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
The adhesion process causes the platelets to undergo an _________ ______ which leads to changes in ……
activation process; platelet shape
Once the platelet changes shape through the adhesion process, what happens to the platelets …..
They then have the ability to bind adhesive proteins , including fibrinogen and von Willebrand factor. The release of various platelet granules (including ADP) also recruits and activates other platelets, growth factors and clotting factors
Platelet aggregation is stimulated by
TXA2 and ADP, which induce fibrinogen receptors on the platelet plug
The formation of a visible fibrin clot on the platelet plug is the conclusion of a complex series of reactions involving different _______ _______
clotting factors
Plasma proteins circulate in ________ forms until stimulated to initiate clotting through one of two pathways, _________ or ________
inactive; intrinsic; extrinsic
How is the intrinsic pathway activated ?
By collagen exposure from endothelial injury when the blood vessel is damaged
How is the extrinsic pathway initiated ?
When tissue factor is released extravascularly from injured tissues
What does thrombin do ?
This enzyme converts fibrinogen into fibrin within the clotting cascade
Platelet plug formation - the final blood clot in the coagulation process is a meshwork of
fibrin strands that stabilizes the platelet plug and traps other cells such as erythrocytes, phagocytes and microorganisms
What helps to keep blood in its fluid state?
Anticoagulants of the body counter the mechanism to blood clotting
Antithrombins help keep blood in a fluid state by
antagonizing thrombin, a powerful coagulant
Endogenous heparin, antithrombin III, protein C, protein S are all examples of
anticoagulants
Fibrinolysis is the
dissolution of a blood clot
When is the fibrinolytic system initiated?
When plasminogen is activated into plasmin - Thrombin is one of the substances that can activate this conversion
Plasmin attacks either fibrin or fibrinogen by splitting molecules into smaller elements known as
fibrin split products (FSPs) or FDP (fibrin degradation products)
If fibrinolysis is excessive, the patient is predisposed to ……
bleeding
Increased FSPs lead to …..
impaired platelet aggregation, reduced prothrombin, and an inability to stabilize fibrin
FSP
fibrin split products - these result from clot dissolution
The spleen is located where?
In the upper left quadrant of the abdomen
4 major functions of the spleen
hematopoietic, filtration, immunologic and storage
True or false ….. the spleen is able to produce RBC during fetal development
True
How does the spleen function in filtration ?
The spleen has the ability to remove old and defective RBC from the circulation by the mononuclear phagocyte system
spleen is also able to breakdown hemoglobin released by hemolysis and return the iron component of the hemoglobin to the bone marrow for reuse
spleen also filters circulating bacteria
Spleens immunologic function - it has a good supply of
lymphocytes, monocytes and stored immunoglobulins
Storage function of spleen - it is a storage site for
RBC, platelets
More than 300 ml of blood can be stored within the …….
spleen
About 1/3 of platelets are stored in the ……
spleen
The lymph system consists of
lymph nodes, lymph fluid, lymphatic capillaries, and ducts
What does the lymph system do ?
Carries fluid from the interstitial spaces to the blood
How does the lymph system help prevent edema ?
It returns excess interstitial fluid into the blood
The formation of lymph fluid increases when ___________ ___________ increases, thereby forcing more fluid into the ________ ______________
interstitial fluid; lymph system
lymphatic capillaries characteristics
thin walled, have irregular diameter, do not contain valves, somewhat larger than blood capillaries
Lymph node shape
round, oval, or bean shaped
Lymph node size
When would they be enlarged ?
vary in size according to their location
Enlarged during an infection
How many lymph nodes are found throughout the body and where are they greatest in number ?
More than 200 lymph nodes are found throughout the body with the greatest in number being in the abdomen surrounding the GI tract
Lymph nodes are situated both _______ and _______
superficially; deep
Can the deep nodes be palpated ?
No; it requires radiologic examination
Primary function of lymph nodes
Filtration of pathogens and foreign particles that are carried by lymph to the nodes
Liver functions as a ____________
filter
What structure produces all the procoagulants that are essential to hemostasis and blood coagulation ?
The liver
Produced by the liver, this is a key regulator of iron balance…..
hepcidin - it inhibits the release of stored iron from enterocytes in the intestines and macrophages
The liver stores iron that is in excess of
tissue needs
Assessment of Hematologic system : past health history
previous problems with anemia, bleeding disorders,
and blood diseases such as leukemia
any kidney, liver, spleen disorders
problems with blood clotting
Assessment of Hematologic system : medications
need complete medication history of prescription and OTC drugs
additional supplements, vitamins, herbal products
Many drugs can interfere with ____________ function
hematologic
Assessment of Hematologic system : surgery or other treatments
specific past surgical procedures such as splenectomy, tumor removal, prosthetic heart valve placement, surgical excision of the duodenum (where iron absorption occurs) partial or total gastrectomy, gastric bypass, and ileal resection
ask about wound healing after surgery and if any bleeding problems occurred
Hematologic problems that have a strong genetic link
sickle cell anemia
hemophilia
thalassemia
hemochromatosis
Should you ask about alcohol and cigarette use when assessing the hematologic system?
Yes, as these can disrupt the hematologic system
Hematemesis
bright red, brown or black vomitus
manifestation of an underlying problem
peptic ulcer disease is a common cause
Lymph nodes that are enlarged and tender are usually associated with an
acute infection
Polycythemia
excessive amount of red blood cells
Assessment of Hematologic system : Elimination pattern
any blood in urine or stool
any black, tarry stools
Assessment of Hematologic system : activity- exercise pattern
ask about tiredness, any weakness of extremities, any change in ability to perform ADLs
Hemarthrosis
blood in a joint
occurs in patient with bleeding disorders and can be painful
Lymph nodes are not ordinarily ________ in adults
palpable
if a lymph node is palpable it should be ……..
small, mobile, firm and nontender
abnormal lymph node finding
tender, hard, fixed or enlarged
tender nodes are usually a result of …..
inflammation
hard or fixed nodes suggest
malignancy
Skin assessment: Petechiae
small, purplish, red, pinpoint lesions
ecchymoses
bruising
Morphology
shape and appearance, as in RBCs
pancytopenia
marked decrease in number of RBC, WBCs, and platelets
blood group antigens (A and B) are found only on
RBC membranes
Blood group A has what kind of antigens ?
A antigens
Blood group B has what kind of antigens ?
B antigens
blood group AB has what kind of antigens ?
both A and B antigens
blood group O has what kind of antigens ?
neither A nor B antigens
B antibodies are found in the serum of people with blood group
A
Agglutinate
clump
the Rh system is based on a third antigen, ____, which is also found on the ______ membrane
D; RBC
Rh- positive people have the _____ antigen
D
Rh negative people do not have the ______ antigen
D
someone with blood type B would have what kind of antibodies
A antibodies
AB+
Blood type AB, along with Rh positive
