Exploding Cells & Acid Trouble Flashcards
Is ATP energy required for apoptosis or necrosis?
ATP energy required for apoptosis (not necrosis).
What is necrosis?
Premature death of cells as a result of cell injury. Cytoplasm swells, cell bursts.
What is the cause of the swelling of a cell during necrosis?
The failure of the Na/K ATPase pump
Does apoptosis or necrosis cause an immune response?
Necrosis does (apoptosis does not)
What is osmosis?
Movement of water molecules from a region of high concentration of free water molecules to a region of low concentration of free water molecules across a selectively permeable membrane
What is oncotic pressure?
A form of osmotic pressure - exerted by proteins in the blood notably albumin
Where is albumin produced?
Liver
Why do cirrhosis of the liver result in fluid build-up in the stomach?
Less albumin produced, water not attracted out of stomach into the blood
What is osmolarity/osmolality?
Refers to the concentration of solutes (proteins etc.) in the blood (a solution)
So… high osmolarity = high [solutes]
Does water move to areas of higher or lower osmolarity?
Water moves wherever there is a higher osmolarity.
Generally increased osmolarity = increased/decreased oncotic pressure?
Increased oncotic pressure
What is tonicity?
RELATIVE concentration of solutes in solution separated by a semi-permeable membrane
What is the normal plasma osmolality?
290 mOsmol/kg
285-295 mOsmol/kg
How is serum/urine osmolality measured?
Using freezing point depression technique
Which 4 solutes does the CALCULATED osmolality take into account?
Sodium, Potassium, Urea and Glucose
Why is 0.9% saline called normal saline?
Has an osmolality similar to that of blood
What is the capillary (plasma) concentration of albumin compared to the interstitial concentration of albumin.
4x greater in the capillaries/plasma.
What would you expect to happen with regards to water movement from the interstitial fluid to cells and why? The action of what prevents this?
You would expect water to move into cells due to the higher osmolarity and result in cells swelling and bursting.
Na/K ATPase pump
What ions does the Na/K ATPase pump move in one cycle?
3 Na+ out and 2 K+ in - requires ATP energy
Why does the action of the Na/K ATPase pump prevent cell swelling/bursting?
More Na pumped out than K in - a net loss of osmotically active ions
What is the typical gastric pH?
1.5-3.5
What can result from gastric acid getting into the oesophagus?
Oesophagitis (acid reflux), inflammation of the oesophagus.
Stricture - narrowing of the oesophagus.
What can result from the stomach losing its mucus protection?
Gastric ulceration/perforation
What is the formula for pH?
PH = -log[H+]
A one unit change in the pH scale results in a X-fold change in the H+ concentration relative to pure water?
A ten-fold change per one unit change in the pH scale.
What is the normal plasma pH? What are the pH limits for survival?
- 4
6. 8-7.8
A 2 fold change in [H+] results in a pH scale change of what?
A pH change of 0.3
What is the [H+] at 7.0 and 7.4 respectively?
100nm/l
40nm/l
What two things can result in abnormal plasma pH?
Major organ dysfunction (lungs, kidneys and liver)
Shock
What is shock?
Poor tissue perfusion resulting in hypoxia in cells and tissues
What are the most common types of shock?
Cardiogenic
Hypovolaemic
Septic
Why do poorly perfused tissues result in a lower pH?
Low oxygen —-> Anaerobic glycolysis —-> increased lactic acid —–> lactic acidosis —-> lower pH —-> impaired cardiac function
What is normal plasma lactate levels?
Less than 1.6 mMol/L
