Hematology Flashcards
Name the various components of blood and state the basic functions of each. This includes the red blood cells, white blood cells, platelets, and plasma (in general).
Red blood cells= erythrocytes
White blood cells=leukocytes-> 5 types
1)Granulocytes (neutrophils, basophils and eosinophils)
2)agranulocytes(lymphocytes and monocytes)
Describe the composition of blood plasma and describe the general functions of plasma proteins
-mostly water about 90%, acts as transport medium
-has electrolytes
-nutrients, wastes, gases, and hormones
Plasma proteins:
-contribute to the osmotic pressure of the blood(capillaries and bulk flow)
-buffer pH changes in blood
-Transport certain substances
-Clotting factors and fibrinogen
Define the following terms associated with blood cell formation: hemopoiesis (also called hematopoiesis)
- the process of blood cell formation
- hormones that affect blood cell formation: EPO and thymosins
Define the following terms associated with blood cell formation: leukopoiesis
formation of white blood cells
Define the following terms associated with blood cell formation: erythropoiesis
- formation of red blood cells
- start off with a nucleus, during development they extrude the nucleus along with more of their other organelles
- need B Vitamins especially folate and B12
- testosterone stimulates erythropoiesis
Define the following terms associated with blood cell formation: colony-stimulating factor
- stimulate different cells
- produced by mature lymphocytes and macrophages in response to specific infections etc…
Define the following terms associated with blood cell formation: pluripotent (as in “pluripotent stem cell”).
- all blood cells originate from pluripotent stem cells (hemocytoblasts)
- pluri= several, potent=potential
Distinguish between myeloid and lymphoid stem cells
Myeloid stem cells:
-can develop into RBCs, platelets, granulocytes, or monocytes
Lymphoid stem cells:
-develop into different types of lymphocytes
Describe erythropoiesis (from pluripotent stem cell to myeloid stem cell, to proerythroblast, erythroblast, and reticulocyte stages, before becoming a mature erythrocyte)
pluripotent stem cell-> myeloid stem cell->proerythroblast-> early, intermediate, and late erythroblast stages-> reticulocytes (nuclei etc. are not lost) (2-3 days) (released out of the bone marrow and into the bloodstream)-> mature erythrocytes (1-2 days)
Explain why certain B vitamins (notably folate and B12) and iron are required for erythropoiesis.
- lots of cell division thats why we need B vitamins to support cell division
- since RBCs are packed with hemoglobin, we also need iron to help make the hemoglobin
Describe how erythropoietin (EPO) helps regulate erythropoiesis (also: what is the main trigger that increases EPO secretion?).
- These cells release erythropoietin when the oxygen level is low in the kidney.
- Erythropoietin stimulates the bone marrow to produce more red blood cells which in turn increases the oxygen-carrying capacity of the blood
- erythropoietin circulates in the plasma and acts on target cells in the bone marrow.
Describe the remainder of the erythrocyte “lifecycle” (degradation and “recycling of parts”), and how this could result in jaundice.
- degradation is when mature RBCs whom lack a nucleus can’t divide or even do cell repair so they just “die” when their existing proteins degenerate (last about 110-120 days)
- old, weak RBCs often burst as they pass through small blood vessels or damaged RBC can be engulfed by phagocytes in the spleen, liver or bone marrow
- “recycling of parts”
- hemoglobin is broken down by macrophages in the spleen, liver, and other lymphatic tissue
- broken into amino acids, heme (separates into iron and biliverdin)
How does Jaundice result
Since heme becomes biliverdin and then biliverdin becomes bilirubin…
- Bilirubin is one component of bile that is produced in the liver ( stored in the gall bladder) and secreted into the small intestine. Some end up in the feces, some get absorbed back into the blood and excreted in the urine
- A build-up of bilirubin can occur if you are breaking down more RBCs than normal or if your liver isn’t quite up to the job = jaundice
Describe the vascular phase of hemostasis (“vascular spasm”): what occurs, and how it helps to prevent blood loss.
- a temporary constriction of a blood vessel
- happens immediately
- result of contraction of smooth muscle in the blood vessel wall
- stimulated by chemicals that are released during the platelet plug formation phase
- slows down the flow of blood through the site of injury(to minimize blood loss)
- not enough to stop blood loss alone in larger vessels
Describe the platelet phase of hemostasis (“platelet plug formation”): what occurs, and how it helps to prevent blood loss.
- many steps; may occur simultaneously
- platelet adhesion platelets “stick” to exposed collagen at damaged site, activates platelets.
- platelet aggregation: platelets “stick together”
- Activated platelets release chemicals that help to attract and activate more platelets= postive feedback
- “degranulate”( release chemicals) that will:
- attract and activate more platelets
- stimulate vascular spasm
- promote coagulation
