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.

View More On Wikipedia.org
Recent contents Top users
  1. A

    Capillary action meniscus height in a tube fitted inside another tube?

    Hello, I was thinking about how would capillary action change in a tube (classic example) and in a tube fitted inside another tube (considering water as the liquid involved). This is no homework question, it's just a thought which striked my mind but I don't have sufficient basic knowledge...
  2. R

    What is the flow rate through a capillary tube?

    Hi, I was wondering if there was an equation for the flow rate through a straight vertical or angled capillary tube. All I can find is how to calculate the height it rises but I would like to know how to find the rate it rises. I imagine it is not a steady rate since it must stop once it...
  3. M

    How to Calculate the Length of a Capillary Tube for a Drip-Irrigation Emitter

    Homework Statement A drip-irrigation emitter constructed of a coiled capillary tube is inserted into the wall of a drip irrigation line with a constant water pressure of 5 psi. Compute the required length of the emitter’s capillary tube to produce an emitter dripping rate of 2 litres per...
  4. F

    Explanation for Capillary Force

    Homework Statement Could some one help me understand capillary Force?Homework Equations The Attempt at a Solution If we use a capillary tube sticking in a water cup as an example. The phenomenon will be water level is higher in the capillary tube than that in the water cup. I understand that...
  5. Y

    Can capillary action lift water to 10 meters?

    Is it feasible to achieve elavation of water to, let's say, 10 m height due to the capillary action effect ? Or the capillary diameter for that to achieve should be less than the water molecules themselves ?
  6. D

    Energy production mechanism using capillary action

    We know that water rises in a glass capillary owing to the surface tension phenomenon. If we make an arrangement as shown in the attachment, (read Water instead of mercury in the attachment, I got confused there) & do the following procedure. The valve at the bottom is open, & the one at the top...
  7. Rugile

    Surface tension and capillary tube

    Homework Statement A capillary tube of radius r = 0.3mm is filled with water. A water droplet is hanging on the bottom of the tube, as shown in the picture. The water level is h = 5.2cm. Estimate the radius of curvature of the droplet R. The coefficient of surface tension of water is σ =...
  8. L

    Capillary Action: Comparing B vs D

    How is B more correct than D? Both show that forces between glass and fluid are stronger than those between fluid molecules. Thank you for any insight!
  9. T

    Capillary action with elemental Selenium

    Greetings PFers. I'm designing an experiment that needs to take elemental selenium gas at 500K at 120 PSI to a liquid form at any temp and pressure. I would like to use capillary tubes in conjunction with a pump to convert the gas to a liquid. However, I'm having difficulty finding...
  10. Saitama

    Surface tension - liquid rising in capillary tube

    Homework Statement Homework Equations The Attempt at a Solution Honestly, I don't have any idea on this. As far as I remember, the usual practice is to equate the excess pressure equal to ##2T/R## (where T is the surface tension and R is the radius of curvature, this may be wrong...
  11. V

    Calculate Capillary Depression of Mercury in Glass Tube

    Homework Statement Given the following information, derive and expression to calculate the capillary depression of mercury in a glass tube given that: Contact angle = 140 degrees Surface tension 'Gamma' = 0.476 Nm^-1 Tube diameter = 1.0mm Density of mercury 'rho' = 13.58x10^3 kgm^-3...
  12. N

    Volume Injected into Capillary

    Homework Statement So for an experiment, we injected a small volume of fluid into a capillary (76 micrometer diameter) through a pressure difference and I'm trying to calculate exactly how much was injected. diameter of capillary = 76e-6 m height one end was raised above the other = 5.334 cm...
  13. E

    Capillary Action and Young-Laplace

    Hello all. This is my first post and I wasn't exactly sure where to put it, so I apologize if it could be in a better place. Ok... here is my issue. I am currently enrolled in a Surfaces/Interfaces course. Capillary action eludes me. I do not understand WHY capillary action occurs in...
  14. W

    Rise and fall of capillary action

    Assume that I have capillary of radius 0.08 cm. I want to test this capillary for capillary rise action. Formula will be T=hrgρ/2cosθ what will be the rise for water.. ( please tell me the calculated value) And, what will be the fall in mercury. ( How to show it negative as its...
  15. W

    Want to know effect of differnet material on capillary action

    Hey, I need to know the effect ( capillary rise) due to different materials on capillary action. Also, what is the reason behind it, not so complex, just in simple language. It will be more good if I'll get the practical and calculated values of height in capillary tube of different...
  16. K

    Water not flow out of capillary

    Why does water, in a small glass tube,open at both sides(for example) not flow out if we put it in vertical position and put our finger on the top?(we close it)?
  17. H

    Mechanics behind capillary depression.

