Canine Circulatory System: Heart, Vessels and Blood Flow

What are the main components of the mammalian circulatory system?

Lungs, Heart, and Blood Vessels.

What is the function of the pulmonary circulation?

It conveys deoxygenated blood from the heart to the lungs for oxygenation and returns oxygenated blood to the heart.

What is the role of the systemic circulation?

It conveys oxygenated blood from the heart to the organs and transports deoxygenated blood back to the heart.

What determines the directional flow of blood within the heart?

The presence of valves.

What are the two types of atrioventricular (AV) valves in the heart?

Right and Left Atrioventricular (AV) valves.

What is the function of the semilunar valves?

They prevent blood from flowing back into the heart.

What heart sound corresponds to the closure of the AV valves?

Lub.

What heart sound corresponds to the closure of the semilunar valves?

Dub.

Where is the heart located in the canine thoracic cavity?

Between ribs 3-6, angled with its base cranial and dorsal to the apex.

What is the cardiac notch?

The region of the heart in direct contact with the body wall.

What are the three layers (tunics) of blood vessels?

Intima, Media, and Adventitia.

What is unique about capillaries compared to other blood vessels?

Capillaries consist of only the intima layer.

What is the primary function of arteries?

To carry blood at high pressure away from the heart.

What are veins considered in terms of pressure?

Capacitance vessels that carry blood at low pressure.

What structural feature prevents backflow in larger veins?

Valves.

What is the role of lymphatic capillaries?

To return excess tissue fluid (lymph) to the blood vascular system.

What is the aorta's role in the systemic circulation?

It exits the left ventricle and distributes oxygenated blood to the body.

What branches does the brachiocephalic trunk form in carnivores?

Right and Left Common Carotid arteries and Right Subclavian artery.

What do the visceral branches of the abdominal aorta supply?

The foregut, midgut, and hindgut.

What is the function of the renal arteries?

To supply blood to the kidneys.

What is the hepatic portal system?

An indirect venous return from the gastrointestinal tract into the caudal vena cava.

What are common blood sample sites in canines?

External Jugular veins, Cephalic veins, and Lateral Saphenous veins.

How does blood flow change during exercise?

Dilation of arteries supplying muscles increases blood flow from 25% to up to 75%.

What is the primary role of the tunica media in blood vessels?

To allow for stretch and constriction, enabling variable distribution of blood.

What type of blood vessels are arterioles?

The final branches of the arterial system embedded in tissues.

What is the primary function of capillaries?

To facilitate the exchange of substances between blood and tissues.

What is the significance of the pericardium?

It is the serous sac surrounding the heart.

What happens to blood flow to 'non-essential' organs during exercise?

Perfusion is reduced but not stopped.