introduction to structure and function of blood Flashcards
What is blood made up of?
β plasma (fluid)
βcells (such as red cells, white cells and platelets).
what are properties of red blood cells?
β known as erythrocytes
βbiconcave discs
βthey have no nucleus and do not contain DNA, RNA or mitochondria
what are properties of white blood cells?
β known as leukocytes
βcolorless
βthe two most common types of leukocytes are neutrophils and lymphocytes
Describe the structure of neutrophils
β it is polymorphonuclear, so it has an irregular, multi-lobed nucleus
βit is a granulocyte, which means that it has prominent cytoplasmic granules which are toxic and used for killing microorganisms
List the three different types of granulocytes, and the differences between them.
NEUTROPHILS:
βweakly staining granules
βthe most common type of WBC
EOSINOPHILS:
βgranules stain red with eosin
β make up 1-4% of WBCs
BASOPHILS:
βgranules stain blue/purple with basic dyes
βmake up <0.5% of WBCs
What are the two types of mononuclear cells?
βmonocytes (the largest type of WBC)
β lymphocytes (it has a large nucleus, and not a lot of cytoplasm).
give some properties of platelets?
βknown as thrombocytes βcytoplasmic fragments β no nucleus βmembrane-bound β contain granules
Where do blood cells come from?
βMature blood cells are produced from the stem cells in the bone marrow.
βThe bone marrow contains many immature cells.
what are the
1) ionic constituents of blood (+ve and -ve)
2) fluid components
of plasma?
β fluid containing water, salts, proteins and organic molecules (eg. metabolites, carbohydrates, lipids, etc.)
βIts ionic constituents are positive ions (such as sodium, potassium, calcium, magnesium and hydrogen ions)
βnegative ions (such as chloride, bicarbonate, phosphate, sulphate and organic anions).
What is the difference between plasma and serum?
βPlasma is the fluid component of the whole blood.
βSerum is the fluid left over after blood clotting factors have been removed from the plasma.
Describe the percentage of protein in the plasma.
βplasma is about 7-9% protein.
βover 90% of them is a single protein, albumin.
What are the three main functions of the blood?
β TRANSPORT
β IMMUNITY
β HOMEOSTASIS
What does the blood transport?
β carries oxygen/nutrients to tissues.
β removes CO2/other waste products from tissues.
β transports other substances (eg. hormones) from the sites of production to the sites of action.
Describe an erythrocyteβs role in oxygen transport and carbon dioxide removal.
βErythrocytes transport oxygen from the lungs to the body tissues.
β removal of CO2 from body tissues to the lungs.
βMost of the CO2 is carried as the bicarbonate ion (HCO3-) in the plasma.
give some properties of haemoglobin and give its function
βThe major constituent in red blood cells is the protein Haemoglobin (Hb).
βHb binds oxygen and carries it from the lungs to the tissues.
βHb is a protein tetramer made up of 4 polypeptide chains, 2 Ξ± and 2 Ξ² globin chains.
βEach globin chain carries a haem molecule.
βEach haem holds a ferrous (Fe2+) iron atom.
what are the two forms of haemoglobin and what are their colors?
βOXYHAEMOGLOBIN, when it is fully saturated with O2, making it bright red
βDEOXYHAEMOGLOBIN, when it has lost all of its O2, making it dark red
What is the difference in what the plasma carries and what the plasma proteins carry?
βPLASMA: carries soluble metabolites in solution
βPLASMA PROTEINS: carry substances which are poorly soluble in water (eg. lipids and lipid-soluble hormones and vitamins), they also carry metal ions (eg. Ca2+, Fe2+, Cu2+).
why do plasma proteins need to carry ions?
βthe ions can be toxic
β if you get a bacterial infection, the bacteria need metal ions (especially Fe2+) for growth, so having them bound slows their growth.
how are platelets generated?
cytoplasmic fragments generated from large cells in the bone marrow
what is the difference between ferrous and ferric iron
βferrous iron has lost 3 electrons
β ferric ion has lost 2 electrons
what does pulse oximetry determine?
the oxygen saturation in the blood
why is oximetry used?
βopiates supress breathing and they are at risk of becoming hypoxic
how much of the red blood cell is taken up by Hb?
β50% of the space
how many Hb molecules are in each RBC
β300,000,000
what is the haematocrit?
βvolume of cells compared to the total volume
what does a low haematocrit mean
βsevere anaemia
what is the lifespan of a RBC?
β120 days
what does FBC measure
βProvides information about the numbers and kinds of cells in the blood.
βRBC, WBC & Platelets.
what is MCV?
the mean red cell volume measures the size of the RBCs
what is an MCHC?
the mean cell haemoglobin content
how much Hb in each red cell
what is WBC
white blood cell count used for diagnosing infection
what is LFT?
βliver function tests
βgroups of blood tests that give information about the state of a patientβs liver.
What is the U+E test for
tests kidney function and metabolic abnormalities
what is a lipid profile?
βtriglycerides
βcholesterol
βLDL and HDL
describe haemostasis
βthe major plasma protein for clotting is fibrinogen
βthere are proteases which process the fibrinogen and turn it into fibrin.
βClotting factors control the process
β fibrin clot reinforces the primary platelet plug.
describe homeostasis with relation to blood
βit keeps the internal environment of the body constant and maintains a pH of 7.4
β it controls the distribution of water and solutes
and distributes heat around the body
what is the role of platelets in haemostasis?
βthey recognize damage at a blood vessel wall and form a platelet plug and prevent bleeding
βthe plug stops the bleeding but itβs temporary
what is the normal time for bleeding to stop?
10-15 seconds is the normal time for bleeding to stop
what are neutrophils for?
βphagocytose and kill bacteria and fungi
βmain mediators of innate immunity
what are lymphocytes for?
βmediators of adaptive immunity
βproduce antibodies
βkill viruses and infected cells
what are eosinophils for?
βthey kill parasites
βinvolved in allergic responses
what are basophils for?
βthey kill parasites
βinvolved in allergic responses
βinvolved in inflammation
what are macrophages for?
βphagocytes of dead cells
βmonocytes in tissues are called macrophages
why is it hard for septicemia to spread?
βbacteria need iron to grow so if the iron is bound to a protein then it is harder to use them.
what is albumin?
albumin is a general purpose carrier
what is transferrin
the iron binding proteins
cells have transferrin receptors
why are some ions potentially toxic if they were free in the blood?
Cu 2+ can become copper free radicals
how are lipid soluble proteins transported in the blood?
they are coated in plasma proteins
why do you use EDTA for some blood tests?
it requires unclotted blood so the anticoagulant EDTA is used because it binds with the calcium ions
how does carbonic anhydrase work?
β It helps CO2 to dissolve in plasma in the tissues
β helps it come out of solution in the lungs.
how does oxygen bind to the iron atom in Hb?
βOxygen binds reversibly to the iron atom by a coordination bond (dative bond).
βThis is known as oxygenation, not oxidation.