Blood Flashcards
How many litres of blood should an average, healthy man have roughly?
5 litres
How much blood roughly should a newborn baby have?
350ml
What are the 4 components of blood?
- plasma
- red blood cells
- white blood cells
- platelets
What does plasma do?
circulates biologically active molecules and compounds
What are the 3 categories that plasma proteins are subdivided into?
- albumin
- globulin
- fibrinogen and other clotting factors
What do plasma proteins generate?
oncotic pressure
Why are plasma proteins responsible for generating oncotic pressure?
they cannot cross the capillary walls
What are the 2 forces required for movement between capillary and interstitial space?
- hydrostatic pressure
2. colloid oncotic pressure
What is hypoproteinaemia?
abnormally low levels of circulating plasma protein
What are 4 factors that can lead to hypoproteinaemia?
- prolonged starvation
- liver disease
- intestinal disease
- nephrosis (kidney disease)
What is a common characteristic of hypoproteinaemia?
oedema due to loss of oncotic pressure
What are the most abundant blood cells?
red blood cells
What is the name given to red blood cell formation?
erythropoeisis
What controls and accelerates erythropoiesis?
erythropoietin
When is erythropoietin secretion enhanced?
when oxygen delivery to the kidneys is reduced
What are the most abundant type of white blood cells?
neutrophils
What do neutrophils do?
form first line of defence
are phagocytic and can also entrap bacteria
What do eosinophils do?
attack pathogens too large for neutrophils and other defence cells
What do basophils do?
release histamine and heparin - trigger inflammation
What do monocytes do?
migrate to spleen, liver, lungs and lymph nodes - become macrophages
What is a macrophage?
a mature monocyte that has migrated from the blood to connective tissue
is phagocytic
What are lymphocytes?
constituents of the adaptive immune system - B cells and T cells
What is leukopoiesis (white blood cell formation) controlled by?
a cocktail of cytokines (proteins/peptides released from one cell type which act on another)
What 3 things realease cytokines for leukopoiesis?
- mature white blood cells
- fibroblasts
- endothelial cells
What do the cytokines stimulate?
mitosis and maturation of leukocyte
What test allows you to differentiate between infection types?
differential white cell count
What are platelets?
membrane bound cell fragments
What is platelet formation governed by?
thrombopoietin
What do platelets do?
adhere to damaged vessel walls and exposed connective tissue. mediate blood clotting
What is haematocrit?
percentage of blood made up by red blood cells
What is viscosity?
how thick/sticky blood is compared to water
What is the viscosity of blood dependent on?
- haematocrit
- temperature- increase decreases viscosity and vice versa
- flow rate - decreased flow rate increases viscosity and vice versa
