Structure & Function of Blood Flashcards
What is blood composed of?
Plasma (fluid) and Cells
What are the 2 major types of leukocytes?
- lymphocytes
- neutrophils
WBCs are described as being polymorphonuclear (lymphocytes) and/or
granulocytes (neutrophils)
How are granulocytes named?
Granulocytes take the name of the dye they affiliat ebest with. The dye used to stain them are basic dyes with an acidic dye called eosin so
Basophil - high affinity fo rbasic dye
Eosinophil - high affinity for eosin (acidic)
Neutrophil - stains weakly with both
Which cells contribute to the composition of blood?
White blood cells (WBCs)
Red Blood Cells (RBCs)
Platelets
How do erythrocytes aid CO₂ removal from tissues via blood?
Most CO₂ carried out of tissues is dissolved in plasma as bicarbonate via a reaction with water
Carbonic anhydrase (RBC enzyme) helps CO₂:
1. Dissolve in plasma in tissues
2. Undissolve from solution in lungs
What is deoxyhaemoglobin?
Unsaturated haemoglobin (lost all O₂) - dark red colour
How does blood separate when centrifuged?
Red cells centrifuge to the bottom
White cells form a thin brown layer on top of red cells (Buffy coat)
Plasma centrifuges at top; has a straw colour
How do Neutrophils provide immunity?
Neutrophils:
- Phagocytose , killing bacteria and fungi
- main mediators of innate immunity (recognise foreign pathogens)
What does polymorphonuclear mean?
Irregular multi lobed nucleus
How can we use a microscope to observe blood cells?
Smear blood on a microscope slide
Stain blood as WBC are colourless
Describe a neutrophil
Can be both polymorphs or granulocytes
What are the types of agranulocytes?
Monocytes - biggest WBcs with lobed kidney shape nucleus
Lymphocytes - vary in size; normally have small room of cytoplasm
What are platelets?
Cytoplasmic fragments generated from large cells in bone marrow
What are granulocytes?
Prominent cytoplasmic granules of which there are 3 types:
- Neutrophils
- Eosinophil
- Basophils
What is the scientific name of RBCs?
Erythrocytes
What is the scientific name given to platelets?
Thrombocytes
What are mononuclear (agranulocytes) cells?
Large regular nuclei lacking granules
Describe the structure of platelets
- No nucleus
- Membrane bound
- Contain granules which are released during clotting
Describe the structure of RBCs
- Biconcave discs
- No nucleus and no RNA/DNA or mt (RNA only present in
early erythrocytes)
How are erythrocytes adapted to aid O₂ transport?
A major constituent of RBC is Haemoglobin protein
- carries O₂ from lungs
Why are RBCs technically not cells?
Don’t contain nucleus so red corpuscle is a more accurate term
How can stem cells be used to treat certain blood diseases?
By bone marrow transplantation (BMT)
Only used in life threatening situations as it is a very strenuous process
How are blood cells formed?
Mature blood cells are produced from stem cells in the bone marrow
- bone marrow contains many immature cells
How do RBCs generate energy?
They are metabolically active and generate energy via glycolysis
Which anions are present in plasma?
Mainly Cl-
bicarbonate, Phosphate , sulphate and other organic anions present
How do erythrocytes aid transport?
Erythrocytes transport O₂ from the lungs to the rest of the body
Aid removal of CO₂ from tissues back to lungs
What is blood plasma?
The fluid component of whole blood
What is the function of the globin chains in haemoglobin?
Each globin chain carries a haem molecule
How ar esubstances transported from the blood into cells?
Many substances have specialised carriers e.g.
- Thyroxine binding globulin (TBG)
- Transferrin (main ion transporting protein)
What is the scientific name of WBCs?
Leukocytes
How do plasma proteins avoid the toxicity of metal ions?
By binding ions tightly to protein makes it harder for bacteria to metabolise & use the ions
What is oxyhaemoglobin?
haemoglobin fully saturated with O₂ - bright red colour
What is the role of albumin plasma protein?
Albumin acts as a general purpose carrier
How is blood used for transport?
Blood carries O₂ and nutrients to tissues
Removes CO₂ / waste products from tissues
Transports substances (e.g. hormones) from production site –> action site
What are bone marrow stem cells?
Very immature cells without lobes
They aren’t toitpotent but give rise to any blood cell lineages (pluripotent)
What are the functions of blood?
- Transport
- Defence
- Homeostasis
What is blood Serum?
The fluid left after blood clotting has occurred
- a lot of proteins are lost after clotting so a watery residue is left
Describe the structure of Haemoglobin
- Protein tetramer made of 4 polypeptide chians
- 2 β globin chains
- 2 α globin chains
What cellular defence does blood provide?
