Erythrocyte
Carrier of hemoglobin and therefore function in O2 and Co2 transport
Regulation of Erythropoiesis
- Erythropoietin
o Produced in the Kidney
o Prevent apoptosis to allow RBC to mature
o Produced in response to hypoxia
o Stimulate stem cell differentiation into rubriblast
- Androgen
o Increase Erythropoietin release from the kidney
- Estrogen
o Have an inhibitory effect on Erythropoiesis
There are 4 division to make 16 RBC
5 days to release the stem cell into the circulation
Intravascular in avian
Extravascular in mammals
Erythropoiesis
- Start with a large RUBRIBLAST
o As the cell divide and mature the cell become smaller.
o The nucleus become smaller and increase hemoglobin concentration
Early Rubricyte- hemoglobin synthesis starts
Late rubricyte-
critical hemoglobin concentration is reached
shut down the cell division
pag na reach na ang tamang hemoglobin level stop na ang hemoglobin synthesis. Kaya walang hyperchromic na mang-yayare
metarubricyte
- Nucleus is small and pyknotic (irreversible condensation of chromatin of cell nucleus undergoing apoptosis)
Reticulocyte
- Have residual RNA and organelles
- Polychromatic cells (RBC that appear blueish gray inn the blood smear) (Polychromasia- abnormal findings, presence of numerous abnormal RBC in the blood)
- Equine- no reticulocyte in the circulation.
RBC
- No RNA
- High hemoglobin concentration
Ageing of erythrocyte is accompanied by changes in enzyme content and cell membrane structure that is subjected by the spleen removal (Phagocytosis of the macrophages)
The body iron content is regulated by the rate of absorption rather than the rate of excretion
Transferrin- transport iron in the blood
- When iron is with transferrin = serum Iron
- SI can be expressed as total iron binding capacity/TIBCB reported as % saturation
- TIBC-SI=UIBC
Ferritin- is the form of iron stored In the RES (correlate with tissue iron reserve)
Causes of decreased SI
- Iron defficiency
- Chronic and acute inflammation
- Hyperproteinemia
- Hypothyroidism
- Renal disease
Cause of increased SI
- Hemolytic anemia (due to the destruction of RBC resulting to escape of iron)
- Lysis of RBC
- Hemolysis
- GCC excess
- Non regen anemia
Erythrocyte metabolism
EMP/Glycolysis
- ATP is generated from glucose to maintain RBC membrane integrity
- Pyruvate kinase and phosphofrutokinase can lead to animia
Hexose monophoshate pathway
- Glutathione is maintained is reduce state (because it can oxidize RBC)
o When RBC undergo oxidation. The RBC will be coated by oxide causing it to rust of become hard resulting to stress RBC meaning that the membrane conformation will change. Now the RBC will become aged and will be send to the spleen for destruction.
- Glutathione reductase deficiency may result to Heinz body and anemia
o Heinz body
Inclusion in the RBC compose of denatured hemoglobin.
Methamoglobin redutase pathway
- Methemoglobin is oxidized hemoglobin
- Reduced hemoglobin is necessary for transport of oxygen
o Oxyhemoglobin – reduced state of hemoglobin
Luenbering-Rapoport pathway
- Allows the formation of 2,3-DPG that regulate transport into tissue by lowering O2 affinity to oxygen
- Increased in 2,4-DPG may be caused by
o Hypoxemia- abnormal low level of O2 in the blood
o Animia
o Hyperphosphatemia- increased level of phosphate concentration. Can be caused by
Chronic kidney disease
Hypoparathyrodism
Metabolic/respiratory acidosis
Clinical features may be due to: hypocalcemia and tetany ( low calcium in the blood. Characterized by spams
Means of evaluating erythrocyte
1. PCV or hematocrit
-the percent of blood compose of erythrocyte
2. RBC count- using hemocytometer, less accurate than the PCV
3. hemoglobin concentration- most direct indication of the oxygen transport capacity if the blood (1/3 of the PCV)
Icterus index
- Hemoglobin fails to be conjugated in liver dysfunction and free bilirubin is allowed to be exess
Factors affecting the PCV, HB and RBC count
- Change in RBC mass
o Anemia
o Absolute polycythemia- increase in RCB mass
o Relative polycythemia- refers to a loss of volume causing an elevated hematocrit
- Change in hydration
o Dehydration
o Over hydration
Erythrocyte indices
MCV/Means Corpuscular volume
- Average volume of erythrocyte of an individual
- Calculation: RCV x 10 / RBC count
Macrocytic anemia
- Increase in MCV
- Example is Responsive anemia
o Mani reticulocyte in the circulation
o Indicate marrow response to anemia
- Vitamin B 12 and folic deficiency
o Vitamin B 12 anemia- is a condition in which the body does not have enough healthy RBC. Vit B 12 is neededd to make RBC
