vascular recruitment

Examples of vascular recruitment in the following topics:

• Blood Flow in Skeletal Muscle

  • This vascular recruitment increases the capillary surface area within a muscle, allowing for enhanced oxygen exchange with the muscle fibers, prolonging the period of aerobic respiration and thus muscle output, and facilitating a more rapid removal of inhibitory waster factors such as lactic acid, reducing fatigue.

• Inflammation

  • Inflammation is part of the biological response of vascular tissues to harmful stimuli.
  • Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, injury or trauma, and irritants.
  • The next step of acute inflammation is an increase in vascular permeability due to inflammatory mediator activity, which causes the blood vessels to become more permeable.
  • Neutrophils are recruited to the site of inflammation by various cytokines.
  • Other inflammatory mediators, such as TNF-alpha and IL-1, increase the expression of adhesion molecules on vascular endothelial cells.

• Capillaries

  • During embryological development, new capillaries are formed by vasculogenesis, the process of blood vessel formation occurring by de novo production of endothelial cells and their formation into vascular tubes.
  • A capillary bed can consist of two types of vessels: true capillaries, which branch mainly from arterioles and provide exchange between cells and the circulation, and vascular shunts, short vessels that directly connect arterioles and venules at opposite ends of the bed, allowing for bypass.
  • When heart rate increases and more blood must flow through the lungs, capillaries are recruited and are distended to make room for increased blood flow while resistance decreases.

• Angiogenesis and Disease

  • Bone marrow cell recruitment also participates in tumor angiogenesis .
  • Diverse chemoattractant factors promote the recruitment and infiltration of bone marrow cells to the tumor microenvironment where they suppress the antitumor immunity or promote tumor angiogenesis and vasculogenesis
  • As malignancy develops, cells progress from a prevascular stage (normal to early hyperplasia) to a vascular stage (late hyperplasia to dysplasia to invasive carcinoma).

• Vascular Spasm

  • The vasoconstriction response is triggered by factors such as a direct injury to vascular smooth muscle, signaling molecules released by injured endothelial cells and activated platelets (such as thromboxane A2), and nervous system reflexes initiated by local pain receptors.
  • Vascular spasm is much more effective at slowing the flow of blood in smaller blood vessels.
  • During inflammation, vasodilation occur, along with increased vascular permeability and leukocyte chemotaxis, ending the spasm of vasoconstriction and hemostasis as wound healing begins.

• Nerve and Blood Supply

  • Synovial joints are highly innervated but vascularized indirectly by nearby tissues.
  • Numerous vessels from this plexus pierce the fibrous capsule and form a rich vascular plexus in the deeper part of the synovial membrane.

• Arrangement of Fascicles

  • Key muscle groups and the associated vascular and nervous systems can also be separated from other tissue, such as in the upper arm.
  • Each individual fiber within a fascicle is surrounded by a thin connective layer termed the endomysium, which helps maintain close association between the muscle fiber and associated vascular and nervous systems.
  • It also maintains the close association of the vascular and nervous system with the muscle, which is required to deliver necessary metabolites and nerve impulses.

• Ischium

  • Two indentations run parallel to the spine—superiorly ,the greater sciatic notch and, inferiorly, the lesser sciatic notch, through which key nervous and vascular vessels pass.
  • Dorsally, the ramus contributes to the obturator foramen, a large opening in the pelvis through which key nervous and vascular vessels pass.

• Supply of Blood and Nerves to Bone

  • The vascular supply of long bones depends on several points of inflow, which feed complex sinusoidal networks within the bone.
  • The blood supply of the immature bones is similar, but the epiphysis is a discrete vascular zone separated from the metaphysis by the growth plate.
  • Young periosteum is more vascular, has more metaphyseal branches, and its vessels communicate more freely with those of the shaft than adult periosteum .

• Short-Term Neural Control

  • The autonomic nervous system plays a critical role in the regulation of vascular homeostasis.
  • The primary regulatory sites include the cardiovascular centers in the brain that control both cardiac and vascular functions.
  • Vascular baroreceptors are found primarily in sinuses (small cavities) within the aorta and carotid arteries.