Blood, Hematopoiesis, and Bone Marrow

Flashcards covering key vocabulary terms related to blood functions, components, hematopoiesis, blood groups, anemia, and clotting, derived from lecture notes.

Blood Functions

Transportation (nutrients, O2, CO2, hormones, immune responses) and Homeostasis (thermoregulation & clotting).

Blood Plasma

The liquid matrix of blood, primarily water (90%) with dissolved proteins (e.g., albumin, globulins, fibrinogen), nutrients, inorganic salts, hormones, and dissolved gases.

Albumin

A protein in plasma that maintains colloid osmotic pressure and acts as a hormone carrier protein.

Globulins

Plasma proteins including immunoglobulins (antibodies) and nonimmune globulins (carrier proteins).

Fibrinogen

A plasma protein converted to fibrin monomers, which cross-link at blood vessel damage sites to form clots.

Erythrocytes (Red Blood Cells)

The majority cell type in blood, responsible for gas exchange, anucleate, biconcave disc shape, and contain hemoglobin.

Thrombocytes (Platelets)

Cytoplasmic fragments that control bleeding by forming plugs and secreting compounds that facilitate clotting.

Leukocytes (White Blood Cells)

Immune defense cells, including granulocytes (eosinophils, basophils, neutrophils) and agranulocytes (lymphocytes, monocytes).

Blood Serum

Plasma without clotting factors, notably fibrinogen.

Hematocrit

The volume percentage of red blood cells in whole blood.

Hematopoiesis

The process of differentiation of all blood cells, occurring in the red bone marrow after birth.

Hematopoietic Stem Cells (HSC)

Multipotent stem cells that are the original source of all blood cell types.

Yolk-sac Phase

The first phase of hematopoiesis in utero, beginning at the 3rd week of gestation.

Hepatic Phase

A major phase of hematopoiesis in utero during the 2nd trimester, where the liver becomes the primary site of blood cell formation.

Bone Marrow Phase

The phase of hematopoiesis beginning in the 2nd trimester and becoming the only location in adulthood.

Common Lymphoid Progenitor (CLP)

A hematopoietic stem cell derivative that gives rise exclusively to lymphocytes (T-cells, B-cells, natural killer cells).

Common Myeloid Progenitor (CMP)

A hematopoietic stem cell derivative that gives rise to granulocytes, monocytes, red blood cells, and thrombocytes.

Erythropoiesis

The process of red blood cell formation and maturation, primarily occurring in the bone marrow.

Megakaryocyte/Erythrocyte Progenitor (MEP)

A bipotent stem cell that can differentiate into either megakaryocytes or erythrocytes.

Erythrocyte Progenitor (ErP)

A committed cell type in erythropoiesis, sensitive to erythropoietin (EPO), which will become an erythrocyte.

Proerythroblast

An early erythrocyte precursor, characterized by a large cell size and a large, spherical nucleus.

Basophilic Erythroblast

An erythrocyte precursor with a large number of basophilic ribosomes in the cytoplasm, actively synthesizing hemoglobin.

Polychromatophilic Erythroblast

An erythrocyte precursor with a slightly smaller nucleus and both hemoglobin (eosinophilic) and ribosomes (basophilic) in the cytoplasm.

Orthochromatic Erythroblast

An erythrocyte precursor with a very small nucleus and a large amount of hemoglobin present.

Reticulocyte

An immature red blood cell that has lost its nucleus but still contains some polyribosomes, filaments, and organelles; it is the first cell type to leave the bone marrow. Clinically, reticulocyte count is an indicator of the bone marrow's red blood cell production rate.

Erythropoietin (EPO)

A hormone produced primarily in the kidneys in response to hypoxia, which stimulates erythrocyte formation and release.

ABO Blood Groups

Blood classifications based on specific glycoprotein antigens on the surface of red blood cells and antibodies present in the plasma.

A Blood Type

Red blood cells possess A antigens, and the plasma contains anti-B antibodies.

B Blood Type

Red blood cells possess B antigens, and the plasma contains anti-A antibodies.