Normocytic anemia- MCV is within the normal interval
- Example: hemorrhages
Microcytic anemia- Decreased MCV
- Example: Iron Deficiency anemia
o In mature animal
o With the deficiency in iron, the body can`t produce enough of a substance in RBC called hemoglobin that enables them to carry O2
o As a result of iron deff anemia It may leave you tired and short of breath
RBC distribution width
- A erythrocyte index used to determine the degree of variation in RBC
- More sensitive than MCV for detecting changes in RBC
- The higher the value above the reference interval, the greater is the erythrocyte size variation
- RDW correlates to the degree of anisocytosis
o Anisocytosis- RBC is unequal in size, found in cases of anemia and other blood conditions
Mean Corpuscular Hemoglobin/ MCH
- Mean amount/weight of Hb contained in an average RBC
- Least accurate
- Calculation: Hb(gram/dL) x 10/RBC count
Mean Corpuscular hemoglobin Concentration/ MCHC
- Concentration if hemoglobin in an average RBC
- Calculation: Hb (g/dL) x 100/ PCV%
Decreased MCHC- Hypochromic anemia
- Hypochromic anemia- general term for any type of anemia in which the RBC is paler than normal
- Hypo means less and chromic means color
- Example: iron deficiency
- Reticulocytosis
o Increase in number of reticulocyte in the circulation (immature RBC)
MCHC within the normal reference interval
- Normochromic anemia- average size and Hb content of RBC is in normal limits.
Increased MCHC- Hyperchromic
- Hemolysis
o Increase MCH
Peripheral blood smear for evaluation of blood cells
1. RBC morphology
- Canine
o Large uniform in size with central pallor
- Feline and Bovine
o With slight central pallor and mild anisocytosis
o Crenation- abnormal notch surface in the cell that result form loss of water through osmosis
- Equine
o Lack central pallor and rouleaux formation is common
2. Rouleaux – grouping of erythrocyte resembling a stack of coins
o Associated with an increase of
Fibrinogen concentration
• Fibrinogen is made by the liver, it convert thrombin to fibrin then to a fibrin-based blood clot.
Qualitative change in serum globulins
• Globulin is made by the liver
• Plays an important role in lover function, blood clotting and fighting infection.
o Common in horses
o In dogs it may occur in mild degree of health but marked during inflammation and neoplastic diseases
o Rare in ruminants in health and disease
Rouleaux formation
- The normal RBC has negatively charged surface that repels neighboring cells, but during inflammation blood protein increases. The plasma protein coats the RBC and mask the negative charge resulting to voiding its repulsion resulting to formation of rouleaux.
Autoagglutination
- Process by which TBC adhere to each other and form cohesive aggregates that no not dissipate when mixed with equal pars of saline
- Occur when the RBC is are coated with Ab that interacts with adjacent RBC.
- Indicate immune-mediated hemolytic anemia or IMHA
o Autoimmune disease in dogs that the body attacks It`s own RBC
o Also predispose dogs to forming blood clots especially in brain and lungs.
3. Anisocytosis
- Variation is size
- Common in cattle
- Occur when there is a degenerative anemia
Macrocyte- RBC is larger than normal with an increase in MCV
Mircocytes- RBC with a diameter less than normal with decrease in MCV
4. Polychromasia- variation in color
- Hypochromasia
o Decreased staining intensity caused by insufficient Hb within the cells
o Seen in iron deficiency
- Normochomasia
o Normal staining intensity
Poikilocytosis - Deviation is normal shape
- Leptocyte-
o thin RBC with increase surface volume but volume is not increased (low concentration of Hb)
o cell membrane can fold or become distorted
o common in non-regenerative anemia
non- regenerative anemia- the bone marrow can not respond in the anemic state.
Codocytes/ target cells
- subclass of leptocye with distribution of Hb in the center and periphery of the of the erythrocyte.
- Formed because of either increased membrane surface area or decreased cytoplasmic volume
- Seen in animals with liver disease IMHA
Stomacytes
- Leptocyte that is bowel shape with 3d
- Seen in
o Liver disease
o Chronic anemia- commonly occur with infection, chronic illness, inflammatory disorders or cancer
Spherocyte
- Small, darkly stained RBC lacking of central pallor
- Have reduced amount of membrane result from partial phagocytosis
- Seen in animals with
o IMHA
o Chronic debilitating disease
Diseases that affect people`s strength leaving them weak.
