Lecture: Blood Flashcards
What are the 3 functions of blood?
1) transportation
2) regulation
3) absortion
What are the 3 things that blood transports?
1) nutrients
2) wastes
3) heat
What are the 3 protective functions of blood?
1) inflammation (limits spread of infection)
2) pathogens (antibodies destroy these)
3) clotting (limits blood loss)
What are the 2 regulatory functions of blood?
1) absorption
2) buffering
What are the 2 most basic components of blood?
1) plasma
2) formed elements
What are the components of blood plasma?
90% water
8% proteins
2% other solutes
-enzymes, hormones, wastes, gases
Define: serum.
plasma without clotting protein fibrinogen
Name and describe 3 important plasma proteins.
Albumins (60%) -transport carriers -blood buffers -contributes to viscosity and osmolarity Globulins (36%) -3 categories: --alpha and beta: transport proteins --gamma: function as antibodies Fibrinogen (4%) -clotting protein
Besides water and proteins, what are 3 other important components of blood?
1) Electrolytes
2) Nutrients
3) Gases
What are the 7 electrolytes present in blood plasma?
sodium ions (90%)
-contribute to plasma osmotic pressure
-major influence on blood volume and pressure
K, Ca, Mg, Cl, Phosphate, Sulfate
What are the 6 nutrients present in blood?
1) simple CHOs
2) amino acids
3) fatty acids
4) lactic acid
5) urea
6) uric acid
What are the 3 gases present in blood?
1) oxygen
2) carbon dioxide
3) nitrogen
What contributes to viscosity in whole blood? In plasma?
in whole blood, RBCs
in plasma, proteins
Define: osmolarity. What contributes to osmolarity?
total molarity of dissolved particles that cannot pass through the blood vessel wall
Na ions, protein, erythrocytes
Define: colloid osmotic pressure (COP).
the contribution of protein to blood osmotic pressure
Define: hemopoiesis
production of blood (all formed elements)
Where does myeloid hemopoiesis take place, and what does it produce?
red bone marrow;
all formed elements
Where does lymphoid hemopoiesis take place, and what does it produce?
thymus, tonsils, lymph nodes, spleen;
lymphocytes produced
Outline the 4 cellular phases of hemopoiesis.
1) pluripotent stem cell (hemocytoblast)
2) colony-forming units; now a committed cell with a surface receptors on membrane
3) precursor cells
4) mature cells
What are the 3 formed elements in blood? Comment on their longevity.
Erythrocytes (RBCs)
Leukocytes (WBCs)
Platelets
most are short lived, so they are frequently renewed/replaced
What is the function of erythrocytes? Comment on their shape, nuclei, mitochondria, and plasma membranes.
function: carry O2 and CO2
shape: biconcave disk, provides larger SA
no nucleus/DNA
no mitochondria: generate ATP through anaerobic metabolism
cytoplasm: 33% hemoglobin, also contains carbonic anhydrase (CAH)
plasma membrane: outer proteins determine blood type;
inner proteins provide durability and resilience
Describe the structure of hemoglobin.
4 globins, or polypeptide chains
- 2 alpha chains (141 AA long each)
- 2 beta chains (146 AA long each)
each chain is conjugated to a heme
- hemes bind O2 to Fe
- 1 heme = 1 oxygen, but 1 hemoglobin has 4 hemes
Define: hematocrit.
% of whole blood volume composed of RBCs
on avg., males have higher hematocrit than females
Describe the 5 cellular phases of erythropoiesis.
1) hemopoietic stem cell (HSC)
2) erythrocyte colony-forming unit (ECFU)
- has receptors for erythropoietin
3) erythroblast
- synthesizes hemoglobin and discards nucleus
4) reticulocyte
- leaves bone marrow, enters blood
- lacks nucelus, has a network of polyribosomes
5) erythrocyte
Name the two cellular phases of erythropoiesis that are considered precursor cells.
erythroblast & reticulocyte
What are the 2 forms of dietary iron?
ferric (Fe3+) ions & ferrous (Fe2+) ions
Explain the function of gastroferritin.
protein produced by the stomach that binds Fe2+ and transports it to the small intestine, where it is absorbed into the blood
Explain the function of transferrin.
plasma protein in the blood that binds Fe2+ and transports it to bone marrow, liver, and other tissues
Explain the function of ferritin.
iron-storage complex located in liver
What are 4 other nutrients required for erythropoiesis?
1) vitamin B-12
2) folic acid
3) copper
4) vitamin C
Explain how erythrocyte homeostasis is maintained. What happens in a state of hypoxemia?
negative feedback loop
during hypoxemia, kidneys release erythropoietin (EPO), which stimulates RBC production in red bone marrow
What are 3 examples of causes of hypoxemia?