- Immunity : WBC and plasma proteins
- Clotting - (haematostasis) by platelets and plasma
proteins
What is the disadvantage of plasma proteins carrying metal ions?
metal ions carried: Mg2+, Fe2+, Cu2+, Ca2+
some of these ions are toxic
e.g. Cu2+ form free radicals
Fe2+ aid bacterial metabolism => septicemia
What are the positive ionic constituents of plasma?
Mainly Na+
Cells rich in K+, extracellular rich in Na+
K+, Ca2+, Phosphate, Mg2+, and H+ also present
What is a haem molecule?
Haem is a prosthetic group (not a protein)
Attaches to a protein to aid its function
What are the contents of plasma fluid?
Water Salts Proteins Organic molecules - metabolites - carbohydrates - lipids
How do Lymphocytes aid immunity?
Lymphocytes:
- main mediators of adaptive immunity
- produce antibodies specific to infection
- kill virus infected cells
What substances are carried by plasma proteins?
Plasma proteins carry metal ions and poorly soluble substances e.g
- dietary lipids coated with apolipoproteins -> globules
- lipid soluble hormones and vitamins
What is the role of Eosinophils in immunity?
Eosinophils:
- kill parasites
- involved in allergic responses
What is the average size of an erythrocyte?
Diameter ~ 8 um
Thickness ~ 2 um
Which proteins are present in the plasma?
There are 1000’s of different proteins present in plasma
Complex albumin protein makes up >90% of plasma protein content
Which fluid is used during blood tests?
Some blood tests require unclotted blood (plasma) - use antcoagulant
e.g. EDTA
Other tests work better with serum than plasma
What kind of substances can plasma carry?
The plasma can carry soluble metabolite sin solution e.g. glucose
What is the normal Hb saturation of a healthy person?
Normal - 98% saturation
How much of the plasma is composed of plasma proteins?
Plasma proteins make up around 7-9% of plasma in normal circumstances
How much Haemoglobin is present in erythrocytes?
In each red cell there are around 300,000,000 Hb molecules
very [high] - almost 50% of space in red cell occupied by Hb
What is the function of the Haem molecule in haemoglobin?
Haem holds a ferrous Fe2+ molecule
Oxygen reversibly binds to Fe2+ via weak coordinate bond
O₂ can easily attach / detach
What is the use of pulse oximetry?
Measure Hb colour determining hypoxia in patients
- routinely used on post surgery patients as opiates given to relieve pain which limit breathing = higher hypoxia risk
How is methaemaglobinemia caused?
If iron ion in haem gets oxidised from Fe2+ –> Fe3+ (Ferric)
O₂ can no longer bind
How do monocytes (macrophages) aid immunity?
Monocytes:
- phagocytosis of dead cells and pathogens
What is the function of basophils in immunity?
Basophils:
- kill parasites
- involved in allergic responses
- involved in inflammation
How is Ht calculated?
Ht = volume of cells / total volume
What is Haematocrit (Ht)?
Volume of cells in cntrifuged blood compared to total blood volume PCV
PCV - packed cell volume
What is the average life span of RBCs?
120 days
How does blood plasma provide defence?
Plasma defence achieved via
Immunity:
- immunoglobulins (Ig):
made by B lymphocytes, act as antibodies against pathogens
- Complement proteins:
kill bacteria and other pathogens by cooperating with Igs and WBCs
regarded as part of innate immunity
How do complement proteins work with WBCs to kill pathogens?
If a complement protein can’t kill a pathogen itself it can attract WBCs to aid phagocytosis
What is the normal total blood volume?
An average (70kg male) total blood volume = 5 litres Plasma volume = 2.5 - 3 litres
What is the major role of platelets?
Primary haemostasis
- recongise damaged blood vessel walls
- form platelet plugs
- prevent/stop bleeding
What factors are controlled for plasma homeostasis?
pH
[protein]
[ion]
What is homeostasis?
Maintaining the internal body environment
- pH 7.4
- distribution of solutes + water
- heat distribution
How does plasma aid haemostasis?
There are plasma proteins available in plasma that aid haemostasis:
- Fibrinogen - forms fibrin protein to form clot
clotting factors + platelets control process
Fibrin clot reinforces primary platelet plug
What tests can be carried out on plasma?
U&E’s - Urea & Electrolytes
- checks kidney functions
- kidney regulates electrolytes in plasma
LFTs - Liver Function Test
- checks correct no. of components in liver (albumin,
serum, clotting factors)
- liver damage causes release of liver enzymes into
plasma which is also
detected
What is the significance of plasma analysis?
Analysis of plasma is an essential part of diagnosis and treatment
Which disorders disturb plasma homeostasis?
- kidney disease
- liver disease
- lung disease
- cardiovascular failure
- endocrine organs failure
