

Question 4

What are the 3 main layers of the Pericardium?

Answer 4

1. Fibrous pericardium: anchoring and structural support.
2. Serous Pericardium: connects fibrous pericardium to Epicardium.
3. Pericardial cavity: contains serous fluid for lubrication.

Question 5

What’s are the main layers of the heart wall?

Answer 5

1. Epicardium: visceral layer of pericardium.
2. Myocardium: muscle layer of the heart, bulk of heart.
3. Endocardium: lining of chambers and valves. (Epithelium cells are similar to endothelium of blood vessels)

Question 6

What’s the internal heart structure like?

Answer 6

4 chambers separated by:
- 2 atrium: separated by a thin interatrial septum.
- 2 ventricles: separated by a thick muscular inter-ventricular septum.

Question 7

What’s the external heart structure like?

Answer 7

1. Coronary sulcus: (atrioventricular groove) encircles the heart.
   - also has thin walls called auricles to increase blood flow.
2. Inter-ventricular sulcus: separates left and right.

Question 8

What are sulcus/sulci?

Answer 8

Indentations on the surface of the heart.

Question 9

What does both sulcui contain?

Answer 9

Coronary vessels

Question 10

What are atria and ventricles separated by?

Answer 10

Atrioventricular valves (AV):
1. Tricuspid
2. Bicuspid/mitral valves.

Question 11

What do valves do?

Answer 11

They control blood flow and prevent back flow.

Question 12

What are associated AV structures?

Answer 12

Papillary muscles that are connected to AV valves via Chordae Tendinae to keep valves tightly shut during ventricular contractions.

Question 13

What is the difference between diastole and systole?

Answer 13

Diastole: Ventricular filling; blood flow is driven by pressure gradient (relaxation)
Systole: Ventricular contraction; driven by inter-ventricular pressure.

Question 14

Why is the myocardium in the left ventricle thicker than the right ventricle?

Answer 14

The systemic circuit encounters more resistance in long pathways.

Question 15

What does an artery blockage caused by arteriosclerosis cause?

Answer 15

Muscle death. Myocardial infarction.

Question 16

How is blood and nutrients delivered to the heart?

Answer 16

Through coronary circulation. By the right and left coronary arteries.

Question 17

What are the main right coronary arteries?

Answer 17

1. Posterior inter-ventricular artery: supplies right and left ventricle.
2. Right marginal artery: supplies right ventricle.

Question 18

What are the main left coronary arteries?

Answer 18

1. Circumflex artery: supplies right and left ventricle.
2. Anterior inter-ventricular artery: left ventricle.

Question 19

What vein is known as the “widow maker” and why?

Answer 19

Anterior inter-ventricular artery due to high death caused by infarction.

Question 20

How is venous blood drained from the heart?

Answer 20

1. Small cardiac vein: drains right ventricle.
2. Middle cardiac vein: drains posterior right and left ventricle.
3. Great cardiac vein: runs parallel to LAD and drains into coronary sinus.
4. Coronary sinus: drains into right atrium along with SVC and IVC.

Question 21

What is the foramen ovale?

Answer 21

In fetal development, it is a hole in the interatrial septum to allow blood to bypass pulmonary circulation as fetuses do not have lungs.

Question 22

What is the ductus arteriosis?

Answer 22

In feral development, it bridges together the pulmonary trunk and descending aorta to allow blood to be pumped to the placenta and not the lungs (babies don’t have lungs yet).

Question 23

What are the main structures of cardiomyocytes?

Answer 23

1. Desmosomes: holds cells together.
2. Gap junctions: allows ions to flow through cells.
   Together this makes a functional syncytium.