|
|
| Line 1: |
Line 1: |
| The fluid portion of the blood, mainly composed of water (90%) but also contains a range of proteins(6.5-8%) and low molecular weight substances(2%). When the blood is separated using centrifugation plasma is viewed as a pale yellow liquid and forms 55% of the total volume of the blood. Plasma holds a key role in the maintaining of osmotic pressure and acts as a transport medium for a range of molecules. Serum is plasma after the removal of clotting factors II, V, VIII and fibrinogen.
| | ===Aim=== |
| | | To understand the principles behind membrane potential, how changes in ionic concentration affect it and to provide a basis for understanding how certain channel blockers (Na<sup>+</sup>, Ca<sup>2+</sup> and K<sup>+</sup>) can be used clinically. |
| == Plasma Proteins == | |
| Over 100 different types of plasma protein exist but they can be grouped into 3 fractions; Plasma Albumin, Plasma Globulin and Fibrinogen.
| |
| {| class="wikitable"
| |
| |-
| |
| ! Protein !! Function !! Site of synthesis
| |
| |-
| |
| | Plasma Albumin ||
| |
| * Generates colloid osmotic pressure (3.3 Kpa/ 25-30 mm Hg)
| |
| *Acts as a buffer for blood pH
| |
| * Carrier of fatty acids and Bilirubin
| |
| || Liver
| |
| |-
| |
| | Plasma Globulin ||
| |
| * α and β specific carriers eg transferrin
| |
| * α and β hemocoagulation factors eg prothrombin
| |
| * Ύ are immunoglobins, vital role in humoral immunity
| |
| || α and β in liver
| |
| Ύ by lymphocytes
| |
| | |
| |-
| |
| | Fibrinogen|| Buffering and hemostatic role || Liver
| |
| |}
| |
| | |
| Alternatively it is possible to group plasma proteins according to their function;
| |
| {| class="wikitable"
| |
| |-
| |
| ! Functional Catergory !! Proteins Included !! Role
| |
| |-
| |
| | Proteins of the Acute Phase ||
| |
| * Interlukins
| |
| * Clotting Factors
| |
| * C reactive protein
| |
| * Serum amyloid A protein
| |
| || Injury/ Inflammation
| |
| |-
| |
| | Plasma Proteolytic Enzymes ||
| |
| * Kinin System
| |
| * Complement system
| |
| * Thrombin
| |
| * Plasmin
| |
| || Hemostasis/ Inflammation
| |
| |-
| |
| | Plasma Protease Inhibitors || Antithrombin III || Anticoagulation
| |
| |-
| |
| | Carrier Proteins ||
| |
| * Transcobalamincobalamin
| |
| * Transferrin
| |
| * Ceruloplasmin
| |
| || Transport of specifc molecules
| |
| |}
| |
| | |
| == Low Molecular Weight substances==
| |
| These substances include K<sup>+</sup>, Na<sup>+</sup>, Ca<sup>2+</sup>, HCO<sub>3</sub><sup>-</sup> , glucose and urea. These molecules and ions all produce osmotic pressure, also in the case of HCO<sub>3</sub><sup>-</sup> forms the principle buffering system of the blood. The combined effect of these molecules results in plasma having an osmolarity of 280-290 mOsm/L . This osmolarity is equal to that of 0.9 % saline solution hence its use to hydrate patients intravenously.
| |
| | |
| <noinclude>
| |
| == Links ==
| |
| === Related Articles ===
| |
| Changes in Serum Protein Levels
| |
| === Bibliography ===
| |
| Lecture Notes: Prof. MUDr. Jaroslav Pokorný DrSc.<br />
| |
| | |
| Mescher, Anthony L. – JUNQUEIRA'S. Basic Histology Text & Atlas. 12. Edition. McGraw Hill Medical, 2010. ISBN 9780071271905.<br />
| |
| | |
| Barrett Kim E., Barman Susan M., Boitano S., Brooks Heddwen L.- GANONG'S. Review of Medical Physiology. 23. Edition. McGraw Hill Medical, 2010. ISBN 9780071270663
| |
| <noinclude>
| |
Latest revision as of 18:44, 5 August 2014
To understand the principles behind membrane potential, how changes in ionic concentration affect it and to provide a basis for understanding how certain channel blockers (Na+, Ca2+ and K+) can be used clinically.
