Blood Flashcards
What are the main two components of blood? And what are their relevant compositions?
Plasma (55%) and Red Blood Cell (45%)
What is the haematocrit?
ratio of the volume of red blood cells to the total volume of blood
What composition of the plasma in blood is made up of water? What is the rest?
Water - 91%
Proteins- 7 %
Other solutes are 2%
How do you collect blood for analysis?
By venipuncture from a superficial vein
Why do you use superficial veins for blood collection?
- easy to locate
- vein walls are thinner than arteries
- blood pressure is relatively low so wound seals quickly
What can you use if the veins are difficult to access for blood collection?
- capillary blood (finger, ear lobe etc)
- arterial puncture for efficiency of gas
Name some functions of blood.
- transporting dissolved gases, nutrients, hormones and metabolic waste
- regulating pH and ion composition of fluids
- restricting blood loss at sites of injury (haemostasis) using platelets and clotting factors
- defence against toxins and pathogens using white blood ells and antibodies
- stabilising body temperature by redistributing heat
What proteins are found in the plasma?
- mainly albumins (regulate osmotic pressure)
- globulins (antibodies, transport globulins)
- fibrinogen (clotting)
- 1% enzymes, hormones and pro-hormones
What solutes are found in the plasma?
- organic nutrients
- electrolytes (Na+, K+, Ca2+)
- organic wastes
What are albumins?
Major plasma proteins
What do albumins do?
- act as molecular taxis - transporting hydrophobic molecules (fatty acids, thyroid hormones and steroid hormones)
- suck water back in to blood due to osmotic pressure - contributing to plasma osmolarity
What do antibodies do?
- Aid in body defence
What are the different regions in an antibody?
- Antigen binding regions
- 2 heavy chains and 2 light chains
- An Fc region that recruits immune cells through interaction
What are transport globulins?
- molecules that bind small ions, hormones and compounds that might otherwise be removed by kidneys or have low solubility in water
What are some examples of transport globulins?
- Hormone-binding proteins
- Metalloproteins
- Apolipoproteins
- Steroid-binding proteins
What is the plasma called after clotting occurs/ the removal of clotting proteins?
Serum
What other plasma proteins are present in the Plasma?
- peptide hormones (insulin and prolactin)
- glycoproteins including thyroid-stimulating hormone, follicle-stimulating hormone and leutinising hormone
What are plasma expanders used for?
- increase blood volume temporarily (e.g. following blood loss after injury such as a major accident or sepsis)
What gives blood its red colour?
Haemoglobin in erythrocytes
What is the ratio of erythrocytes: platelets: leucocytes in the blood?
1000: 100: 1
What is the red blood cell structure?
- biconcave disc
- large SA:V ratio
- forms stacks like plates through narrow vessels (rouleaux) (occur when plasma protein conc is high)
- bend and flex when entering small capillaries
What is the red blood cell composition?
- lose most organelles during differentiation
- no cell division or protein synthesis
- haemoglobin >95% of the intracellular protein
What organelle do red blood cells retain?
the cytoskeleton
What is the lifespan of a red blood cell?
120 days
How do erythrocytes obtain energy?
By anaerobic metabolism of glucose absorbed from the plasma
What is the function of erythrocytes?
- transport of respiratory gases (oxygen and carbon dioxide)
How are red blood cells formed?
Differentiation takes 6-8 days.
Addition of hormone EPO (erythropoietin) promotes the formation of red blood cells in the bone marrow
What is the red blood cell turnover?
300 million red blood cells enter circulation per second
What are the Blood types?
ABO and Rhesus blood types are based on antigen-antibody responses
A, B, AB, O
What do each ABO blood types produce in terms of antigens and antibodies in their plasma?
A - produces B antibodies and A antigen
B - produces A antibodies and B antigen
AB - produces A and B antigens and no antibodies
O - produces A and B antibodies but no antigen
What is the difference between the Rhesus and ABO Blood types?
Unlike ABO types, Rh - individuals do not contain anti- Rh antibodies.
When are antibodies present in Rhesus blood types?
Only present if individuals sensitises by previous exposure to Rh+ blood
What are the functions of white blood cells?
- defends the body against pathogens
- removes toxins, wastes and abnormal or damaged cells
Where do white blood cells reside in?
Connective tissue proper or the lymphatic system
What are the characteristics of circulating leucocytes?
- can migrate out of the blood stream
- are capable of amoeboid movement
- are attracted to chemotaxis ( a specific chemical stimuli)
- many are capable of phagocytosis
What are platelets?
Cells that clump together at sites of injury, forming a platelet plug to prevent excessive blood loss
What are platelets made by?
bone marrow megakaryocytes
What is haemostasis?
- prevention of excessive blood loss upon injury ( the stopping of bleeding )
What are the 4 phases of haemostasis?
- Vasoconstriction to limit blood flow
- Platelet plug formation
- Coagulation (clotting) to stabilise the platelet plug
- Fibrinolysis
