Blood Flashcards
Define circulatory shock.
Blood vessels are inadequately filled with blood (have lower BP) and blood cannot circulate normally. Can be due to: - hypovolemic shock - vascular shock - cardiogenic shock
What is hypovolemic shock? How can it be treated?
Due to large scale fluid loss (haemorrhage, dehydration).
Treat with replacing fluid (saline drip - replaces volume)
BUT - also need blood transfusion (replace oxygen carrying capacity)
What is vascular shock?
Due to large scale vasodilation. May be due to:
- anaphylactic shock (allergic reaction - large scale relate of histamine - vasodilation)
- septic shock (toxins released from bacteria which are vasodilators)
What is cariogenic shock? How is it treated?
Due to pump failure (heart is insufficient and cannot maintain adequate cardiac output). Due to MI / chronic hypertension
Treat with positive inotropes (e.g., digitalis)
What are the three main roles of blood?
Distribution (transport materials, hormone delivery)
Regulation (pH, heat, fluid)
Protection (prevents blood loss, delivers antibodies and WBC)
What % of body weight is blood? What volume?
7-8%
5-6 L in 75 kg males (female slightly less)
Why is a cardio vascular system required?
Diffusion distance is too large and therefore too slow
Discuss the composition of blood
55% plasma (fluid)
Plasma proteins account for ______ of blood plasma.
10%
Plasma proteins are produced by the _______.
Liver
Plasma contains:
Water (90% plasma volume) / ions / salts
Amino acids / proteins (8-10% plasma volume)
Lipids (generally bound to proteins) / CO2
Nitrogen wastes (urea) and hormones
What are three plasma proteins? What %?
Albumin 60%
Globulins 35%
Fibrinogen 5%
What is the role of albumin? What percentage?
60% of plasma proteins
Potent pH buffer
Carrier protein
Colloid osmotic pressure
What is the role of globulins? What percentage?
35% plasma proteins
Carrier protein
Gamma globulins
What is the role of fibrinogen? What percentage?
5%
Blood clotting
What are the true and not-true cells?
Not true cells = non nucleus = platelets and erythrocytes
True cells = nucleus = leukocytes
What are the formed elements of the blood?
Platelets, leukocytes, erythrocytes
Leukocytes can be: _______ or _______.
________ can be _________
________ can be _________
Leukocytes can be GRANULOCYTES or AGRANULOCYTES.
Granulocytes can be NEUTROPHILS, EOSINOPHILS, BASOPHILS
Agranulocytes can be LYMPHOCYTES, MONOCYTES
What is the difference between a granulocyte and an agranulocyte?
Granules in cytoplasm vs clear cytoplasm
Granulocytes = neutrophils, eosinophils, basophils
Agranulocytes = monocytes, lymphocytes
What is the diameter of a RBC?
7.5 um
What is the importance of the shape of a RBC?
Biconcave shape - very large SA to volume ratio (increased by 30%)
Decreased distance for CO2 and O2 to diffuse
What is spectrin?
A scaffolding protein on the inside surface of a RBC membrane
Maintains the biconcave shape, even when RBCs are deformed when squeezing through capillaries
RBCs are _______ and have no ________
Anuclear
Have no mitochondria
Define haematocrit
Percentage of blood volume made up by erythrocytes
What are the % haematocrit for males and females?
Males = 45% Females = 43%
What happens to haematocrit during anaemia?
Haematocrit may fall to 15%
What happens to haematocrit during polycythaemia? When does it occur?
Haematocrit may rise to 75%.
Can be caused by blood doping, EPO, altitude altitude
What happens to haemoatrocrit during dehydration?
IN MCQ!!
The plasma volume decreases but the number of RBCs does not change
BUT - plasma volume decreases, so % haematocrit increases
Haemoglobin is a ______ protein.
Globin
Adult haemoglobin is made of _____ ________________. 2 ____ and 2 ______.
Each chain has a _____ _____, which contain an ______.
Made of 4 polypeptide chains 2 alpha chains 2 beta chains Heme group Iron ion
An iron ion can _________.
Reversibly bind to 1 oxygen
What is haemoglobin called when oxygen is bound?
Oxyhemoglobin
What is haemoglobin called when no oxygen is bound?
Deoxyhemoglobin
How many molecules of oxygen can we carry in Hb? How many RBCs?
4 Iron per Hb.
250 million Hb per RBC
1 billion O2 molecules per RBC
We create and destroy 2 million RBCs per second
How does foetal haemoglobin differ from adult haemoglobin?
2 alpha and 2 gamma (foetus)
vs.
2 alpha and 2 beta chains (adult)
Foetal Hb has higher affinity for O2 than Adult Hb - allows oxygen to diffuse across placenta from adult Hb to foetal Hb
What is carbaminohaemoglobin?
When CO2 binds to POLYPEPTIDE CHAIN (not Fe)
20% CO2 on polypeptide chain
80% CO2 in plasma
Discuss carbon monoxide poisoning.
Carboxyhemoglobin - CO binds in place of O2 (binds to Fe) preventing oxygen from binding as Hb has a very high affinity for CO.
What is erythropoiesis?
The formation of RBC.
What is haematopoiesis?
Formation of ALL blood cells (not just RBC)
Where does haematopoiesis occur?
Adults - in red bone marrow of axial skeleton and limb girdles, and epiphyses of humerus and femur.
Foetus - in foetal yolk sac, liver, spleen. By 7 months - red bone marrow is primary haematopoietic area
How many RBCs are produced and removed per second?