Keratocyte/horn cells/helmet cells
- Partial RBC with one or more incomplete cuts
- Projection result form ruptured vesicles
Acantocytes/spur cells/spicules cells
- Form secondary to an altered membrane lipid and cholesterol content
- Seen in patient with severe liver disease
Echinocytes
- Characterized by the presence of multiple, rounded edge projection, evenly spaced along the RBC surface
- Seen in various metabolic disorders.
Erythrocytes Inclusions
1. Reticulocytes
2. Punctate Basophillia
- Aggregation of basophillic staining materials seen as granules of different size RBC
- Attributed to degenerative changes in RNA of young cells
3. Howell- Jolly bodies
- Remnant of nuclear material after the nucleus has been extruded
4. Heinz bodies
- Irregularly shaped refractile bodies representing denatured Hb
- Occur in horses with hemolytic animia caused by PTZ therapy or wild onion poisoning
o PTZ or Pentylenetetrazol- a drug formerly used as circulatory and respiratory stimulant.
o Wild onion poisoning in horses- causes Heinz body hemolytic anemia in horses. The toxic principle is n-propyl disulfide.
Anemia- reduction in number of erythrocyte, Hb or both in the circulation
Classification of anemia
Etiology classification
Four major categories
1. Blood loss
2. Excessive destruction of RBC or shorten life span
3. Depression of bone marrow
4. Nutritional deficiency
Anemias can be classified as regenerative or non- regenerative. In general:
marcrocytic anemias are responding
normocytic anemia are non responding
microcytic anemias can be either the two
regenerative anemia
- bone marrow responds to anemia by increasing RBC production and releasing immature erythrocyte
Non Regenerative anemia
- the bone marrow in unable to respond to anemic state
- reticulocyte is absent, suggesting marrow dysfunction
Polycythemia
- increase in number of RBC and is usually accompanied by a corresponding increase in the amount of Hb and PCV
1. absolute polycythemia
- an absolute increase in PCV, RBC count and Hb concentration by increased total body RBC mass occur
- plasma volume and protein are normal
2. primary absolute polycythemia/ polycythemia vera
- disease characterized by absolute increase in total blood volume with increase in total circulating erythrocyte.
3. Secondary absolute polocythemia
- Caused by increase erythropoietin level (occur in hypoxia)
Relative polycythemia/Spurious
- Increase in PCV but total RBC mass in normal
- Cause
o Hemoconcentration: fluid loss
o Excited animal.
Water, Electrolyte and Acid-Base balance
Two compartment
ICF- water contained within the cell
ECF- fluid outside the cell
- Consist of plasma, lymph and fluids found in the CSF and joints
Intracellular Fluid/ICF
- Contains a higher concentration of K and Ph and lower concentration of Na and Cl
- Major cations
o K
o Mg
- Major anions
o Organic Ph
o Proteins
Extracellular fluid/ECF
- Compose of fluids found in
o Intravascular/Plasma
o Interstitial/including lymph
o Transcellular- including fluids in the CSF and joints
- Water and major electrolyte move freely within the compartment and between it and intravascular fluids
- Major cations
o Na
- Major anions
o Cl
o Bicarbonate
Note:
Na regulates the osmotic pressure in the ECF and K in the ICF
Water movement between ICF and ECF is partially dependent upon the physical effected by:
- Hydrostatic pressure
- Osmotic effects of ECF proteins
Note:
hydrostatic pressure pushes fluids outside the BV
Oncotic pressure (protein) counter act the movement of water out of the BV
Electrolytes
1. Na
- 50% found in the ECF, the quantity is controlled by dietary intake and loss
- In carnivores, it usually preset in adequate amount in the diet
- In herbivores may occasionally experience deficiency
- Excretion:
o Kidney
o Sweat
o Digestive tract
- 90% of sodium present in the renal tubule is reabsorbed
- Controlled by aldosterone
o When the Na is low, there will be an increase in the secretion of aldosterone resulting to an increase of Na reabsorption (vive versa when the Na is In high amount)
Electrical neutrality must be maintain in the body, the increase of cations will result to the decrease of the other
2. K
- Concentration is low in the ECF and high in the most part of the body
- Carnivores and herbivores. Their diet contain an adequate amount of K
- Kidney ability to conserver K is not efficient as that with Na
- K excretion is also controlled by aldosterone
o Aldosterone causes increased Na reabsorption by promoting the exchange Na in the tubular fluid for K in the tubular cell
3. Cl
- Small quantities in the ICF but high quantities in the ECF
- Cl excretion, absorption and distribution is passive. It follows the Na
