Additional Questions - Chapter 8 Excretion 11th Biology Zoology Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Additional Questions & Answers
I. Multiple Choice Questions
Choose The Correct Answer
Question 1.
The elimination of requires large amount of water.
(a) Urea
(b) Uric acid
(c) Ammonia
(d) creatinine
Answer:

(c) ammonia
Question 2.
Reptiles, birds, land snails and insects excrete
(a) Ammonia
(b) Urea
(c) Uric
(d) purines
Answer:
(c) uric acid
Question 3.
Solenocytes are the specialized cells for excretion in
(a) Flatworms
(b) Molluscs
(c) Insects
(d) Amphioxus
Answer:
(d) amphioxus
Question 4.
Insects have for excretion.
(a) Flame cells
(b) Malphigian tubules
(c) Solenocytes
(d) Green glands
Answer:

(b) Malphigian tubules

Question 5.
have antennal glands or green glands which perform excretory function.
(a) Insects
(b) Annelids
(c) Crustaceans
(d) Flatworms
Answer:
(c) Crustaceans
Question 6.
Reptiles produce very little urine
(a) Hypotonic
(b) Hypertonic
(c) Isotonic
(d) None of the above
Answer:
(a) Hypotonic
Question 7.
Mammals have long Henle's loop, hence they produce urine.
(a) Hypotonic
(b) Hyperosmotic
(c) Isotonic
(d) None of the above
Answer:
(b) Hyperosmotic

Question 8.
Aglomerlar kidneys of marine fishes produce little urine that is to the body fluid.
(a) Hypotonic
(b) Hyperosmotic
(c) Isoosmotic
(d) None of the above
Answer:
(c) Isoosmotic
Question 9.
The external parietal layer of the Bowman's capsule is made up of simple epithelium.
(a) Columnar
(b) Ciliated
(c) Squamous
(d) Glandular
Answer:
(c) Squamous
Question 10.
The nitrogenous wastes are formed as a result of catabolism of
(a) Carbohydrates
(b) Proteins
(c) Fats
(d) Minerals

Answer:
(b) proteins
Question 11.
The net filtration pressure of is responsible for renal filtration.
(a) $15 \mathrm{mmHg}$
(b) $30 \mathrm{mmHg}$
(c) $55 \mathrm{mmHg}$
(d) $10 \mathrm{mmHg}$
Answer:
(d) $10 \mathrm{mmHg}$
Question 12.
Glucose, amino acids, $\mathrm{Na}+$ and water in the filtrate are reabsorbed in the
(a) descending limb of Henle's loop
(b) ascending limb of Henle's loop
(c) proximal convoluted tubule
(d) distal convoluted tubule
Answer:
(c) Proximal convoluted tubule
Question 13.
Defects in $\mathrm{ADH}$ receptors or inability to secrete ADH leads to a condition called
(a) diabetes mellitus
(b) diabetes insipidus
(c) Cushing's syndrome
(d) renal failure
Answer:
(b) diabetes insipidus
Question 14.
The process of release of urine from the bladder is called
(a) Ultra filtration
(b) Reabsorption
(c) Micturition

(d) Secretion
Answer:
(c) Micturition
Question 15.
The $\mathrm{pH}$ value of human urine is
(a) 7.5
(b) 6.0
(c) 4.3
(d) 9.5
Answer:
(a) 6.0
Question 16.
On an average, gm of urea is excreted per day.
(a) $10-15$
(b) $15-20$
(c) $40-50$
Answer:
(d) $25-30$
Question 17.
is characterised by increase in urea and other non-protein nitrogenous substances like uric acid and creatinine.
(a) Renal calculi
(b) Uremia
(c) Glomerulonephritis
(d) Renal failure
Answer:
(b) Uremia
Question 18.
The formation of hard stone like masses in the renal tubules of renal pelvis is called
(a) Uremia
(b) Micturition

