L3-factors Affecting Erythropoiesis and hemoglobin function Flashcards
What is the hematocrit value
Percentage of red blood cells in relation to the whole blood
Where does a normal blood count range from
From 4.5 to 5.5 million cells per microliter of blood
What do red blood cells do in pulmonary capillaries
Pick up oxygen in oxyhemoglobin is formed
What do red blood cells do in systemic capillaries
OxyHemoglobin gives up much of its oxygen and becomes reduced to hemoglobin
Where does erythropoiesis occur during embryonic life
In the liver
What are the factors affecting erythropoiesis
General factors
maturation factors
factors necessary for hemoglobin formation
What are the general factors
A)hormones 1)erythropoietin hormone 2)other hormones such as thyroxine Androgens Growth hormone B)vitamins: vit c C)liver:manfactures globin and stores iron, copper, vit b12, folic acid and also secrets small amount of erythropoietin D)bone marrow
Describe the erythropoietin hormone
Most is formed in the kidney rest is formed in the liver
Hypoxia is responsible for production of erythropoietin
Lack of O2 stimulates formation of erythropoietin
When O2 transport to tissues rise above normal the rate of erythropoietin formation decreases
What would cause aplastic anemia
Destruction of bone marrow by irradiation, chemicals, drugs or bacterial toxins will lead to deficiency of blood cells leading to aplastic anemia
What are the maturation factors
Vitamin B 12 and folic acid or essential for formation of red blood cells
they are important for nuclear maturation and cell division of red cell prescuors and are called maturation factors
How is vitamin B 12 combined and why
Parietal cells of the stomach lining produce the intrinsic factor: a chemical that combines the vitamin B 12 in food to prevent its digestion and promote its absorption in the small intestine
Once absorbed it’s stored in the liver and is released slowly as needed by the bone marrow and other tissues
What are the factors necessary for hb formation
▪️Protein: animal protein that are presents delivered kidney and muscles are superior in production of HB compared to plant derived proteins
▪️Iron: iron is necessary for the formation of the heme part of hemoglobin 70% of the iron in the body is present in hemoglobin
▪️Copper and cobalt : copper and cobalt act as a catalyst in hemoglobin synthesis ▪️copper is necessary for iron reabsorption from the gastrointestinal tract
▪️Cobalt is essential for utilization of iron during hb formation
What are the nutritional factors required for erythropoiesis
Proteins vitamins iron and copper
Average hemoglobin concentration in blood for females and males
16+ -2 g/dL in men
14 g+-2/dL in women
How many human fractions does each hemoglobin molecule contain
Four
Each can carry one O2
Where does O2 attach in the hemoglobin
To the Fe++(ferrous) in the haem
Describe oxyhemoglobin
Formed by the combination of Hb with O2 by the process of oxygenation the iron remains in the ferrous state in this compound
Deoxy or reduced hemoglobin
When O2 is released from oxyhemoglobin it’s called reduced hemoglobin
Carbaminohemoglobin
Formed by combination of hemoglobin with CO2
CO2 can easily be released from this affinity of hemoglobin to CO2 is 20 times more than for O2
Carboxyhemoglobin
Combination of hemoglobin with carbon monoxide the affinity of hemoglobin for carbon monoxide is 200 times more than its affinity for O2
Methaemoglobin
If blood is exposed to various drugs and oxidizing agents the ferrous iron in the hemoglobin molecule will be converted to ferric iron forming Methaemoglobin which is unable to carry 02
