Blood Flashcards
Blood Composition
Plasma-Proteins, Water, Other Solutes
Formed Contents-Platelets, Leukocytes, Neutrophils, Lymphocytes, Macrocytes, Eosinophils, Basophils, Erthrocytes
Blood Functions
Complex transport medium that performs vital pickup and delivery services
keystone of body’s heat-regulation (blood slightly warmer than rest of body)
Volume of Blood
Young adult male - 5L
Varies by size of person
Hematocrit
volume percentage of RBC in the blood
Platlets
Also known as thrombocytes
Red Blood Cells
Also known as erythrocytes no nucleus Biconcave disk Do not contain ribosomes, mitochondria, etc Primary component is hemoglobin Most numerous formed element
Function of Red Blood Cells
Critical role in O2 and CO2 transport
Carbonic Anhydrase
Emzyme in RBC that catalyzes a reaction that joins CO2 and H2O to form carbonic acid
Carbonic Acid
Dissocaite and generates bicarbonate ion which diffuses out of RBC and transports CO2 into blood plasma
Erthropoiesis
The formation of RBC
begins in red bone marrow as hematopoietic stem cells and goes through stages of development to become RBC
Will take ~4 days
RBC creation and destruction
~100 million per minute RBC are created and destroyed in an adult
Destruction of RBC
Macrophage cells phagocytize the aged, abnormal, or fragmented RBCs
Hemoglobin is broken down and amino acids, iron, and bilirubin are released and/or recycled.
Life Span of RBC
105-120 days
Hemoglobin
Within each RBC are approximately 200 to 300 million molecules of hemoglobin
Hemoglobin is able to unite with four oxygen molecules to form oxyhemoglobin to allow RBCs to transport oxygen where it is needed
Males have a greater amount of hemoglobin than females
Anemia: a decrease in number or volume of functional RBCs in a given unit of whole blood
Hemoglobin Composition
Hemoglobin is composed of four globin chains, each attached to a heme group
Types of Granulocytes
Neutrophils
Eosinophils
Basophils
Neutrophils
approximately 65% of total WBC count in a normal blood sample
highly mobile and active phagocytic cells
capable of diapedesis
cytoplasmic granules contain lysosomes
Eosinophils
2% to 5% of circulating WBCs
Numerous in lining of respiratory and digestive tracts
Weak phagocytes
Capable of ingesting inflammatory chemicals and proteins associated with antigen-antibody reaction complexes
Provide protection against infections caused by parasitic worms and allergic reactions
Basophils
0.5% to 1% of circulating WBCs
Motile and capable of diapedesis
Cytoplasmic granules contain histamine and heparin
Types of Agranulocytes
Lymphocytes
Monocytes
Lymphocytes
Smallest of the WBCs
Second most numerous WBC Account for approximately 25% of circulating WBCs
T lymphocytes and B lymphocytes have an important role in immunity:
T lymphocytes directly attack an infected or cancerous cell, and B lymphocytes produce antibodies against specific antigens
Monocytes
largest leukocytes;
Mobile and highly phagocytic cells
White Blood Cells Numbers
1 mm^3 of normal blood usually contains 5000 to 9000 leukocytes, with different percentages for each type
WBC numbers have clinical significance because they change with certain abnormal conditions; infection etc.
Formation of WBCs
Granular and agranular leukocytes mature from the undifferentiated hematopoietic stem cell
Neutrophils, eosinophils, basophils, and a few lymphocytes and monocytes originate in red bone marrow; most lymphocytes and monocytes develop from hematopoietic stem cells in lymphatic tissue
Platelet Structure
In circulating blood, platelets are small, pale bodies that appear as irregular spindles or oval disks
Three important properties are agglutination, adhesiveness, and aggregation
Platelet counts in adults average 250,000/mm3 of blood; normal range is 150,000 to 400,000/mm3
Function of Platelets
Important role in hemostasis and blood coagulation; secondary role in defending against bacterial attacks
Hemostasis With Platelets
Stoppage of blood flow; however, if injury is extensive, the blood-clotting mechanism is activated to assist retention of blood volume.
Platelet Plug Formation
One to five seconds after injury to vessel wall, platelets adhere to damaged endothelial lining and to each other, forming a temporary platelet plug
Normal platelets (positive charge) adhere to damaged capillary wall and underlying collagen fibers, both of which have a negative charge
Sticky platlets will form
Fibrin will accumulate
Physical plug and secretion of several chemical involved in coagulation process
Formation and Life Span of Platelets
Life span 7-10 days
Formed in red bone marrow, lungs, and spleen by fragmentation of magakaryocytes
Blood Typing-ABO System
Type A: antigen A on RBCs
Type B: antigen B on RBCs
Type AB: both antigens A and B on RBCs; known as universal recipient.
Type O: neither antigen A nor B on RBCs; known as universal donor.
Blood Typing-Rh System
Rh-positive: Rh antigen is present on the RBCs
Rh-negative: RBCs have no Rh antigen present
Anti-Rh antibodies are not normally present in blood; anti-Rh antibodies can appear in Rh-negative blood if it has come in contact with Rh-positive RBCs
Blood Plasma
Liquid part of blood;
clear to straw-colored fluid; composed of 90% water and 10% solutes
Plasma proteins have an essential role in maintaining normal blood circulation. (Osmosis)
Blood Plasma Solutes
Solutes: 6% to 8% of plasma solutes are proteins, consisting of three main compounds
Albumins: help maintain osmotic balance of the blood
Globulins: essential component of the immunity mechanism
Fibrinogen: key role in blood clotting
Coagulation
Blood clotting which goal is to stop bleeding to prevent loss of vital body fluid
Components Critical to Coagulation
Prothrombin
Thrombin
Fibrinogen
Fibrin
Steps of Coagulation
Stage 1) Production of Thromboplastin activator
Stage 2) Conversion of prothrombin to thrombin
Stage 3) Conversion of fibrinogen to fibrin and production of fibrin clot
Thromboplastin activation
Will be activated through chemicals from damaged tissues (extrinsic pathway)
Activated through present in blood (intrinsic pathway)
Factors Opposing Clotting
Clot formation in intact vessel will be suppressed when no injury is present
Perfectly smooth surface of the normal endothelial lining of blood vessels does not allow platelets to adhere.
Antithrombins: substances in the blood that oppose or inactivate thrombin; prevents thrombin from converting fibrinogen to fibrin (e.g., theraputic heparin)
Condition that Initiate or Speed Up Clotting
Rough spot in endothelium (plaque)
Abnormally slow blood (DVT)
Fibrinolysis
physiological mechanism that dissolves clots
Fibrinolysin: enzyme in the blood that catalyzes the hydrolysis of fibrin, causing it to dissolve.
Additional factors are presumed to aid clot dissolution. (e.g., substances that activate profibrinolysin)
