Structure & Function of the Hematologic System Flashcards
What is normal blood volume in adults?
around 6 quarts (5.5L) in adults
______ & ______ maintain the osmolarity and acid-base balance of the blood
ELECTROLYTES & PROTEINS
What is plasma made of? See picture on study guide
solution of protein (mainly synthesized in liver) and inorganic materials that is approx. 92% water, and 8% dissolved substances
Plasma makes up what % of blood volume
50-55%
Plasma proteins (the three most important, but there are four) & their functions
- ALBUMINS - function as carriers, and CONTROL PLASMA ONCOTIC PRESSURE
- CLOTTING FACTORS - mainly fibrinogen, which is the most abundant clotting factor and is the precursor to the fibrin clot
- LIPOPROTEINS - triglycerides, cholesterol, and fatty acids
- globulins are carrier proteins and immunoglobulins (Ig) (antibodies); primarily IgG - these are made by plasma cells, and are not synthesized in the liver
What is serum?
plasma w/o clotting factors - plasma that has been allowed to clot in the lab in order to remove fibrinogen and other clotting factors
What are pluripotential cells?
precursor cells in BM that can become any cell in the bloodline (RBC, WBC, or platelets)
Whole blood includes what two components?
plasma (water, proteins, other solutes) & formed elements (platelets, leukocytes, RBCs)
What is the most abundant of cells in the blood? % in men? % in women?
ERYTHROCYTES
M = 48% W = 42%
Lifespan of RBCs? Why? Old ones removed by?
120 days - can’t undergo mitotic division so limited lifespan - removed by spleen when old
RBCs have ____ & _____ that increases surface area and allows them to squeeze through the microcirculation
biconcavity and reversible deformity
Leukocytes - Granulocytes include?
neutrophils, basophils, eosinophils, mast cells
Leukocytes - Agranulocytes include?
monocytes and macrophages (phagocytes) & lymphocytes (immunocytes)
Normal count for thrombocytes (platelets)
150,000-400,000
What are platelets made of? Where are they produced & stored?
irregularly-shaped cytoplasmic fragments formed by the fragmentation of megakaryocytes
Produced in BM and stored in the spleen where they are slowly released
Platelets are incapable of ______ d/t no nucleus or DNA. This means lifespan of? Removed by?
mitotic division
lifespan of 5-9 days
removed by spleen
Platelets also have _______ that secrete biochemical mediators when stimulated by ______. What are these pro-inflammatory mediators?
- granules
- simulated by injury to blood vessel
- ADP, ATP, calcium, serotonin, histamine
What is the link b/w the hematologic and immune system?
lymphoid organs
Primary lymphoid organs?
BM and thymus
Secondary lymphoid organs?
spleen, lymph nodes, tonsils, Peyer patches of the small intestine
Largest lymphoid organ and its function?
spleen
- site of fetal hematopoiesis
- filters/cleans blood
- mounts immune response
- blood reservoir
Lymph nodes = first encounter b/w?
lymphocyte and antigen
macrophages reside in lymph nodes and…
- filter the lymph of debris, foreign substances, and microorganisms
- provide antigen-processing functions
What is hematopoiesis?
the process of blood cell (all) production in adult BM or in the liver and/or spleen of the fetus (mostly in spleen)
Two stages of hematopoiesis?
MITOSIS (PROLIFERATION) = stimulation of pluripotent cells that are similar to divide by mitosis
MATURATION (DIFFERENTIATION) = then become mature hematological cells
BM is also called?
MYELOID TISSUE (where hematopoietic stem cells are)
Red BM does what? Yellow BM does what?
Red produces RBCs, Yellow does not produce RBCs
A common myeloid progenitor cell can become…
*remember common myeloid vs. common lymphoid progenitor
- megakaryocte –> thrombocytes
- erythrocyte
- mast cell
- myeloblast (basophil, neutrophil, eosinophil, monocyte/macrophage)
To become an RBC you go from common myeloid progenitor to _______ and then what?
Process of erythropoiesis
Where does EPO enter this scenario?
common myeloid progenitor to erythroid progenitor!
erythroid progenitor + EPO (ERYTHROPOIETIN) = committed proerythroblast (blast on the end means it’s committed to becoming that line)
erythroid progenitor –> committed proerythroblast –> normoblast (nucleus shrinks and is reabsorbed) –> reticulocyte (cell leaves BM and enters bloodstream) –> erythrocyte (cell achieves final shape and size; hemoglobin synthesis ceases)
*Remember as it loses its intracellular components it is also producing hemoglobin
See hematopoiesis chart process slide 16
How many RBCs are stored? How much storage for granulocytes, and thrombocytes?
…No RBCs are stored, so ALL are functional
- 50% stored, 50% functional WBCs (granulocytes)
- 30% stored, 70% functional platelets (thrombocytes)
FACTORS THAT INCREASE HEMATOPOIESIS (rem. this is development of ALL blood cells)
- conversion of yellow BM (does not produce blood cells) to red BM by actions of EPO
- faster differentiation of progenitor cells
- faster proliferation of stem cells into progenitor cells
Erythropoiesis maturation is stimulated by…what does it stimulate stem cells to form?