(c) Renal calculi
(d) Renal failure
Answer:
(c) Renal calculi
Question 19.
The inflammation of the glomeruli of kidneys due to Streptococcus bacteria is called
(a) Renal failure
(b) Uremia
(c) Glomerulonephritis
(d) Renal calculi
Answer:
(c) Glomerulonephritis
Question 20.
Through haemodialysis, can be removed from the blood.
(a) Ketone bodies
(b) Glucose
(c) Amino acids
(d) Urea
Answer:
(d) Urea
Question 21.
The transfer of healthy kidney from one person to another person with kidney failure is called
(a) Kidney failure
(b) Haemodialysis
(c) Kidney transplantation
(d) Uremia
Answer:
(c) Kidney transplantation
II. Fill in the Blanks

..................... regulation is the control of tissues osmotic pressure which acts as a driving force for movement of water across biological membranes.
Answer:
Osmotic
Question 2.

........................ regulation is the control of the ionic composition of body fluids. Answer: lonic
Question 3

........................... . is the toxic nitrogenous end product of protein catabolism.
Answer:
Ammonia
Question 4.

......................... are able to change their internal osmotic concentration with change in external environment.
Answer:
Osmoconformers
Question 5

............................. maintain their internal osmotic concentration irrespective of their external osmotic environment.
Answer:
Osmoregulators
Question 6.
The ......................... animals can tolerate only narrow fluctuations in the salt concentration.
Answer:
stenohaline
Question 7.
The ..................... animals are able to tolerate wide fluctuations in the salt concentrations.

Answer:
euryhaline
Question 8.

........................ is the waste product of protein metabolism in spiders.
Answer:
Guanine
Question 9.

........................ requires large amount of water for its elimination.
Answer:
Ammonia
Question 10.

....................... is the least toxic waste product of protein metabolism.
Answer:
Uric acid
Question 11.
Animals that excrete ammonia are called .........................
Answer:
Ammonoteles
Question 12.
The animals that excrete uric acid crystals are called ..................
Answer:
Uricoteles
Question 13.
The animals that excrete urea are called .................
Answer: 
Ureoteles
Question 14.

......................... are the excretory structures in flatworms.
Answer:
Flame cells

Question 15.
Solenocytes are the excretory cells present in ......................
Answer:
Amphioxus
Question 16.

.................... are the excretory structures in insects.
Answer:
Malphigian tubules
Question 17.

..................... function excretory function in prawns.
Answer:
Antennal glands/ Green glands
Question 18.

....................... are the structural and functional unit of kidneys.
Answer:
Nephrons
Question 19.
The right kidney is placed slightly lower than the left kidney due to the presence of .................
Answer:
liver
Question 20.
The medulla of kidney is divided into a few conical tissue masses called ....................
Answer:
Renal pyramids
Question 21.
The urinary bladder opens into ............................
Answer:
Urethra

Question 22.
The Bowman's capsule and the glomerulus together constitute the .............
Answer:
Renal corpuscle
Question 23.
Some nephron have very long loop of Henle that run deep into the medulla and are called .............
Answer:
Juxta medullary nephrons
Question 24.
The nitrogenous waste formed as a result of breakdown of amino acids is converted to urea in the ................... Ornithine cycle.
Answer:
Liver
Question 25.
The filtration of blood that takes place in the ...............
Answer:
Glomerulus.
Question 26.
The fluid that leaves the glomerular capillaries and enters the Bowman's capsule is called the .......................
Answer:
Glomerular filtrate
Question 27.
Sodium is reabsorbed by .................... in the proximal convoluted Tubule.
Answer:
Active transport
Question 28.
Descending limb of Henle's loop is permeable to water due the presence of .......................

Answer:
Aquaporins
Question 29.
Reabsorption of ions regulates the $\mathrm{pH}$ of blood ...................
Answer:
Bicarbonate
Question 30.
........................ Is the hormone that facilitates reabsorption of water by increasing the number of aquaporins on the DCT and collecting duct.
Answer:
Antidiuretic hormone/ vasopressin
Question 31.
The under secretion of $\mathrm{ADH}$ leads to .................
Answer:
Diabetes insipidus
Question 32.
The granular cells of afferent arteriole secrete an enzyme called ....................
Answer:
Renin
Question 33.
Renin converts ................. into angiotensin.
Answer:
Angiotensinogen
Question 34.
Atrial Natriuretic Peptide or factor decreases release of ....................... thereby decreasing angiotensin II.
Answer:
Renin
Question 35.
The process of release of urine from the bladder is called ..................

