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what is blood?
a connective tissue composed of a liquid extracellular matrix (plasma) that suspends vaires cells and cell fragments.
What are the 3 main functions of blood?
- transportation - O2, CO2, wastes, hormones, heat
- regulation- buffers regulate pH, H2O in blood absorbs heat or cools blood to control body temp
- protection- blood clots prevent blood loss, white blood cells, blood proteins protect
Is blood more viscous than water?
Yes, Blood is thicker and denser than water
what is the temp of blood?
38 (one degree higher than body temp)
what is the pH of blood?
7.35 - 7.45, slightly alkaline
Is bright red blood oxygenated or deoxygenated?
what does blood consist of?
- 45% formed elements
- 55% plasma
what are the formed elements?
- RBC over 99%
- WBC and platelets less than 1%
Explain the buffy coat.
WBC and platelets are less dense than RBC but more dense than plasma and thus forms a buffy coat betweent the other two when seperated.
what is the other term for RBC?
what is the other term for WBC?
what % of total body weight is blood?
8%. Apprx 5-6 litres Males, 4-5 litres Female
what does plasma consist of?
- 91.5% water
- 7% proteins
- 1.5% other solutes
where are plasma protiens synthesized?
hepatocyes (liver cells)
Plasma protein - Albumins
54% of plasma proteins; helps maintain blood osmotic pressure which affects the exchange of fluids across capillary walls.
Plasma protein - Globulins
38% of Plasma protein; include antibodies (immunoglobulins) which are defensive proteins produced during certain immune responses
Plasma protein - Fibrinogen
7% Plasma proteins, key protein in blood clot formation
what is the life cycle of a RBC?
what are the granular leukocytes?
- Eosinophil, basophil,
what are the agranular leukocytes?
monocyte, T lymphocyte, B lymphocyte
What are the functions of leukocytes?
To combat pathogens and other foreign substances that enter the body.
What feature differentiates lymphocytes from the other types of leukocytes?
- Lymphocytes recirculate between blood, interstitial space, lymph and return to blood. Other leukocytes
- cannot return to the blood once they leave it.
Describe the 3 types of Lymphocytes
- T lymphocytes (Tcells) attack viruses, fungi, cancer cells, some bacteria.
- B lymphocytes (Bcells) destroy bacteria and inactivate their toxins.
- Natural killer (NK) cells attack wide range of infectious microbes and certain tumour cells.
Describe the process of haematopoiesis
- Haematopoiesis is the production of formed elements. Liver, spleen, thymus and lymph nodes of foetus form this role then red bone marrow in last 3 months before birth and throughout life. Pluripotent stems cells comprised about 1% of red bone marrow cells. These pluripotent cells become either myeloid or lymphoid stem cells.
- Myeloid stem cells differentiate into erythrocytes, platelets, eosinophils, basophils, neutrophils and monocytes. Lymphoid stem cells differentiate into lymphocytes
Describe the process of erythropoiesis.
Erythropoiesis is formation of erythrocytes. Myeloid stem cells forms precursor cell proeryhtroblast, ejects nucleus and forms reticulocyte, then erythrocyte.
What is erythroprotien and where is it released?
Hypoxia of blood flowing through kidney triggers release of erythropoietin which circulates through blood to red bone marrow where it speeds up development of of proerythroblasts into reticulocytes
Discuss the anatomy and composition of erythrocytes.
Biconcave disc, 8 micrometer diameter, no nucleus, contain haemoglobin molecules, lack mitochondria and generate ATP anaerobically.
What is the function of haemoglobin
to transport oxygen to tissues and carbon dioxide to lung
How is haemoglobin recycled?
Erythrocytes phagocytosed and split into haem and globin. Globin broken down to amino acids. Haem broken down to (1) iron which is transported attached to transferrin in the blood and taken back to red bone marrow to be reused in erythropoiesis, and (2) non-iron portion, which is converted to biliverdin and then bilirubin which is transported to liver, enters bile, SI, LI where it is converted to urobilinogen which is excreted in faeces or transported to kidney to form urobilin.
The percentage of the blood volume occupied by erythrocytes. Typically 45%, meaning 45% of the blood is RBC.
where are antigens and anitbodies found?
