sem 1: Red Blood Cell Flashcards
what is the rbc capable of doing in order to traverse the microvascular system
deform without fragmentation- flexible- can fit into small gaps
what 3 things does the rbc not contain
nucleus
ER
mitochondria
outer hydrophilic lipid layer:
glycoproteins
glycolipids
proteins
central hydrophobic layer:
proteins
cholestrol
phospholipids
inner hydrophilic layer
cytoskeletal proteins to support lipid bilayer
which phospholipid remains on inside because macrophages detect it and phagocytose them
phosphatidyl serine (eat me signal)
what is the relationship between membrane and plasma cholestrol
free equilibrium
what would happen to the RBC if there is increased cholestrol
appear distorted- aconthocytosis
what do the cells become after aconthocytosis
target cells- increase in haemoglobin in center and outer region of RBC
peripheral proteins (4)
spectrin
ankyrin
actin
proein 4.1
integral proteins
glycophorins
Band 3
surface receptors
Na+/K+ ATPase
what does spectrin do
- binds with other peripheral proteins from cytoskeletal network of microfilaments
- controls biconcave shape and deformability of cell
what does ankyrin do
anchors lipid bilayer to membrane skeleton
what does protein 4.1 do
stabilises interaction of spectrin with actin
what are the functions of the membrane (4)
- shape- provides optimum SA:V ratio
- provides deformability and elasticity
- regulated intracellular cation concentration
- acts as interface between cell and environment through membrane surface receptors
what is spherocytosis due to
spectrin deficiency
what cant the rbc do with spherocytosis
maintain shape and become spherical
is the inner layer of phospholipids charged or not?
charged
2 phospholipids on the inner layer
phosphatidyl ethanolamine
phosphatidyl serine
is the outer layer of phospholipids charged or not
not charged
2 phospholipids on the outer layer
phosphatidyl choline
sphingomyelin
what is inbetween the charged and uncharged phospholipids
unesterified cholestrol
what subunits does each haemoglobin have
2 alpha- globin chains
2 b-globin chains
what is the haem a complex between
protoporphyrin IX and ferrous iron ion (Fe2+)
when we were born what type was our haemoglobin mostly
HbF
what did it change to as we grew
Hb A
when oxygenated what gets pushed out to allow the B-chains to move closer
2,3-DGP
when oxygen is unloaded, 2-3 DGP enters, what happens the B chains
pulled apart
what lowers the affinity for oxygen
entry of 2,3-DGP
matobolism provides energy for(4)
- Maintenance of cation pumps
- Maintenance of Hb in reduced state
- Maintenance of reduced sulfhydryl groups in Hb and other proteins
- Maintenance of RBC integrity and deformability
key metabolic pathways(4)
- Glycolytic or Embden-Meyerhof pathway
- Pentose Phosphate pathway
- Methaemoglobin Reductase pathway
- Luebering-Rapoport shunt
what are the main actions of the key metabolic pathways
use enzyes to supply energy for the system
reduce oxidants in system
what does the glycolytic pathway do
generates 90-95% of energy
glucose metabolised to 2 ATP’s
what does the pentose phosphate pathway do
protect from oxidative damage
what does the methaemoglobin reductase pathway do
maintains iron in the ferrous state
what does the luebering rapoport shunt pathway do
permits accumulation of 2,3- DGP, to regulate haemoglobin affinity