Answer:
Micturition
Question 36.
The yellow colour of the urine is due to the presence of a pigment, ............
Answer:
Urochrome
Question 37.
The presence of ketone bodies in the urine is called ............
Answer:
Ketonuria
Question 38.
.............. is characterized by increase in urea and other non-protein nitrogenous substances like uric acid and creatinine in blood.
Answer:
Uremia
Question 39.
The formation of hard stone like masses in the renal tubules of renal pelvis is called ...............
Answer:
Renal calculi
Question 40.
Renal calculi is due to accumulation of soluble crystals of .....................and certain phosphates.
Answer:
Sodium oxalates
Question 41.
Renal stones can be removed by techniques like .................... or lithotripsy.
Answer:
Pyleothotomy

Question 42.
Inflammation of the glomeruli of both kidneys is known as .............
Answer:
Glomerulonephritis/ Bright's disease
Question 43.
haematuria, proteinuria, salt and water retention, oligouria, hypertension and pulmonary oedema are symptoms of ..................
Answer:
Glomerulonephritis/ Bright's disease ..................
Question 44.
The process of removing toxic urea from the person with kidney failure is called ............
Answer:
Haemodialysis
Question 45.

.....................  drugs are administered to the patient after kidney transplantation to avoid tissue rejection.
Answer:
Immunosuppressive
III. Answer The Following Questions
Question 1.
What is osmotic regulation?
Answer:
Osmotic regulation is the control of tissue osmotic pressure which acts as a driving force for movement of water across biological membranes.
Question 2.
What is ionic regulation?
Answer:
lonic regulation is the control of the ionic composition of body fluids.

Question 3.
Define excretion?
Answer:
The process by which the body gets rid of the nitrogenous waste products of protein metabolism is called excretion.
Question 4.
Distinguish between Osmoconformers and Osmoregulators?
Answer:

Question 5.
Distinguish between Stenohaline and Euryhaline animals?
Answer:

Question 6.
Name some nitrogenous waste product produced by various animals?
Answer:
Some of the nitrogenous wastes produced by various animals other than ammonia, urea and uric acid are:
Jrimethyl amine oxide (TMO) in marine teleosts, guanine in spiders, hippuric
acid in mammals, reptiles and other nitrogenous wastes include allantonin, allantoic acid, omithuric acid, creatinine, creatine, purines, pyramidines and pterines.
Question 7.
What are ammonotelic animals?
Answer:
Animals that excrete ammonia with excess of water are called ammonoteles. e.g., fishes, aquatic amphibians and aquatic insects.
Question 8.
What are the excretory organs of crustaceans?
Answer:
Antennal glands or green glands.
Question 9.
What is the difference between nephron present in reptiles and mammals?
Answer:
Reptiles have reduced glomerulus or lack glomerulus and Henle's loop.
Mammals have a long Henle's loop. Reptiles produce hypotonic urine whereas mammals produce hypertonic urine.

Question 10.
Explain the structure of human excretory system?
Answer:
1. Excretory system in human consists of a pair of kidneys, a pair of ureters, urinary bladder and urethra. Kidneys are reddish brown, bean shaped structures that lie in the lumbar region between the last thoracic and third lumber vertebra.
2. The right kidney is slightly lower than the left kidney. Each kidney weighs about 120-170 grams. The outer layer of the kidney is covered by three layers of supportive tissues namely, renal fascia, perirenal fat capsule and fibrous capsule.
3. The longitudinal section of kidney shows an outer cortex, inner medulla and pelvis. The medulla is divided into a few conical tissue masses called medullary pyramids or renal pyramids.
4. The part of cortex that extends in between the medullary pyramids is the renal columns of Bertini. The centre of the inner concave surface of the kidney has a notch called the renal hilum.
5. Through this ureter, blood vessels and nerves innervate. There is a broad funnel shaped space called the renal pelvis with projection called calyces.
6. The walls of the calyces, pelvis and ureter have smooth muscles. The calyces collect the urine and empties into the ureter. It is stored in the urinary bladder temporarily. The urinary bladder opens into the urethra through which urine is expelled out.

