<< Chapter < Page Chapter >> Page >

A pie graph showing the proportion of total body fluid in each of the body’s fluid compartments

This pie chart shows that about 55% of water in the human body is intracellular fluid. About 30% of the water in the human body is interstitial fluid. Most of the remaining 15% of water is plasma, along with a small percentage labeled “other fluid”.
Most of the water in the body is intracellular fluid. The second largest volume is the interstitial fluid, which surrounds cells that are not blood cells.

Extracellular fluid

The ECF accounts for the other one-third of the body’s water content. Approximately 20 percent of the ECF is found in plasma. Plasma travels through the body in blood vessels and transports a range of materials, including blood cells, proteins (including clotting factors and antibodies), electrolytes, nutrients, gases, and wastes. Gases, nutrients, and waste materials travel between capillaries and cells through the IF. Cells are separated from the IF by a selectively permeable cell membrane that helps regulate the passage of materials between the IF and the interior of the cell.

The body has other water-based ECF. These include the cerebrospinal fluid that bathes the brain and spinal cord, lymph, the synovial fluid in joints, the pleural fluid in the pleural cavities, the pericardial fluid in the cardiac sac, the peritoneal fluid in the peritoneal cavity, and the aqueous humor of the eye. Because these fluids are outside of cells, these fluids are also considered components of the ECF compartment.

Composition of body fluids

The compositions of the two components of the ECF—plasma and IF—are more similar to each other than either is to the ICF ( [link] ). Blood plasma has high concentrations of sodium, chloride, bicarbonate, and protein. The IF has high concentrations of sodium, chloride, and bicarbonate, but a relatively lower concentration of protein. In contrast, the ICF has elevated amounts of potassium, phosphate, magnesium, and protein. Overall, the ICF contains high concentrations of potassium and phosphate ( HPO 4 2 ), whereas both plasma and the ECF contain high concentrations of sodium and chloride.

The concentrations of different elements in key bodily fluids

This bar graph shows the concentration of several ions and proteins in intracellular fluid, interstitial fluid and plasma. The ions and proteins are categories on the X axis . The Y axis shows concentration, in milliequivalents per liter, ranging from zero to 160. Three different colored bars are shown above each compound on the X axis. One bar represents intracellular fluid (ICF), a second bar represents interstitial fluid (IF, which is part of ECF) and the third bar represents plasma (ECF). Intracellular fluid contains high concentrations of K plus and HPO four two minus. It has lower concentrations of MG two plus and protein, and negligible amounts of the other compounds. Interstitial fluid contains high concentrations of NA plus and CL minus, along with a smaller amount of HCO 3 minus, and negligible amounts of the other compounds. Plasma contains large concentrations of NA plus and CL minus, with smaller concentrations of HCO 3 minus and protein, and negligible amounts of the other compounds.
The graph shows the composition of the ICF, IF, and plasma. The compositions of plasma and IF are similar to one another but are quite different from the composition of the ICF.
QR Codes representing a URL

Watch this video to learn more about body fluids, fluid compartments, and electrolytes. When blood volume decreases due to sweating, from what source is water taken in by the blood?

Most body fluids are neutral in charge. Thus, cations, or positively charged ions, and anions, or negatively charged ions, are balanced in fluids. As seen in the previous graph, sodium (Na + ) ions and chloride (Cl - ) ions are concentrated in the ECF of the body, whereas potassium (K + ) ions are concentrated inside cells. Although sodium and potassium can “leak” through “pores” into and out of cells, respectively, the high levels of potassium and low levels of sodium in the ICF are maintained by sodium-potassium pumps in the cell membranes. These pumps use the energy supplied by ATP to pump sodium out of the cell and potassium into the cell ( [link] ).

Questions & Answers

through remodeling and formation of new bones
Amoako Reply
please what is it
Monica
what is blood pressure
HALLELUYAH
what is blood pressure reading
HALLELUYAH
sketch and label blood vessels
HALLELUYAH
draw the male reproductive system
Jeremaih Reply
hello am new here
Pednyin
how life
Jeremaih
Explain how different foods can affect metabolism
Abraham Reply
what is Endocrine system?
Islam Reply
which secrete hormones and other products direct into the blood
Aadi
Cell is basic, structural and functional unit of life
Kabuja Reply
The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life." Some organisms, such as bacteria, are unicellular, consisting of a single cell.
Br_
hi am new here..wish to join you in this conversation
Rachel
welcome Rachel am Brianito
hingi
hey
HALLELUYAH
can some one help
HALLELUYAH
what is the basic function of the lymphatic system
HALLELUYAH
The other main function is that of defense in the immune system. Lymph is very similar to blood plasma: it contains lymphocytes. It also contains waste products and cellular debris together with bacteria and proteins. Associated organs composed of lymphoid tissue are the sites of lymphocyte producti
Adnan
the function of lymphatic system are 1fluid balance 2 lipid absorption and 3 defence
Sidra
destroyed microognism
Usman
lymphatic systems main function is to transport lymph
Colleen
may i know the meaning of infestation of parasite?
Aminiely
Which of the following accurately describe external respirations
Robin Reply
different between anatomy and physiology
Samwel Reply
anatomy is the study of STRUCTURE of the body while physiology is the study of the function of the part of the body
Gborgbor
Anatomy deals with the structure and parts of the body while physiology is the function of the the body parts
Archie
not understanding what is a cell
Kesa Reply
its the fundamental unit of life or its the primary step in which two or more cell combine to form a tissue .
Sidra
Is the smallest structural and functional unit of life
Aliyu
cell is the basic you unit of life
Esther
what is osteomalàcia
Ellen Reply
what is hydroxyapitate
Ellen
Hydroxyapatite, also called hydroxylapatite, is a naturally occurring mineral form of calcium apatite with the formula Ca₅(PO₄)₃, but it is usually written Ca₁₀(PO₄)₆(OH)₂ to denote that the crystal unit cell comprises two entities. Hydroxyapatite is the hydroxyl endmember of the complex apatite gro
Br_
..up
Br_
what's the best way to memorize the terms and what it does
Kesa
osteomalacia is where inorganic or mineral which is calcium and phosphorus are removed from a bone....this will make the bone become flexible n in children is called ricket
Rashida
wat work does anatomy do in the hospital and can they get work fast after finishing
SULE Reply
what is the meaning of suture?
praba Reply
it is a protective layer of brain
Madhureddy
it is a kind of non movable joint present between skull bones
neha
suture is an example of fibrous joint and is synatrosys(is not movable)
Rashida
a junction between the sclerites of an imsect's body
Aadi
c organ,organ system, organism
Dorothy Reply
reproductive sytstem
Dorothy
describe structure and functions of spleen
Umesh Reply
why calcium does not prodecessed by biological process?
James Reply
when calcium isn't processed that becomes Calcium Homeostasis
Br_
follow this link for extra info on all processes of calcium including calcium metabolism > ***google.com/url?sa=t&source=web&rct=j&url=***opentextbc.ca/anatomyandphysiology/chapter/6-7-calcium-homeostasis-interactions-of-the-skeletal-system-and-other-organ-systems/&ved=2ahUKEwi06LTw-sP
Br_
Copy it and paste it on your browser url
Br_
What are the functions of batholine glan
Aliyu Reply
secretions
Sadia
Of what
Aliyu

Get the best Anatomy & Physiology course in your pocket!





Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?

Ask