Introduction to CV Anatomy

Question 1

Why do we need a CV system ?

Answer 1

1) all living cells are metabolically active - there is a high demand for O2 and high demand to remove co2
2) larger organisms have a smaller surface area to volume ratio and so need a system to get o2 and nutrients close to cells
3) single celled organisms can get o2 directly by diffusion from the environment

Question 2

Does the heart need it’s OWN blood supply ?

Answer 2

Yes

Question 3

What is the role of the right and left coronary arteries ?

Answer 3

• they are vital to supply well oxygenated blood to the myocardium
• but they are end arteries because they have few anastomoses ( they do not connect together much) so they are more prone to atheroma ( fatty material which deposits in the arteries)

Question 4

How do you remove the pericardial sac from the heart during dissection ?

Answer 4

• you need to make two vertical incisions and one horizontal incision

Question 5

What are the layers of the pericardium ?

Answer 5

• fibrous layer
• parietal layer ( outer serous layer)
• visceral layer ( inner serous layer) also known as epicardium
• myocardium
• endocardium

Question 6

Where is the position of the heart in situ?

Answer 6

• the human heart is located within the thoracic cavity - medially between the lungs in the space known as the mediastinum

Question 7

What is the role of the right side of the heart ?

Answer 7

• the right atrium receives deoxygenated blood from the Vena cava ( superior/ inferior) , which then flows through the right ventricle which pumps the deoxygenated blood out through the pulmonary artery to the lungs where the deoxygenated blood would pick up oxygen in the lungs.
• this is known as the pulmonary circuit

Question 8

What is the role of the LEFT side of the heart ?

Answer 8

• the oxygenated blood that flows from the lungs enters the left atrium via the pulmonary veins. The blood then flows into the left ventricle where it is then pumped out of the aorta to supply oxygenated blood to all body tissues.
• this is known as the systemic circuit

Question 9

What forms the right border of the heart , the left border and the inferior border ?

Answer 9

Right border - right atrium

Left border - left ventricle

Inferior border - mostly right ventricle

Question 10

How to calculate cardio-thoracic ratio and what is considered normal ?

Answer 10

Maximum width of the heart divided by the maximum internal diameter of the thoracic cage.

A normal cardio thoracic ratio is one below 50%. Anything above is considered abnormal

Question 11

Give two reasons why heart shadow may become enlarged

Answer 11

1. Pericardial effusion

2. Ventricular hypertrophy

Question 12

Where on the precordium +( chefs wal) would you feel for the apex beat if the heart is normal ?

Answer 12

In the 5th intercostal space at the mid clavicular line

Question 13

What regions of the heart is supplied by the LAD ?

Answer 13

Anterior left ventricule ( part of it) , Interventricular septum, and part of the right ventricle

Question 14

Describe the sequence of changes in an arterial wall which could lead to arterial occlusion

Answer 14

1. Atheromatous plaque forms.
2. This gets ruptured
3. This allows for a thrombus to form.
4. Thrombus either occluded artery or embolises to occlude a smaller artery.

Question 15

What typical symptoms are experienced by a patient with a MI ?

Answer 15

Central , crushing chest pain which radiates to the arm , neck or jaw.

Question 16

Explain why an occlusion of the right coronary artery is likely to lead to rhythm disturbance?

Answer 16

Because is 60% of individuals the right coronary artery supplies the SA node and 80% individuals the right coronary artery supplies the AV node.

Question 17

What is meant by the term cardiac tamponade ?

Answer 17

Heart becomes compressed and leads to a fall in arterial blood pressure.

Question 18

Why would cardiac output fall in a patient with cardiac tamponade ?

Answer 18

Reduced ventricular filling during diastole and outer fibrous layer cannot expand l