All questions of Excretory System for Grade 9 Exam

The functional structural unit of the kidney is the nephron.

The nephron is the microscopic structural and functional unit of the kidney. It is responsible for the filtration, reabsorption, and secretion of various substances to maintain the body's fluid and electrolyte balance. Each kidney contains millions of nephrons, which work together to perform the vital functions of the kidney.

Components of a nephron:
A nephron consists of several distinct components, each playing a crucial role in the overall function of the kidney. These components include:

1. Renal corpuscle: It is the initial structure of the nephron and is composed of the glomerulus and Bowman's capsule. The glomerulus is a network of tiny blood vessels called capillaries, which function to filter the blood. Bowman's capsule surrounds the glomerulus and collects the filtrate.

2. Proximal convoluted tubule (PCT): After the filtrate is collected in Bowman's capsule, it enters the PCT. This section of the nephron is responsible for reabsorbing most of the filtered water, ions, and nutrients back into the bloodstream.

3. Loop of Henle: The PCT leads into the loop of Henle, which consists of a descending and ascending limb. The loop of Henle plays a crucial role in concentrating the urine by creating a concentration gradient in the surrounding tissue.

4. Distal convoluted tubule (DCT): After passing through the loop of Henle, the filtrate enters the DCT. This section of the nephron is responsible for fine-tuning the reabsorption and secretion of specific ions, such as sodium and potassium.

5. Collecting duct: The DCT leads into the collecting duct, which is responsible for further reabsorption of water and concentration of urine. Multiple nephrons drain into a single collecting duct, which eventually leads to the renal pelvis and out of the kidney.

Functions of the nephron:
The nephron performs several essential functions to maintain homeostasis in the body. These functions include:

1. Filtration: The glomerulus filters the blood, allowing small molecules like water, ions, and waste products to pass through into Bowman's capsule. This process is known as glomerular filtration.

2. Reabsorption: The PCT reabsorbs most of the filtered water, ions, and nutrients back into the bloodstream. This helps maintain the body's fluid balance and prevents excessive loss of valuable substances.

3. Secretion: The DCT is responsible for the secretion of certain substances, such as hydrogen ions and drugs, into the filtrate. This process helps regulate the body's pH and eliminate waste products.

4. Concentration of urine: The loop of Henle and collecting duct play a crucial role in concentrating the urine. By creating a concentration gradient in the surrounding tissue, water can be reabsorbed from the filtrate, resulting in the production of concentrated urine.

In conclusion, the nephron is the functional structural unit of the kidney. It performs the essential functions of filtration, reabsorption, and secretion to maintain the body's fluid and electrolyte balance.

All parts of nephron other than loop of henle lie in the cortex of kidney but the loop of henle lie in medulla of kidney

Bowman's capsule is lined by 'simple squamous epithelium'..option B

Ureter opens into urinary bladder and bladder opens into the urethra.

Visceral peritoneum. a continuation of the parietal peritoneum reflected at various places over the viscera, forming a complete covering for the stomach, spleen, liver, intestines from the distal duodenum to the upper end of the rectum, uterus, and ovaries; it also partially covers some other abdominal organs.

False statement: Renin-Zymogen

Explanation:
• Nephron-Excretion: Nephron is the functional unit of the kidney which removes waste products from the body in the form of urine. Hence, this statement is true.
• Alveoli-Respiration: Alveoli are the tiny air sacs present in the lungs where exchange of gases (oxygen and carbon dioxide) takes place during respiration. Hence, this statement is true.
• Kidney-osmoregulation: The kidneys regulate the water balance in the body by filtering excess water and salts from the blood and excreting them in the form of urine. Hence, this statement is true.
• Renin-Zymogen: Renin is an enzyme secreted by the kidneys that plays a role in regulating blood pressure by converting angiotensinogen (a plasma protein) into angiotensin I. It is not a zymogen (inactive precursor of an enzyme). Hence, this statement is false.

Therefore, the false statement is option D - Renin-Zymogen.

The nephron plus the collecting tubule and collecting duct makes the uriniferous tubule (anatomofunctional unit of the kidney).The uriniferous tubule consists of the nephron and the collecting ducts.The nephron consists of the renal corpuscle(glomerulus and the Bowman’s capsule), proximal convoluted tubules, loop of henle(thick, thin and thick portions) and the distal convoluted tubule.so we can't say nephron is also known as Uriniferous tubules

Answer is option.A

Malpighian corpuscles are a number of small, round, deep-red bodies in the cortex of the kidney, each communicating with a renal tubule. Malpighian corpuscles average about 0.2 mm in diameter. Each capsule is composed of two parts: a central glomerulus and a glomerular capsule or Bowman's capsule. The corpuscles are part of a filtering system through which nonprotein components of blood plasma enter the tubules for urinary excretion.

Most kidney stones are calcium stones, usually in the form of calcium oxalate, phosphate, or maleate. Urinary sulfate is a reflection of dietary protein intake, particularly meat, fish, and poultry, which are rich in sulfur-containing amino acids methionine and cysteine. Urinary sulfate can be used to assess dietary protein intake for nutritional purposes. A protein-rich diet has been associated with an increased risk for stone formation. Some patients form stones that are composed of a mixture of magnesium, ammonium, phosphate, and calcium carbonate, which is known as struvite. These stones form as a result of infection with certain types of bacteria that can produce ammonia.CORRECT OPTION IS (D).

Mammals is ureolatic so urea is produced.

