Lecture 2: Cell Membranes and Transport Flashcards
What is the disease mechanism behind Niemann-Pick Disease?
Deficiency of enzyme Acid Sphingomyelinase, which leads to an accumulation of sphingomyelin
Normal: Sphingomyelin breaks down into ceramide and phosphorylcholine
What are some clinical manifestations of Niemann-Pick Disease?
Hepatomegaly and Slenomegaly
Neurological Damage
Cherry Red Spot in Eye
Fatal in infants
What are the composition of antigens on RBC?
Antigens are either glycoproteins or glycolipids on RBC membrane
What happens when mother is Rh- and baby is Rh+
The mother can produce anti-RH antibodies, which will attack the fetus.
Risk increases in future pregnancies
How do proteins and lipids move in cell membrane?
They can rotate and move laterally.
Cannot move up/down (between layers).
What is the disease mechanism behind Spur Cell Anemia?
RBC membranes has an increased uptake of cholesterol, making it quite rigid. The rigid RBC will lyse in capillaries.
The extra free cholesterol is due to impaired liver metabolism.
In cystinuria, what amino acid transporters are defective?
Think COAL
Cystine, Ornithine, Arginine, Lysine
What are clinical manifestations of cystinuria?
Renal Cholic
-Abdominal pain
In Hartnup Disease, what amino acid transporters are defective?
Non-polar and neutral amino acids
- Alanine
- Valine
- Threonine
- Leucine
- Tryptophan!!
What are clinical manifestations of Hartnup?
Intermittent cerebral ataxia
Nystagmus
Photodermatitis
Photosensitivity
How do cardiotonic drugs work?
Goal: Increase sarcoplasm Ca2+ concentration inside cells
Cardiotonic drugs inhibit Na+/K+ pump (more Na+ inside cell). This inhibits Na+/Ca2+ exchanger, causing increased sarcoplasmic Ca2+ concentration
What are examples of cardiotonic drugs?
Ouabin and Digoxin
What is mutated in Cystic Fibrosis?
Defective CFTR protein (chloride ion channel).
This causes accumulation of Cl- inside the cell, which causes Na+ and water to accumulate.
