introduction to structure and function of blood Flashcards
What is blood made up of?
→ plasma (fluid)
→cells (such as red cells, white cells and platelets).
what are properties of red blood cells?
→ known as erythrocytes
→biconcave discs
→they have no nucleus and do not contain DNA, RNA or mitochondria
what are properties of white blood cells?
→ known as leukocytes
→colorless
→the two most common types of leukocytes are neutrophils and lymphocytes
Describe the structure of neutrophils
→ it is polymorphonuclear, so it has an irregular, multi-lobed nucleus
→it 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:
→weakly staining granules
→the most common type of WBC
EOSINOPHILS:
→granules stain red with eosin
→ make up 1-4% of WBCs
BASOPHILS:
→granules stain blue/purple with basic dyes
→make up <0.5% of WBCs
What are the two types of mononuclear cells?
→monocytes (the largest type of WBC)
→ lymphocytes (it has a large nucleus, and not a lot of cytoplasm).
give some properties of platelets?
→known as thrombocytes →cytoplasmic fragments → no nucleus →membrane-bound → contain granules
Where do blood cells come from?
→Mature blood cells are produced from the stem cells in the bone marrow.
→The bone marrow contains many immature cells.
what are the
1) ionic constituents of blood (+ve and -ve)
2) fluid components
of plasma?
→ fluid containing water, salts, proteins and organic molecules (eg. metabolites, carbohydrates, lipids, etc.)
→Its ionic constituents are positive ions (such as sodium, potassium, calcium, magnesium and hydrogen ions)
→negative ions (such as chloride, bicarbonate, phosphate, sulphate and organic anions).
What is the difference between plasma and serum?
→Plasma is the fluid component of the whole blood.
→Serum is the fluid left over after blood clotting factors have been removed from the plasma.
Describe the percentage of protein in the plasma.
→plasma is about 7-9% protein.
→over 90% of them is a single protein, albumin.
What are the three main functions of the blood?
→ TRANSPORT
→ IMMUNITY
→ HOMEOSTASIS
What does the blood transport?
→ carries oxygen/nutrients to tissues.
→ removes CO2/other waste products from tissues.
→ transports other substances (eg. hormones) from the sites of production to the sites of action.
Describe an erythrocyte’s role in oxygen transport and carbon dioxide removal.
→Erythrocytes transport oxygen from the lungs to the body tissues.
→ removal of CO2 from body tissues to the lungs.
→Most of the CO2 is carried as the bicarbonate ion (HCO3-) in the plasma.
give some properties of haemoglobin and give its function
→The major constituent in red blood cells is the protein Haemoglobin (Hb).
→Hb binds oxygen and carries it from the lungs to the tissues.
→Hb is a protein tetramer made up of 4 polypeptide chains, 2 α and 2 β globin chains.
→Each globin chain carries a haem molecule.
→Each haem holds a ferrous (Fe2+) iron atom.
what are the two forms of haemoglobin and what are their colors?
→OXYHAEMOGLOBIN, when it is fully saturated with O2, making it bright red
→DEOXYHAEMOGLOBIN, 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?
→PLASMA: carries soluble metabolites in solution
→PLASMA 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?
→the ions can be toxic
→ 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
→ferrous iron has lost 3 electrons
→ ferric ion has lost 2 electrons
what does pulse oximetry determine?
the oxygen saturation in the blood
why is oximetry used?
→opiates supress breathing and they are at risk of becoming hypoxic
how much of the red blood cell is taken up by Hb?
→50% of the space
how many Hb molecules are in each RBC
→300,000,000
what is the haematocrit?
→volume of cells compared to the total volume
Normal value is 0.4-0.5
what does a low haematocrit mean
→severe anaemia
what is the lifespan of a RBC?
→120 days
what does FBC measure
→Provides information about the numbers and kinds of cells in the blood.
→RBC, 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?
→liver function tests
→groups of blood tests that give information about the state of a patient’s liver.
What is the U+E test for
tests kidney function and metabolic abnormalities
what is a lipid profile?
→triglycerides
→cholesterol
→LDL and HDL
describe haemostasis
→the major plasma protein for clotting is fibrinogen
→there are proteases which process the fibrinogen and turn it into fibrin.
→Clotting factors control the process
→ fibrin clot reinforces the primary platelet plug.
describe homeostasis with relation to blood
→it keeps the internal environment of the body constant and maintains a pH of 7.4
→ it controls the distribution of water and solutes
and distributes heat around the body
what is the role of platelets in haemostasis?
→they recognize damage at a blood vessel wall and form a platelet plug and prevent bleeding
→the plug stops the bleeding but it’s 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?
→phagocytose and kill bacteria and fungi
→main mediators of innate immunity
what are lymphocytes for?
→mediators of adaptive immunity
→produce antibodies
→kill viruses and infected cells
what are eosinophils for?
→they kill parasites
→involved in allergic responses
Involved in inflammation
Tissue becomes mast cells
what are basophils for?
→they kill parasites
→involved in allergic responses
→involved in inflammation
what are macrophages for?
→phagocytes of dead cells
→monocytes in tissues are called macrophages
why is it hard for septicemia to spread?
→bacteria 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?
→ It helps CO2 to dissolve in plasma in the tissues
→ helps it come out of solution in the lungs.
how does oxygen bind to the iron atom in Hb?
→Oxygen binds reversibly to the iron atom by a coordination bond (dative bond).
→This is known as oxygenation, not oxidation.
How are plasmas involved in immune defence?
Immunoglobulins (Ig):
Made by B-lymphocytes
Act as antibodies against pathogens
Complement proteins:
kill bacteria and other pathogens
cooperate with Ig and WBC
What organ disturb haemostasis?
- Kidney
- Liver
- Lungs
- Cardiovascular system
- Endocrine organs
what are compositions of plasma protein?
Normal: 7-9% of plasma is protein
Complex- thousands of different proteins
But > 90% is a single protein: albumin
What is albumin?
a protein made by your liver. Albumin helps keep fluid in your bloodstream so it doesn’t leak into other tissues.
