Excretory Products and Their Elimination (VSAQs)
Zoology-2 | Unit-2B: Excretory Products and Their Elimination – VSAQs:
Welcome to VSAQs in Unit-2B: Excretory Products and Their Elimination. This page includes the most important FAQs from previous exams. Each answer is presented in the exam format to help you prepare effectively and aim for top marks in your final exams.
VSAQ-1: Name the Blood Vessels That Enter and Exit the Kidney
The renal artery is responsible for bringing oxygen-rich blood into the kidney, much like how a delivery truck brings fresh supplies to a warehouse. This artery supplies the kidney with the blood it needs to filter out waste and regulate various functions. On the flip side, the renal vein carries the now deoxygenated blood away from the kidney, similar to how a shipping truck takes away the processed goods from the warehouse.
VSAQ-2: What Are the Columns of Bertin?
The columns of Bertin, also known as renal columns, are like the walls between different sections of a warehouse. These projections of renal cortex extend between the renal pyramids within the kidney. They help to organize and support the structure of the kidney, ensuring that everything stays in place and functions efficiently, much like how these walls keep different parts of a warehouse distinct and functional.
VSAQ-3: Define Glomerular Filtration
Glomerular filtration is the first step in how your kidneys make urine. Imagine it as a fine sieve that separates useful items from waste. In this process, blood flows into the glomerulus (a network of tiny blood vessels), and through a filtration process, water and small molecules pass into Bowman’s capsule. Larger molecules, like proteins and cells, stay in the bloodstream. This filtration is crucial for removing waste and balancing the body’s fluids and electrolytes.
VSAQ-4: Define Glomerular Filtration Rate (GFR)
Glomerular filtration rate (GFR) measures how well your kidneys are working. It’s like checking how efficiently a factory produces goods. The GFR tells us how much blood is filtered by the kidneys per minute, usually around 125 mL. This rate is crucial because it helps assess kidney function by showing how well the kidneys are filtering out substances like glucose, sodium, and urea, ensuring they’re not overloaded or malfunctioning.
VSAQ-5: What Is the Juxtaglomerular Apparatus?
The juxtaglomerular apparatus (JGA) is a key regulatory component in the kidney, like the control panel of a factory. Located where the distal convoluted tubule meets the afferent arteriole near the glomerulus, it consists of two main parts: the macula densa and juxtaglomerular cells. The JGA monitors blood pressure and sodium levels and adjusts kidney function accordingly by releasing renin, which helps regulate blood pressure and fluid balance, ensuring the body’s internal environment remains stable.
VSAQ-6: Distinguish Between the Enzymes Renin and Rennin
Renin and rennin are different enzymes with distinct roles. Renin, produced in the kidneys, helps regulate blood pressure by converting angiotensinogen into angiotensin I, which eventually turns into angiotensin II. This helps manage blood pressure and fluid balance, much like a regulatory system in a factory that keeps production levels stable.
Rennin, on the other hand, is found in the stomach, especially in infants. It helps curdle milk protein (casein) into a semi-solid form, aiding in milk digestion. This enzyme is more relevant to infants, helping them digest their primary food source. Think of rennin as a tool specifically designed for breaking down a key ingredient in an infant’s diet.
VSAQ-7: Name the Structural and Functional Units of the Kidney. What Are the Two Main Types of Structural Units in It?
The nephron is the kidney’s fundamental unit, functioning like a complex filter and processing plant. Each kidney contains about a million nephrons, each consisting of two main parts: the renal corpuscle and the renal tubule. The renal corpuscle includes the glomerulus, where blood is filtered, and Bowman’s capsule, which collects the filtered fluid. The renal tubule processes this fluid further, reabsorbing useful substances and forming urine.
There are two main types of nephrons: cortical nephrons and juxtamedullary nephrons. Cortical nephrons are like the front-line workers in the kidney’s cortex, handling the bulk of blood filtration. Juxtamedullary nephrons, located closer to the medulla, are specialists that help concentrate urine and maintain water balance by extending deep into the medulla.
VSAQ-8: Distinguish Between Cortical and Juxtamedullary Nephrons
Cortical nephrons make up the majority of nephrons and are primarily located in the outer part of the kidney. They have shorter loops of Henle that barely dip into the medulla. Their main job is to filter blood and reabsorb necessary substances.
Juxtamedullary nephrons, making up about 20% of the nephrons, have long loops of Henle that extend deep into the medulla. They play a crucial role in concentrating urine and managing water balance, which is essential for maintaining the body’s hydration and electrolyte levels. These nephrons help create a concentration gradient in the medulla, similar to how certain systems in industries are designed to maintain specific conditions for optimal product quality.