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Blood

2010-11-17T18:32:39Z

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Blood is a major part of the human body. It is required for most functions of cells. Blood is comprised of 3 main sections: [[Plasma|Plasma]], [[Thrombocytes|Thrombocytes]], red blood cell ([[Erythrocytes|Erythrocytes]]), White Blood Cells ([[Leukocytes|Leukocytes]]).

== Composition ==

=== Plasma ===

[[Plasma|Plasma]] contains many molecules ranging from clotting factors, dissolved [[Proteins|proteins]] and even [[Carbon dioxide|carbon dioxide]] through respiration. Plasma is extremely important in the transport of metabolites such as ATP an glucose around the body. It also can contain waste molecules such as urea and lactic acid. 

=== Thrombocytes ===

[[Thrombocytes|Thrombocytes]] are used in the clotting process and used to clog a broken seal with the aid of clotting factors via the [[Intrinsic Pathway|Intrinsic pathway]]. 

=== Erythrocytes ===

[[Erythrocytes|Erythrocytes]] are used in gas exchange using the [[Proteins|protein]] [[Haemoglobin|Haemoglobin]] (Hb). The most distinct characteristic of the Erythrocytes is their unique biconcave shape. To be more specific, [[Erythrocytes|erythrocytes]] are flat and disc-shaped with indentations in the middle of both sides. This contribute to the ease of carrying and transporting [[Molecule|oxygen]] across the whole blood stream. [[Erythrocytes|Erythrocytes]] are also able to demonstrate their membrane flexibility by  being able to squeeze through the very tiny and narrow blood capillaries<ref>Sherwood (2010) Human Physiology (From Cells to Systems), 7th edition, Canada : BROOKS/COLE CENGAGE Learning. page 392-4</ref>. 

=== Leukocytes ===

[[Leukocytes|Leukocytes]] are used to defend the body against [[Pathogens|pathogens]] via [[Phagocytosis|phagocytosis]] or [[Antibody|antibody]] production. There are many leukocytes differing in their mechanisms and appearance (granular/agranular): l[[Lymphocyte|ymphocytes]], [[Monocyte|monocytes]], [[Basophil|basophils]] and [[Eosinophil|eosinophils]]. 

== Blood Pressure ==

''Main article:'' [[Blood Pressure]]

Blood pressure is the pressure of the blood vessels exerted by circulating blood. It is normally measured at upper arm using a sphygmomanometer. During a heartbeat, there are two types of blood pressure is measured. One is 'upper' systolic pressure (contraction) and another is 'lower' diastolic (relaxation) pressure. Normal blood pressure for a healthy person is 120/80 mmHg (systolic/diastolic). 

== Blood Group Systems ==

''Main article:'' [[Blood group systems]]

There are 30 blood groups systems recognised by International Society of Blood Transfusion. The major blood group systems are ABO Blood Group System and Rh Blood Group System.

== See also ==

#[[Haemoglobin]]
#[[Hypertension]]

== References ==

<references />

== External Links ==

#[http://www.isbtweb.org/home/ ISBT]. International Society of Blood Transfusion.
#[http://ibgrl.blood.co.uk/isbt%20pages/isbt%20terminology%20pages/table%20of%20blood%20group%20systems.htm Table of blood group systems.]

Blood group systems

2010-11-15T18:15:53Z

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'''Blood group''' (or '''blood type''') is a term used to clasify blood based on the presence or absence of a specific antigen on red blood cells surface. According to the International Society of Blood Transfusion, there are about 30 human blood group systems recognized so far<ref>Table of blood group systems, ISBT (August 2008). Retrieved on 15 November 2010.</ref>. 

== ABO blood group system ==

The most common blood group system being used nowadays is ABO blood group system. In this system, there are 4 classification of blood types. They are group A, B, AB and O. These groups are classified according to the presence or absence of ABO antigen. 

''' '''

{| cellspacing="1" cellpadding="1" border="1" align="center" style="width: 451px; height: 140px;"
|-
| '''Blood group'''
| '''Antigen(s) present on erythrocytes'''
| '''Antibodies present in plasma'''
| '''Genotype(s)'''
|-
| A
| A antigen
| Anti-B
| AA or AO
|-
| B
| B antigen
| Anti-A
| BB or BO
|-
| AB
| A and B antigens
| none
| AB
|-
| O
| none
| Anti-A and B
| OO
|}

== Rh blood group system ==

Rh blood group system is the second most important system in determining blood groups. It is based on the presence or absence of D antigen on the red blood cells surface.

== See also ==

*[[Blood]]

== References ==

<references />

== External links ==

*[http://ibgrl.blood.co.uk/isbt%20pages/isbt%20terminology%20pages/table%20of%20blood%20group%20systems.htm Table of blood group systems] 
*[http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=rbcantigen&part=ch05ABO The ABO blood group]

2010-11-15T13:56:14Z

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The Renin-Angiotensin system (RAS), also Renin-Angiotensin-Aldosterone system, is one of the mechanisms used by the body to regulate [[blood pressure|blood pressure]]. It comes into play when the [[blood pressure|blood pressure]] is too low, in disease it can happen when the [[blood pressure|blood pressure]] is not low which can lead to [[hypertension|hypertension]]. 

== Mechanism ==

Low [[Blood pressure|blood pressure]] is detected by the juxtaglomerular apparatus which secretes renin. This [[Enzyme|enzyme]] hydrolyses angiotensinogen in the blood stream to [[Angiotensin I|angiotensin I]]. Angiotensin I is further processed; [[Angiotensin-converting-enzyme|angiotensin-converting-enzyme]] (ACE), released from the lungs, cleaves further [[Amino acids|amino acids]] from the protein resulting in [[Angiotensin II|angiotensin II]]. This [[Protein|protein]] help the body to raise the [[Blood pressure|blood pressure]] by many mechanisms including [[Vasoconstriction|vasoconstriction]], [[ADH|ADH]] secretion and [[Aldosterone|aldosterone]] secretion.

Blood

2010-11-15T13:54:49Z

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Blood

2010-11-15T13:54:35Z

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File:Nernst equation3.png

2010-11-14T21:35:57Z

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