Physiology - Exam 1, Deck #3 Flashcards
How is blood maintained?
- Its composition and volume are maintained within narrow limits by homeostatic mechanisms = CONSTANT;
- Despite additions/losses of water and metabolic/nonmetabolic substances
What is Blood Volume?
- The sum of the volume of cells and plasma in the circulatory system;
- Ordinarily plasma volume and blood volume are determined separately
What is the equation for determining Plasma Volume?
- FICK equation = [C1 x V1 = C2 x V2];
1. Dye dilution technique –TR-1824, Evans Blue Dye;
2. Radioisotope dilution technique- RI138SA
What is the process for using Evan’s Blue Dye/Radioisotope for PV?
- Injected concentrated dye into the circulatory system;
- Allow enough time for it to mix thoroughly and sample it;
- Determine concentration of the dye and determined the dilution factor;
- PV is determined by the FICK equation
What is the composition of Blood when centrifuged?
- Plasma on top;
- Buffy coat between = Platelets and WBC
- Formed elements on the bottom = RBCs
What is the Cell Volume by % Hematocrit?
- Cellular portion of the blood;
- 45%
How is Blood Volume determined?
BV = [(PVx100)/100-H] x 100;
-Avg blood volume = 5.5 liters = 9-10 pints
What are the factors that vary blood volume?
- Age
- Gender
- Build
- Race
- Environment
- Disease
- Body Position
- Degree of Recent Exercise
What is the composition of Blood Plasma (Fluid blood)?
- *Plasma = 55% of blood volume
1. H2O = 92%
2. Solids = 8% - Ions =Na+, Ca++, K+, Mg++, Cl-, HCO3-, PO4— ,SO4—
- Proteins = 6-8grams / 100 mls of blood = serum albumin, serum globulin, fibrinogen
What happens when Plasma is resolved?
- Can be resolved into SERUM and the FIBRIN CLOT
1. Albumin = 55% of total plasma proteins – COP
2. Globulins = 44.8% of total plasma proteins - Alpha 1
- Alpha 2
- Beta
- Gamma = Immunoglobulin – circulating antibodies which play a role in the immune response
3. Fibrinogen = 0.2% - substrate which will be converted into the blood clot
Where are the Plasma proteins made?
- Globulins (except immunoglobulins), albumin, and fibrinogen – synthesized in the liver;
- Immunoglobulins – synthesized by lymphocytes and plasma cells of the REC
What are the functions of the plasma proteins?
- Exert colloidal osmotic pressure on tissue fluids;
- Amphoteric character – aid in regulation of pH;
- Fibrinogen is the substrate of the blood clot;
- Immunoglobulins are antibodies;
- Transport lipids;
- Source of nutrition during starvation
What is the concentration of blood glucose?
- Normal range – 70-140 mg/dl;
- Replenished from absorption and liver glycogen;
- Under hormonal control from insulin, glucagon, and epinephrine
What are the NON-PRO Nitrogen Substances in Plasma?
- Urea;
- Free Amino Acids;
- Uric Acid;
- Creatinine
Urea
end product of protein catabolism in man
Free Amino Acids
transported throughout the body for cellular protein synthesis
Uric Acid
end product of purine catabolism in man; elevated uric acid concentration in gout and nephritis
Creatinine
- End product of muscle phosphocreatine catabolism;
- Plasma creatinine levels are often used clinically as an index of kidney function
- Since its secretion closely matches the GFR, an **abnormal decrease in GFR causes the plasma creatinine concentration to rise
What are the Blood Lipids?
- Neutral Fats;
- Phospholipids
- Cholesterol
Neutral Fats
- transported as chylomicrons which are elevated during intestinal fat absorption
Phospholipids
Transport and utilization of fats;
-Lipoprotein structure
Core of nonpolar triglycerides and cholesterol esters;
-Coated by proteins (apolipoproteins), phospholipids, and some free cholesterol
Cholesterol
- Needed in membranes and steroid hormones, excess → ATHEROSCLEROSIS;
- Sources are animal fats and endogenously produced in the liver;
- People with dangerously high LDL cholesterol often take drugs called STATINS = inhibit the enzyme HMG-coenzyme A reductase which catalyzes the rate limiting step in cholesterol synthesis in the liver;
- Lower intracellular cholesterol stimulates the production of LDL receptors in the liver allowing the liver to uptake more LDL cholesterol from the blood which decreases the amount of LDL cholesterol uptake into the endothelial cells of arteries
What are the types of Blood Cells?
- Erythrocytes — RBCs — transport O2 and CO2;
- Leukocytes — WBCs — immunological;
- Thrombocytes — platelets — blood clotting
What are Erythrocytes?
RBCs; -Transports hemoglobin which carries O2 and CO2; -Shape – biconcave disc 8 x 2 µ; -99% erythrocytes (mature) -1% reticulocytes (immature) -Normal concentration = Men – 5.2 million/mm3; Women — 4.8 million/mm3
Where do RBCs come from?
