Hematology (exam 4) Flashcards
What are the chief functions of blood?
Delivery of substances needed for cellular metabolism
Removal of wastes
Defense against microorganisms and injury
Maintenance of acid-base balance (buffer system= bicarb_
What makes up the composition of blood?
How much of the blood does each make up?
Plasma (~55%) Formed elements (Cells= RBC, WBC, platelets, ~45%)
What makes up the blood plasma?
How much of the blood plasma does each make up?
Water (~90%)
Solutes (organic and inorganic/ proteins and electrolytes, ~10%)
What are the plasma proteins?
What do they do?
Which is the most abundant?
Where are they made?
Albumin: most abundant, carriers of calcium, control the plasma oncotic pressure (pull fluid into capillaries), ~58%
Globulins: carrier proteins and immunoglobins (antibodies), ~38%
Clotting factors: mainly fibrinogen, ~4%
All made in the liver except the immunoglobins
What are the formed elements (cells)?
Which is the most abundant?
Erythrocytes: red blood cells, most abundant
Leukocytes: white blood cells, least abundant
Thrombocytes: platelets, middle amount
What are erythrocytes?
What do they do?
What characteristics do they have?
How long do they live?
Red blood cells, floating packets of hemoglobin
Most abundant cell in the body
Biconcavity and reversible deformity (moldable, high surface area)
120 day life cycle
What are leukocytes?
What do they do?
What types are there?
White blood cells
Defend the body against infection and remove debris
Granulocytes (basophils, eosinophils, neutrophils)
Agranulocytes (T & B cells, natural killers, monos/ macros
What do basophils do?
Induce inflammation= histamine
Basophils in blood
Mast cells in tissues
What do eosinophils do?
Regulate inflammation= histaminase
Immmune fighting in parasitic infections
What do neutrophils do?
1st responders
Phagocytes in early inflammation
What do monos/ macros do?
Make up the mononuclear phagocyte system (MPS)
Ingest and digest (destroy) microorganisms and foreign material
What are the lymphocytes?
T & B cells
Natural killer cells
What characteristics do T & B cells have?
Specific
Memory
What do natural killer cells attack?
Viral and cancer cells
non-specific
What are thrombocytes?
What is their shape?
What do they do?
What regulates them?
Platelets
Disk-shaped cytoplasmic fragments
Essential for blood coagulation and control of bleeding
Regulated by thrombopoietin (TPO): released by liver, stimulate platelet production after blood loss, trauma
What is the spleen?
What does the spleen do?
Largest secondary lymphoid organ
Filters the blood
Masses of lymphoid tissue containing macros, T & B cells
Phagocytosis of old, damage, dead blood cells
Blood storage
What are lymph nodes?
What systems are they a part of?
What do they do?
How many vessels in? out? why?
Lymphoid organ
Part of the immune and hematologic systems
Facilitates maturation of lymphocytes
Transports lymphatic fluid back into circulation
Cleanses the lymphatic fluid of microbes and foreign particles
Multiple vessels in, 1-2 out to ensure filtration
What is the MPS?
What makes it up?
Where does it work?
Mononuclear Phagocyte System
Mons/ macros
Ingest and destroy microbes and foreign material
Mostly the liver and spleen
What is hematopoiesis?
How many stages are there?
What are the types?
The process of blood cell production in the bone marrow (myeloid tissue), red produce blood cells, yellow= fat
2 stages: mitosis, maturation and differentiation
Erythropoiesis, Leukopoeisis, Thrombopoeisis
What is erythropoiesis?
What is the stimuli for it?
How does it work?
Making red blood cells (floating packets of hemoglobin)
Stimulated by hypoxia which stimulates EPO
Erythroblasts have a nuclei and go through steps that gradually increase the amount of hemoglobin and decrease the nucleus size to form erythrocytes
Erythropoietin (EPO) is produced and secreted by the liver to stimulate maturation of RBCs
Where is erythropoietin produced?
Peritubular cells of the kidney
What is hemoglobin?
What are its subunits?
Oxygen-carrying protein of the erythrocyte
2 alpha, 2 beta (protein subunits) containing an iron heme which binds to oxygen, causing red color
What are the nutritional requirements for hemoglobin?
Proteins/ amino acids
Vitamins: B12 and folic acid for the lifespan of the RBC
Iron: to build heme, carry oxygen
Folate (folic acid)
What is the destruction of erythrocytes called?
What destroys them?
Where are they destroyed
How are they destroyed?
Senescent
Macros of the MPS destroy them
Destroyed primarily in spleen, liver if spleen doesn’t work
Globins are broken down to amino acids
Porphyrins are broken down to bilirubin which is secreted as bile or the yellow pigment in urine
What is leukopoeisis?
What do the cells arise from?
Where does maturation occur?
Producing white blood cells (leukocytes)
Arise from stem cells in the bone marrow
Granulocytes (basos, eos, neutros) mature in bone marrow
Agranulocytes (T & B cells) must exit blood and be activated to mature
Agranulocytes (monos) are activated when they leave the blood to macros
What is thrombopoeisis?
How does it work?
What regulates levels?
What is the lifespan?
Producing platelets
Endomitosis is the process where a megakaryocyte undergoes nuclear phase of cell division but the cell does not divide
DNA continues doubling, expanding the cell
Cell explodes into cytoplasmic fragments (platelets)
Maintained by thrombopoietin (TPO)
Lifespan is 10 days
What is hemostasis?
What does it require?
To arrest or stop bleeding
Requires: platelets, clotting factors, blood flow, endothelial cells, fibrinolysis (break apart and dissolve a clot
What are the steps of hemostasis?
Vascular spasm/ vasoconstriction: spasms in response to injury, induce vasoconstriction
Platelet plug formation: expose colagen so steps start= activation, adhesion, activation, aggregation, secretion
Coagulation/ formation of the fibrin clot: classical pathway of coagulation
What is the vascular spasm/ vasoconstriction phase of hemostasis?
1st step
Spasms in response to injury, induce vasoconstriction
Cause endothelial damage and colagen exposure
What is the platelet plug formation phase of hemostasis
expose colagen so:
Activation: due to calcium
Adhesion: of platelets due to the von Willebrand factor (vWF)
Activation: due to calcium, chemotaxis for more platelets
Aggregation: of platelets to form a temporary clot
Secretion: of calcium, histamine, seratonin, epinephrine, factors that increase or quicken coagulation
What are the 4 most important players in the Classical Pathway of Coagulation?
Prothrombin
Thrombin
Fibrinogen
Fibrin