peritubular capillaries

(noun)

Tiny blood vessels that travel alongside nephrons, allowing reabsorption and secretion between blood and the inner lumen of the nephron.

Related Terms

Examples of peritubular capillaries in the following topics:

  • Tubular Secretion

    • Hydrogen, creatinine, and drugs are removed from the blood and into the collecting duct through the peritubular capillary network.
    • Tubular secretion is the transfer of materials from peritubular capillaries to the renal tubular lumen; it is the opposite process of reabsorption.
    • Passive diffusion—the movement of molecules from the peritubular capillaries to the intersitial fluid within the nephron.

  • Kidney Function and Physiology

    • In the loop of Henle, the filtrate continues to exchange solutes and water with the renal medulla and the peritubular capillary network.
    • Finally, some substances, such as electrolytes and drugs, are removed from blood through the peritubular capillary network into the distal convoluted tubule or collecting duct.
    • Sodium (Na+) is the most abundant ion; most of it is reabsorbed by active transport and then transported to the peritubular capillaries.
    • Water is also independently reabsorbed into the peritubular capillaries due to the presence of aquaporins, or water channels, in the PCT.
    • This occurs due to the low blood pressure and high osmotic pressure in the peritubular capillaries.

  • Renal Clearance

    • Clearance is a function of glomerular filtration, secretion from the peritubular capillaries to the nephron, and reabsorption from the nephron back to the peritubular capillaries.

  • Bulk Flow: Filtration and Reabsorption

    • Bulk flow is used by small, lipid-insoluble solutes in water to cross the the capillary wall and is dependent on the physical characteristics of the capillary.
    • Continuous capillaries have a tight structure reducing bulk flow.
    • Fenestrated capillaries permit a larger amount of flow and discontinuous capillaries allow the largest amount of flow.
    • This indicates that capillaries are normally in a state of filtration along their entire length.
    • Blood continues to flow around the nephron until it reaches another capillary-rich region the peritubular capillaries, where the previously filtered molecules are reabsorbed from the tubule of the nephron.

  • Overview of Urine Formation

    • During secretion some substances±such as hydrogen ions, creatinine, and drugs—will be removed from the blood through the peritubular capillary network into the collecting duct.

  • Nephron, Parts, and Histology

    • The glomerulus is a capillary tuft that receives its blood supply from an afferent arteriole of the renal circulation.
    • Peritubular capillaries, 10.

  • Capillaries

    • Capillaries, the smallest blood vessels in the body, are part of the microcirculation.
    • Capillaries do not function independently.
    • The capillary bed is an interwoven network of capillaries that supplies an organ.
    • Sinusoidal - Sinusoidal capillaries are a special type of fenestrated capillaries that have larger openings (30-40 μm in diameter) in the endothelium.
    • Capillary beds may control blood flow via autoregulation.

  • Capillary Dynamics

    • Hydrostatic and osmotic pressure are opposing factors that drive capillary dynamics.
    • Capillary exchange refers to the exchange of material between the blood and tissues in the capillaries.
    • Hydrostatic pressure is the force generated by the pressure of fluid within or outside of capillary on the capillary wall.
    • However, because large plasma proteins, especially albumin, cannot easily cross through the capillary walls, their effect on the osmotic pressure of the capillary interiors will to some extent balance the tendency for fluid to leak from the capillaries.
    • Describe hydrostatic pressure and osmotic pressure, the factors of capillary dynamics

  • Lymphatic Capillaries

    • Lymphatic circulation begins in the smallest type of lymph vessels, the lymph capillaries.
    • Lymphatic capillaries are slightly larger in diameter than blood capillaries and contain flap-like "minivalves" that permit interstitial fluid to flow into them but not out, under normal conditions.
    • This opens the lymph capillaries more, increasing their volume and reducing their pressure to further facilitate fluid flow into the capillaries.
    • During inflammation, fluid leaks into the tissues at a rate faster than it can be removed by the lymph capillaries due to the increased permeability of cardiovascular capillaries.
    • The lymphatic capillaries bring lymph further into the lymphatic vessels.

  • Arterioles

    • An arteriole is a small diameter blood vessel in the microcirculation system that branches out from an artery and leads to capillaries.
    • An arteriole is a small-diameter blood vessel which forms part of the microcirculation that extends from an artery and leads to capillaries.
    • The microcirculation involves the flow of blood in the smallest blood vessels, including arterioles, capillaries, and venules.
    • This reduces the pressure and velocity of blood flow to enable gas and nutrient exchange to occur within the capillaries.
    • Arterioles are part of the microcirculation system, along with capillaries, arteries, veins, venules, and tissue cells.