L16 Cardiovascular System

Question 1

The pericardium surrounds the heart. What are the layers of the pericardium?

Answer 1

Outermost surface is the parietal pericardium; deep layer is visceral pericardium.

Between the 2 layers is the pericardial cavity.

Question 2

What are the layers of the heart wall?

Answer 2

The most superficial (excluding the pericardium) is the epicardium, then the myocardium (thick muscle), and the innermost layer is the endocardium (epithelium).

Question 3

Where will you find pectinate muscles?

Answer 3

In the atria of the heart

Question 4

From which sources does blood enter the right atrium of the heart?

Answer 4

Superior vena cava (upper body, head)

Inferior vena cava (lower body)

Coronary sinus (heart)

Question 5

From which sources does blood enter the left atrium of the heart?

Answer 5

Via the 4 pulmonary veins

Question 6

What is the pulmonary circuit?

Answer 6

The route that takes blood from the right ventricle to the lungs for gas exchange.

Question 7

What is the systemic circuit?

Answer 7

The route that takes oxygenated blood from the left ventricle to the body tissues.

Question 8

What are the heart valves called and where are they found?

Answer 8

2 Atrioventricular vales (tricuspid on the right, bicuspid/mitral on the left)

2 semilunar valves (one aortic and one pulmonary)

Question 9

Are there any valves between the vena cava/pulmonary veins and their atria?

Answer 9

No - there is some backflow during atrial compression; controlled by compression and collapse of atrial myocardium.

Question 10

Where would you find vasomotor nerves and what is there function?

Answer 10

In the tunica media of blood vessels. They control vasoconstriction to maintain blood pressure and regulate body temperature.

Question 11

What is the tunica media composed of?

Answer 11

Smooth muscle and elastin.

Question 12

What is the tunica adventitia made of?

Answer 12

Loosely woven collagen fibres

Question 13

Where would you not find capillaries?

Answer 13

Ligaments, tendons, cartilage, epithelia, cornea, lens

Question 14

Where would you find sinusoidal capillaries?

Answer 14

Where you require large molecule exchange (large pores) or immune surveillance (sluggish flow).

Liver, bone marrow, lymphoid tissues, endocrine organs.

Question 15

Where would you find fenestrated capillaries?

Answer 15

Regions of active absorption - gut, kidney.

Question 16

True or false: Veins are thinner than arteries, with smaller lumens.

Answer 16

False. While walls of veins are thinner than arteries, they have a larger lumen.

The blood pressure in veins is lower, therefore they don’t need thick walls. But they do need valves to prevent backflow.

Question 17

Where do venous valves form?

Answer 17

Venous valves form from folds in the tunica intima.