1 - 2 million RBCs per second
What releases EPO? What stimulates EPO release?
Kidney releases EPO.
Altitude, low Hb, low RBC and testosterone stimulate kidneys to releases EPO
Do males or females have a higher haematocrit? Why?
Males = 45%. Females = 43%.
Males have more testosterone, which stimulates EPO release, which result in formation of RBC
How long do RBCs circulate for?
120 days
Haemoglobin is made of a ____ and _____ part.
Haemoglobin is made of a HEME (IRON) and GLOBIN (POLYPEPTIDE CHAINS) part.
How can kidney failure result in anaemia?
Kidney failure - lack of EPO production and secretion - decreased production of RBC - decrease oxygen carrying capacity of blood
What symptoms does high bilirubin result in?
Jaundice
The globin portion of haemoglobin is broken down into __________.
Amino acids, which are reused.
The heme portion of the haemoglobin is broken down into __________.
Bilirubin (yellow pigment) and iron (Fe ions)
What is bilirubin?
Formed from degradation of heme portion of Hb - yellow pigment - not water soluble - secreted in bile - gives urine yellow colour - by products give faeces brown colour
Where are ageing RBCs degraded? Why are they degraded?
Degraded in the liver and spleen, by macrophages (which recognise and phagocytise aged cells)
Aged cells = cell properties change (cell membrane changes)
What are the dietary requirements of erythropoiesis?
Amino acids = form polypeptide chain
Lipids = form phospholipid bilayer
Carbohydrates = glycoproteins (antigens on RBCs)
Iron (in heme group)
Vitamin B12 and folic acid = needed for rapid cell division forming RBCs
What % of the body’s iron is found in haemoglobin? Where is the rest.
65%. The rest is in the liver, spleen and bone marrow.
What does iron bind to?
In tissues = binds to protein-iron complexes (Ferritin)
In circulation = binds to transport protein (transferrin)
What is an anaemia?
Insufficient oxygen carrying capacity of blood due to insufficient RBCs and/or insufficient Hb.
What are symptoms of anaemia?
Fatigue, breathlessness, chills, pale
What types of anaemia can be caused by insufficient RBCs?
Hemorrhagic anaemia
Haemolytic anaemia
Aplastic anaemia
What is haemorrhagic anaemia?
Insufficient RBCs due to excess blood loss. Can be due to peptic ulcers (bleeding into stomach/SI)
What is haemolytic anaemia?
Insufficient RBCs due to premature breakdown of blood cells. Can be due to mismatched blood, sickle cell anaemia
What is aplastic anaemia?
Caused by radiation and chemicals (chemotherapy).
This targets rapidly dividing cells - BUT also stem cells in bone barrow - disrupts haematopoiesis (formation of RBC, WBC, platelets).
Low WBC = prone to infection
Low platelets = prone to bleeding
Low RBC = anaemic
What types of anaemia can be caused by insufficient Hb?
Iron deficiency
Pernicious anaemia
What does iron deficiency do? (anaemias)
Lack of dietary iron - results in formation of microcytes (small erythrocytes).
Treat - increase iron dietary intake
What is pernicious anaemia?
Autoimmune disease which attacks stomach mucosa cells. These cells usually produce intrinsic factor which is required for Vit B12 absorption. Therefore - without intrisinc factor - decreased vitamin B12 absorbed - erythrocytes grow but do not divide (produce large macrocytes)
How could stomach surgery cause anaemia?
Removal of stomach mucosal cells - no intrinsic factor released - decreased reabsorption
What types of anaemia can be caused by abnormal Hb?
Thalassemias
Sickle cell anaemia
What is thalassemias?
Global chain abnormality (one single amino acid out of place)
Cells are very fragile - Hb deficient
What is sickle cell anaemia?
Haemoglobin S.
Once Hb delivers oxygen, Hb changes shape and becomes pointy (crescent shaped). These cells are fragile and randomly rupture and block capillaries.
What is haemostasis?
Process of preventing blood loss. Occurs in three stages:
- Vascular spasm
- Platelet plug formation
- Coagulation
Blood clotting is usually prevented by __________.
Nitric oxide and prostacyclin
Discuss the vitamin K clotting disorder.
Vitamin K used by liver to produce several pro-coagulations (clotting factors)
Deficiency of Vitamin K - bleeding disorders
Discuss the haemophilia clotting disorder.
Genetically inherited bleeding disorder
Discuss the effect of aspirin on blood clotting.
Used to prevent unwanted clotting. This inhibits / reduces thromboxane release from platelets - less fibrinogen converted to fibrin - less clotting
What does warfarin do?
Prevents unwanted clotting
What is another name for an antibody? Where are these found?
Antibody = agglutinins
Distributed in plasma
What is another name for an antigen? Where are these found?
Antigen = agglutinogens
Located on surface of RBCs
What occurs during a transfusion reaction? What symptoms does this have? How is it treated?
Antigen / antibody reaction causes haemolysis and agglutination of RBCs in recipient
Diminishes oxygen carrying capacity (as clumps cells also impeded blood flow)
Ruptured RBCs release haemoglobin into bloodstream - which is nephrotoxic (can cause kidney renal failure).
Treatment: large volume of fluid introduced, to dilute the Hb.
What is the difference between blood typing and cross matching?
Blood typing determines blood types
Cross matching is mixing of donor and recipient blood for compatibility
What is the universal donor? What is the universal acceptor?
Donor = O (no antigens on cell surface) Recipient = AB (no antibodies in plasma)