Blood Flashcards
What are the characteristics of blood?
Viscosity- thicker and flows slower
Temperature- higher than tissues, redistributes
Alkaline - pH 7.35-7.45 (arterial more alkaline due to less CO2)
Functions of blood
Clotting
Immune response
Transport -nutrient, gasses, wastes, hormones, heat
Regulation - water, electrolytes, temp and acidity
How does blood maintain a relatively stable pH?
Buffering
Carbonic anhydrase coverts CO2 to H2CO3
CO2 + H2O <==> H2CO3 <==> H+ and HCO3-
Hemoglobin binds H+
How do plasma proteins maintain water balance?
Starlings forces.
Colloid osmotic pressure promotes reabsorption of fluid from tissues.
Prevent excessive loss of plasma proteins
What are the classes of plasma proteins?
Albumins
Globulins
Fibrinogen
Function of albumins
Major contributor to ontonic pressure of plasma
Important in transport of fatty acid
What are the types of Globulins and what is their main function?
Transport globulins- binding hormones or small molecules for transport in the body
Immunoglobulins- antibodies in immune response
What is the function of fibrinogens?
Blood clotting
Where are albumins and fibrinogens produced?
Liver
Where are immmunoglobulins produced?
Lymphocytes
What are the primary differences between blood plasma and interstitial fluid?
Concentration of dissolved proteins
Levels of respiratory gases
What is the process of producing formed elements of the blood called?
Haemopoiesis or hematopoiesis
Where does hematopoiesis take place?
Bone marrow
All formed elements in blood are derived from what type of cell?
pluripotent hematopoietic stem cell
The pluripotent hematopoietic stem cell can differentiate into which two types of cells?
Lymphoid stem cell
Colony forming unit
A colony forming unit can form what types of cells?
Erythrocytes
Leukocytes
Megakaryocytes (platelets)
How are erythrocytes formed?
CFU-S differentiates into CFU-E, produces hemoglobin.Under the influences of erythropoietin CFU-E develops into a recticulocyte (no nucleus). Recticulocytes leave the bone marrow. Recticulocyte loses ER, mitochondria, and ribosomes to become a mature RBC.
CFU-GM forms what types of cells?
Granulocytes and Monocytes
= basophils, eosinophils, neutrophils, monocytes.
CFU-M forms what types of cells?
Megakaryocytes which form platelets (influenced by thrombopoietin)
Lymphocyte stem cells form what?
T lymphocytes and B lymphocytes
What are the characteristics of RBC?
Flat
Biconcave
Disc-shaped
The characteristics of the RBC allows for what functions?
High surface area for diffusion of O2
Narrow shape for diffusion of O2 between exterior and interior of cell (Ficks Law)
Bending of cell to travel through capillary
Ficks Law
Diffusion rate is proportional to the partial pressure of O2, proportional to SA of diffusion, and inversely proportional to thickness of the membrane (distance travelled)
Describe the process of erythrocytes degradation
RBC have no nucleus and cannot replace enzymes. Membrane proteins are degraded over time and the integrity of the plasma membrane decreases. RBC travel through narrow vessels of spleen and membrane ruptures. Macrophages phagocytose RBC and hemoglobin is recycled
What is anemia?
Reduction below normal isn’t he O2 carrying capacity of blood and is characterized by a low number of RBC
What is a hematocrit?
Ratio of RBC volume to total volume of blood
Aka Packed cell volume
What are the 3 causes of anemia?
Decreased rate of erythropoiesis
Excessive loss of erythrocytes
Deficiency in hemoglobin concentration of RBC
Anemia due to a deficiency of a factor required for erythropoiesis
Nutritional anemia
What nutritional factors may be lacking in nutritional anemia?
Iron- not enough for Hb synthesis
Folic Acid- critical for stem cell division and maturation of RBC
What type of anemia results from an inability to absorb vitamin B12?
Pernicious anemia
B12 required for development of RBC
Intrinsic factor lacking preventing sufficient absorption from GI tract
What is aplastic anemia?
Failure of bone marrow to produce adequate amounts of RBC
Toxic chemicals
Radiation exposure
Bone marrow cancer
Renal anemia is caused by what?
Erythropoietin(stimulant for RBC production) is not released from the kidney