6. Constituents Of Blood And Oxygen Delivery Flashcards
Define perfusion.
How does this definition relate to organs in the body?
- the act of pouring a liquid over or through the tissue of a particular organ
Perfusion in the body is the passage of fluid through the circulatory system or lymphatic system to an organ or tissue, usually referring to the delivery of blood to a capillary bed in tissue
How much blood on average do we have in our body?
4-6L
Where are RBCs, WBCs and platelets made?
RBCs - red bone marrow
WBCs and platelets - yellow bone marrow
After delivering oxygen, what do erythrocytes bind to and why?
Bind to CO2 to transport it back to the lungs where it is removed from the body when we exhale
What is the average lifespan of erythrocytes and where are they destroyed?
~120 days
Liverpool
What are the 5 types of leukocytes and what is the function of each?
Neutrophils - squeeze through capillary walls into tissue fluid and phagocytose foreign substances
Macrophages - release wbc growth factors - causes a population increase for wbcs
Lymphocytes - fight infection
T cells - attack cells containing viruses
B cells - produce antibodies. Antigen-antibody complexes are phagocytosed by macrophages
How do leukocytes fight infection in interstitial tissues?
Squeeze through pores in capillaries
How do platelets stop a bleeding?
Blood vessel damaged- blood leaks out
Platelets start to stick to teh opening of damaged blood vessels
As platelets stick to opening the attract more platelets, fibres and other blood cells to form a plug - seals broken blood vessel
When the plug is completely formed the wound stops bleeding
Platelets survive for 10 days before being removed by liver and spleen
What are three things that cause bronchoconstriction?
Cold
Allergens
Parasympathetic activity
What are four things that cause bronchodilation?
Sympathetic activity
Adrenaline/noradrenaline
Excericse
B2 agonists [salbutamol]
How much blood goes through the pulmonary system per minute?
~4-6L
Why is the vascular resistance in the pulmonary system much lower than systemic system?
Because its a much smaller system so doesnt need to be as high pressure and also there are a lot of small vessels that would be damaged if the system was at higher pressure
What is Dalton’s law?
Total pressure pf a mixture of gases equals the sum of partial pressures of individual gases in that mixture
What is Henry’s law?
When a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure
What structures in the lungs regulate airflow?
Bronchioles
How is oxygen transported around the body? Percentages
2% dissolved in blood
98% combined with haemoglobin
What mass of haemoglobin does an average person have in their body?
16-18g
How is carbon dioxide transported in the blood?
60-70% as bicarbonate ions
7-10% dissolved in blood
20% bound to haemoglobin
Which has a higher affinity for oxygen myoglobin/ haemoglobin? And why?
Myoglobin
Transport oxygen from outside the cell to organelles inside the cell
A steep saturation curve for myoglobin means that there’s a very efficient delivery of oxygen to the mitochondria
Why are free fatty acids the preferred metabolite for the heart?
Very efficient way of making atp
Each of the three chains of hydrocarbons on a fatty acid molecule can be made into 120-130 molecules of atp
In moderate excercise, how much of the energy to the heart is supplied by FFA?
~80%
In heavy excercise what other metabolite can be used to make energy?
Lactate
Oxidising it can give a high percentage of atp
During Ischaemia, what is used to generate atp?
Anaerobic glycolysis
What adaptation of cardiomyocytes leads to efficient atp synthesis?
Large number of mitochondria [largest conc of all tissues]
