The Components of Blood

Which of the following functions is NOT primarily associated with blood?

• Transport of hormones from endocrine glands to target organs.

• Regulation of pH balance by buffering acidic and alkaline substances.

• Production of digestive enzymes for breaking down food in the stomach.

• Removal of metabolic waste products such as carbon dioxide and urea.

Answer explanation

The production of digestive enzymes occurs in the stomach, not in the blood. The other functions listed, such as hormone transport and waste removal, are directly related to blood's roles in the body.

Plasma accounts for ____% of all blood, and water accounts for ____% of plasma.

• 55;90

• 90;55

Answer explanation

Plasma makes up about 55% of total blood volume, while water constitutes approximately 90% of plasma. Therefore, the correct answer is 55% for plasma and 90% for water in plasma.

The most numerous formed element in the blood are the __________, and their function is ___________.

• Platelets; to prevent bleeding from open wounds.

• White blood cells; to carry oxygen.

• White blood cells; to fight infection.

• 
  Erythrocytes; to carry oxygen and CO₂

Answer explanation

The most numerous formed elements in blood are erythrocytes, which are responsible for carrying oxygen and carbon dioxide throughout the body, making this the correct answer.

Why is it important for erythrocytes to have a high surface area to volume ratio?

• Increased cell flexibility.

• 
  Allows for more efficient gas exchange.

• 
  Allows each RBC to carry more hemoglobin.

• 
  Allows RBCs to ft through small gaps.

Answer explanation

A high surface area to volume ratio in erythrocytes allows for more efficient gas exchange, enabling better oxygen uptake and carbon dioxide release, which is crucial for their role in respiration.

Which granulocyte is the first to respond to an infection, has hydrolytic enzymes in its granules, and possesses the ability of phagocytosis?

• 
  Basophil

• Eosinophil

• Neutrophil

Answer explanation

The neutrophil is the first granulocyte to respond to infection, equipped with hydrolytic enzymes in its granules, and is capable of phagocytosis, making it essential for the initial immune response.

White blood cells are referred to as _____________.

• Platelets

• Erythrocytes

• Leukocytes

Answer explanation

White blood cells are known as leukocytes. They play a crucial role in the immune system, helping to fight infections. Platelets are involved in blood clotting, and erythrocytes are red blood cells that carry oxygen.

Platelets are similar to erythrocytes in that both structures do not contain a _________________. Platelets are similar to leukocytes in that both their primary functions involve ________________ the body.

• Plasma membrane; nourishing.

• Plasma membrane; protecting.

• Nucleus; protecting.

• Nucleus; nourishing.

Answer explanation

Platelets, like erythrocytes, lack a nucleus, which is a key similarity. Both platelets and leukocytes primarily function in protecting the body, with leukocytes playing a crucial role in the immune response.

Correctly order the three steps of hemostasis.

• (1) vascular spasm, (2) platelet plug formation, (3) coagulation

• (1) platelet plug formation, (2) vascular spasm, (3) coagulation

• (1) coagulation, (2) platelet plug formation, (3) vascular spasm

Answer explanation

Hemostasis occurs in three steps: first, vascular spasm constricts blood vessels to reduce blood flow; second, platelet plug formation occurs as platelets adhere to the site; finally, coagulation reinforces the plug with fibrin.

Inadequate blood oxygen levels causes the kidneys to release which chemical messenger?

• Thrombopoietin

• Erythropoietin

Answer explanation

Inadequate blood oxygen levels trigger the kidneys to release erythropoietin, a hormone that stimulates red blood cell production to enhance oxygen transport. Thrombopoietin, on the other hand, is involved in platelet production.

Which statement correctly describes the activities of the components of human blood shown in the diagram?

• Both A and B function in immune responses, and C transports oxygen

• A, B, and C are able to synthesize hemoglobin

• Both B and C provide immunity, and A transports nutrients

• A transports oxygen, B starts clots, and C functions in immune response to fight infections