Zusammenfassung der Ressource
HEMOGLOBIN
- Structure
- 4 Globin
- Polypeptide chains
- A and B
- 4 Heme groups that bind O2
- 4 O2/Hb
- Hemoglobin and O2
Transport
- Iron
- Containing protein found in RBC
transports respiratory gases
- Loading (Hb bindding to O2) occurs in lungs
- Unloading occurs in tissues
- Affinity of Hb for O2 changes
with a number of physiological
variables
- Temperature altitude pH
- Most 02 in blood is
bond to Hb inside
RBC as
OXYHEMOGLOBIN
- Hb increases the O2 carrying capacity of blood
- Carbon Monoxide &
O2 Transport
- Carboxyhemoglobin
- Heme combined with CARBON MONOXIDE
- Bond with CO is 250 times stronger than bond with O
- so heme cannot bind 02
- Thus interferes with Oxygen carrying capacity of blood
- Hemoglobin & O2 transports
- O2 Carrying capacity of blood also
depends on Hb Levels
- ANEMIA
- Hb levels are below normal
- Reduction of RBC
- physiological adaptations include:
- each RBC produces more DPG
- Hb production normally controlled
by Erythropoietin
- Stimulated by
low PO2
- High PO2 of lungs
favors loading
- Low PO2 in tissues
favors unloading
- Hb 02 affinity should allow
maximum loading in lungs &
unloading in tissues
- Oxyhemoglobin Dissociation
Curve
- Hb-oxygen binding depends on
oxygen pressure (amount)
- 98% Saturation at 100mmHg oxygen (arteries )
- 75% Saturation at 40mmHg at 40mmHg oxygen (veins)
- 60 mmHg unloaded at tissues
- Bohr Effect
- Hb-Oxygen affinity decreases due to
pH, increase CO2 and Increase
temperature
- Occurs in metabocally active tissues
- caused Hb-O2 curve to shift right (more unloading
- Oxygen INCREASES at lungs
DECREASES Hb-CO2 affinity
(Haldane Effect)
- Effect of hypoxia on O2 transport
- Hypoxia LOW OXYGEN
- Less oxygemoglobin
- less tissue transport
- 2,3 DPG gycolysis by
product RBC no
mitochondria
- Binds to Hb
- Adaptations to hypoxia:
- DECREASE DPG INCREASES HB
OXYGEN AFFINITY
- INCREASE DPG DECREASES
OXYGEN AFFINITY AND
FACILITATES DELIVERY TO
TISSUES
- Fetal Hemoglobin
- Cant bind DPG
- Have higher O2 affinity
thus facilitates mother
fetus oxygen delivery
- Pathologies
- SICKLE-CELL ANEMIA
- Affects 8-11% African A.
- Valine substituted fro glutamic acid
on B chains
- Formation of hemoglobin S
- RBC become fragile, rigid sticky and clump together
- Impaired O delivery to organs
- Reactivation of HbG HYDROXYUREA AS A TREATMENT
- Thalassemia
- Mostly affects people of Asian Mediterranean origin
- Failure in production of either B or A chains
- Small RBCs
- Anemia
- Imapired Oxygen delivery to organs
- CABON DIOXIDE TRANSPORT
- CO2 transported in blood as:
- dissolved CO2 in plasma 10%
- Bicarbonate ion HCO3- 70%
- Carbaminohemoglobin 20%
- Carbonic anhyfrase
catalyzes formation of
H2CO3
- Carbonic acis from CO2 + H2O
Dissociates into H+ and HCO3-
- ACIDOSIS
- pH lower than 7.35
- Respiratory
acidosis caused
- Hypoventilation
- Causes rise in
blood CO2 &
carbonic acid
- Metabolic Acidosis
- Result form excess nonvolatile acids
- fat breakdown in diabetes or
loss of HCO3- in diarrhea
- Alkalosis
- pH greater 7.45
- Respiratory alkalosis
- hyperventilation
- too little CO2
- Response to high altitude low Oxygen to correct the pH balance
- Metabolic Alkalosis
- caused by too much
HCO3- or too little acids
- from vomiting out
stomach acid