Kidney, with renal papilla labeled at upper right. The renal papilla is the location where the renal pyramids in the medulla empty urine into the minor calyx in the kidney. Histologically it is marked by medullary collecting ducts converging to form a papillary duct to channel the fluid.

Renal cortex, renal medulla and pelvis all are the parts of kideny. so ans. is all of the above.

When we do any hard physical activity then body losses more salts in the form of sweat and for that excretion of salts water is required. so workers loss more than normal quantity of water therefore they suffer from dehydration...

Loop of Henle. The Loop of Henle (LoH) is a long, straight, tubular segment connecting the proximal tubule to the distal convoluted tubule and lies parallel to the collecting ducts. The LoH descends from the cortex or medulla (depending on the size/length of the nephron) into the papilla of the kidney.

This fissure is a hilum that transmits the vessels, nerves, and ureter. From anterior to posterior, the renal vein exits, the renal artery enters, and the renal pelvis exits the kidney.

Afferent arterioles has more diameter than efferent. and that's why there is generation of filtration pressure.

The inner lining of the urinary bladder is a mucous membrane of transitional epithelium that is continuous with that in the ureters. ... The second layer in the walls is the submucosa, which supports the mucous membrane. It is composed of connective tissue with elastic fibers.

The minor calyces surround the apex of the renal pyramids. Urine formed in the kidney passes through a renal papilla at the apex into the minor calyx; two or three minor calyces converge to form a major calyx, through which urine passes before continuing through the renal pelvis into the ureter.

In the kidney, the loop of Henle (or Henle's loop, Henle loop, nephron loop or its Latin counterpart ansa nephroni) is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule.

Answer:

Introduction:
The position and arrangement of the kidneys in the human body can vary slightly from person to person. In most cases, the right kidney is slightly lower than the left kidney. This is due to the presence of the liver on the right side of the body. The liver takes up space and can prevent the right kidney from ascending to the same level as the left kidney during embryonic development.

Explanation:

1. Embryonic Development:
During embryonic development, the kidneys form in the pelvis and gradually ascend to their final position in the upper abdomen. The ascent of the kidneys occurs due to the rapid growth of other organs and structures in the abdomen. However, the presence of the liver on the right side can hinder the ascent of the right kidney, causing it to be slightly lower than the left kidney.

2. Liver's Position:
The liver is a large organ located on the right side of the abdomen. It occupies a significant amount of space and can restrict the upward movement of the right kidney. As a result, the right kidney typically remains at a slightly lower level than the left kidney.

3. Impact of Liver on Kidney Ascent:
The liver exerts pressure on the right kidney, preventing it from ascending to the same level as the left kidney. This pressure can alter the position and orientation of the right kidney. However, it is important to note that the difference in position between the two kidneys is generally minimal and does not cause any significant functional or anatomical issues.

Conclusion:
In conclusion, the right kidney is typically at a slightly lower level than the left kidney in humans due to the presence of the liver on the right side of the body. The liver occupies space and hinders the ascent of the right kidney during embryonic development. This anatomical variation is normal and does not usually cause any health concerns.

Osmoregulators

Osmoregulators are animals that have the ability to regulate their body osmolarity, or the concentration of solutes in their body fluids, despite changes in the external environment. This is in contrast to osmoconformers, which are animals that allow their body osmolarity to vary with the surrounding environment.

Key Points:
- Osmoregulators can maintain a relatively stable internal osmolarity even when faced with changes in the osmolarity of their environment.
- This ability is crucial for osmoregulators to survive and function optimally in different habitats.
- Osmoregulators can actively regulate the concentration of solutes and water in their body fluids to maintain homeostasis.
- They have specialized organs and systems that are involved in the regulation of osmolarity.
- Osmoregulators can excrete excess solutes or retain essential solutes depending on their needs.

Explanation:

Osmoregulators are able to maintain a relatively constant internal osmolarity, regardless of the osmolarity of their external environment. This is important because changes in osmolarity can have significant impacts on cellular function and overall homeostasis. Osmoregulation allows animals to adapt and survive in a wide range of environments, including freshwater, saltwater, and terrestrial habitats.

Specialized Organs and Systems:

Osmoregulators have specialized organs and systems that are involved in maintaining osmolarity. These include:

1. Kidneys: The kidneys are responsible for filtering the blood and regulating the concentration of solutes and water in the body. They can excrete excess solutes and conserve essential solutes depending on the animal's needs.

2. Gills: Aquatic osmoregulators, such as fish, have gills that are involved in the exchange of gases and ions. They can actively transport ions across their gills to maintain osmotic balance.

3. Malpighian tubules: Insects and other terrestrial arthropods have Malpighian tubules, which are involved in the excretion of waste products and the regulation of osmolarity.

4. Skin: Some animals, such as amphibians, can absorb water and ions through their skin. They also have specialized skin cells that can actively transport ions to maintain osmotic balance.

Conclusion:

In conclusion, osmoregulators are animals that have the ability to regulate their body osmolarity despite changes in the external environment. They have specialized organs and systems that allow them to actively regulate the concentration of solutes and water in their body fluids. This ability to maintain homeostasis is crucial for their survival and optimal functioning in different habitats.

Bowman's cup

Uriniferous tubule also known as nephron , and nephron is functional unit of kidney

also, uriniferous u can relate word with urine , and the formation of urine is function of kidney .

hence option (D) is correct

Vasa rectae is the extention of peritubular capillaries while both of them arise from efferent artetioles . peritubular capillaries are confidence to cortex reagion will VASA RECTAE dipps into medullary reagion along with loop of henle and help in counter current mechanism .