Blood Flashcards
What are the cells in blood known as?
Formed elements
What is the blood composed of?
Cells / formed elements and plasma
What cells / formed elements are found in blood?
erythrocytes, leucocytes, thrombocytes (platelets)
What does plasma consist of?
extracellular fluid, water, electrolytes (e.g. sodium), organic molecules (glucose, fatty acids, glycerides, amino acids…), plasma proteins.
What are the plasma proteins?
albumins (60%), globulins (35%), fibrinogen (4%), regulatory proteins (1%)
What are the most abundant plasma proteins?
Albumins (60%)
Function of albumin
Maintains oncotic pressure - helps retain water in the bloodstream and prevents fluid leaking excessively into tissues. Also responsible for transport of lipids.
Name of swelling caused by excess fluid leaking into tissues
oedema
Function of globulins
Responsible for transport of ions, hormones, lipids and immune function.
Function of fibrinogen
key component of blood clotting
What constitutes regulatory proteins?
Enzymes, hormones
How does blood volume differ between individuals?
Blood volume depends on size with males typically having a greater blood volume (70ml/kg) than females (60ml/kg).
What percentage of the blood volume is made from plasma?
55% (46-63%)
What percentage of blood volume is made of cells/formed elements?
45% (37-54%)
What is the most abundant blood cell?
Over 99% of blood cells are erythrocytes, followed by leucocytes and thrombocytes)
What is the morphology of erythrocytes? (diameter, shape)
6-8um diameter and has a biconcave disk shape
Advantages of biconcave disk shape of erythrocytes
Provides a large SA:vol ratio which allows rapid diffusion of CO2 and O2 across plasma membrane. Can bend in narrow capillaries and expand in hypotonic solutions.
Behaviour of older erythrocytes in hypotonic solutions
older erythrocytes are more fragile and therefore more likely to haemolyse
Appearance of erythrocytes in blood film
Halo effect - outer thicker portion of RBC stains more intensely than thinner, concave centre which appears pale.
Term for red blood cell formation
erythropoiesis
Where are red blood cells formed?
red bone marrow
Average lifespan of erythrocytes
120 days
How are old erythrocytes broken down?
MPS system (mononuclear phagocyte system) which is part of the immune system, removes and breaks down RBCs in the spleen.
Where does the MPS system mostly remove and breakdown old red blood cells?
in the spleen mainly (also in liver and bone marrow)