    As the question states I have hard time understanding that how does a liquid reach equilibrium in case of capillary depression (mercury for example ). I know how it goes down but not how it 'stops'. like in case of liquids which have more force of adhesion ,as the liquid goes up because of...
  18. S

    Difference between Capillary Rise and Capillary Depression

    As the title states, can anyone help me understand what the difference between the two is? I've been trying to look everywhere but nothing really explains why they're different. I just thought it would be the same. This is based on the capillary rise method for surface tension.
  19. F

    Surface tension capillary rise method equation

    http://en.wikipedia.org/wiki/Surface_Tension Could someone help me solve the capillary rise method equation, with a worked example: y= hpgr/2 Thank you soo much
  20. M

    Can Branching Capillary Increase Water Height?

    Say I have a single capillary that can raise water to height H. If I split the capillary to make another meniscus, say δ distance from the top, and both branches are of the same radius as before, will I be able to bring water up higher (i.e. could I add another H-δ high column of water to the...
  21. 1

    Calculating Drop Size, Number and Time for Water Flow Through Capillary

    Homework Statement Trough a capillary with an inner radius r=1mm water flows in a form of small spherical droplets. What is the radius of the drops, the number of drops in m=10g water and the time needed the water to expire, if the surface tension of the water is =72x10^-3N/m, and the period...
  22. B

    Effect of temperature on capillary rise

    We all think that by increasing the temp of a liquid, the surface tension would reduce and so capillary rise will not be as high. But on increasing the temp, the liquid's density also decreases and so the weight of liquid to be lifted also reduces. Which will have the dominating effect, decrease...
  23. M

    Capillary Action: Exploring Very Thin Capillaries

    Considering very thin capillaries, such as found in wood to transport water (~100Micron), I understand that the two main factors in play are gravity and the adhesive forces between the water and the surface of the capillary tube. I understand that gravity is proportional to volume that is...
  24. Y

    Capillary Action and Paper Towel Physics

    Hey guys, I am a little confused with the concept of Capillary actions with specific regards to paper towels. I understand the mechanics behind a single capillary tube and the height that water reaches in relation to surface tension. However, my professor claims that paper towels absorb as...
  25. A

    What causes liquid to rise in a capillary tube?

    This question struck me when i was watching a liquid rise in a capillary tube. I'm curious to know from where the energy gets transferred to the liquid to rise above the surface. Well, one possible explanation that i can think of is air pressure. Though, it can be a possible reason only if the...
  26. C

    Air Trapped in Capillary Tubes: Understanding Pressure and Volume Changes

    Homework Statement Hey folks, here is a question: A thread of mercury of length 15cm is used to trap some air in a capillary tube with uniform cross-sectional area and closed at one end. With the tube vertical and the open end uppermost, the length of the trapped air collumn is 20cm...
  27. A

    Capillary Tube Rise: Does Water Reach Max Height & Stop?

    Does the water approach the maximum height in a capillary tube with 0 velocity?I mean to say that does it go to the maximum height and just stop or perform simple harmonic motion ?Water is in equilibrium but velocity need not be 0 or is it(why?).The expression we derive for h should be for...
  28. J

    Derivation of formula for capillary action

    the height upto which liquid rises in capillary tube is 2S cosθ / ρgR I need a derivation for this - please I know that a combination of adhesive force , surface tension and weight creates the contact angle θ but how to proceed after that? To calculate height h i need to know the force by...
  29. C

    Air Traped In A Capillary Tube

    Hey folks, here is a question: A thread of mercury of length 15cm is used to trap some air in a capillary tube with uniform cross-sectional area and closed at one end. With the tube vertical and the open end uppermost, the length of the trapped air collumn is 20cm. Calculate the length of the...
  30. M

    Using capillary action to raise water (Is perpetual flow possible?)

    I know there have been a number of posts relating to capillary action but after reading through them I cannot find an obvious answer to my query. Although capillary action can be used to explain the properties of 'wicking' materials that can raise water vertically I am unsure as to whether it is...
  31. M

    Finding Absolute Zero Experimentally: Investigating a Capillary Tube

    We were presented with a task of calculating the temperature of absolute zero experimentally. To do this, we were given a capillary tube with one end sealed. Then we heated the tube up in a bunsen burner and quickly put the open end in some cooking oil. The oil was sucked up as the gas within...
  32. W

    Pressure diffence between water column in capillary tube and open vessel

    Homework Statement It is known that water in a capillary will rise to a certain height, as shown in the figure. Comparing the points P and Q, which point exhibit larger pressure? a. P b. Q c. The pressure of P and Q are the same Homework Equations F_upward=2*pi*R*T*cos⁡θ W=pi*R^2*...
  33. N

    How Does Buoyant Force Influence Water Flow Through a Hole in a Sinking Bowl?

    Homework Statement so i have an to do an EEI for an assignment due this friday. My experiment involves me putting a rounded bowl with a flat bottom and a hole in the center on the bottom onto some still water and testing how the bowl sinks faster as weight is added to the bowl. The water comes...
  34. P

    How does capillary action not violate conservation of energy?