Rh Blood Groups

Blood classifications based on specific polypeptide antigens (D, C, or E) on the red blood cell surface, with antibodies usually only present after sensitization. Clinical Relevance: Rh incompatibility between an Rh-negative mother and an Rh-positive fetus can lead to Hemolytic Disease of the Newborn (HDN) if the mother becomes sensitized and produces anti-Rh antibodies.

O Blood Type

Red blood cells lack A and B antigens, while the plasma contains both anti-A and anti-B antibodies, making O type a universal donor (for cells).

AB Blood Type

Red blood cells possess both A and B antigens, and the plasma contains no anti-A or anti-B antibodies, making AB type a universal recipient (for cells).

Rh Positive (Rh+)

Blood type where D, C, or E antigens are present on red blood cells.

Rh Negative (Rh-)

Blood type where no Rh antigens are present on red blood cells.

Anemia

A condition characterized by a reduction in red blood cells or hemoglobin, leading to reduced oxygen-carrying capacity.

Macrocytic Anemia

Anemia characterized by larger than normal red blood cells, often due to vitamin B12 or folate deficiency.

Normocytic Anemia

Anemia characterized by normal-sized red blood cells, with causes including acute blood loss or EPO deficiency.

Microcytic Anemia

Anemia characterized by smaller than normal, pale red blood cells, often due to iron deficiency.

Thrombocyte Peripheral Zone

The outer region of a platelet including the cell membrane and glycocalyx, which contains integral membrane glycoproteins and coagulation factors.

Thrombocyte Organelle Zone

The central region of a platelet containing mitochondria, peroxisomes, glycogen, and granules that store substances like ADP and serotonin.

Serotonin

A substance secreted by platelets that causes vasoconstriction during clotting.

Adenosine Diphosphate (ADP)

A substance secreted by platelets that acts as a platelet activator, contributing to clot formation.

Thromboxane A2

A substance secreted by platelets that causes vasoconstriction and platelet activation.

Primary Hemostatic Plug

A temporary plug formed by clumps of platelets at the site of blood vessel damage, primarily driven by ADP and thromboxane A2.

Secondary Hemostatic Plug

A more stable clot formed by fibrin cross-linking, which is converted from fibrinogen on the platelet glycocalyx.

Thrombus

A stationary blood clot formed within a blood vessel, obstructing blood flow.

Embolus

A detached blood clot or other foreign material that travels through the bloodstream and can lodge in smaller vessels.

Tissue Plasminogen Activator (TPA)

An enzyme released by endothelial cells that triggers the conversion of plasminogen into plasmin, leading to clot resolution.

Thrombopoiesis

The process of platelet formation, which occurs in the bone marrow.

Megakaryoblast

A large cell with a multilobed nucleus that undergoes endomitosis (nuclear replication without cell division) as a precursor to megakaryocytes.

Megakaryocyte

A very large cell with a complex, multi-lobed nucleus, responsible for fragmenting its cytoplasm to produce platelets.

Thrombopoietin (TPO)

A hormone produced primarily by the liver, kidneys, and bone marrow that regulates platelet production and promotes the proliferation and maturation of megakaryocytes.

Thrombocythemia

Overproduction of platelets due to a genetic disorder.

Thrombocytosis

Overproduction of platelets due to a secondary mechanism.

Thrombocytopenia

Reduced levels of platelets, often associated with spontaneous small vessel bleeding.

A 16 y/o female mountain bike enthusiast arrives to the ED after falling off her bicycle. She has lacerations to her lateral and anterior thigh and suffered significant blood loss. A blood sample is drawn for a CBC and blood typing. Blood typing shows that the sample does not clot in the presence of antibodies to type A or B antigens. However, blood does clot when exposed to antibodies to surface antigen D. This patients blood type is: 

O positive

A 16 y/o female arrived to the ED following a bicycle accident two days ago. She suffered significant blood loss. She sustained severe lacerations to the lateral and anterior thigh and now has clots forming in the affected vessels. Which is true regarding the cells responsible for clotting? 

They secrete ADP and serotonin to promote platelet aggregation.