Editorial The Mechanism of Afferent Arterioles

Takashi OITE INTRODUCTION a well-organized rete mirabile. This rete is responsible for osmotic separation of the inner medulla from the rest of the kidney, allowing hypertonic urine to be excreted when necessary. Since the rete also isolates the inner medulla The efferent arterioles are blood vessels found in organisms' urinary from gaseous exchange, any metabolism there is anaerobic, and red cells, tracts. Efferent (from Latin ex + ferre) means "outgoing," in this case which would be useless there, are normally shunted from the arteriolae recti referring to the process of transporting blood away from the glomerulus. into the capillary plexus covering the tubules of the outer zone of the The efferent arterioles link the glomerulus's capillaries and transport blood medulla by an unknown mechanism. away from the glomerulus's already-filtered blood. They are crucial in Blood in this plexus and returning from the inner medulla passes through preserving the glomerular filtration rate through blood pressure pathways identical to those that drain the rest of the cortex, eventually fluctuations. reaching the renal vein and the general circulation. As the renin– They take two distinct paths in the mammalian kidney, depending on the angiotensin–aldosterone system is activated, angiotensin II levels rise, position of the glomeruli from which they emerge. causing most of the body's arteries to constrict in order to maintain a healthy blood pressure. This, on the other hand, limits blood supply to the Juxtamedullary glomeruli are glomeruli that are located on the border kidneys. In addition to elevated levels of angiotensin II, the efferent between the renal cortex and the renal medulla in the mammalian kidney. arterioles constrict more than the other arteries to compensate. As a result, The remaining cortical glomeruli are undifferentiated cortical glomeruli. the pressure in glomerular capillaries is preserved, and the glomerular The undifferentiated cortical glomeruli's efferent arterioles are the most filtration rate is sufficient. complicated. They split up into capillaries as soon as they leave the The colloid oncotic pressure of the capillaries will increase in states where glomerulus and become part of a rich plexus of vessels that surrounds the angiotensin II is very high for a long time, counteracting the increased cortical portions of the renal tubules. hydrostatic pressure from the efferent constriction. Depending on the degree of oncotic increase in the capillaries, this will lower the glomerular Efferent Arteriole Study filtration rate, resulting in a lower filtration fraction. The efferent arterioles The efferent arterioles of the juxtamedullary glomeruli are very distinct. By connect the capillaries of the glomerulus and move blood away from the interspersing themselves in a highly repetitive pattern among the descending already-filtered blood. They are important for maintaining the glomerular arteriolae recti, vessels returning from the inner medulla (venulae recti) form filtration rate during blood pressure changes.

Professor, Faculty of Medical Technology, Department of Clinical Engineering and Medical Technology, Niigata University of Health and Welfare, Niigata City, Japan. Correspondence: Takashi Oite, Professor, Faculty of Medical Technology, Department of Clinical Engineering and Medical Technology, Niigata University of Health and Welfare, Niigata City, Japan. Email: [email protected]

Received date: May 22, 2021; Accepted date: May 24, 2021; Published date: May 29, 2021

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Clin Nephrol Res Vol.5 No.3 2021 1