Blood 4 Flashcards
What is each heme unit associated with?
One ferrous iron
How many O2 can each ferrous ion bind to?
One O2 molecule
How many O2 molecules can each O2 molecule bind to?
Four
Why is it important for Hemoglobin to bind oxygen in a loose and reversible manner?
Because you don’t want it to be too difficult to remove oxygen and give it to the tissues
What is meant by Deoxyhemoglobin being in a tense state?
It is no easy for oxygen to get into one of the crevices and bind to the iron at the center of the heme unit
What makes more hemoglobin more able to bind to oxygen?
The binding of one oxygen which creates a conformational change in the hemoglobin molecule which opens up the other subunits allowing for more oxygens to bind
What is the transport of oxygen by hemoglobin under the control of?
Hormones
Why is the transport of oxygen by hemoglobin under the control of hormones?
Because there is a hormone (erythropoietin or EPO) which determines how many RBCs are produced
Which hormone determines how many RBCs are produced?
Erythropoietin (EPO)
What is the stimulus for increasing EPO in the blood?
Hypoxia (low levels of oxygen in the blood)
Where is Hypoxia sensed?
In the kidneys
Why are the kidneys Endocrine glands?
Because they produce Erythropoietin
Where does EPO go from the kidneys when Hypoxia is sensed?
It goes into the blood and is sent to the bone marrow
What does EPO do once at the bone marrow?
Stimulates the production of red blood cells at various places in the pathway
What cells are old RBCs taken up by in the spleen?
Macrophages by the process of phagocytosis
What happens once an RBC is phagocytized in the spleen?
The hemoglobin is broken down into Globin and Heme
What is Globin of Hemoglobin broken down into in the spleen?
Amino acids
What happens to the Amino acids that the spleen takes from RBCs?
It can be used to make new proteins or it can enter metabolic pathways
What happens once the Heme is separated from Globin in the Spleen?
The iron is removed and reused
What happens to the Heme once iron is removed in the spleen?
It is a waste product and is broken down as Bilirubin and sent to the liver
Which Biopigment is responsible for the greenish yellowish color of the bile in the liver?
Bilirubin
What does the Bile do to bilirubin?
It stores and concentrates it
Where does the liver send biopigments?
To the small intestine and kidneys to be secreted as poo and urine
