What is Capillary: Definition and 113 Discussions

A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter, and having a wall one endothelial cell thick. They are the smallest blood vessels in the body: they convey blood between the arterioles and venules. These microvessels are the site of exchange of many substances with the interstitial fluid surrounding them. Substances which cross capillaries include water, oxygen, carbon dioxide, urea, glucose, uric acid, lactic acid and creatinine. Lymph capillaries connect with larger lymph vessels to drain lymphatic fluid collected in the microcirculation.
During early embryonic development, new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a de novo production of endothelial cells that then form vascular tubes. The term angiogenesis denotes the formation of new capillaries from pre-existing blood vessels and already present endothelium which divides.

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  1. S

    Will the water rise in a capillary when placed on a freely falling lift?

    Homework Statement A capillary is dipped in water vessel kept on a freely falling lift, then a)water will not rise in the tube b)water will rise to the maximum possible height of the tube Homework Equations W=2\pir S cos\theta or h=(2S cos \theta)/(r\rhog) The Attempt at a...
  2. L

    Capillary action: mercury depression

    hi guys, need some help for this question. a capillary of unknown internal radius was inserted into a pool of mercury into a pool of mercury. the height of mercury within the capillary was depressed 1.6cm below the free liquid. Calculate the internal diameter of the capillary. For the...
  3. P

    Can capillary forces act upside down?

    This is fairly amateur but I'm not an engineer so: If you have a drop of water on a table and you stick a straw in it some of the water goes up the straw until gravitational force equals the capillary force. Am I right in saying, (generally): 1) If you have a small drop of water hanging from...
  4. A

    Capillary waves - surface standing

    With capillary waves I need to calculate where surface standing waves will occur. Assume mediums are pure water and air. Assume the capillary waves are bounded in a box such that the wavelength matches the height of the water and width/length of the box. Assume effects of gravity and...
  5. R

    Simulating Capillary Effects in Femlab (pre-new version)

    Is it possible to simulate capillary effects in a channel using femlab (exclude the newest version)? I mean the new version has wetted wall boundary condition setting, which can set the wall adhesion and the contact angle between the air/liquid interface and the wall. But the older version...
  6. P

    Capillary forces, intermolecular forces and surface tension questions

    I tried posting a similar question before, however, I've found the 1 reply is actually wrong. Hopefully with better illustrations, someone will know. The situation in the picture is a drop of water entering a capillary tube. It is located here...
  7. P

    Capillary Action (Capillary Depression)

    Hi, I have questions regarding capillary action and capillary depression for practical purposes. I'm fairly educated in physics and chemistry, but have some "what would happen if..." questions. Please help, and add any information you'd think helpful! 1) Imagine you have your typical...
  8. C

    Capillary Tubes (purchase in Canada)

    Hey everybody I'm looking to buy a set of these: http://www.sciencelab.com/page/S/PVAR/10615/10-2410 the 5mm OD tubes that become malleable when subjected to heat (for a little project I want to do). Unfortunately, this website does not ship to Canada. Anyone know of any brick & mortar...
  9. K

    Capillary Action: Physically Possible Forms

    Homework Statement (see figure) Three forms of capillaries are given, and the question is simple : which of these are physically possible? There are no data given (such as densities or dimensions of the capillaries), so it is just the form that is of importance here. The three cases...
  10. A

    Will there be a capillary rise of liquid in vaccume with gravitation present?

    if gravitation is present, will there be a capillary rise of liquid in vaccume?
  11. M

    Capillary Action- Rate/Temp- How would you analyze?

    Hi Folks - This started out as a simple experiment we could do for my daughter's science fair (9th grade). Now I am truly ashamed to admit that I don't really know the best way to analyze the reasonably good results of the experiment. The experiment was to measure the effect of fluid...
  12. A

    Surface tension, capillary action, viscous fluid

    I was having trouble with this problem. please let me know how to approach this. thanks. The density of ice is 920 kg/m3, and that of seawater is 1030 kg/m3. What fraction of the total volume of an iceberg is exposed?
  13. Loren Booda

    The heart's overcoming capillary viscosity

    The human heart is able to power viscous blood through ~100,000 miles of narrow capillaries in less than a minute. Do the capillaries themselves provide a substantial fraction of the needed impulse?
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