1) hemorrhage
2) high altitude
3) exercise
Explain hemolysis and all of its outcomes.
hemolysis = rupture of RBCs; releases hemoglobin and plasma membranes
PMs digested by macrophages in liver & spleen
Hemoglobin broken down into heme & globin
-heme is broken down into iron and biliverdin>bilirubin>bile>feces
-globin is broken down into free amino acids
Define: polycythemia.
erythrocyte disorder: excess RBCs
Define: anemia.
erythrocyte disorder: deficiency of RBCs or hemoglobin
Define: sickle cell anemia.
erythrocyte disorder: altered hemoglobin structure alters RBC shape and becomes sticky
Comment on the prevalence, form, and function of leukocytes.
least abundant formed element form = complete cells with rough ER, ribosomes, & Golgi complex to synthesize proteins and store them in lysosomes which appear as identifying cytoplasmic granules function = defend against pathogens via phagocytosis and immune response
Name the 2 general categories of leukocytes and the subtypes within each.
Granulocytes -Neutrophils -Eosinophils -Basophils Agranulocytes -Lymphocytes -Monocytes
Describe neutrophils.
most abundant leukocyte;
fight bacterial infections via immediate phagocytosis and production of antimicrobial chemicals such as defensins
Describe eosinophils.
release anti-histamines;
destroy parasitic worms
Describe basophils.
secrete histamine & heparin;
histamine: vasodilator, speeds blood flow to injured tissues, makes blood flow more permeable
heparin: anticoagulant, promotes mobility of WBCs
Describe lymphocytes.
2nd most abundant leukocyte;
role in adaptive immunity: specificity and memory;
secrete antibodies, coordinate immune cells
Describe monocytes.
differentiate into macrophages to engage in phagocytosis; # increases during infection/inflammation great capacity
Outline the 4 cellular phases of leukopoiesis.
1) hemopoietic stem cell (HSC)
2) colony-forming units (CFUs)
- have receptors for specific colony-stimulating factors (CSFs)
3) precursor cells
- myeloblasts
- monoblasts
- lymphoblasts
4) mature cells
Name each leukocyte precursor cell, which leukocyte(s) it forms, and where it is stored.
myeloblasts differentiate into all 3 types of granulocytes and are stored in red bone marrow;
monoblasts differentiate into monocytes and are stored in red bone marrow
lymphoblasts differentiate into lymphocytes; development begins in red bone marrow but some mature in the thymus
Describe the form of platelets.
not cells but fragments of marrow cells called megakaryocytes; complex internal structure: -lysosomes, mitochondria, microtubules -granules containing platelet secretions -open canalicular system -no nucleus
Describe the function of platelets.
secrete vasoconstrictors secrete clotting factors platelet plugs dissolve blood clots phagocytize and destroy bacteria attract neutrophils & monocytes secrete growth factors
Outline the 4 cellular phases of thrombopoiesis.
1) hemopoietic stem cell (HSC)
2) megakaryoblast
- has receptors for thrombopoietin
3) megakaryocyte
- numerous mitotic divisions with cytokinesis
4) platelets
- form when cytoplasm breaks
- 25-40% stored in spleen, rest circulate in blood
Define hemostasis and describe its 3 mechanisms.
cessation of bleeding; hemostatic response is quick, localized, and carefully controlled
1) vascular spasm, platelet plug formation, coagulation
Explain vascular spasm. What 3 things trigger it?
immediate contraction to constrict vessel (reduces blood flow)
1) direct injury to vascular smooth muscle
2) chemicals from platelets and endothelial cells
3) stimulation of local pain receptors
Explain the process of platelet plug formation.
broken vessel: damaged collagen fibers exposed;
platelet adhesion occurs via pseudopods;
degranulation of platelets
-release 5-HT, ADP, and thromboxane A2
thromboxane A2 promotes platelet aggregation, degranulation, and vasoconstriction;
positive feedback cycle
Describe coagulation.
most effective defense against bleeding;
complex: over 30 chemical rxns;
converts fibrinogen to fibrin;
2 pathyways:
-extrinsic (clotting factors external to blood); faster
-intrinsic (clotting factors in blood itself); slower
Describe clotting factors.
a.k.a. procoagulants or coagulation factors b/c they enhance clotting;
plasma proteins made by liver, numbered I to XIII (order of discovery), circulate in inactive form
Explain the initiation of coagulation via both the extrinsic and intrinsic mechanism.
Extrinsic: thromplastin released from vessels or tissues
Intrinsic: Factor XII released from platelets causes a cascade of events
*both lead to activation of Factor X
Explain the completion of coagulation.
Activated Factor X activates prothombin;
prothrombin converted to thrombin;
thrombin converts fibrinogen to fibrin
Explain the process of clot retraction.
spinous pseudopods of platelets adhere to fibrin and contract, compacting the blood clot
