Blood cell lineage

Blood cell lineage.

Blood is a constantly circulating fluid in the body that carries substances such as nutrients and oxygen to the cells and transports waste products away. Blood is composed of formed elements (erythrocytes, leukocytes, and platelets) suspended in blood plasma, which contains 7% proteins and 93% water with dissolved minerals, nutrients, and wastes. The physiology of blood involves discussion of a variety of subjects including the production and degradation of blood cells, oxygen transport, carbon dioxide transport, thermoregulation and pH balance.

WikiPremed Resources

Blood Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Blood
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Learning Goals


Be comfortable in describing blood composition including the cell types and cell fragments found in the blood as well as the chemical composition of plasma.

Be able to describe the development of formed elements in the blood from hemopoeitic stem cells in the bone marrow including the distinction between myeloid and lymphoid cell types as well as the steps of erythropoeisis.

Be prepared to describe the factors regulating the developmental path taken by a stem cell.

Understand the structure and composition of an erythrocyte as well as its life cycle.

Have a firm grasp of the structure of the hemoglobin protein and its prosthetic groups.

Have a good sense of how the heme group and the globin protein portions of hemoglobin interact in oxygen binding and dissociation.

Be familiar with how the cooperative interaction between different binding sites enhances hemoglobin as an oxygen-transport protein and how this is reflected in the oxygen-hemoglobin dissociation curve.

Understand the roles of carbon dioxide, hydrogen ion (Bohr effect), chloride ion (chloride shift), and 2,3-bisphosphoglycerate as regulators of the affinity of hemoglobin for oxygen.

Understand the fundamentals of carbon dioxide transport in the blood.

Be able to characterize ABO and Rh blood types; have a basic sense of the underlying genetics, and be able to describe the significance of the Rh factor in pregnancies.

Understand the distribution and histological characteristics of leukocytes in the blood.

Understand how blood volume is determined and regulated by the renin-angiotensin-aldosterone (RAAS) system, natriuretic peptides (NPs), and the hormone vasopresin (ADH).

Know how the narrate the sequence of vascular damage, platelet plug formation, and blood clotting.

Suggested Assignments

Review the terminology for blood using the question server. Complete the fundamental terms crossword puzzle. Here is the solution to the puzzle.

Complete the advanced crossword puzzle for blood. Here is the solution to the puzzle.

Read pp. 115-124 in ExamKrackers Biology II. Perform practice items 81-88 on pg. 125.

Review the web resources for blood.

Conceptual Vocabulary for Blood

Blood is a specialized biological fluid consisting of erythrocytes, leukocytes, and thrombocytes suspended in a complex fluid medium known as plasma.
Blood plasma
Blood plasma is the liquid component of blood, in which the blood cells are suspended.
Red blood cell
Red blood cells are the most common type of blood cell and the body's principal means of delivering oxygen from the lungs to body tissues via the blood.
Platelets or thrombocytes are the cell fragments circulating in the blood involved in the cellular mechanisms of primary hemostasis leading to the formation of blood clots.
Hemoglobin is the iron-containing oxygen-transport metalloprotein in red blood cells.
Carbonic anhydrase
Carbonic anhydrase is a family of metalloenzymes that catalyze the rapid conversion of carbon dioxide to bicarbonate and protons.
ABO blood group system
The ABO blood group system is the most important blood type system (or blood group system) in human blood transfusion.
Human serum albumin
Human serum albumin is the most abundant protein in human blood plasma.
Bohr effect
The Bohr effect states that in the presence of carbon dioxide, the oxygen affinity of respiratory pigments such as hemoglobin decreases.
Coagulation is a complex process by which blood forms solid clots.
Fibrin is a protein involved in the clotting of blood which is polymerised to form a mesh that forms a hemostatic plug or clot over a wound site.
Thrombin is a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions.
Plasmin is an important enzyme present in blood that degrades many blood plasma proteins, most notably fibrin clots.
Sickle-cell disease
Sickle-cell disease is a group of genetic disorders caused by an abnormal form of hemoglobin.
Hemophilia is the name of a family of hereditary genetic illnesses that impair the body's ability to control coagulation.
Globulin is one of the two types of serum proteins, the other being albumin. This term encompasses a heterogeneous series of families of proteins.
A heme is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin.
A porphyrin is a heterocyclic macrocycle derived from four pyrrole-like subunits interconnected via their alpha carbon atoms.
Haldane effect
The Haldane effect is a property of hemoglobin that leads to deoxygenated blood's increased ability to carry carbon dioxide.
2,3-Bisphosphoglycerate is a three carbon compound whose binding to partially deoxygenated hemoglobin allosterically upregulates the release of the remaining oxygen molecules bound to the hemoglobin.
Chloride shift
Chloride shift is a process which occurs in a cardiovascular system and refers to the exchange of bicarbonate and chloride across the membrane of red blood cells.
Erythropoiesis is the process by which red blood cells are produced.
Rhesus blood group system
The Rhesus blood group system refers to the five main Rh antigens (C, c, D, E and e) as well as the many other less frequent Rh antigens.
Gamma globulin
Gamma globulins, or Ig's, are a prominent type are immunoglobulins.
Cooperative binding
Cooperative binding is exhibited by a macromolecule if its affinity for a ligand increases with the amount of ligand already bound.
Oxygen-haemoglobin dissociation curve
The oxygen-haemoglobin dissociation curve plots on the vertical axis the proportion of haemoglobin in its saturated form against the prevailing oxygen tension on the horizontal axis.
Hematopoiesis is the formation of blood cellular components.
Hemostasis refers to a process whereby bleeding is halted.
Fibrinolysis is the process where a fibrin clot, the product of coagulation, is broken down.
Carboxyhemoglobin is a stable complex of carbon monoxide and hemoglobin that forms in red blood cells when carbon monoxide is inhaled.
Fetal hemoglobin
Fetal hemoglobin is the main oxygen transport protein in the fetus during the last seven months of development in the uterus.
Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body.
Advanced terms that may appear in context in MCAT passages
Prothrombinase is the protein complex for the conversion of prothrombin into thrombin consisting of negatively charged phosphatidylserine, prothrombin, and Factors Va and Xa.
Fibronectin is a high-molecular-weight glycoprotein containing about 5% carbohydrate that binds to membrane spanning receptor proteins called integrins as well as extracellular matrix components.
A macroglobulin is a plasma globulin of high molecular weight.
Oncotic pressure
Oncotic pressure is the difference between the colloidal osmotic pressure exerted by blood plasma proteins and that exerted by tissue fluid proteins.
Tissue factor
Tissue factor, also called thromboplastin, factor III or CD142, is a protein present in subendothelial tissue, platelets, and leukocytes necessary for the initiation of thrombin formation from the zymogen prothrombin.
Globin fold
The globin fold is a common three-dimensional fold in proteins typically consisting of eight alpha helices, although some proteins have additional helix extensions at their termini.
Methemoglobin is a form of the oxygen-carrying protein hemoglobin, in which the iron in the heme group is in the Fe3+ state instead of the Fe2+ of normal hemoglobin.
Platelet alpha-granule
The term alpha granules is used to describe granules within platelets containing several growth factors, platelet factor 4, which is a heparin-binding chemokine, and other clotting proteins.
Methemoglobin reductase
Methemoglobin reductase is an enzyme which converts methemoglobin to hemoglobin.
Protein C
Protein C is a major physiological anticoagulant, a vitamin K-dependent serine protease that is activated by thrombin to degrade Factor Va and Factor VIIIa (with protein S as a cofactor).