ERYTHROPOIETIN
- STIMULATE STEM CELLS TO FORM PROERYTHROBLAST, WHICH ARE COMMITTED INTO PRODUCING ERYTHROID CELLS
- THIS PROCESS PROMOTES RELEASE OF RETICULOCYTES
*in each step of erythropoiesis, the quantity of hemoglobin increases and the nucleus decreases in size
Hormone released from the kidney in response to low renal oxygenation? What is it NOT released by?
Where is this also produced in small amounts?
ERYTHROPOIETIN (EPO)
- it is NOT released by the number of RBCs but rather oxygen delivery
- also produced in the liver (10%)
The RBC production increases within _______ after EPO release? EPO lifespan? Increases RBCs in how many days?
production increases w/i 24 hours; lifespan of EPO is 4-12 hrs (short half life) for this reason might have to give dialysis or chemo pts several times/wk
-causes increased RBC number in 5 days
EPO IS ALWAYS PRESENT IN THE _______
PLASMA
Reticulocytes contain what? Make up what % of total RBCs? How many days after leaving the BM does it become a mature RBC?
contains polyribosomes (globin synthesis) and mitochondria (heme synthesis)
- 1 to 2 days after leaving the BM matures into RBC and loses polyribosomes/mitochondria
- make up about 1-2% of total RBCs
Indicates whether new RBCs are being produced, and is a good indicator of erythropoiesis. What percent of total RBCs?
RETICULOCYTE COUNT
-which is normally 1-2% of total RBCs
See slide 22…
negative feedback!
Oxygen-carrying protein of the erythrocyte
hemoglobin
A single erythrocyte contains as many as ______ hemoglobin molecules
300
each hgb molecule has…
2 PAIRS of globin chains & 4 complexes of iron + heme
what is heme? where is it synthesized?
large, flat, iron-protoporphyrin disk that is synthesized in the mitochrondria and can carry ONE MOLECULE OF OXYGEN
Each heme can carry _____ molecule of oxygen….so there are _____ heme groups on one molecule of hgb, so one molecule of hgb can carry ______ molecules of O2
each heme can carry 1 molecule of O2, and since there are 4 heme groups on each molecule of hgb then it can carry 4 molecules of O2
The most common globin chain found in hemoglobin?
Remember each hgb molecule has 2 pairs of polypeptide globin chains
Most common is Hgb A: 2 alpha and 2 beta chains
*for this course just understand that there are different chains, but don’t need to understand different types
mature RBC includes what on the inside?
no nucleus, no mitochondria, only HGB and some enzymes surrounded by a membrane
Since RBCs do not have mitochondria, they rely on what for energy?
glycolysis
Deficiencies in two enzymes can cause anemias?
G6PD - involved in protecting RBC from oxidative stress
Pyruvate kinase - necessary for glycolysis - absence will result in damage to RBC
What is an old RBC called?
senescent (old)
What digests the old RBC?
macrophages in the spleen
When an old RBC is broken down what happens to iron?
Iron IS LIBERATED FROM HEME, OXIDIZED AND RECYCLED (TRANSFERRIN TO FERRITIN)
Process of bilirubin production and secretion of old RBC
Porphyrin of heme is metabolized to bilirubin – transported to liver and conjugated – excreted
as bile into intestine – transformed to urobilinogen – excreted with feces, some through kidneys
Production of RBCs regulated by? How much produced and destroyed daily?
EPO
-1% produced/day and around 1% destroyed/day
Normal hematocrit level for M & F?
M = 45%, W = 40%
% volume of blood that is RBCs
Normal HGB levels M & F?
15-16 (male) gm Hb/100 mL blood
13-14 (female) gm Hb/100mL blood
Around 67% of total body iron is bound to…
heme in RBCs (hemoglobin) and muscle cells (myoglobin)
____mg of iron is required daily for erythropoiesis; ____mg of iron is dietary. The remainder is obtained from iron recycling
25mg of iron is required daily; 1-2mg of iron is dietary, and the remainder is obtained from iron recycling
The major intracellular IRON STORAGE PROTEIN? Where is it produced?
FERRITIN - produced in the intestines
TRANSFERRIN IS ________. What does it do? Where does it travel?
Transferrin is the iron bound to apotransferrin (precursor)
- It TRANSFERS IRON in the circulation
- IRON FOR HEMOGLOBIN PRODUCTION IS CARRIED BY TRANSFERRIN TO THE BM WHERE IT BINDS TO TRANSFERRIN RECEPTORS ON ERYTHROBLASTS
What is apotransferritin? Where is it secreted from?
ferritin w/o attached iron (precursor)
liver secretes apotransfeerrin and then it binds with free iron and becomes trasnferrin
See picture slide 33
…
Iron absorption from where in the intestines? Around what amount?
duodenum and upper jejunum 1-1.5mg/day
Iron absorption is enhanced by?
meat, poultry, fish
HCl
citrus also increases
Iron absorption is inhibited by?
carbonates, tannate (tea), oxalate (spinach, rhubarb), phosphates (vegetables), clay
menstruating women lose how much iron/period?
14mg/period on average
Lose on average 60mL of blood
_____ secretes apotransferrin
liver
Remember difference b/w apotransferrin and apoferritin
…
see slide 35
…
excess iron goes to
what is the stored form of iron called?
liver & BM where apoferritin becomes ferritin
*Hemosiderin (stored form of iron): small quantity (excess iron) collects in cells (insoluble/water
soluble)
