Introduction to the Structure & Function of Blood Flashcards
what is the structure of blood?
fluid? cells?
PLASMA (fluid)
CELLS
Red cells
White cells
Platelets
Blood after Centrifuging
layers?
red cells at bottom
white cells will be buffer
plasma and platelets sit at the top
RBC
sturcture? (2)
A.k.a. Erythrocytes
Biconcave discs - allows it to go into lung capillaries to provide o2
No nucleus and do not contain DNA, RNA or mitochondria
WBC
colour?
2 common types?
A.k.a. leukocytes
Colourless
The two commonest types are
Neutrophils
Lymphocytes
Neutrophils
how common? size compared to rbc?
nuclues?
other feature?
Polymorphonuclear
Irregular, multi-lobed nucleus
Granulocyte
prominent cytoplasmic granules
most common wbc and bigger than RBC
other granulocytes
other two types?
how do they all stain?
there are two other types of granulocytes
- neutrophils: weakly staining, some basic some acidic (99% of all WBC)
- eosinophil: granules stain red with eosin (1-4% of all WBC) (for allergies)
- basophil: stains blue purple with basic dyes (less than 0.5% of all WBC (involved in bacterial defence)
mononuclear cells
what do they lack?
2 types?
Lack granules
Large, regular nuclei
there are two types of mononuclear cells
- monocytes: biggest, vacuoles are artifacts of staining
- lymphocytes: have very less cytoplasm, specific antobodies produced
Platelets
what are they?
features? (3)
Cytoplasmic fragments
No nucleus
Membrane bound
Contain granules
where do blood cells come from?
Mature blood cells are made from stem cells in bone marrow
The bone marrow consists of many immature cells
Bone marrow transplants treat genetic, blood and other diseases
Plasma
what does it contain?
fluid containing
water
salts
proteins
organic molecules e.g. metabolites carbohydrates lipids hornomes
plasma + serum
difference?
for unclotted blood what do you use?
Plasma is the fluid component of whole blood
Serum is the fluid left after blood clotting
Some blood tests require unclotted blood
Use anticoagulant e.g. EDTA
Other tests work better with serum than plasma
Plasma proteins
what is most of the proteins?
Normal: 7-9% of plasma is protein
Complex- thousands of different proteins
But > 90% is a single protein: albumin
Function of blood (3)
transport defence homeostastis (maintain a blood clot)
Transport (3)
Carry oxygen / nutrients to tissues
Remove CO2 / other waste products from tissues
Transport other substances (e.g. hormones) from sites of production -> sites of action
Enthrocytes
2 roles?
enzyme in rbc? role?
major constituent of rbc?
Transport oxygen from lungs -> body tissues
Help in removal of CO2 from body tissues -> lungs
- Most CO2 carried as bicarbonate in plasma
- Red cell enzyme carbonic anhydrase helps CO2
to dissolve in plasma in the tissues
Come out of solution in the lungs
Major constituent is the protein haemoglobin (Hb)
Hb binds oxygen
Carries it from the lungs to the tissues
Haemoglobin
what is it? made up of what?
what does each chain carry?
what does this hold?
how does o2 bind? what kind of bond?
Haemoglobin is a protein tetramer made up of 4 polypeptide chains-
- 2 alpha globin chains
- 2 beta globin chains
Each globin chain carries a haem molecule
The haem holds a ferrous (Fe++) iron atom.
Oxygen binds reversibly to the iron atom by a coordination bond.
what does iron defiency mean? what does it affect?
iron defiency means haemoglobin doesn’t form well
low haemoglobin hence low blood count hence can’t carry o2 well
pulse oximetry
what does it measure?
what colour is oxyhaemoglobin?
dexoxyhaem?
oxyhaemoglobin is fully saturated with O2 and is bright red
- deoxyhaemoglobin has no oxygen and is dark red
- the colors are used for pulse oximetry
- it helps in measuring the O2 saturation
- it is used with patients after surgery, as morphine
inhibits respiration and increases the chances of a patient becoming
hypoxic (body deprived of oxygen)
- almost 50% of a RBC contains Hb
plasma - transport
what does plasma carry in solution?
what does plasma proteins carry? e.g
Plasma carries soluble metabolites in solution!
