Introduction to Blood and Hemopoiesis

Flashcards covering the physical properties of blood, plasma composition, the structure and life cycle of erythrocytes, hemopoiesis, and blood-related pathologies based pathologies.

pH of Blood

A physical property of blood maintained at a homeostatic set point of around $7.4$, with a normal dynamic range between $7.35$ and $7.45$.

Osmolarity of Blood

A maintained range of $280$ to $296$ mOsm/L, often rounded to $300$ for ease of calculation, and equivalent to $0.9\%$ sodium chloride ($NaCl$).

Viscosity

A property of liquids describing resistance to flow resulting from particle cohesion; whole blood is $4.5$ to $5.5$ times more viscous than water.

Temperature of Blood

The temperature is approximately $38\,^{\circ}\text{C}$, which is about one degree warmer than the normal core body temperature of $37\,^{\circ}\text{C}$ ($98.6\,^{\circ}\text{F}$).

Hemoglobin (Hb)

A pigment protein inside red blood cells that transports oxygen; normal ranges are $13$ to $18\,\text{g/dL}$ for genetic males and $12$ to $16\,\text{g/dL}$ for genetic females.

Formed Elements

The cellular components of blood, which include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

Plasma

The liquid extracellular matrix of blood, constituting about $55\%$ of whole blood, composed of water ($91\%$), ions, proteins, gases, and nutrients.

Hematocrit

The percentage of whole blood volume that is packed with red blood cells, averaging approximately $45\%$.

Buffy Coat

A thin layer formed after centrifuging blood that contains leukocytes and platelets, making up less than $1\%$ of whole blood.

Albumin

A protein made by the liver comprising about $60\%$ of plasma proteins; it acts as a carrier and is vital for maintaining blood osmolarity.

Fibrinogen

A fibrous precursor protein ($4\%$ of plasma protein) that is converted into fibrin to assist in blood clotting.

Carbonic Anhydrase

An enzyme found in plasma and red blood cells that converts carbon dioxide ($CO_2$) and water ($H_2O$) into bicarbonate.

Biconcave Shape

The specialized shape of red blood cells, approximately $7.5\,\mu\text{m}$ in diameter, providing a large surface area for gas exchange and high flexibility.

Heme

An organic molecule within each hemoglobin subunit containing an iron atom that binds oxygen ($O_2$) in a reversible manner.

Hemopoiesis

The process of making mature blood cells from pluripotent stem cells.

Myeloid Hemopoiesis

The production of blood cells occurring in the medullary cavity (red bone marrow) of bones, generating all formed elements except lymphocytes.

Erythropoiesis

The specific process of red blood cell formation, which takes $3$ to $5$ days and involves synthesizing hemoglobin and ejecting the nucleus.

Reticulocyte

The penultimate stage of red blood cell development where organelles and the nucleus have been ejected, but the cell is not yet fully mature.

Erythropoietin (EPO)

A glycoprotein hormone secreted by granular cells in the kidney and liver that stimulates the differentiation of erythroblasts.

Gastroferritin

A protein in the stomach that binds to iron to facilitate its transport to the small intestine.

Transferrin

A plasma protein that transports iron through the blood to the liver, bone marrow, and other tissues.

Ferritin

The storage form of iron inside cells, where iron is bound to the protein apoferritin to prevent cellular damage.

Bilirubin

A yellow-green pigment derived from the breakdown of the heme portion of hemoglobin, eventually excreted in bile or urine.

Polycythemia

An abnormal increase in the number of red blood cells, which increases blood viscosity and can strain the heart; can be primary (cancer) or secondary (dehydration, hypoxia).

Sickle Cell Anemia

A genetic condition involving a recessive mutation in the hemoglobin beta subunit, causing red blood cells to adopt a rigid sickle shape when oxygen is low.

Thalassemia

Also known as Mediterranean anemia, it is a hereditary condition involving mutations in the non-coding regions that regulate hemoglobin gene expression.