Difference between revisions of "Plasma"

Revision as of 10:58, 12 August 2010

Introduction

Plasma is the fluid portion of the blood in which the blood cells are suspended. Plasma in combination with the interstitial fluid makes up the extracellular body fluid compartment. Blood plasma can be prepared following centrifugation of a fresh sample that has been placed in a sample pot containing anti-coagulant. Whilst in the centrifuge the red blood cells separate and fall to the bottom leaving a layer of yellow plasma on top. The plasma can consequently be drawn off.

Blood plasma is to be distinguihed from serum which is plasma without fibrinogen which is separated following the clotting process.

Composition

Plasma is mostly water (90%) but it also contains dissolved substances. These are circulated throughout the body and diffuse into tissues and cells where needed. Thes substances include proteins which are responsible for oncotic pressure within the blood vessels. The main proteins in plasma are albumin, globulins and clotting factorsparticularly fibrinogen.

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-{{review}}
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-'''Serum''' is plasma without fibrinogen
 ==Introduction==
 Plasma is the fluid portion of the blood in which the blood cells are suspended. Plasma in combination with the interstitial fluid makes up the extracellular body fluid compartment.
 Blood plasma can be prepared following centrifugation of a fresh sample that has been placed in a sample pot containing anti-coagulant.
-Whilst in the centrifuge the [[Erythrocytes|red blood cells]] separate and fall to the bottom leaving a layer of yellow plasma on top. The plasma can subsequently be drawn off.
+Whilst in the centrifuge the red blood cells separate and fall to the bottom leaving a layer of yellow plasma on top. The plasma can consequently be drawn off.
-'''Blood plasma''' is to be distinguished from '''serum''' which is plasma without fibrinogen which is separated following the clotting process.
-Some [[:Category:Electrolytes|electrolytes]] whilst in plasma are bound to plasma proteins and hence are termed '''protein bound'''; this must be factored in when calculating plasma (or serum) levels for diagnostic purposes. A good example would be Calcium.
+Blood plasma is to be distinguihed from '''serum''' which is plasma without fibrinogen which is separated following the clotting process.
 ==Composition==
-Plasma is mostly water (90%) but also contains the following substances:
+Plasma is mostly water (90%) but it also contains dissolved substances.  These are circulated throughout the body and diffuse into tissues and cells where needed. Thes substances include proteins which are responsible for oncotic pressure within the blood vessels. The main proteins in plasma are albumin, globulins and clotting factorsparticularly fibrinogen.
-*Plasma Proteins
-*Electrolytes
-*Nutrients
-*Minerals
-*Gases
-*Waste products
-*Hormones and enzymes.
-These substances are circulated throughout the body by plasma and diffuse into tissues and cells where needed.
-'''Plasma  proteins'''  are large molecules of which there are four main types, [[Albumin|albumin]], Globulin, fibrinogen and prothrombin. Albumin maintains oncotic pressure within the blood vessels and hence blood volume and [[:Category:Blood Pressure|blood pressure]]. Globulins which are produced by lymphocytes act in immune reactions and fibrinogen and prothrombin are required in order for clotting to occur.
-'''Electrolytes''' include Calcium, Sodium, Chloride and Potassium. Calcium is present in three forms within the plasma: bound to protein (approx. 50%), complexed and ionised. Sodium is an important cation of the extracellular fluid and contributes to plasma oncotic pressure. Potassium is the main intracellular cation, and levels in plasma are rarely reflective of the total body level of this electrolyte.
-'''Nutrients in solution''' include the breakdown products of digestion, amino acids, glucose and fatty acids.
-'''Mineral Salts''' in solution include sodium, potassium, calcium, chloride, bicarbonate, sulphate and phosphate. The salts are ions which act to maintain the PH of the blood at 7.4.
-'''Gases in solution''' include oxygen and carbon dioxide. Oxygen is carried mainly by the red blood cells but a small amount is dissolved in the plasma. Carbon dioxide is carried by the plasma as carbonic acid and bicarbonate ions.
-'''Waste products''' carried by the plasma include urea and creatinine which are nitrogenous waste. They are taken to the [[Liver - Anatomy & Physiology|liver]] and [[Kidney Endocrine Function - Anatomy & Physiology|kidneys]] where they are removed via the bile or [[Urine Normal Composition|urine]].
-'''Hormones and Enzymes''' including cortisol and thyroxine are transported around the body in plasma bound to plasma proteins.
-[[Category:WikiBlood]]

Difference between revisions of "Plasma"

Revision as of 10:58, 12 August 2010

Introduction

Composition

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