Chapter 1-8: Blood, Plasma, Hematopoiesis, and Erythrocytes

Flashcards cover the lecture topics on blood composition, plasma and its proteins, osmolarity, erythrocyte structure and production, and related pathophysiology.

What is the main function of blood regarding oxygen?

To carry oxygen from the lungs to tissues that need it (and to help distribute heat and regulate pH).

What is plasma?

The liquid component of blood, mostly water, containing solutes; accounts for about 55% of blood.

What are formed elements in blood?

Living cells in blood: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

What is hematocrit?

The percentage of blood volume occupied by red blood cells.

Name the three layers of spun whole blood from bottom to top.

Bottom: erythrocytes; middle: leukocytes and platelets (buffy coat); top: plasma.

What is plasma osmolarity?

The concentration of dissolved particles in plasma that cannot cross the vessel wall, determining water movement; largely maintained by plasma proteins like albumin.

Which plasma protein is the major contributor to osmotic pressure?

Albumin, accounting for about 60% of plasma proteins.

What are the other major categories of plasma proteins and their roles?

Globulins (alpha, beta transport carriers; gamma globulins are antibodies) and fibrinogen (clotting).

What percentage of blood is plasma and what is its water content?

Plasma accounts for about 55% of blood; ~90% of plasma is water.

What is hematopoiesis?

Formation of blood cells.

Where does hematopoiesis occur in adults?

Red bone marrow (axial skeleton, girdles; proximal epiphyses of long bones like the humerus and femur).

What is the reticulocyte index?

An index indicating the rate of red blood cell (erythrocyte) formation.

What are the structural components of hemoglobin?

Globin (two alpha and two beta chains) and four heme groups; each heme contains iron.

How many heme groups are in a hemoglobin molecule?

Four.

How many oxygen molecules can one hemoglobin molecule bind at once?

Up to four (one per heme).

Why do red blood cells lack mitochondria?

To avoid consuming the oxygen they transport; they rely on anaerobic metabolism.

What is the shape of red blood cells and why is it important?

Biconcave discs that maximize surface area and enable flexible movement through small vessels.

Do red blood cells have nuclei and organelles?

No; mature erythrocytes lack nuclei and most organelles.

Where do red blood cells originate and mature?

Formed in the red bone marrow via hematopoiesis; mature RBCs are released into circulation.

What stimulates erythropoiesis?

Erythropoietin (EPO) from the kidneys, in response to hypoxia.

What happens to iron after red blood cells are broken down?

Iron is stored as ferritin and transported by transferrin; heme iron is recycled; bilirubin is produced from heme and excreted.

What proteins store and transport iron, respectively?

Ferritin stores iron; transferrin transports iron in the blood.

What is anemia and what are microcytic and macrocytic forms?

Anemia is a low red blood cell count or impaired production; microcytic anemia features small RBCs (often iron-deficiency); macrocytic anemia features large RBCs (often B12 deficiency).

What is pernicious anemia and how is it treated?

A macrocytic anemia caused by B12 deficiency; treatment may involve B12 injections if absorption is impaired.

What is renal anemia?

Anemia due to insufficient erythropoietin production by the kidneys.

What is polycythemia?

Excessive red blood cell production leading to high hematocrit and thickened blood.

What is the function of platelets and what are they?

Platelets (thrombocytes) are fragments of cells important for blood clotting; they are not true cells.

What factors contribute to blood viscosity and how is this related to hematocrit?

Blood is more viscous than water (about five times); higher hematocrit increases viscosity, which can impair flow.

What is the typical pH range of blood?

Usually slightly basic, around 7.35 to 7.45.

What buffer system helps maintain blood pH and what is its key component?

Bicarbonate buffering system; bicarbonate (HCO3-) is a key buffer.

What determines the color of blood in arteries vs veins?

Oxygen content: oxygen-rich arterial blood is bright red, deoxygenated venous blood is darker.

What is stercobilin and how is it produced?

A brown pigment in feces produced from bilirubin, which comes from heme breakdown.

What is the function of fibrinogen?

A plasma protein essential for blood clot formation.

What is the 'buffy coat' in centrifuged blood?

The thin middle layer containing leukocytes and platelets.