Cardiovascular system

Question 1

What are the main functions of the cardiovascular system?

Answer 1

• Circulates oxygen and nutrients around the body.
• Removes waste products from tissues.
• Maintains body temperature.

Question 2

What are the two types of circulation in the cardiovascular system?

Answer 2

• Pulmonary circulation (heart to lungs and back).
• Systemic circulation (heart to the body and back)

Question 3

What is the pericardium, and what are its functions? - heart

Answer 3

• A fibroserous sac that surrounds the heart.
• Consists of fibrous and serous layers.
• Helps protect the heart and reduce friction.

Question 4

What can happen if the pericardium is pierced?

Answer 4

It can lead to fluid leakage, affecting heart function and potentially causing heart failure

Question 5

Where is the heart located?

Answer 5

In the middle mediastinum (the central chest area between the lungs)

Question 6

What is the asymmetrical shape of the heart?

Answer 6

• The heart’s weight is distributed in a 4:5 ratio between the right and left sides.
• More weight is on the left side.

Question 7

What are the three layers of the heart wall?

Answer 7

• Epicardium (outer layer).
• Myocardium (middle muscle layer).
• Endocardium (inner endothelial layer, continuous with blood vessels).

Question 8

What is the myocardium?

Answer 8

A striated muscle layer that allows the heart to contract and pump blood

Question 9

What is the pericardial cavity, and where is it located?

Answer 9

It is the space between the serous layers of the pericardium where the heart sits

Question 10

What is the apex of the heart?

Answer 10

The pointed lower end of the heart

Question 11

How much does the heart weigh in relation to body mass?

Answer 11

About 0.7% of body mass, but varies from 0.4% to 2%

Question 12

How much does the heart weigh in a racehorse?

Answer 12

Up to 10 kg (compared to 4 kg in an average horse)

Question 13

Why do racehorses have larger hearts?

Answer 13

Due to exercise-induced cardiac remodeling for better performance

Question 14

What causes the lub-dub sound of the heart?

Answer 14

The closing of heart valves

Question 15

How do skeletal muscle cells differ from cardiac muscle cells in action potential generation?

Answer 15

• Skeletal muscle cells require a nerve signal.
• Cardiac muscle cells have intrinsic activity controlled by the sinoatrial (SA) node.

Question 16

What is the sinoatrial (SA) node, and what does it do?

Answer 16

• It is the heart’s pacemaker, located in the atrium.
• It controls heart rate by generating electrical impulses.

Question 17

What is an arrhythmia?

Answer 17

Any abnormality in cardiac electrical activity

Question 18

What is the function of heart valves?

Answer 18

To prevent backflow of blood in the heart

Question 19

What is the atrioventricular (AV) node, and what is its function?

Answer 19

• It slows the electrical signal before it reaches the ventricles.
• Ensures proper contraction sequence.

Question 20

How does the autonomic nervous system regulate the heart?

Answer 20

• Sympathetic stimulation: Increases heart rate.
• Parasympathetic stimulation: Decreases heart rate.

Question 21

What are the three layers of arteries and veins?

Answer 21

• Tunica externa (outer protective layer).
• Tunica media (smooth muscle layer, controls blood flow).
• Tunica interna (endothelial lining of the lumen)

Question 22

How do arteries differ from veins?

Answer 22

• Arteries: Have a thicker tunica media with an elastic layer to withstand high pressure.
• Veins: Have valves to prevent backflow.

Question 23

What are capillaries, and where are they located?

Answer 23

• Tiny blood vessels between arteries and veins.
• Allow gas and nutrient exchange.

Question 24

What is the aorta, and what does it do?

Answer 24

The largest artery in the body, supplying blood to all organs and tissues

Question 25

What are the two main branches of the aorta?

Answer 25

- Cranial branch (supplies the upper body). - Caudal branch (supplies the lower body).

Question 26

What are the main branches of the aorta?

Answer 26

- Brachiocephalic trunk (supplies limbs, neck, and upper body). - Intercostal arteries (supply the vertebrae). - External iliac arteries (supply the hind limbs). - Coeliac artery (supplies the digestive tract).

Question 27

What are facial arteries, and what do they supply?

Answer 27

- External carotid artery: Supplies the face and external head. - Internal carotid artery: Supplies the brain.

Question 28

How are veins named?

Answer 28

They are named similarly to their accompanying arteries.

Question 29

How do veins compare to arteries?

Answer 29

Larger in diameter. Often duplicated (multiple veins for the same artery)

Question 30

How does blood move through vessels?

Answer 30

Driven by heart contractions. Moves from high to low pressure.

Question 31

Why do arteries have low compliance?

Answer 31

Due to their thick muscle layer, which maintains high pressure

Question 32

Why do veins have high compliance?

Answer 32

Their thin muscle layer allows them to accommodate blood volume changes

Question 33

What is vascular resistance, and what affects it?

Answer 33

- The resistance to blood flow created by blood vessels. - Arterioles act as a switch to control blood flow.

Question 34

How does the sympathetic nervous system affect blood flow?

Answer 34

Constriction of arterioles → Smaller diameter → Increased resistance.

Question 35

What are vasoactive agents, and what do they do?

Answer 35

- Paracrine factors (e.g., lactic acid, CO₂) increase metabolism. - Increase capillary perfusion for better oxygen delivery.