Regulation Of Kidney Function: Structure, Flow Chart, Regulation

Excretion

Excretion can be explained as a biological process of the elimination of waste products from an animal's body. This is a process that is geared toward the pursuance of homeostasis, protection from the accumulation of harmful substances, and the general smooth running of several physiological systems. In the human body, the major excretory organs include the kidneys, lungs, skin, and liver.

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This Story also Contains

1. Excretion
2. Kidney
3. Control Of Kidney Function
4. Regulation Involving The Hypothalamus
5. Regulation Involving Juxtaglomerular Apparatus (JGA)
6. Recommended video on Regulation Of Kidney Function

Kidney

The kidneys are some of the most important organs of the body. They serve to filter all the blood to remove waste products and excess fluids, as well as maintain fluid and electrolyte balance and perform many other functions. Each kidney contains about one million functional units called nephrons; within the nephrons, the actual filtering process occurs along with secretion and reabsorption. Apart from that, kidneys also help in maintaining blood pressure and the number of red blood cells and control the body's acid-base status.

Control Of Kidney Function

The regulation of kidney function is a complicated process to ensure that the kidneys produce effective filtration of blood and also maintain the internal environment of the surroundings of the body. Mechanisms involved in this regulation are renal, neural, and hormonal, that is intrinsic renal processes.

Regulation Involving The Hypothalamus

This is a part of the brain that is involved in the functions regulating the kidney through the release of a set of different hormones. An important hormone in this system is Antidiuretic Hormone, more commonly known as vasopressin.

Antidiuretic Hormone (ADH)

The hypothalamus detects changes in blood osmolarity and, in high osmolarity conditions, releases ADH from the posterior pituitary. It increases water reabsorption in the kidney, reducing urine output and returning blood osmolarity to normal by dilution.

Regulation Involving Juxtaglomerular Apparatus (JGA)

The juxtaglomerular apparatus is, therefore, the structure in the kidney critical in increasing blood pressure and filtration rate. It is mainly composed of juxtaglomerular cells, the macula densa, and extraglomerular mesangial cells.

Renin-Angiotensin-Aldosterone System (RAAS)

In response to the decrease in blood pressure, the juxtaglomerular cells secrete the enzyme renin, which will give rise to a renin-angiotensin-aldosterone cascade. Angiotensin II is a strong vasoconstrictor and mediates the release of aldosterone from the adrenal cortex. Aldosterone increases the reabsorption of sodium, and its reabsorption increases water reabsorption, which will then increase the blood.

Tubuloglomerular Feedback

The macula densa cells of JGA can sense the alteration in the concentration of sodium chloride in the filtrate. In the event of a decreased concentration of Na+, the macula densa can cause juxtaglomerular cells to secrete renin the enzyme in circulation, which alters the level of filtration and reabsorption in Na+.

Conclusion

Control of renal function is complex and vital for maintaining a variety of mechanisms underpinning homeostasis and health in general. The kidneys occupy an incredibly central position in blood filtration or waste/fluid and electrolyte-balancing activity. Neural inputs, intrinsic-renal processes, and hormonal controls—for example, the hypothalamus and the juxtaglomerular apparatus—come together in determining the overall effective functioning of the kidneys. The hypothalamus does this through the release of an antidiuretic hormone, whereas the juxtaglomerular apparatus maintains the blood pressure through filtration rates via the renin-angiotensin-aldosterone system and tubuloglomerular feedback.

All these mechanisms ensure that appropriate responses to changes in blood pressure, osmolarity, and sodium levels occur in the kidneys en­suring homeostasis. Underlined in the mechanisms of regulation is renal physiology that works not just to contribute to overall health but to stress the other way around—the needs of lifestyle behaviours underpinning renal health itself. Save for a balanced diet, adequate hydration, sufficient exercise, and avoidance of taking known noxious substances should also be a routine in life to keep up renal functions and avoid their associated diseases.

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