4. HCO3
- Greatly influence the maintenance of the Acid-Base balance in the body
- Endogenic in origin
- Produced by hydration of CO3 and H2CO3 which then dissociated to HCO3 and H (via Carbonic Anhydrase)
- Excretion:
o Digestive tract
o Urine
Measurement of dehydration
1. PCV
- In dehydration PCV will increase because there is decrease in the level of plasma
2. Urinalysis
-the SG will increase in dehydrated animal because the solute in the urine increase because there are low amount of fluid
3. Determination of plasma protein concentration
- Increase plasma concentration in dehydrated animals
4. Body weight changes
Electrolyte Abnormalities
- Mercury metric titrimetric technique
- Plasma photometry for determination of Na and K
- Serum is the desired sample
o The serum must be separated as soon as possible to prevent further ion exchange
1. Hyponatremia or decrease Na in the blood
- Diarrhea and vomiting
o Caused by toxins and LT toxins
o Because the Na is not absorbed
- Renal disease
- Osmotic diuresis in cases of diabetes mellitus
o Increase in glucose result to increase in ECF osmolarity= Na secretion to avoid hyperosmolarity
o Osmolarity- the concentration of a solution expressed as the total number of solute particle per liter
o Hyperosmolarity- is a condition in which the body has a high concentration of salt, glucose and other substances
o Diabetes mellitus- is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar or glucose level to be abnormally high
- Excessive sweating
- Adrenocortical insufficiency- aldosterone deficiency
- Exudation from burns and wounds
- Delusional hyponatremia
2. Hypernatremia (rare)
- Occurs when there is loss of body fluids containing less Na than plasma and water intake is restricted (increase in concentration of Na in the blood)
- Advance chronic renal failure with low GFR
o Sever reduction of glomerular filtration rate
- Primary hyperaldosteronemia
o Secretion of excess aldosterone
- Diabetes insipidus
o Pure water is only being loss because of the opening of aquaporins in the kidney and the Na is being retained and not being loss
o DI is an uncommon disorder that causes an imbalance of fluids in the body
3. Hyperkalemia or increase K in the blood/ hyperpotanemia
- Acute renal failure
o Failure to excrete K out of the blood
- Hypoadrenocorticotism is associated with administration of K sparing diuresis
o Decrease in mineralocorticoid leading to less reabsorption of Na
o In case of hypoadrenocorticotism there is less secretion of aldosterone resulting to less reabsorption of Na, pag ganon nangyare mag stay lang Na pa excrete so mag stay den ang K sa loob. Kase palitan dapat sila.
- Urethral obstruction and bladder rupture
o K is not excreted
- Metabolic acidosos
o K go out of the vessel to the cell in exchange of H. when this happen the pH will increase due to the presence of H in the circulation.
- Insulin deficiency
o Because the entry of K into the cell is regulated by Insulin and Mg
4. Hypokalemia
- Occurs as a result of decreased K loss or a shift of K from the ECF to the ICF
- Vomiting and diarrhea
- Metabolic alkalosis
o K is excreted to the urine in exchange of H
- Hyperaldosteronism
o K is attributed with aldosterone
5. Hypochloridemia
- Losses from the GIT due to prolong vomiting
- Advance renal failure
o Failure of Cl reabsorption
- Adrenal insufficiency- lack of aldosterone
- Exudation from burns and wounds
6. Hyperchloridemia
- Dehydration
- Congestive heart failure
Acid base balance
pH determine by the number of free H in a solution
- pH=log H+
acid is the proton donor that contribute free H to a solution
base is the proton acceptor that takes free H out of the solution
normal blood pH: 7.3 to 7.5
pH maintenance is controlled by the combines effects of:
- blood buffer system
- respiratory system
- renal system
1. blood buffer system
a. buffer
- mixture of weakly dissociated acid and a salt of that acid
- prevent a major shift in pH by binding or releasing H+
- consist of the following
o hemoglobin
o protein buffer system
o Phosphate buffer system
o HCO3/H2Co3 system
b. The Bohr effect- how Hb buffer the blood
c. HCO3/H2CO3 system
2. Respiratory control
- Respiratory center in the medulla oblongata is sensitive to pCO2 blood levels, Increase in blood pCO2 causes the an increase in respiratory rate which has tendency to return pCO2 and H2CO3 to normal
3. Renal control
- Kidneys exchange Na for H causing production of acidic urine
- NH2 may diffuse into the tubules and combine with H. this permits increased H excretion and Na preservation
- Non volatile acid when there is decrease in bicarbonate sodium and bicarbonate will go to the blood and H into the urine
