filtration

(noun)

In bulk flow, this refers to the movement of proteins or other large molecules from the blood into the interstitium.

Related Terms

Examples of filtration in the following topics:

  • Glomerular Filtration

    • Glomerular filtration is the renal process whereby fluid in the blood is filtered across the capillaries of the glomerulus.
    • Glomerular filtration is the first step in urine formation and constitutes the basic physiologic function of the kidneys.
    • The positively charged podocytes will impede the filtration of negatively charged particles as well (such as albumins).
    • The process by which glomerular filtration occurs is called renal ultrafiltration.
    • These factors will influence the glomeruluar filtration rate, along with a few other factors.

  • Bulk Flow: Filtration and Reabsorption

    • Capillary fluid movement occurs as a result of diffusion (colloid osmotic pressure), transcytosis, and filtration.
    • The movement of materials across the capillary wall is dependent on pressure and is bidirectional depending on the net filtration pressure derived from the four Starling forces.
    • When moving from the bloodstream into the interstitium, bulk flow is termed filtration, which is favored by blood hydrostatic pressure and interstitial fluid oncotic pressure.
    • This indicates that capillaries are normally in a state of filtration along their entire length.

  • Kidney Function and Physiology

    • Second, the renal tubules collect the filtrate.
    • There is no energy requirement at this stage of the filtration process.
    • Glomerular filtration rate (GFR) is the volume of glomerular filtrate formed per minute by the kidneys.
    • It tends to absorb water from the renal tubule and concentrate the filtrate.
    • Further up, Na+ is actively transported out of the filtrate and Cl- follows.

  • Overview of Urine Formation

    • Urine is a waste byproduct formed from excess water and metabolic waste molecules during the process of renal system filtration.
    • Urine formation occurs during three processes: filtration, reabsorption, and secretion.
    • These filterable components accumulate in the glomerulus to form the glomerular filtrate.
    • Normally, about 20% of the total blood pumped by the heart each minute will enter the kidneys to undergo filtration; this is called the filtration fraction.
    • The end product of all these processes is urine, which is essentially a collection of substances that has not been reabsorbed during glomerular filtration or tubular reabsorbtion.

  • Filtration

    • Some studies have shown that prions can be removed or reduced by filtration.
    • The filtration equipment and the filters may be purchased as pre-sterilized disposable units in sealed packaging, or must be sterilized by the user, generally by autoclaving at a temperature that does not damage the fragile filter membranes.

  • Flame Cells of Planaria and Nephridia of Worms

    • Flame cells and nephridia remove the waste from bodies through filtration in a manner similar to a kidney.
    • The filtrate is secreted through these pores.
    • Flame cells function like a kidney, removing waste materials through filtration.
    • The cilia propel waste matter down the tubules and out of the body through excretory pores that open on the body surface; cilia also draw water from the interstitial fluid, allowing for filtration.

  • Regulation of Glomerular Filtration Rate

    • Glomerular filtration rate (GFR) is the measure that describes the total amount of filtrate formed by all the renal corpuscles in both kidneys per minute.
    • The glomerular filtration rate is directly proportional to the pressure gradient in the glomerulus, so changes in pressure will change GFR. 
    • Osmotic pressure is the force exerted by proteins and works against filtration because the proteins draw water in.
    • GFR is the rate at which is this filtration occurs.
    • List the conditions that can affect the glomerular filtration rate (GFR) in kidneys and the manner of its regulation

  • Tubular Reabsorption

    • As the fluid filtered from blood, called filtrate, passes through the nephron, much of the filtrate and its contents are reabsorbed into the body.
    • As filtrate passes through the nephron, its osmolarity (ion concentration) changes as ions and water are reabsorbed.
    • The filtrate entering the proximal convoluted tubule is 300 mOsm/L, which is the same osmolarity as normal plasma osmolarity.
    • In the proximal convoluted tubules, all the glucose in the filtrate is reabsorbed, along with an equal concentration of ions and water (through cotransport), so that the filtrate is still 300 mOsm/L as it leaves the tubule.
    • The filtrate osmolarity drops to 1200 mOsm/L as water leaves through the descending loop of henle, which is impermeable to ions.

  • Glomerular Diseases

    • The Bowman's capsule empties the filtrate into a tubule that is also part of the nephron.
    • A glomerulus and its surrounding Bowman's capsule constitute a renal corpuscle, the basic filtration unit of the kidney.
    • The glomerular filtration rate (GFR) is the rate at which blood is filtered through all of the glomeruli, and, thus, the measure of the overall renal function.

  • Wastewater and Sewage Treatment

    • Wastewater is treated in 3 phases: primary (solid removal), secondary (bacterial decomposition), and tertiary (extra filtration).
    • Sand filtration, where water is passed through a sand filter, can be used to remove particulate matter.