What are the functions of blood?
-Transports all necessary fluids, gases, chemicals, nutrients, and wastes throughout the body
- Protection; WBCs, antibodies, and platelets
- Regulation of fluid and buffering
What is Osmolarity?
Total molarity of dissolved particles
- sodium ions, protein, and RBCs
High Osmolarity - causes fluid absorption into blood, raises BP
Low Osmolarity - causes fluid to remain in tissues, may result in edema
What are the three major categories of plasma proteins?
-Albumins (most abundant; contributes to viscosity and osmolarity, influences blood pressure, flow, and fluid balance)
- Globulins (antibodies; provide immune system functions such as gamma globulins are antibodies)
- Fibrinogen( precursor of fibrin threats that help form blood clots)
What is formed elements?
-RBCs: carry oxygen and some carbon dioxide
-WBCs: important in immunity, allergic responses, antibody production and inflammation
- Platelets: essential for hemostasis
What the function of Erythrocytes (RBCs)?
- Gas transport (major function); increased surface area and volume ratio no nucleus or mitochondria
- Carbonic anhydrase (CAH); produces carbonic acid from CO2 and water; important role in gas transport and pH balance
Why are RBCs and Hemoglobin lower in women?
-adrogens stimulate RBC production
-periodic mestrual losses
-hematocrit inversely proportional to percent body fat
the production of new blood cells,
-stimulated by a # of chemical messengers in response to alterations in body homeostasis
Negative feedback control
- drop in RBC count causes kidney hypoxemia
- EPO production stimulates bone marrow
- RBC count increases in 3-4 days
What stimulates erythropoiesis?
-low levels of O2
- increase in exercise
- loss of lung tissue in emphysema
What are the nutritional needs for erythrocyte production?
- Iron (for hemoglobin production)
- Vitamin B12 and folic acid
- Vitamin C and copper (cofactors for enzymes synthesizing RBCs
a protein that consists of four polypeptide chains called globins.
Each heme group, bound to iron, can then bind to an oxygen molecule
How many oxygen molecules can a one hemoglobin bind to?
One hemoglobin molecule can bind to a maximum of 4 oxygen molecules.
What is Anemia and causes of it?
Inadequate erthropoiesis or hemoglobin synthesis (decreased production)
- kidney failure and insufficient erythropoietin
Sickle-cell Disease- homozygous
Hereditary Hb 'defect'
-recessive allele modifies hemoglobin structure
- individual has shortened life
What are the 2 types of Leukocytes?
- Grandulocytes (Neutrophils, Eosinophils, Basophils)
- Agranulocytes (lymphocytes, monocytes)
Increases in bacterial infections
-phagocytosis of bacteria
-release antimicrobial chemicals (hydrogen peroxide)
Increase in parasitic infections or allergies
-phagocytosis of antigen-antibody complexes, allergens and inflammatory chemicals
-release enzymes to destroy parasites
Increase in diverse infections and immune responses
- destroy cancer cells
- "present" antigens to activate other immune cells
- coordinate actions of other immune cells
- secrete antibodies and provide immune memory
increase in viral infections and inflammation
- differentiate into marcrophages
- phagocytize pathogens and debris
- "present" antigens to activate other immune responses
Low WBC count
causes: radiation, poisons, infectious diseases
effects: elevated risk of infection
High WBC count
Causes: infection, allergy and disease
Differential count -distinguishes % of each cell type
Cancer of hemopoietic tissue
-myeloid and lymphoid- uncontrolled WBC production
- acute and chronic- death in months or 3 years
Effects: normal cell % disrupted; impaired clotting
Responsible for hemostasis; aid in vascular constriction, platelet plug formation, and coagulation.
-chemically attract neutrophils and monocytes to sites of inflammation
(started out as Stem cells)
-repeatedly replicate DNA w/o dividing cytoplasm
-forms gigantic cell called megakaryocyte
Infoldings of cytoplasm splits off cells fragments that enter bloodstream as platelets
homeostatic mechanism that prevents the loss of blood due to trauma or other damage to blood vessels
promote the prompt constriction of a broken blood vessel.
-pain receptors (short duration-minutes)
-smooth muscle injury(longer duration)
-platelet release serotonin (vasoconstrictor)
-provides time for other two-clotting pathways
Platelete Plug Formation
Endothelium smooth, coated with prostacyclin
-broken vessel exposes collagen
-platelet pseudopods stick to damaged vessel and other platelets- pseudopods contract an draw walls of vessel togethere forming a platelet plug
- Platelets degranulate releasing serotonin (vasoconstrictor), ADP (attracts and degranulates more platelets), Thromboxane A
- positive feedback cycle is active until break in vessel is sealed
conversion of plasma protein fibrinogen into insoluble fibrin threads to form framework of clot
-Procoagulants (clotting factors) are present in plasma
-extrinsic pathway: factors released by damaged tissues begin cascade
-intrinsic pathway: factors found in blood begin cascade (platelet degranulation)
Genetic lack of any clotting factor affects coagulation
- Sex-linked recessive
- physical exertion causes bleeding and excruciating pain