Plasma Composition & Red Cell Metabolism Flashcards
What is hereditary sphirocytosis?
Defect in erythrocyte cytoskeletal proteins
How is G6PD deficiency transmitted?
- X-linked disease (mothers ‘carry’ and give to their sons)
- Most common enzyme def. in humans
- Many variants have been detected for G6PD
- PPL with disease are resistant to malaria
- Disease severity depends on mutation
Albumins
- Constitute roughly 60 percent of the plasma proteins
- Contribute 70-80% of total oncotic pressure (draw of fluid from tissue to blood vessel related to plasma protein concentration - can cause a number of disease states) of the plasma
What happens with albumin in liver failure?
Albumin is low so you have a net flow of fluid out of the blood vessels into the tissue
What does protein concentration in the blood dictate?
- There is always a draw of fluid into the blood vessel from the tissue that is dictated by the protein concentration
- Most protein concentration in blood is ALBUMIN
How does oncotic pressure/fluid exchange work in the body?
- As the arterial blood enters the capillaries, fluid move from the intravascular space into the interstitial space (surrounding capillaries because of starling forces
- The hydrostatic pressure in the arteriolar end of the capillaries (about 37 mm Hg) exceeds the sum of the tissue pressure (0-1 mm Hg) and the osmotic pressure of the plasma proteins (about 25 Hg), which is largely albumin related
- This cause water to leave the capillaries and enter the extravascular spaces
- At the venous end of the capillaries hydrostatic pressure falls to about 17 mm Hg while osmotic pressure and tissue pressure remain constant, drawing fluid back from the extravascular (interstitial) spaces into the blood
What is Acytes?
- Fluid building up in abdomen
- Often caused by cirrhosis = liver dysfunction, not making protein
What causes the fluid build up in acytes?
-Increase in hydrostatic pressure in the blood vessel - hydrostatic pressure is TOO HIGH in BLOOD VESSEL so fluid is pushed into the tissues
How is congestive heart failure caused?
-Increase in hydrostatic pressure!! in the blood vessel causes fluid to flow into heart.
How to treat congestive heart failure?
- Lasix to remove some water
2. Augment the cardiac output - licinopril, beta blocker –> reduce hydrostatic pressure
Congenital Methemoglobinemia?
- Patients appear cyanotic, but have few clinical problems
- Excess methemoglobin due to a deficency in cytochrome b5 reductase
- Excess methemoglobin in inherited hemoglobin M disease
What causes acquired methemoglobinemia?
- Ingestion of certain oxidants such as nitrites, quinone, aniline, and sulfonamides
- Can be related to benzocaine, lidocaine, dapsone use
- Can be treated by administration of reducing agents, such as ascorbic acid or methylene blue
Why do you need G6PD?
You need NADPH+ for Glutathione reductase. Glutathione is needed in order to clear and take care of oxidants in the cell (infections, certain drugs, fava beans)
What does 2, 3 BPG do?
It stabilized the deoxy form of Hemoglobin, facilitating the oxygen release to the tissues
What happens to the oxygen saturation curve when 2.3 BPG is increased (in tissues)?
- More oxygen is delivered/released to the tissues
- The tissue has elevated levels of 2,3 BPG