Question 11.
Explain the structure of Nephron?
Answer:
Each kidney has nearly one million tubular structures called nephrons. Each nephron consists of a filtering corpuscle called renal corpuscle or malphigian body and a renal tubule. The renal tubule opens into a longer tubule called the collecting duct. The renal corpuscle has a double walled cup shaped structure called the Bowman's capsule. It encloses a ball of capillaries called the glomerulus.
The Bowman's capsule and the Glomerulus together constitute the renal corpuscle. The endothelium of glomerulus has many pores called fenestrae.
The external parietal layer of the Bowman's capsule is made up of simple squamous epithelium. The visceral layer is made of epithelial cells called podocytes. The podocytes end in foot processes which cling to the basement membrane of the glomerulus. The openings between the foot processes are called filtration slits.

The renal tubule continues further to form the proximal convoluted tubule, Henle's loop and the distal convoluted tubule. The Henle's loop has a thin descending limb and a thick ascending limb.

The distal convoluted tubule of many nephrons open into a collecting duct. The proximal and the distal convoluted tubule are situated in the cortical region whereas the Henle's loop is situated in the medullary region of the kidney.

Question 12.
Explain the mechanism of urine formation in human?
Answer:
The nitrogenous waste formed as a result of breakdown of amino acids is converted to urea in the liver by the Ornithine cycle or urea cycle. Urine formation involves three main processes:
1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion
1. Glomerular Filtration:
Blood enters the kidney from the renal artery, into the glomerulus. The glomerular membrane has a large surface area and is more permeable to water and small molecules present in the blood plasma.

Blood enters the glomerulus faster with greater force through the afferent arteriole and leaves the glomerulus through the efferent arterioles, much
slower. This is because of the wider afferent arteriole and glomerular hydrostatic pressure which is around $55 \mathrm{~mm} \mathrm{Hg}$.
This is the chief force that pushes water and solutes out of the blood and across the filtration membrane. The pressure is much higher than in other capillary beds. The colloidal osmotic pressure $(30 \mathrm{~mm} \mathrm{Hg})$ and the capsular hydrostatic pressure $(15 \mathrm{~mm} \mathrm{Hg})$ are the opposing forces.

The net filtration pressure of $10 \mathrm{~mm} \mathrm{Hg}$ is responsible for the renal filtration. 

Net filtration pressure $=$ Glomerular hydrostatic pressure $-($ Colloidal osmotic pressure + Capsular hydrostatic pressure $)=55 \mathrm{~mm} \mathrm{Hg}-(30 \mathrm{~mm} \mathrm{Hg}+15 \mathrm{~mm}$ $\mathrm{Hg})=10 \mathrm{~mm} \mathrm{Hg}$.
The effective glomerular pressure of $10 \mathrm{~mm} \mathrm{Hg}$ results in ultrafiltration. The fluid that leaves the glomerular capillaries and enters the Bowman's capsule is called the glomerular filtrate.

It is similar to blood plasma except that there are no plasma proteins. Kidneys produce about $180 \mathrm{~L}$ of glomerular filtrate in 24 hours. It has water, glucose, amino acids and minerals along with urea and other nitrogenous waste.
2. Tubular Reabsorption:
The substances of glomerular filtrate are reabsorbed by the renal tubules as they are needed by the body. This process is called selective reabsorption.
In the Proximal Convoluted Tubule, glucose, lactate, amino acids, $\mathrm{Na}^{+}$and water are reabsorbed. Sodium is reabsorbed by active transport through sodium-potassium pump. The descending limb of Henle's loop is permeable to water due to the presence of aquaporins, but impermeable to salts.
Water is lost in this region and hence $\mathrm{Na}^{+}$and $\mathrm{Cl}^{-}$gets concentrated in the filtrate. In the ascending limb of Henle's loop, $\mathrm{Na}^{+}, \mathrm{Cl}^{-}$and $\mathrm{K}^{+}$are reabsorbed. This region is impermeable to water. The distal convoluted tubule reabsorbs water and secretes potassium into the tubule. $\mathrm{Na}+\mathrm{Cl}^{-}$and water remains in the filtrate. In the collecting duct, water and $\mathrm{Na}^{+}$are reabsorbed and $\mathrm{K}^{+}$is secreted.

