lecture 13 - blood composition & function Flashcards
What are the 3 general functions of blood?
Transport, immune response, coagulation
What things does the blood transport (7)?
O2 & nutrients, CO2 & wastes, ions, heat, hormones, immune cells, coagulation factors
The ions transported in the blood determine what?
Blood pH
Why does the blood carry heat?
Water (blood’s main constituent) is able to absorb a lot of heat that is the product of oxidative reactions in cells.
What is the function of blood transported hormones?
Co-ordinate organ activity
What is the immune function of blood?
Fight infection via white blood cells
What is the coagulation function of blood?
Platelets and coagulation factors in the plasma prevent bleeding.
What is the body’s blood volume proportional to?
Lean body mass
What is the ratio of blood to kilogram of body mass?
60-80mL per kg
What are the 2 major components of blood?
Plasma, formed elements
What are the 3 components of plasma?
Plasma Proteins, other solutes, water
What are the 4 types of plasma proteins found in blood plasma?
Albumins, globulins, fibrinogens, enzymes & hormones
What is the role of albumins in the blood plasma?
Maintains osmotic pressure to prevent blood cells from absorbing water and swelling/rupturing
What is the role of globulins in blood plasma?
Involved in the immune response
What is the role of fibrinogen?
Coagulation factor
What are the 3 key solutes found in plasma?
Electrolytes, organic nutrients, organic wastes
What is the role of the electrolytes in blood plasma?
Maintain pH and ion balance
What is the role of dissolved organic nutrients in blood plasma?
Support cell function and are carried to the periphery
What is the role of organic wastes in blood plasma?
Cell waste products are removed via the blood
What percentage of plasma is made up of water?
~90%
What are the 3 formed elements of blood?
Platelets, white blood cells, red blood cells
What are platelets?
Cell fragments that participate in clotting to stop bleeding
What are white blood cells?
Immune response and defensive mechanisms that destroy pathogens
What is the most common cell in the blood?
Red blood cells
What is the name for the formation of blood cells?
Haematopoiesis
Where does haematopoiesis occur?
In red bone marrow
What is the progenitor stem cell for all blood cells?
Haemocytoblasts
What type of stem cell do red blood cells develop from?
Myeloid stem cells
What is the alternative name for red blood cells?
Erythrocytes
Why do red blood cells have a large surface area?
For efficient diffusion of gases
Why are red blood cells flexible and rounded?
For free movement through narrow capillaries
What is the name for the shape of a red blood cell?
Biconcave disc
What proportion of RBC mass consists of haemoglobin?
1/3
How does haemoglobin bind oxygen?
Uses iron on 4 haem units to bind 4 oxygen per haemoglobin
What is hematocrit?
The part of centrifuged blood that contains the red blood cells
What is the alternative name for hematocrit?
Packed cell volume (PCV)
Do men or women tend to have a higher proportion of hematocrit in their blood?
Men
What is anaemia, in terms of hematocrit level?
Low hematocrit due to iron deficiency
What is polycythemia, in terms of hematocrit level?
High hematocrit causing the blood to become thick
What is erythropoiesis?
The generation of red blood cells
What stimulates erythropoiesis?
Erythropoietin (EPO)
What is erythropoietin?
A hormone that simulates red blood cell production
What hormone has a secondary role in augmenting red blood cell production?
Testosterone
Why do athletes train at high altitude?
There is less O2 a available so the body adapts by producing more EPO which increases red blood cell count and therefore O2 capacity, leading to increased performance.
What are the short term effects of altitude on the body?
Increased HR and Breathing rate
How does the body detect low blood O2 levels due to high altitude?
The kidneys detect O2 levels
What are the long term mechanism employed by the body at high altitude?
Kidneys release EPO to stimulate the production of red blood cells, increasing hematocrit.
