blood_-_composition_anf_function

Blood: Its Composition and Function The blood in our circulatory system is a watery based fluid and consists of two basic components: 1) Plasma (55%) and, 2) Formed elements (45%) Part A: Plasma The Plasma is the light yellow liquid portion of the blood and is about 90% water. Dissolved in the plasma are: 1) Gases (e.g. nitrogen carbon dioxide, and oxygen) 2) Ions (e.g. sodium, chloride and calcium) 3) Nutrients (e.g. glucose, amino acids) 4) Hormones 5) Proteins (most abundant) 6) Lipid molecules 7) Various wastes Proteins are the most abundant of all dissolved substances in the plasma. Some plasma proteins serve as carrier proteins. There are three types: Table 1: Summary of plasma proteins Protein Albumins Function 1. Maintain osmotic pressure by drawing water back into capillaries to help maintain body fluid levels. 2. Transport smaller molecules such as hormones and ions Globulins 1. Help protect again invading microbes by binding to foreign substances 2. Transport hormones and fat soluble vitamins Fibrinogens 1. Converted into fibrin networks that form blood clots. Part B: Formed elements There are three types of formed elements that are suspended in the plasma: 1) Red blood cells 2) White blood cells 3) Platelets Red Blood Cells (Erythrocytes) The red blood cells are the most abundant cells in the human blood. They are highly flexible (as they must bend and twist as they pass through the capillaries), biconcave disks that transport oxygen, and to a lesser degree, carbon dioxide in the blood. The unique shape of the red blood cells simply increase its surface area. Hemoglobines, the oxygen-transporting protein found in the RBC’s contains a ring of iron. Inside the RBC’s, oxygen binds to the ring of iron in hemoglobine molecules for transport through the circulatory system. In facet, 98% of oxygen is transported bound to iron in hemoglobine while the other 2% dissolves in the blood plasma. Anemia is a condition resulting in a decrease in the ability to transport oxygen in the blood. A deficiency in either hemoglobine or in red blood cells decreases the oxygen transported to the tissue. This condition is characterised by weakness and fatigues. People suffering from anemia often: i. Are pale and end to faint easily ii. iii. Become short of breath easily Have an increased heart rate i. This is to offset the reduction in the oxygen in the oxygen carrying