W9 Intro to blood

Question 1

RBC

Answer 1

AKA Erythrocytes

Biconcave discs

No nucleus and do not contain DNA, RNA or mitochondria (still metabolically glucose by glycolysis)

Question 2

WBC

Answer 2

AKA leukocytes

Colourless

Question 3

Neutrophils

Answer 3

Polymorphonuclear
Irregular, multi-lobed nucleus

Granulocyte
prominent cytoplasmic granules

Question 4

Two other types of granulocyte

Answer 4

Eosinophil (granules stain red w/eosin) = 1-4% of WBC

Granules contain substances that are going to be released from the cell

Basophil (granules stain blue/purple w/basic dyes) = <0.5% of WBC

In basophil can’t see nucleus because of granules

Question 5

Mononuclear cells

Answer 5

Lack granules
Large, regular nuclei
Two types: 
Monocytes
Lymphocytes

Question 6

Platelets (a.k.a. “thrombocytes” )

Answer 6

Cytoplasmic fragments
No nucleus
Membrane bound
Contain granules

Question 7

Where do blood cells come from?

Answer 7

Mature blood cells are produced from stem cells in the bone marrow

Bone marrow contains many immature cells

Some blood diseases can be treated by bone marrow transplantation

Question 8

Plasma fluid contains…

Answer 8

Water
Salts
Proteins
Organic molecules e.g.
Metabolites
Carbohydrates
Lipids

Question 9

Ionic constituents of plasma

Answer 9

Positive ions (cations)
Sodium (Na+)
Also potassium, calcium, magnesium and hydrogen ions

Negative ions (anions)
Chloride (Cl-)
Also bicarbonate, phosphate, sulphate & organic anions

Question 10

Plasma V serum

Answer 10

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 (as proteins removed)

Question 11

Plasma proteins

Answer 11

Normal: 7-9% of plasma is protein

Complex- thousands of different proteins

But > 90% is a single protein: albumin (or = serum albumin)

Question 12

Function of blood - transport

Answer 12

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

Question 13

Erythrocytes - function

Answer 13

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 (because CO2 doesn’t readily dissolve in water → forms carbonic acid)
• Come out of solution in the lungs

Question 14

Erythrocytes - major consituent

Answer 14

Major constituent is the protein haemoglobin (Hb)

Hb binds oxygen

Carries it from the lungs to the tissues

Question 15

Haemoglobin

Answer 15

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

Haem group not prosthetic + extra group carried by protein

Question 16

Haemoglobin - saturated/unsaturated

Answer 16

Oxyhaemoglobin
Fully saturated with O2 = bright red

Deoxyhaemoglobin
Lost all O2 = dark red

Question 17

Haemoglobin - binding to ferrous ion

Answer 17

The haem holds a ferrous (Fe2+) iron atom

Oxygen binds reversibly to the iron atom by a coordination bond

Question 18

Basis of pulse oximetry

Answer 18

Measures the colour of the haemoglobin = measures SATS

Determines if patient is hypoxic

Question 19

[Hb] in RBC

Answer 19

There are about 300,000,000 Hb molecules in each RBC

Very high concentration
Almost 50% of the space in a red cell is taken up by Hb

Question 20

Plasma transport

Answer 20

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.
Ca2+
Fe2+ (needed for bacterial growth)
Cu2+

All ions above toxic

Question 21

Plasma transport - examples

Answer 21

Albumin acts as a general purpose carrier

But many substances have a specialised carrier e.g.

Thyroxine binding globulin (TBG) = as thyrohormones not v.water soluble

Transferrin

Question 22

Transferrin

Answer 22

Binds to ion in blood + carries to tissue

Keeps it away from bacteria
Cells have receptor which binds to transferrin
Ion taken up

Question 23

WBC function

Answer 23

Neutrophils
Phagocytose and kill bacteria & fungi
Main mediators of innate immunity

Lymphocytes
Main mediators of adaptive (acquired) immunity
Produce antibodies
Kill virus infected cells

Question 24

Eosinophils - function

Answer 24

Kill parasites

Involved in allergic responses

Question 25

Basophils - function

Answer 25

Kill parasites
Involved in allergic responses
Involved in inflammation

Question 26

Monocytes (macrophages) - function

Answer 26

Phagocytosis of dead cells and pathogens

Show antigens to antigen presenting cells

Question 27

Plasma- immune defense

Answer 27

Immunity
Immunoglobulins (Ig)
Made by B-lymphocytes
Act as antibodies against pathogens

Complement proteins
kill bacteria and other pathogens
cooperate with Ig and WBC

Question 28

Platelets - function

Answer 28

Major role: Primary Haemostasis
Recognise damage at blood vessel wall
Form a platelet plug
Prevent / stop bleeding

Platelet plug stops bleeding– but insecure & temporary

Question 29

Blood clotting in plasma

Answer 29

Fibrinogen is a major plasma protein
Converted to Fibrin, forms blood clot
Clotting factors control process
Fibrin clot reinforces primary platelet plug

Question 30

Homeostasis

Answer 30

Keeping the internal environment of the body constant

Maintaining pH (7.4)

Controlling distribution of water and solutes

Distributing heat

Question 31

Plasma - homeostasis = tests

Answer 31

“U and Es”- urea and electrolytes
- Check kidney function

“LFTs” – Liver function tests

Analysis of plasma = essential part of diagnosis & treatment

Question 32

Blood in numbers

Answer 32

Total blood volume ~ 5 litres “for a 70Kg male”
(70 ml.kg-1 body weight)

Plasma volume ~ 2.5-3 litres

Question 33

Haematocrit

Answer 33

H (aka packed cell volume = PCV) = Vol of cells/Total vol

Normal ~ 0.4-0.5

Ratio by volume of cells to plasma

Question 34

RBC life span + measurements

Answer 34

Average life span ~ 120 days

Diameter ~ 8 μm
Thickness ~ 2 μm

Question 35

FBC includes…

Answer 35

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 (WBC)
Neutrophil count
Lymphocyte count

IMPORTANT FOR DIAGNOSING INFECTION

Question 36

LFTs

Answer 36

Liver function tests

Albumin concentration

Liver enzymes (released from damaged liver cells)

Clotting factors

Question 37

Urea and electrolytes (U&E) “you and ees”

Answer 37

Test kidney function and metabolic abnormalities

Question 38

Blood glucose test

Answer 38

Tests for diabetes mellitus

Question 39

Lipid profile - test

Answer 39

Triglycerides
Cholesterol
LDL and HDL

Risk of cardiovascular disease