Blood Flashcards
Blood is a connective fluid made up of plasma, proteins and formed elements like…
Erythrocytes, Leukocytes, and Platelets
What is a normal hematocrit reading?
45% RBC volume
What are the 3 main characteristics of blood?
Viscosity (thicker)
Temperature ( heat generation by active skeletal m.)
Slightly alkaline ( pH between 7.35 and 7.45)
List 6 functions of blood…
- Clot to prevent blood loss
- Combat microorganisms with immune response
- Transport O2 from lungs to cell & CO2 from cells to lungs
- Regulate body temperature
- Regulate pH via buffering
- Control water & electrolyte amount
How does blood regulate pH via buffering?
haemoglobin of RBC can combine with CO2 to transport it from tissues to lungs, Hb binds H+ ions and alters pH of blood
What is the red blood cell equation?
CO2 + H2O = H2CO3=H+ + HCO3
What is the function(s) of plasma proteins?
- Establish osmotic gradient between blood and interstitial fluid
- Act as buffer systems
What are three classes of plasma proteins?
Albumins, Globulins, Fibrinogens
What is the function of albumins?
contribute to osmotic pressure of plasma and transport fatty acids
What is the function of globulins?
thyroid binding ( binds thyroxine)
transcortin (transports ACTH and cortisol)
transferrin ( transports iron)
What is the function of fibrinogens?
blood clotting
Where are plasma proteins produced?
liver
What are 2 differences between plasma and interstitial fluid?
concentration of dissolved proteins and levels of respiratory gases
What is the process of production of formed elements called?
hematopeiesis
What does PHSC stand for?
Pluripotent hematopoietic stem cell
What does PHSC divide into?
PHSC, lymphoid stem cell (LSC) and colony forming unit
What do lymphoid stem cells produce and were are they produced?
T cells and B cells and spleen
What is colony forming unit -E influenced by and what does it produce?
Erthyropoietin, develops into reticulocytes and then erythrocytes
What is colony forming unit-M influenced by and what does it produce?
Thrombopoietin, develops into megakaryocytes and then platelets
How are RBC’s formed?
common myeloid progenitor cells begin synthesizing haemoglobin, after several divisons the erythroblast loses its nucleus and becomes immature reticulocyte, it then leaves bone marrow, 2-3 days later loses ER, mitochondria and ribosome’s and become mature erythrocyte (RBC)
T or F: Production and destruction of RBC are maintained at an equal rate?
True
T or F: Decreased oxygen levels cause kidney to release erythropoietin?
True
How are RBC destroyed?
Spleen has narrow capillaries, as aged RBC move through their membranes will rupture
T or F: Macrophages will engulf dead RBC
True
What is anaemia?
low number of red blood cells, reduction in O2 carrying capacity
What is a anaemic hematocrit?
30 % total RBC volume
What are three main causes of anaemia?
decreased rate of RBC production
excessive loss of RBC
deficiency in hemoglobin of RBC
What is nutritional anaemia?
dietary deficiency of a factor needed for RBC production ( ex. not enough iron or folic acid)
What is aplastic anaemia?
failure of bone marrow to produce adeqaute numbers of RBC
What is haemolytic anaemia?
rupture of excessive numbers of circulating RBC’s
What happens in a foal who’s mother had haemolytic anaemia?
mare produces antibodies against foal’s blood type and trasnfers antibodies through milk, foal may develop anemia as mare’s antibodies destroy foal’s RBC
What is AIHA?
Autoimmune haemolytic anemia, body attacks RBC, common in dogs
What is polycythemia?
excess of circulating RBC’s
What is primary polycythemia?
tumor-like condition of bone marrow in which RBC production proceeds at excessive, uncontrolled rate
What is secondary polycythemia?
“physiological”, prolonged reduction to O2 delivery to tissues, high altitudes
What does thrombin do?
converts fibrinogen to fibrin
T or F: Serotonin inhibits platelet plug formation?
False
T or F: Vascular spasm occurs at the begging of haemostasis?
True
What is osmosis?
Movement of solvent from an area of high solvent activity to lower solvent activity through a selectively permeable membrane
Where is haemoglobin produced?
Red blood cells
T or F: HCO3 diffuses out of RBC’s and Cl- diffuses in?
True
What cell type gives rise to platelets?
Megakaryocytes
How are platelets produced?
Mature megakaryocytes shed cytoplasm, then enter circulation and gradually lose cytoplasm to produce platelets
Where is thrombopoietin produced?
kidneys
T or F: Platelets leave the blood?
False
What are the main functions of platelets?
- transport chemicals
- formation of platelet plug
- active contraction
What is vascular spasm?
cutting of blood vessel wall triggers contraction of smooth muscle fibers, decreses the diameter of the injured vessel, and constriction slows blood flow to minimize blood loss
What do endothelial cells do during a vascular spasm?
contract and expose underlying basement membrane to the blood stream, then release endothelin to constrict blood vessels
T or F: Do endothelial cells become sticky during a vascular spasm?
True
What is the process of platelet plug formation?
When blood vessel lining is injured, platelets attach to exposed collagen, they become activated and change shape and extend and release several compounds
What does ADP do in platelet plug formation?
platelet aggregation and shape changes
What does thromboxane A2 do in platelet plug formation?
stimulates platelet aggregation and releases ADP, and stimulates smooth muscle contractions in vessel walls enhancing vascular spasms
What does calcium do in platelet plug formation?
clotting process and aggregation
What is a key factor that limits the growth of platelet plug?
prostacyclin
T of F: Vascular spasm and platelet phases begin within a few seconds of injury?
True
T or F: Fibrinogen is always circulating in blood stream
True
What are procoagulants?
clotting factors
What are anticoagulants?
prevent clotting
Where are procoagulants released from (think all but 3)
liver
T or F: Calcium is invovled in every step of the clotting process?
True
T or F: Vitamin K must be present in adequate amounts for liver to synthesize clotting factors?
True
What is prothrombin?
Factor II
What is proconvertin?
Factor VII
T or F: reduction in vitamin k causes breakdown of clotting process due to lack of procoagulants?
True
What is an intrinsic pathway?
in the blood, exposure of blood to collagen, takes 1-6 minutes to cause clotting
What is an extrinsic pathway?
in liquid of blood, trauma to vessel wall, takes 15 seconds to cause clotting
What is clot retraction?
Fluid is squeezed from clot (serum) reduces size of damaged area, fibroblast, smooth muscle cells and endothelial cells complete repairs
T or F: Fibrinolysis is clot removal?
True
T or F: Plasminogen converts in plasmin and degrades fibrin
True
T or F: Plasminogen is activated by t-PA
True
List 3 reasons why blood doesn’t clot all the time?
Smoothness of vessel wall
substance inside of wal
thrombomodulin
Name two anticoagulants
Prostacylin and tissue plasminogen activator
What does heparin do? and is it a pro or anti coagulant?
Anti, and it accelerates activation of anti- thrombin III that inhibits the production of several different procoagulants
What does Warfarin do?
depress the synthesis of clotting factors by blocking the use of Vitamin K by the liver
What are the three factors NOT released by the liver ?
Factor 3, 4 and 8
