Explain the kidney function in human biology, Biology

Assignment Help:

Explain the Kidney Function in human biology?

Blood first enters the capillaries in Bowman's capsule where it is filtered. The pores in the capillary walls allow water and small molecules to pass through, but are too small to allow red blood cells and large protein molecules to pass. The process by which material is filtered into Bowman's capsule is not very selective, and some of these substances that are of value to the body need to be reclaimed. Material filtered through the capillary walls into Bowman's capsule flows along the renal tubules. The process by which material is returned to the blood through the walls of the tubules is called tubular reabsorption.

Sodium, potassium, calcium, other minerals, and glucose are returned by active transport. These substances then enter the capillaries by diffusion. Water is returned by osmosis mostly in the proximal convoluted tubule, following the movement of glucose. There is additional reabsorption of salts and nutrients from the distal convoluted tubule, but this section of tubule also removes wastes and other substances not originally filtered out by Bowman's capsule through a process called tubular secretion. The pH of the blood is adjusted by the secretion of hydrogen ions into the filtrate. Potassium ions, ammonia, and certain drugs are eliminated by secretion from the distal convoluted tubules.

The loops of Henle function to concentrate the filtrate by establishing an osmotic gradient in the extracellular fluid around the loops that will later pull water from the collecting ducts. The ascending limb of the loop pumps NaCl out by active transport, but the ions cannot diffuse back in because this portion of the loop is impermeable to water. Salts can diffuse into the descending limb, but these are pumped out again when they reach the ascending loop, increasing the extracellular ionic concentration. When the filtrate reaches the collecting ducts, its osmotic concentration is much lower than the extracellular fluid of the medulla, so it loses water by osmosis and becomes more concentrated. As much as 99% of the water that goes through the tubules and collecting ducts is returned to the blood.

 


Related Discussions:- Explain the kidney function in human biology

What are the amphibian features, Q What are the amphibian features that mak...

Q What are the amphibian features that make them dependent on water to survive? Permeable skinexternal fecundation, body subject to dehydration, larval stage and eggs without s

What are epithelial tissues, What are epithelial tissues? What are their ge...

What are epithelial tissues? What are their general function and how is that function associated to the features of the tissue? Epithelial tissues, also known as epithelia, are

Why is ph regulation important for living beings, Why is pH regulation impo...

Why is pH regulation important for living beings? How do mineral salts participate in this regulation? The potential of hydrogen (pH) is a measure of the amount of hydrogen ion

Explain in details class hirudenia - leeches, Explain in details Class Hiru...

Explain in details Class Hirudenia - Leeches? This group includes the leeches. Most leeches grow in tropical freshwater habitats, and are familiar to most people as bloodsucker

Explain risk factors for cad, Explain Risk Factors For CAD? As has been...

Explain Risk Factors For CAD? As has been noted, CAD is very common among the Indians and many studies have been undertaken to find out the reasons behind this predilection. Wh

Methods by which diseases are transmitted, There are several methods by whi...

There are several methods by which a disease-causing organism can be transferred from the reservoir to the host organism. Direct contact : Disease - causing organism may be tr

Snake bite, S n ake bite Biting by a poisonous snake is manifested by...

S n ake bite Biting by a poisonous snake is manifested by clinical findings of local swelling and nervous symptoms. E t iology: The poisonous snakes have different typ

What are the results of prosthetic valve endocarditis, What are the Results...

What are the Results of prosthetic valve endocarditis? The hospital mortality for valve replacement for endocarditis varies between 4- 30 per cent. Operative mortality is highe

Classification levels of blood pressure, Table gives the current classifica...

Table gives the current classification of hypertension as recommended by JNC VII. The classification is based on the mean of two or more seated readings on two or more occasions.

Cell Cycle. M-cdk , Cell cycle Urgent question?? please biology expert! it'...

Cell cycle Urgent question?? please biology expert! it''s for an exam? When M-Cdk gets attached to cyclin, it doesn''t just get activated. phosphate has to be added by an activatin

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd