Introduction to structure and function of blood Flashcards
What is the shape and dimensions of erythrocytes
- Biconcave
- Around 8 micrometers in length, 2.5 micrometers in height
What do erythrocytes not have
A nucleus, DNA, RNA or mitochondria
What are the two most common leukocytes
Neutrophils and lymphocytes
What is a neutrophil
A polymorphonuclear granulocyte
What does polymorphonuclear mean
Irregular and multi-lobed nucleus
What does a granulocyte mean
Prominent cytoplasmic granules
What are the 3 type of granulocytes
Neutrophil
Eosinophil
Basophil
What is characteristic about a neutrophil
Weakly staining granules, commonest WBC
What is characteristic about an eosinophil
Prominent granules stain red with eosin, make up 1-4% of WBCs
What is characteristic about a basophil
Granules stain blue/purple with basic dyes, make up less then 0.5% of WBCs
What are the two types of mononuclear cells
Monocytes
Lymphocytes
What is characteristic about a mononuclear cell
They lack granules and have large, regular nuclei
What are thrombocytes
Cytoplasmic fragments that have no nucleus, are membrane bound and contain granules
Where do blood cells come fro
Mature blood cells are produced from stem cells in the bone marrow
How are some blood diseases treated
Bone marrow transplantation
What is plasma
A fluid containing water, salts, proteins and organic molecules (metabolites, carbohydrates and lipids)
What positive ions (cations) exist in blood plasma
Mainly sodium, but also potassium, calcium, magnesium and hydrogen ions
What negative ions (anions) exist in blood plasma
Mainly chloride but also bicarbonate, phosphate, sulphate and organic anions
What is serum
The fluid left after blood clotting
What happens when a blood test requires un-clotted blood
Use an anticoagulant e.g. EDTA
How much of the plasma is blood proteins and what do they do
7-9% of plasma is protein
Complex; thousands of different proteins
90% is single protein called albumin
Maintains the osmotic pressure in blood
What are the 3 functions of blood
- Transport
- Defense
- Homeostasis
How is the blood involved in transport
Carries oxygen/nutrients to tissues
removes CO2/other waste products from tissues
Transport other substances like hormones from sites of production to sites of action
How are erythrocytes involved in transport
Transports oxygen from lungs to body tissues
Help in removal of CO2 from body tissues to lungs
How is CO2 carried in plasma
Carried as bicarbonate
Red cell enzyme carbonic anhydrous helps CO2 o dissolve in plasma in the tissues and to come out of solution in the lungs
What is the structure of haemoglobin
Its a tetramer made up of 4 polypeptide chains; 2 alpha and 2 beta chains
Each chain has a haem molecule that holds a ferrous Fe2+ ion
How does haemoglobin carry oxygen
Oxygen binds reversibly to the iron atom through a co-ordination bond
What is oxyhemoglobin
Fully saturated with O2 = bright red
What is deoxyhemoglobin
Fully desaturated without O2 = dark red
What do plasma proteins do
Carry substances which are poorly soluble in water e.g. Lipids and lipid soluble hormones/vitamins
What kind of metal ions do plasma proteins carry and why
calcium, ferrous and copper ion
These ions can be toxic and if you get a bacterial infection, bacteria wont be able to uptake these required ions
What does thyroxine binding protein (TBG) do
Somewhat hydrophobic molecule that carries thyroxine
What does transferrin do
Carries ferrous ions
What does a neutrophil do
Phagocytose and kill bacteria and fungi
The main mediators of innate immunity
What does a lymphocyte do
Main mediators of adaptive/acquired immunity
Produces antibodies
Kills virus infected cells
What do eosinophils do
Kills parasites
Involved in allergic responses
What do basophils do
Kills parasites
Involved in allergic responses
Involved in inflammation
What do monocytes/macrophages do
Phagocytosis of dead cells and pathogens
Presentation of antigens
What does the plasma carry for immune defence
Immunoglobins, complelement proteins and platlets
How are immunoglobins made and what do they do
Made by b-lymphocytes
Act as antibodies against pathogens
What do complement proteins do
Kill bacteria and other pathogens
Cooperate with Ig and WBC
What do platelets do
Its major role is primary haemostasis; stops blood flow
Recognises damage at a blood vessel wall
Forms a plug that stops bleeding but it insecure and temporary
Fibrinogen is a major plasma protein; secondary haemostasis
What is homeostasis
Keeping the internal environment of the body constant
- Maintaining pH at 7.4
- Controlling distribution of water and solutes
- Distributing heat
What must be kept within safe limits through homeostasis
Plasma pH
Ion concentrations
Protein concentrations
What does a full blood count include
Haemoglobin concentration -Used to diagnose anemia Mean red cell volume -Size of RBCs Mean red cell haemoglobin content -How much Hb in each red cell Haematocrit -These help to diagnose the type of anaemia Total white blood cell count -Important for diagnosing infection
Liver function tests (LFT’s)
Albumin concentration
Liver enzymes (released from damaged liver cells)
Clotting factors
Urea and electrolytes (U&E’s)
Test kidney function
Metabolic abnormalities
Blood glucose
Test for diabetes
Lipid profile
Triglycerides
Cholesterol
LDL and HDL
Risk of cardiovascular disease
