Adv.biom15 Review

Erythropoiesis specifically refers to the process of producing red blood cells, not the breakdown of red blood cells, movement of white blood cells, or generation of platelets.

Renal blood flow rate refers to the rate at which blood flows through the kidneys, usually measured in liters per minute. It is an important parameter in understanding kidney function.

Filtrate refers to blood plasma without proteins that is filtered out in the nephrons of the kidneys during the process of urine formation.

The glomerular filtration rate refers to the rate at which filtrate is produced in glomerular filtration, typically around 125 mL per minute.

Tubular maximum refers to the maximum rate of reabsorption by active transport through the nephron tubules, not the other options provided.

A buffer system is specifically related to chemistry and refers to a solution that can resist changes in pH by neutralizing small amounts of added acid or base.

The incorrect answers provided do not correspond to the structures typically found in the urinary system. The gallbladder, pancreas, and spleen are not part of the urinary system anatomy.

Stratified transitional epithelium is specifically found in the urinary bladder to allow it to stretch and accommodate varying levels of urine.

The urinary system is responsible for specific functions related to urine production, storage, and release, as well as maintaining proper pH levels, blood pressure, and other processes unrelated to digestion, body temperature, or saliva production.

The correct answer draws a parallel between the process of cleaning a desk drawer and urine formation, stating that both involve filtering out unnecessary components to retain what is essential. The three incorrect answers fail to establish a connection between the analogy and urine formation, leading to their dismissal.

The correct answers are based on the anatomy and physiology of the nephron in the kidney. The proximal tubule and descending limbs of the loop of Henle are always permeable to water due to the presence of aquaporin channels. The ascending limb of the loop of Henle does not allow water reabsorption. The distal tubule and collecting duct's permeability to water is regulated by ADH levels in the body.

A high GFR is primarily determined by the high permeability of the glomerular capillaries allowing for filtration and the high glomerular capillary pressure that drives the filtration process. Factors such as kidney size, urine production, electrolyte concentration, hydration level, length of renal tubules, and number of nephrons do not directly assure a high GFR.

The correct answer explains the relationship between GCP, capsular pressure, and colloid osmotic pressure leading to renal shutdown when GCP decreases by 7 mmHg. The incorrect answers provide different incorrect explanations to test understanding of the concepts.

In this question, the correct answer explains the general requirements for active reabsorption of substances along with the exception of protein. The incorrect answers provide plausible but inaccurate statements regarding the requirements and exceptions in substance reabsorption.

Water is the main substance that is passively reabsorbed in the kidney to maintain proper fluid balance, while urea is another prime example that gets reabsorbed. Sodium and potassium are actively reabsorbed. Glucose and protein usually get filtered out and should not reabsorbed. Calcium and phosphate also undergo active reabsorption and regulation.

If the reabsorption T-max is high, it means that a lot of the substance is actively reabsorbed, leading to a lower amount being excreted in the urine.

When a substance is secreted by the nephron, it means it is being actively removed from the blood and added to the urine, leading to a decrease in concentration in the blood.

In the proximal tubule, filtration occurs where small molecules are filtered out of the blood and into the tubule. This initial filtrate is similar in solute concentration to blood plasma before reabsorption and secretion processes take place further along the nephron.

In the lower portion of the descending limb of the loop of Henle, water leaves the nephron, leading to a higher concentration of solutes in the filtrate compared to blood plasma.

At the bottom of the loop of Henle, due to the reabsorption of water, the filtrate becomes more concentrated with solutes compared to blood plasma. This concentration gradient is essential for the kidneys to regulate water balance and osmolarity in the body.

As the filtrate moves up the ascending limb of the loop of Henle, solutes are actively pumped out, leading to a lower concentration compared to plasma where the balance shifts towards a higher concentration. This concentration gradient facilitates the reabsorption of water and allows the nephron to regulate the body's overall solute levels.

The correct answer highlights the distinction between automatic and conscious control in the urinary system.

The juxtaglomerular cells are specialized cells in the kidney that are responsible for monitoring blood pressure and sodium levels in the blood and initiating mechanisms to correct any significant changes. The other options do not accurately describe the specific cells involved in this regulatory process.

The correct answer is aldosterone because it is the hormone affected by the juxtaglomerular cells. Renin, angiotensinogen, and angiotensin I are not hormones, although angiotensin II does stimulate the release of aldosterone.