- Antigens are found on erythrocytes
- while antibodies are found in plasma.
What is meant by the +ve or -ve after the letter describing blood type?
This refers to Rh (Rhesus) type. People with the Rh antigen are termed Rh +ve and those without it are termed Rh –ve.
What are the functions of platelets?
Formation of platelet plug in haemostasis, release chemicals that promote vascular spasm and blood clotting
Differentiate between the intrinsic and
extrinsic pathways of haemostasis.
- Extrinsic- rapid, tissue factor leaks into blood from damaged tissue
- Intrinsic – slow, activators are within the blood. Endothelial cells become roughed and blood contacts collagen fibres below.
Why is the clotting mechanism described as
a positive feedback cycle?
- As thrombin forms it activates more platelets, increasing their release of phospholipds and prothrombinase. Thrombin also increases formation of prothrombinase. Fibrin
- clot grows.
What is clot retraction and how does it
assist in blood vessel repair?
- Clot retraction is the consolidation and tightening of the fibrin clot by platelet contraction. This brings the edges of the damaged blood vessel surfaces closer together so
- permanent repair can occur.
A blood clot, debris, air bubble transported by the blood stream
Clotting in an unbroken blood vessel
Plasma minus clotting proteins
Insoluable protein fibres forming a network that traps formed elements of blood during clotting
Haemostasis stops bleeding when blood vessels are injured
erythropoietin speeds up development of proerythroblasts into reticulocytes in response to hypoxia
What antibodies does a person with type O blood have in their plasma?
A and B
What destroys antigen-antibody complexes?
The process by which formed elements of the blood develop is called:
What plasma proteins plays a role in disease resistance
Considering Rh blood types, what situation could result in maternal antibodies attacking the fetus?
Mom is Rh negative and fetus is Rh positive
A megakaryoblast will develop into
Name an anticoagulant?
What antigens does a person have on their RBC if their plasma has antibody A?
This hormone causes the development of megakaryoblasts
A negative agglutination result in the blood RhD anti-D panel indicates....?
RhD -ve group
Anaemia can be due to
- a decreased haemoglobin concentration and/or
- a reduced erythrocyte number
Hormone that stimulates the production RBCs. Testosterone stimulates the synthesis of this so higher heamocrit in males. Endurance athletes use for doping
significant drop in the hematocrit
hematocrit high, over 65%, can be caused by dehydration, low O2 levels,use of EPO
blood cell production
red bone marrow
highly vascular connective tissue,
lasck nucleus, mitochondria, cannot reproduce, specialised for O2 transport, generates ATP anaerobically (breaks down glucose) so doesn't use O2 it is transporting.
the production of RBC. Precusor cell is proerythroblast which then divides adn ejects nucleus to become reticulocyte which develops into RBC 2 days after being released from marrow.
O2 deficiency in cells, triggers kidneys to release more EPO to stimulate mature RBC production
sickle cell anemia
genetic blood disorder, RBCs are misshapen and stiff, casuing blockages, less surface area for O2 to attach, live 20 days, provides immunity to Malaria
describe an incompatable blood transfusion
if incompatible, the antibodies in recipient will attack the antigens of donated blood causing agglutination (clumping of RBC). The destroyed RBC release haemoglobin into system adn damage kidneys by clogging filtration membranes.
release harpin histamine adn seotonin, involved in allergic reactions
antibiotic activity against bacteria and fungi
turn into macrophages and clean up debris
- B Cells - differentiate into cells that produce antibodies
- T cells - attack viruses, transplanted cells, cancers,
Natural Killer Cells
attack a wide veriety of infectious microbes
WBC life span
only a few days, some B & T cell live for years,
other name for platelets
why is calcium very important?
helps cell contraction, cell signalling, the brian to function, extremely important for blood clotting
blood clot in undamaged vessel
what is clot retraction?
the fibrin threads attached to edges of damaged vessel are pulled together when the clot retracts to assist in repair
A haemoglobin concentration of 82 g/L typically indicates
A negative agglutination result in the blood RhD anti-D panel indicates....
In the blood group panel test, type O blood would normally react (agglutinate) to
none of the serums - O type erythrocytes possess neither antigen
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