venous pooling

Examples of venous pooling in the following topics:

• Venous Blood Pressure

  • Variants of venous pressure include:
  • Jugular venous pressure (JVP), the indirectly observed pressure over the venous system.
  • Portal venous pressure or the blood pressure in the portal vein.
  • Standing or sitting for a prolonged period of time can cause low venous return in the absence of the muscle pump, resulting in venous pooling (vascular) and shock.
  • Jet pilots wear pressurized suits to help maintain their venous return and blood pressure, since high-speed maneuvers increase venous pooling in the legs.

• Veins

  • Standing or sitting for prolonged periods can cause low venous return from venous pooling.
  • In venous pooling, the smooth muscles surrounding the veins become slack and the veins fill with the majority of the blood in the body, keeping blood away from the brain, which can cause unconsciousness.
  • Venous valves prevent back flow and ensure that blood flows in one direction.

• Blood Flow in Skeletal Muscle

  • The opposite effect would be seen if measuring venous outflow.
  • The skeletal muscles of the legs are particularly important skeletal muscle pumps as they prevent pooling of the blood in the feet and calves due to gravity.

• Development of Blood

  • When they proliferate, at least some of their daughter cells remain as HSCs, so the pool of stem cells does not become depleted.
  • The human arterial and venous systems develop from different embryonic areas.
  • While the arterial system develops mainly from the aortic arches, the venous system arises from three bilateral veins during weeks 4 to 8 of human development.

• Development of the Heart

  • The human arterial and venous systems develop from different embryonic areas.
  • While the arterial system develops mainly from the aortic arches, the venous system arises from three bilateral veins during weeks four through eight of human development.
  • The human venous system develops mainly from the vitelline veins, the umbilical veins, and the cardinal veins, all of which empty into the sinus venosus.

• Venules

  • In contrast to regular venules, high-endothelial venules (HEV) are specialized post-capillary venous swellings.

• Veins of the Head and Neck

  • Two main jugular veins are responsible for the venous draining of the head and neck.
  • The deep-lying internal jugular vein receives blood from the dural venous sinuses in the brain as well as the cerebral and cerebellar veins.

• Artery Function

  • The pressure in the arterial system decreases steadily, highest in the aorta and lowest in the venous system, as blood approaches the heart after delivery of oxygen to tissues in the systemic circulation.
  • Distinguish the function of the arterial system from that of venous system

• Motor Units

  • Groups of motor units are innervated to coordinate contraction of a whole muscle and generate appropriate movement; all of the motor units within a muscle are considered a motor pool.
  • There are often multiple sizes of motor unit within a motor pool as a means of modulating the precision and force produced by a single muscle.
  • These multiple motor units of different sizes within a motor pool allow for very fine control of force either spatially or temporally.

• Chambers of the Heart

  • One of the defining characteristics of the atria is that they do not impede venous flow into the heart.
  • Atria have four essential characteristics that cause them to promote continuous venous flow:
  • The venous blood entering the heart has a very low pressure compared to arterial blood, and valves would require venous blood pressure to build up over a long period of time to enter the atria.
  • The atrial contractions are slight, preventing significant back pressure that would impede venous flow.