-Making RBCs;
-in adults derived from cells called HEMOCYTOBLASTS in the red bone marrow;
-MATURE erythrocytes = lack a nucleus, mitochondria, the golgi apparatus, and the endoplasmic reticulum;
ATP is produced by glycolysis
-Reticulocytes are IMMATURE erythrocytes that pass from the bone marrow into capillaries
What is Eryhtropoiesis?
- Process of RBC formation;
- In bone marrow in adults;
- RBC forming tissue diminishes as we age;
- Tissue oxygenation (Hypoxia) is the basic regulator of erythropoiesis;;
- Stimuli - any condition that decreases the amount of O2 transported to tissues (anemia, life at high altitude)
What is the process of making more RBCs?
- ERYTHROPOIETIN , a glycoprotein hormone, stimulates the conversion of proerythroblasts to erythroblasts in bone marrow;
- Hypoxia in kidneys → release of an enzyme into the plasma that converts renal erythropoietin factor (plasma globulin) into erythropoietin;
- Procrit and EPO are commercially available erythropoietin
What are the cell stages of RBCs?
- Hemocytoblast;
- Proerythroblast;
- Reticulocyte - into capillaries;
- Erythrocyte = Mature
What vitamins are needed for the formation of erythrocytes?
- B12;
2. Folic Acid;
Role of B12
-Maturation factor - Vitamin B12;
-Required for the synthesis of DNA;
-Most common cause of maturation failure anemia is the failure to ABSORB Vitamin B12 from the Ileum
Often occurs in PERNICIOUS ANEMIA where an atrophic gastric mucosa fails to secrete normal quantities of INTRINSIC FACTOR WHICH combines with Vit. B12 and is necessary for absorption
Role of Folic Acid
-needed for DNA and RNA synthesis
How is Hemoglobin formed?
- Begins in erythroblasts and continues into reticulocyte stage;
1. Heme – from acetic acid and glycine in the mitochondria;
2. Globulin molecules – 4 = 2 alpha chains and 2 beta chains;
3. 4 heme molecules + 4 globulin molecules = hemoglobin
How much IRON is found within the body?
- Important in the formation of hemoglobin, myoglobin, and the cytochrome enzymes;
- Quantity of iron in the body = 4 gm;
- 65% in hemoglobin
- 4% in myoglobin
- 1% in the cytochromes (ETS)
- 15 -30% in the liver, principally as ferritin
How is Iron transported and stored?
- Absorbed from SI and combines with transferrin(globulin) in blood plasma;
- Excess iron→ liver cells (Iron + apoferritin → ferritin;
- Low blood iron: ferritin → iron and apoferritin → plasma where it combines with transferrin;
- Transferrin carries iron to bone marrow where it is used in hemoglobin synthesis
What are the daily losses of Iron?
Males = 0.6mg/day – mainly in the feces; Females = 1.3 mg/day – feces and menstrual flow
What is the rate of destruction of RBCs?
- Average erythrocyte life span is 120 days;
- Cells rupture when squeezed in capillaries
1. Globulin is degraded by reticuloendothelial cells
2. Iron → transferrin
3. Heme → biliveridin → bilirubin
What is Anemia?
-Any pathological reduction in the number of RBC’s or in the amount of hemoglobin/ unit volume of blood;
-Normal Hb concentration
♂ = 15g%
♀ = 14g%;
-Minimum to give blood = 13.5g% — reason women can become so easily anemic
What are the common causes of Anemia?
- Hemmorrhage = blood loss;
- Iron deficiency anemia
- Bone marrow aplasia = aplastic anemia: Common causes – drug poisoning, gamma ray radiation
- Maturation failure- Lack of Vitamin B12 or folic acid
- Hemolysis (rupture) – many causes: drug poisoning, hereditary diseases, snake bites
What are White Blood Cells?
- Leukocytes (circulating) and the reticuloendothelial system (stationary) combat infectious agents in two ways;
1. Phagocytosis or cell contact;
2. Form antibodies that destroy the invader; - Leukocytes are the MOBILE units of the body
Where are the WBCs (leukocytes) made?
- Bone marrow –granulocytes, monocytes – phagocytosis of invading organisms;
- Lymph Nodes, spleen, thymus, tonsils – lymphocytes
= Lymphocytes – attach to specific invading organisms and destroy them or produce antibodies against the invading organism
What is the WBC concentration in the body?
- Average concentration = 7000/mm3;
- Normal composition with Wright’s stain
1. Granulocytes – granules in cytoplasm
2. Agranulocytes – Lack granules in cytoplasm
What are the Granulocytes?
- Granules in cytoplasm
1. Neutrophils – 62.0% of total
2. Eosinophils – 2.3%
3. Basophils – 0.4%