Question

Glomerular Filtration 1. Blood entering the glomerulus contains blood cells, proteins, glucose, amino acids, salts, urea. wall and enter the filtrate. acids, salts, urea, and water to exit the blood and 2. Blood pressure causes small molecules of glucose, amino enter the glomerular capsule. The fluid in the glomerular capsule is called the filtrate. become part of the filtrate. 3. In the list that follows, draw an arrow from left to right for the small molecules that leave the glomerulus and Draw an artouw Glomerular (Filtrate) Glomerulus Cells Proteins Glucose Amino acids Urea Water and salts 4. Complete the second column in Table 16.4, page 220. Use an X to indicate that the substance is at the locations noted. Tubular Reabsorption When the filtrate enters the proximal convoluted tubule, it contains glucose, amino acids, urea, water, and salts. Some water and salts remain in the nephron, but enough are passively reabsorbed into the peritubular capillary to maintain blood volume and blood pressure. Use this information to state a way kidneys help maintain homeostasis 1. 2. The cells that line the proximal convoluted tubule are also engaged in active transport and usually completely reabsorb nutrients (glucose and amino acids) into the peritubular capillary. What would happen to cells if the body lost all its nutrients by way of the kidneys? 3. Which of the filtrate substances is reabsorbed the least and will become a part of urine? Urea is a nitrogenous waste. State here another way kidneys contribute to homeostasis. 4. In the list that follows, draw an arrow from left to right for all those molecules passively reabsorbed into the blood of the peritubular capillary. Use darker arrows for those that are normally reabsorbed completely by active transport. rraw Adive Peritubular Capillary Proximal Convoluted Tubule Water and salts Glucose Amino acids

Answer 1

Tubular re-absorption

1. Kidneys maintain the homeostasis of the body by either increasing or decreasing the rate of filtration. In case of  low blood volume the sodium level goes down so, it increase the peritubular capillary absorption to increase the the sodium and water level. This is actually triggered by an array of enzyme called renin angiotensin system released by kidney cell.

2. Nutrients are the building block of the body especially nutrients like glucose and amino acid. To make a body function both voluntarily and in voluntarily cells need energy or ATP which is obtained essentially from glucose. The amino acids are building blocks of protein such as enzymes which are integral part of different mechanisms like Glycogenesis,   Creb cycle, Fatty acid synthesis etc., carried out to sustain the life. Thus cells can't carry out the basic function and eventually dies.

3. Creatinine is the least absorbed filtrate.

Urea is the waste generated during breakdown of protein in liver which is carried to kidney for part re-absorption and eventual filtration. Basically kidney by filtering nitrogenous waste maintain a acid base balance.

4. Water & salts- active

Glucose- passive due to concentration gradient

Amino acid- passive

Urea- passive