Editing Blood (section)

===In mammals===
{{See also|Reference ranges for common blood tests}}

Blood accounts for 7% of the human body weight,<ref name="alberts_table">{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK26919/table/A4143/ |title=Table 22-1 Blood Cells |access-date=1 November 2012 |publisher=NCBI Bookshelf |year=2012 | last = Alberts | first = Bruce | name-list-style = vanc |website=Molecular Biology of the Cell |url-status=live |archive-url=https://web.archive.org/web/20180327160412/https://www.ncbi.nlm.nih.gov/books/NBK26919/table/A4143/ |archive-date=27 March 2018 }}</ref><ref name="PhysFactVol">{{Cite web |url=http://hypertextbook.com/facts/1998/LanNaLee.shtml |title=Volume of Blood in a Human |access-date=2012-11-01 |archive-url=https://web.archive.org/web/20121103090043/http://hypertextbook.com/facts/1998/LanNaLee.shtml |archive-date=3 November 2012 |year=2012 | last = Elert | first = Glenn | name-list-style = vanc |website=The Physics Factbook |url-status=dead}}</ref> with an average density around 1060&nbsp;kg/m<sup>3</sup>, very close to pure water's density of 1000&nbsp;kg/m<sup>3</sup>.<ref>{{cite web |url=http://hypertextbook.com/facts/2004/MichaelShmukler.shtml |title=Density of Blood |access-date=4 October 2006 |year=2004 |website=The Physics Factbook |last=Shmukler |first=Michael |url-status=dead |archive-url=https://web.archive.org/web/20060919051122/http://hypertextbook.com/facts/2004/MichaelShmukler.shtml |archive-date=19 September 2006 }}</ref> The average adult has a [[blood volume]] of roughly {{convert|5|L|USpt|lk=in}} or 1.3 gallons,<ref name="PhysFactVol"/> which is composed of plasma and ''formed elements''. The formed elements are the two types of blood cell or ''corpuscle'' – the [[red blood cells]], (erythrocytes) and [[white blood cells]] (leukocytes) – and the cell fragments called [[platelets]]<ref name="SEER">{{cite web |title=Composition of the Blood {{!}} SEER Training |url=https://training.seer.cancer.gov/leukemia/anatomy/composition.html |website=training.seer.cancer.gov |access-date=30 December 2020 |archive-date=16 October 2020 |archive-url=https://web.archive.org/web/20201016211542/https://www.training.seer.cancer.gov/leukemia/anatomy/composition.html |url-status=live }}</ref> that are involved in clotting. By volume, the red blood cells constitute about 45% of whole blood, the plasma about 54.3%, and white cells about 0.7%.

Whole blood (plasma and cells) exhibits [[non-Newtonian fluid|non-Newtonian]] [[Blood viscosity|fluid dynamics]].{{specify|reason="Non-Newtonian" encompasses several different types of properties.|date=April 2021}}

<gallery>
File:Krew Frakcjonowana.jpg|Human blood fractioned by centrifugation: Plasma (upper, yellow layer), buffy coat (middle, thin white layer) and erythrocyte layer (bottom, red layer) can be seen.
File:Blutkreislauf.png|Blood circulation: Red = oxygenated, blue = deoxygenated
File:Blausen 0425 Formed Elements.png|Illustration depicting formed elements of blood
File:Blut-EDTA.jpg|Two tubes of [[EDTA]]-anticoagulated blood.<br /> Left tube: after standing, the RBCs have settled at the bottom of the tube.<br /> Right tube: Freshly drawn blood
</gallery>

====Cells====
{{Further|Complete blood count}}

[[Image:Red White Blood cells.jpg|thumb|right|A [[scanning electron microscope]] (SEM) image of a normal [[red blood cell]] (left), a [[platelet]] (middle), and a [[white blood cell]] (right)]]
One microliter of blood contains:
*'''4.7 to 6.1&nbsp;million (male), 4.2 to 5.4&nbsp;million (female) [[erythrocyte]]s:'''<ref>{{cite web |url=https://www.nlm.nih.gov/medlineplus/ency/article/003644.htm#Normal%20Values |title=Medical Encyclopedia: RBC count |website=Medline Plus |access-date=18 November 2007 |url-status=live |archive-url=https://web.archive.org/web/20071021042354/http://www.nlm.nih.gov/medlineplus/ency/article/003644.htm#Normal%20Values |archive-date=21 October 2007 }}</ref> Red blood cells contain the blood's [[hemoglobin]] and distribute oxygen. Mature red blood cells lack a [[Cell nucleus|nucleus]] and [[organelles]] in mammals. The red blood cells (together with [[endothelial]] vessel cells and other cells) are also marked by [[glycoproteins]] that define the different [[Human blood group systems|blood types]]. The proportion of blood occupied by red blood cells is referred to as the [[hematocrit]], and is normally about 45%. The combined surface area of all red blood cells of the human body would be roughly 2,000 times as great as the body's exterior surface.<ref>{{cite book | first1 = Robert B. | last1 = Tallitsch | first2 = Martini | last2 = Frederic | first3 = Timmons | last3 = Michael J. | name-list-style = vanc |title=Human anatomy |publisher=Pearson/Benjamin Cummings |location=San Francisco |year=2006 |page=529 |isbn=978-0-8053-7211-3 |edition= 5th}}</ref>
*'''4,000–11,000 [[leukocytes]]:'''<ref name = "Ganong WF">{{cite book | last = Ganong | first = William F. | name-list-style = vanc |title=Review of medical physiology | url = https://archive.org/details/reviewmedicalphy00gano | url-access = limited |publisher=Lange Medical Books/McGraw-Hill |location=New York |year=2003 |page=[https://archive.org/details/reviewmedicalphy00gano/page/n517 518] |isbn=978-0-07-121765-1 |edition= 21}}</ref> White blood cells are part of the body's [[immune system]]; they destroy and remove old or aberrant cells and cellular debris, as well as attack infectious agents ([[pathogens]]) and foreign substances. The cancer of leukocytes is called [[leukemia]].
*'''200,000–500,000 [[thrombocytes]]:'''<ref name = "Ganong WF"/> Also called [[platelets]], they take part in blood clotting ([[coagulation]]). Fibrin from the coagulation cascade creates a mesh over the [[platelet plug]].

{| class="wikitable" style="float:center; margin-left:auto; margin-right:auto;"
|+ <div class="center" style="width:auto; margin-left:auto; margin-right:auto;">Constitution of normal blood</div>
|-
!Parameter
!Value
!Refs.
|-
| [[Hematocrit]] ||
45 ± 7 (38–52%) for males<br />
42 ± 5 (37–47%) for females
|
|-
| [[pH]] || 7.35–7.45
|<ref name=":1">{{Cite book |url=https://www.worldcat.org/oclc/1018308697 |title=Medical-surgical nursing : concepts for interprofessional collaborative care |date=2018 |publisher=[[Elsevier]] |editor-first1=Donna D. |editor-last1=Ignatavicius |editor-first2=M. Linda |editor-last2=Workman |editor-first3=Cherie R. |editor-last3=Rebar |editor-first4=Nicole M. |editor-last4=Heimgartner |isbn=978-0-323-46158-0 |edition=9th |location=St. Louis, Missouri |page=190 |language=en-US |oclc=1018308697}}</ref>
|-
| [[base excess]] || −3 to +3
|
|-
| P[[oxygen|O<sub>2</sub>]] || 10–13 kPa (80–100&nbsp;mm Hg)
|
|-
| P[[carbon dioxide|CO<sub>2</sub>]] || 4.8–5.8 kPa (35–45&nbsp;mm Hg)
|
|-
| [[Carbonic acid|HCO<sub>3</sub><sup>−</sup>]] || 21–27 mM
|
|-
| [[Oxygen saturation]] ||
Oxygenated: 98–99%<br />
Deoxygenated: 75%
|
|}
{{clear}}

====Plasma====
{{Main|Blood plasma}}
About 55% of blood is [[blood plasma]], a fluid that is the blood's liquid medium, which by itself is straw-yellow in color. The blood plasma volume totals of 2.7–3.0 liters (2.8–3.2 quarts) in an average human. It is essentially an [[water|aqueous]] solution containing 92% water, 8% blood plasma [[proteins]], and trace amounts of other materials. Plasma circulates dissolved nutrients, such as [[glucose]], [[amino acid]]s, and [[fatty acids]] (dissolved in the blood or bound to plasma proteins), and removes waste products, such as [[carbon dioxide]], [[urea]], and [[lactic acid]].

Other important [[List of human blood components|components]] include:
*[[Serum albumin]]
*Blood-clotting factors (to facilitate [[coagulation]])
*Immunoglobulins ([[antibodies]])
*[[lipoprotein]] particles
*Various other proteins
*Various [[electrolytes]] (mainly [[Sodium in biology|sodium]] and [[chloride]])

The term '''serum''' refers to plasma from which the clotting proteins have been removed. Most of the proteins remaining are albumin and immunoglobulins.

====Acidity====
{{See also|Acid–base homeostasis}}

[[pH#Living systems|Blood pH]] is regulated to stay within the narrow range of 7.35 to 7.45, making it slightly [[Base (chemistry)|basic]] (compensation).<ref name="Waugh">{{cite book |last1=Waugh |first1=Anne |chapter-url=https://archive.org/details/rosswilsonanatom0000waug_x2u4/page/22/mode/2up |title=Anatomy and Physiology in Health and Illness |last2=Grant |first2=Allison |publisher=Churchill Livingstone Elsevier |year=2007 |isbn=978-0-443-10102-1 |edition=Tenth |page=22 |chapter=2 |chapter-url-access=registration |name-list-style=vanc}}</ref><ref name="ReferenceA">{{MerckManual|12|157|a||Acid–Base Regulation and Disorders}}</ref> Extra-cellular fluid in blood that has a pH below 7.35 is too [[acid]]ic, whereas blood pH above 7.45 is too basic.<ref name=":1" /> A pH below 6.9 or above 7.8 is usually lethal.<ref name=":1" /> Blood pH, [[Oxygen#partial pressure|partial pressure of oxygen (pO<sub>2</sub>)]], [[PCO2|partial pressure of carbon dioxide (pCO<sub>2</sub>)]], and [[bicarbonate]] (HCO<sub>3</sub><sup>−</sup>) are carefully regulated by a number of [[homeostasis|homeostatic mechanisms]], which exert their influence principally through the [[respiratory system]] and the [[urinary system]] to control the [[acid–base homeostasis|acid–base balance]] and respiration, which is called compensation.<ref name=":1" /> An [[arterial blood gas test]] measures these. Plasma also circulates [[hormones]] transmitting their messages to various tissues. The list of normal [[Reference ranges for blood tests|reference ranges]] for various blood electrolytes is extensive.