Erythrocyte and Leukocyte Introduction

Flashcards covering the physiology of red blood cells, the process of erythropoiesis, hemoglobin degradation, various blood disorders like anemia and polycythemia, and an introduction to white blood cells.

Oxyhemoglobin

Hemoglobin with oxygen bound to it, which occurs in the lungs and gives blood a bright scarlet red color.

Deoxyhemoglobin

Hemoglobin that has unloaded its oxygen in the tissues, resulting in a darker, more maroon red blood color.

Heme

The pigment part of hemoglobin containing iron, which serves as the binding site for oxygen.

Globin

The protein chains of hemoglobin where $CO_2$ binds for transport.

Hemocytoblast

The hematopoietic stem cell from which all formed elements, including red and white blood cells, originate.

Erythropoiesis

The specific process of red blood cell formation or production.

Proerythroblast

The committed cell stage in erythropoiesis that possesses receptors for the hormone erythropoietin ($EPO$).

Reticulocyte

An immature red blood cell that is ejected from the red bone marrow and typically matures into a full erythrocyte within $2$ days in the bloodstream.

Erythropoietin ($EPO$)

An amino acid-based hormone, primarily produced by the kidneys, that acts as the direct stimulus for red blood cell production.

Hypoxia

A condition of oxygen deprivation or low oxygen levels that acts as the initial indirect stimulus for erythropoiesis.

Hypoxia Inducible Factor ($HIF$)

An intracellular signaling molecule in the kidneys that accumulates when oxygen is low, triggering the synthesis and release of $EPO$.

Ferritin and Hemosiderin

The forms in which iron is safely stored in cells to prevent the toxicity of free iron ions.

Spleen

The organ often referred to as the "red blood cell graveyard" because it traps and destroys aged, rigid red blood cells.

Bilirubin

A yellow pigment produced from the degradation of heme that is secreted by the liver into bile.

Stereobulin

A brown pigment resulting from the bacterial metabolism of bilirubin in the gut, which gives feces its color.

Anemia

A condition where blood has an abnormally low oxygen-carrying capacity, often serving as a sign rather than a disease itself.

Microcytes

Abnormally small, pale red blood cells typically associated with iron deficiency anemia.

Intrinsic Factor

A substance produced by the stomach required for the small intestine to properly absorb vitamin $B_{12}$.

Pernicious Anemia

Anemia caused by a lack of vitamin $B_{12}$ or intrinsic factor, leading to the production of large red blood cells called macrocytes.

Aplastic Anemia

Anemia resulting from the failure or destruction of red bone marrow, affecting all blood cell lines including white blood cells and platelets.

Polycythemia

An excess of red blood cells that increases blood viscosity and can lead to sluggish blood flow.

Diapedesis

The process by which white blood cells leap across blood vessel walls to enter tissue spaces.

Positive Chemotaxis

The movement of leukocytes toward chemical signals released by damaged tissues or pathogens.

Neutrophils

The most abundant white blood cell ($50\% - 70\%$), characterized by a multi-lobed nucleus and an active role as "bacteria slayers."

Never Let Monkeys Eat Bananas

A mnemonic device used to remember the order of leukocyte abundance from most to least (Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils).