blood Flashcards
where is all the blood
how much is there
5 litres
3 in the systemic venous circulation
1 in lungs
1 in heart and arterial circulation
what are the functions of blood
carries physiological active compounds - enzymes, hormones
clotting - prothrombin + fibrinogen
defence - leukocytes
carriage of gas - O2
thermos regulation - COnstriction when COld
maintenance of ECF pH
what is the composition of blood
plasma
erythrocytes
leukocytes
platelets
what is meant by haematocrit
the percentage of blood made up Red Bood Cells
what are the normal values of haematocrit for each sex
40-54% for males
37-47% for females |(menstruation)
how might the haematocrit change due to conditions
living at altitude
increase haematocrit as more haemoglobin to bind the lower conc. of oxygen
what is mean by viscosity
the thickness of blood
what is the viscosity of the different parts of blood - in relation to water
plasma is 1.8X thicker
whole of blood is 3-4X thicker
how can viscosity change
haematocrit increase (50% increase = 100% to viscosity)
temperature = cold is thicker and vice versa
flow rate = slower is thicker as grater cell to cell adhesion
what are platelets
membrane bound cell fragments from megakaryocytes
what is the life span of platelets
roughly 10 days
what is the job of platelets
adhere to damaged endothelium to mediate blood clotting
what is the life span of blood
120 days
what are the 3 plasma proteins
albumin
globulin
fibrinogen
what does albumin do
most abundant drugs lipids TRANSPORTER (colloid oncotic pressure)