Plasma proteins carry substances which are poorly soluble in water e.g.
lipids
lipid soluble hormones and vitamins
Plasma proteins also carry metal ions e.g.
Ca++
Fe++
Cu++
• plasma proteins carry other substances as well
- albumin acts as a general purpose carrier
- many substances have a specialized carrier
- thyroxine binding globulin
- transferrin
• Remove carbon dioxide/waste products from tissues
• most CO2 is carried in plasma
• red cell (erythrocyte) enzyme carbonic anhydrase helps CO2
- to dissolve in plasma in tissues
- come out of solution in lungs
• Transport other substances eg hormones to target sites
WBC - immunity function
neutrophils (2)? lymphocytes (2)
Neutrophils
Phagocytose and kill bacteria & fungi
Main mediators of innate immunity
Lymphocytes (b and t)
Main mediators of adaptive (acquired) immunity
Produce antibodies (B)
Kill virus infected cells (T)
Other White blood cells functions
name 3 other types
their functions?
Eosinophils (3%)
Kill parasites
Involved in allergic responses
Basophils (less than 1%)
Kill parasites
Involved in allergic responses
Involved in inflammation (can increase in heamotological problem)
Monocytes (macrophages)
Phagocytosis of dead cells and pathogens
Plasma - immune defense
2 different proteins
state their fucntions
Immunity
Immunoglobulins (Ig)
Made by B-lymphocytes
Act as antibodies against pathogens
Complement proteins
kill bacteria and other pathogens
cooperate with Ig and WBC
Platelets function
major role?
Major role: Primary Haemostasis
Recognise damage at blood vessel wall
Form a platelet plug
Prevent / stop bleeding
Platelet plug stops bleeding– but insecure & temporary.
(before clotting factors begin to work)
haemostasis - plasma
what is this major plasma protein?
what does it conver to and from?
what does it reinforce?
Fibrinogen is a major plasma protein
Converted to Fibrin, forms blood clot
Clotting factors control process
Fibrin clot reinforces primary platelet plug
Blood in L
Total blood volume ~ 5 litres “for a 70Kg male”
(70 ml.kg-1 body weight)
Plasma volume ~ 2.5-3 litres
Haematocrit
equation?
approx value?
Haematocrit (Ht)
aka packed cell volume (PCV)
= Volume of cells / Total volume
~0.4 – 0.5
rbc life span and size
Average life span ~ 120 days
Diameter ~ 8 μm
Thickness ~ 2 μm
summary
Transport
RBC- oxygen, (CO2)
Plasma- CO2, metabolites
Plasma proteins- lipids, hormones, metal ions
Defence- immunity WBC Polymorphonuclear granulocytes = neutrophils, eosinophils, basophils Monocytes Lymphocytes
Plasma proteins
Immunoglobulins
complement
Defence- haemostasis Platelets primary haemostasis (platelet plug)
Plasma proteins
Fibrinogen makes fibrin blood clot
Controlled by clotting factors
Homeostasis
Plasma
pH
Ion concentrations
Protein concentration
Full blood count test
what does it include?
Full blood count (FBC) includes
Haemoglobin concentration (Hb in g/l)
Overall concentration of haemoglobin in the blood
Used to diagnose anaemia
Mean (red) cell volume (MCV) Size of the rbcs Mean (red) cell haemoglobin content (MCHC) How much Hb in each red cell Haematocrit (Ht or Hc)
These help to diagnose the type of anaemia
Total white blood cell count
what does it include?
Full blood count (FBC) also includes
Total white blood cell count (WBC)
Neutrophil count
Lymphocyte count
IMPORTANT FOR DIAGNOSING INFECTION
Liver function tests
what does it include?
Liver function tests (LFTs)
Albumin concentration
Liver enzymes (released from damaged liver cells)
Clotting factors
Other tests
3 other tests?
Urea and electrolytes (U&E) “you and ees”
test kidney function
And metabolic abnormalities
Blood glucose
Tests for diabetes mellitus
Lipid profile Triglycerides Cholesterol LDL and HDL Risk of cardiovascular disease