    I know that the law of conservation of energy is not violated by either complete destructive interference or capillary action, but I'm curious then what happens to the energy and where it comes from in these cases, since I can't figure it out. Consider the case of complete destructive...
  35. P

    What will happen to capillary rise effect if we take capillary to

    what will happen to capillary rise effect if we take capillary to space g=0?
  36. D

    Capillary Force in a V shaped tube

    Suppose we have a very small V shaped tube-like vessel that is closed at the bottom (see attached picture). Question 1: If a drop of liquid enters the vessel from the top, what determines the stopping point of the drop (i.e. at what point is the force of gravity countered and the drop...
  37. V

    Rise of Water in a 20 cm Capillary Tube

    hello :) Homework Statement (Q)A 20 cm long capillary tube is dipped in water.The water rises up to 8 cm . If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be <a>8 cm <b>6 cm <c>10 cm <d>20 cm Homework Equations...
  38. V

    What is the height of water in an inclined capillary tube?

    heya :D Homework Statement (Q)Water rises in a vertical capillary tube upto a length of 10 cm. If the tube is inclined at 45 degrees, the length of water risen in the tube will be <a>10 cm <b>10/(2)1/2 <c>10(2)1/2 <d>None of these Homework Equations Height raised in capillary, h =...
  39. M

    Can materials with different surface properties move without external forces?

    Ok, let's say you have a short cylinder (about a quarter inch tall and a three inch diameter) now take that cylinder and make one half of the circle hydrophilic and the other half hydrophobic (not the top one way and the bottom the other, I am talking about half the circle like how you would cut...
  40. R

    Help with Capillary Rise Equation for Differential Equations Class

    Hey guys, I have a problem in one of my classes where I need to make an equation of capillary rise in a strip of paper towel. I am given data points and I need to make an equation that fits the points. Can someone please help me through the physics and derivation behind this. I tried doing some...
  41. A

    Capillary action for non-polar substances?

    I thought I understood capillary action, but according to my understanding, non-polar substances shouldn't undergo capillary action. Today in lab, we were working with ether, which is non-polar, and I noticed it climbed up a paper towel. It was slower than water, but still... what intermolecular...
  42. Z

    Capillary Rise and Pressure in Sealed Capillary Tubes

    Will there be any difference in capillary rise if the capillary tube is sealed at one end? What is the value of pressure at a point in the capillary tube on the same horizontal level as that of liquid outside? - Is it equal to the atmospheric pressure + the height of liquid column above it?
  43. Z

    Capillary Tube and Surface Tension

    Homework Statement A glass capillary sealed at the upper end is of length 0.11m and internal diameter 2 x 10^-5 m. The tube is immersed vertically into a liquid of surface tension 5.06 x 10^-2 N/m. To what length has the capillary to be immersed so that the liquid level inside and outside...
  44. D

    Capillary Action: Exploring Questions & Origins

    I'm not too sure if this is the right board, but it seems the most apt, so here it goes: Question 1: If a column of water rises due to capillary action, its centre of mass must rise too, so where does the energy come from? Question 2: Regarding the origin of capillary action; most...
  45. S

    Capillary force when immersed in liquid

    Hi I have a question about the capillary force between two hydrophilic surfaces. I am working with small cantilevers (5-50 um long, 5 um wide, 200 nm thick). If L represents the lever, which is hydrophilic, and X represents some bulk material (also hydrophilic), a profile of the lever looks...
  46. S

    What is fenestrated capillary?

    Hello everyone, In fenestrated capillary there are holes inside the endothelial cell, I don't understand how cells can have holes? Does this mean that individual holes in endothelial cells are covered by a lipid membrane? Can anyone tell how can there be holes in an individual cells when...
  47. T

    Does Capillary Diameter Affect Flow Rate Stability in a Decreasing Vacuum?

    we vacate a cannister using a vacuum pump using a range from 200-900 mbar of vaccum. Will the flow rate remain constant as the vacuum decreases over 24 hrs or does it tail off at a given pressure, a capillary of diameter 0.102mm is used ?
  48. E

    Using capillary action to generate energy

    Hello. I've had this idea floating around in my head for a long time and lately it's really been bugging me. Say you had a tray of water, and suspended another tray above that, and then you connected the two trays vertically with some very thin tubes, say, 0.2mm in diameter. Now, due to...
  49. S

    How do blood cells pass through a capillary?

    Hello guys, A capillary is made up of a single layer of endothelial cells right. So when blood cells pass through it, do the endothelial cells take blood cells up by endocytosis and then release it to other side. How do capillaries take up nutrients, do the endothelial cells take it up...
  50. G

    Capturing paramagnetic beads in a capillary

    Hello, I'm a biologist trying to work out a technique using magnetic beads, so please bear with me if my understanding of magnetism isn't up to snuff. I use paramagnetic beads to capture cells, and I'd like to capture these beads under flow in a capillary and visualize them on a...
Back
Top