Cardiovascular System Questions and Answers

Answer: D

The vessels carrying oxygenated blood are 2 and 4 only: the pulmonary vein and the systemic artery.

Blood is oxygenated in the lungs and returns to the left atrium through the pulmonary veins. The left ventricle then pumps it through the aorta and the systemic arteries to the body.

The pulmonary artery is the exception among arteries: it carries deoxygenated blood from the right ventricle to the lungs. Systemic veins return deoxygenated blood from the body to the right atrium. So options with 1 or 3 are wrong.

Answer: A

The jugular vein is located in the neck.

The external jugular vein runs down each side of the neck in the jugular groove, carrying blood from the head back to the heart. It is large and close to the surface, so in cattle, sheep, goats and horses it is the usual site for collecting blood and for intravenous injection.

The tail (coccygeal) vein is another collection site in cattle, but it is not the jugular. The limbs carry the cephalic and saphenous veins, used mainly in dogs and cats.

Answer: D

The study of the circulatory system is angiology.

Angiology (Greek angeion, vessel) is the branch of anatomy dealing with the heart, blood vessels and lymphatic vessels.

Arthrology is the study of joints, myology of muscles, and esthesiology of the sense organs.

Answer: C

Thrombocytes function in blood-clotting.

Thrombocytes (platelets in mammals) gather at a damaged blood vessel, stick together to form a plug, and release substances that start the clotting cascade, stopping bleeding.

Phagocytosis is carried out by neutrophils and macrophages, erythrocytes carry oxygen themselves and need no transport, and detoxification of foreign proteins is a job of the liver and the immune system.

Answer: D

Nucleated erythrocytes and thrombocytes are found in the blood of the chicken.

Birds, like reptiles, amphibians and fish, have oval red blood cells that keep their nucleus, and their thrombocytes are also nucleated cells rather than cell fragments.

Mammals such as the cat, goat and horse have red cells that lose their nucleus as they mature, and their platelets are small fragments of megakaryocytes without a nucleus.

Answer: B

The life span of erythrocytes is 120 days.

Red blood cells have no nucleus and cannot repair themselves. After about 120 days in circulation they become fragile and are removed by macrophages, mainly in the spleen and liver, where their haemoglobin is broken down into bilirubin and recycled iron.

160, 140 and 180 days are all longer than the normal red cell life span. By contrast, platelets survive about 7 to 10 days and many white cells only hours to days.

Answer: B

The largest cell in the bone marrow is the Megakaryocyte.

Megakaryocytes are giant cells, often 50 to 100 micrometres across, with a large lobed nucleus. Fragments of their cytoplasm break off to form the platelets that circulate in the blood.

Lymphocytes and neutrophils are far smaller white blood cells. Monocytes are the largest cells in normal circulating blood, which is the usual trap, but they are much smaller than megakaryocytes.

Answer: A

Cardiac output is stroke volume × heart rate per minute.

Cardiac output is the volume of blood the heart pumps each minute. Stroke volume is the volume ejected by the left ventricle in one beat.

\[ \begin{aligned} \text{CO} &= \text{SV} \times \text{HR} \\ &= 70\ \text{ml} \times 72\ \text{/min} \\ &\approx 5\ \text{L/min} \end{aligned} \]

Respiratory rate concerns breathing, not the heart. End-systolic and end-diastolic volumes are used to work out stroke volume itself (EDV minus ESV), so multiplying stroke volume by either of them gives no meaningful output.

Answer: C

The correct matching is 1-b, 2-d, 3-c, 4-a.

Lymph is the fluid that contains lymphocytes (1-b). Lymph capillaries are blind-ended tubes in the interstitial spaces that collect tissue fluid (2-d). Lymph nodes filter the lymph and trap microbes (3-c). The spleen is the largest lymphoid organ (4-a).

The other options misplace the capillaries or the spleen; for example, 1-a would make lymph itself the largest lymph organ.

Answer: B

The correct matching is 1-b, 2-a, 3-d, 4-c.

The right atrium receives deoxygenated blood from the body through the venae cavae (1-b). The left ventricle pumps oxygenated blood to the body through the aorta (2-a). The pulmonary valve prevents backflow into the right ventricle (3-d). The pulmonary artery carries deoxygenated blood to the lungs (4-c).

The other options misplace these functions; for example, 1-a would have the right atrium pumping oxygenated blood to the body.