Reticuloendothelial system

• blood is a type of conective tissue consistinh of cells and cell fragments
• connective tissue develops from mesenchyme and consits of blood celss which suurround by non living fluid called plasma
• red blood cells is also known as erythrocytes which account fro 45% of the blood
• plasma makes up 55 % of total blood volume
• 1% remaining is consists of white blood cells and platelets
• blood compose of plasma, a yellowish liquid contains nutrients, hormones, minerals and cells mainly red blood cells, white blood cells, and plateles
• blood formed about 7-9% of total body weight
• man has 5-6 L of blood
• woman has 4-5 L of blood
• blood is thinker, denser and flows muc slower than water due to RBC and proteins such as albumin and fibrinogen
• RBC and proteins contribute to the viscosity of blood ranges from 3.5 to 5.5 compared to water 1.0
• RBC ranges from 3.5 to 5.5
• Gravity (density) of blood is 1.045-1.065 than water 1.00
• the pH of blood ranges from 7.35 to 7.45
• Formed elements of blood: RBC, WBC and Platelets
• RBC a small biconcave dics shape
• biconcave shape maintained by a network of protein called spectrin
• spectrin allows the RBC to change shape and transported to blood vessel
• 4-5.5 million of RBC in each cubic millimetre of blood
• Young RBC contains nucleus
• Nucleus is not present in mature RBC or any organelles such as mitochondria
• main function of RBC is to transport respiratory gases oxygen and carbon dioxide
• As RBC lack of mitochondria to produce energy they use Anaerobic respiration to produce energy
• Haemoglobin is composed of protein called globin
• globin is bound to the iron-containing pigments called haem
• each globin has 4 polypeptide chains consists of 2 alpha and 2 beta chains
• one molecule of haemoglobin will transport 4 molecule of oxygen
• 250 milion oof haemoglobin in one RBC
• RBC formed from the stem cells in the red bone marrow
• multipotent stem cells divide to product myeloid stem cells which divide to produce erythroblasts
• erythroblast develop in the red bone marrow
• RBC lost their nucleus and organells and gains more haemoglobin molecules
• mature RBC do not have nucleus their lifespan is approximately 120 days
• approximately 2 million RBC are destroyed per second
• production of RBC is controlled by the hormone erythropoeitin
• essential components of the RBC: iron, folic and Vitamin B12
• Haemolysis carried out by macrophages in the spleen, liver, and bone marrow
• haem and globin are separated
• globin is broken down into amino acids used for protein synthesis
• iron is separated from haem and stored in muscle and liver