Assessment of Hematologic System Flashcards
What is hematology?
The study of blood and blood forming tissues. Includes the bone marrow, blood, spleen, and lymph system
A basic knowledge of hematology is useful in clinical settings to evaluate the patients ability to transport 02 and CO2, maintain ____________ volume, coagulate blood and combat ____________
intravascular volume; infections
The assessment of the hematologic system is based on ……
diagnostic studies, physical examination and the patients health history
What is hematopoiesis ?
Blood cell production that occurs within the bone marrow
Which type of marrow actively produces blood cells ?
Red bone marrow
Where is the red marrow primarily found ?
In the flat and irregular bones such as the ends of long bones, vertebrae, sacrum, sternum, ribs, flat cranial bones and scapulae
What are the three types of blood cells ?
WBC, RBC, platelets
When tissue hypoxia occurs, what happens , regarding the production of blood cells ?
Erythropoietin, a cytokine protein, is released by the liver and kidney and it circulates to the bone marrow and stimulates the production of RBC.
Albumin helps to regulate the ________ ____________ within the blood
oncotic pressure
Thrombocytes
another name for platelets
Blood is a type of ___________ tissue that performs 3 major functions: ______, ______ , ______.
connective; regulation; protection; transportation
primary function of erythrocytes
transport O2 and CO2 and maintain acid base balance
Hemoglobin that has oxygen bound to it is referred to as
oxyhemoglobin
hemoglobin is composed of what two compounds?
Heme (an iron compound) and globin (a simple protein)
The heme portion of hemoglobin binds to ……
oxygen
The globin portion of hemoglobin binds to
CO2
Erythropoiesis
the process of RBC production
What is erythropoiesis regulated by ?
cellular O2 requirements and general metabolic activity
Erythropoiesis is stimulated by _________ and controlled by _________________
hypoxia; erythropoietin
What glycoprotein growth factor stimulates the red bone marrow to produce RBC ?
Erythropoietin
About how many RBC are produced per second during erythropoiesis?
2.5 million
Erythropoiesis is influenced by the availability of certain ______________ and _______________
nutrients and hormones
What is a reticulocyte?
Immature red blood cell
A reticulocyte can develop into mature RBCs within how many hours upon release into the circulation ?
48 hours
Assessing the number of reticulocytes is a useful means of evaluating …….
the rate and adequacy of erythrocyte production
hemolysis
destruction of RBC by macrophages and monocytes `
Hemolysis normally occurs where?
In the bone marrow, spleen, and liver
bilirubin; how does it relate to hemolysis ?
one of the components of RBC; when hemolysis occurs, there is an increased amount of bilirubin to be processed by the body. When hemolysis occurs via normal mechanisms, the liver is able to conjugate and excrete all bilirubin that is released
Leukocytes have a widely available life span: granulocytes may only live for ________, yet some T lymphocytes may live for _______
hours; years
What is the primary function of granulocytes ?
Phagocytosis
What is the most common type of granulocyte?
Neutrophils - accounting for 50-70% of all WBC
Once neutrophils engulf the pathogen, they die in ___________________
1-2 days
a mature neutrophil is called what ?
A segmented neutrophil or “seg” or poly segmented neutrophil
Eosinophils account for only ______ % of all WBC
0-4%
Basophils accounts for less than ______________ % of all leukocytes
2%
Lymphocytes account for what percentage of WBC
20-40%
About 2/3 of total body iron is bound to ______ in erythrocytes (hemoglobin) and muscle cells (myoglobin).
The other 1/3 of iron is stored as …….
heme
The other 1/3 is stored as ferritin and hemosiderin (degraded form of ferritin) in the bone marrow, spleen, liver and macrophages
This is a carrier plasma protein for iron
Transferrin
The degree to which transferrin is saturated with iron is a reliable indicator of ………………….
the iron supply for developing RBC’s
Is iron usually recycled ?
Yes - only 3% is lost daily in urine, sweat, bile and epithelial cells in the GI tract.
Iron is recycled after macrophages in the liver and spleen phagocytize, or ingest and destroy old and damaged RBCs
There is normally very little iron loss except from ______ _____
blood loss
Hemostasis is a term that means
arrest of bleeding
Hemostasis stages
vascular injury and subendothelial exposure Adhesion Activation Aggregation Platelet Plug formation Clot retraction and Dissolution
Upon injury to a blood vessel, an immediate local vasoconstrictive response occurs. How does vasoconstriction reduce the leakage of blood from the vessel?
By restricting the vessel size and by pressing the endothelial surfaces together The latter reaction enhances vessel wall stickiness and maintains closure of the vessel even after vasoconstriction subsides
What triggers the platelet response and plasma clotting factors ?
Endothelial injury and the release of substances such as TXa2
TXA2
Thromboxane A2 - this is produced by platelets in response to endothelial injury and subendothelial exposure… causes vasoconstriction and promotes the degranulation of platelets
The loss of endothelial cells exposes adhesive glycoproteins such as
collagen and von Willebrand factor
The adhesion of platelets refers to
the platelets adhering to the exposed collagen and von Willebrand factors in the subendothelial tissue.
The formation of clumps is referred to as
aggregation