3. Tubular secretion:
In this process, substances such as $\mathrm{H}_{+}, \mathrm{K}_{+}, \mathrm{NH}_{+}$, creatinine and organic acids move into the filtrate from the peritubular capillaries into the tubular fluid. Human produces $1.5 \mathrm{~L}$ of urine per day.

Question 13.
What is Diabetes insipidus?
Answer:
The defect in the production of ADH results in the excretion of large quantities
of dilute urine, this is called Diabetes insipidus. This results in the dehydration and fall in blood pressure.
Question 14.
What is Micturition?
Answer:
The process of release of urine from the bladder is called micturition or urination.
Question 15.
What is the nature of urine of human being?
Answer:
The urine formed is a yellow coloured watery fluid which is slightly acidic in nature $(\mathrm{pH} 6.0)$.
Question 16.
What is glucosuria and ketonuria?
Answer:
The presence of glucose in the urine is called glucosuria. The presence of ketone bodies in the urine is called ketonuria. These are the indications of Diabetes Mellitus.

Question 17.
Name the pigment present in the urine?
Answer:
The yellow colour of the urine is due to the presence of pigment urochrome.
Question 18.
Explain the excretory role of other organs?
Answer:
- Lungs: Lungs remove large quantities of carbon dioxide (18 L /day) and significant quantities of water.
- Liver: Liver secretes bile which contain bilirubin, biliverdin, cholesterol, steroid hormones, vitamins and drugs. These are excreted out along with the digestive wastes. .
- Skin: Sweat glands eliminate certain wastes like urea and lactate. Sebaceous glands eliminate sterols, hydrocarbons and waxes through serum.
- Saliva: Small quantities of nitrogenous wastes are excreted through saliva.
Question 19.
Explain the hormones regulating the kidney function?
Answer:
Antidiuretic hormone or Vasopressin, juxtaglomerular apparatus and atrial natriuretic factor regulate the kidney function. Antidiuretic hormone or Vasopressin When there is excessive loss of fluid from the body or when there is an increase in the blood pressure, the osmoreceptors of the hypothalamus stimulates the neurohypophysis to secrete the antidiuretic hormone or vasopressin.
It facilitates reabsorption of water by increasing the number of aquaporins on the cell surface membrane of the distal convoluted tubule and collecting duct.
When the water loss from the body is less or when you drink excess amount of juice, osmoreceptors stop secreting ADH and the aquaporins of the collecting ducts move into the cytoplasm. Hence dilute urine is produced to maintain the blood volume.
Renin angiotensin:
Juxtaglomerular apparatus (JGA) is a specialized tissue in the afferent arteriole of the nephron. It consists of macula densa and granular cells. The macula densa cells sense distal tubular flow and affect afferent arteriole diameter.
The granular cells secrete an enzyme called renin. A fall in glomerular blood flow, glomerular blood pressure and glomerular filtration rate, can activate JG cells to release renin.
This converts angiotensinogen into angiotensin-I. Angiotensin converting enzyme converts angiotensin-I to angiotensin- II. Angiotensin-II stimulates $\mathrm{Na}^{+}$reabsorption in the proximal convoluted tubule by vasoconstriction of the blood vessels and increases the glomerular blood pressure.
Angiotensin- II stimulate adrenal cortex to secrete aldosterone that causes reabsorption of $\mathrm{Na}^{+}, \mathrm{K}^{+}$excretion and absorption of water from the distal convoluted tubule and collecting duct. This increases the glomerular blood pressure and glomerular filtration rate. This complex mechanism is generally known as Renin-Angiotensin-Aldosterone System (RAAS).

Atrial natriuretic factor:
Excessive stretch of cardiac atrial cells cause an increase in blood flow to the atria of the heart and release Atrial Natriuretic Peptide or Factor (ANF). It
travels to the kidney where it increases $\mathrm{Na}^{+}$excretion and increases the blood flow to the glomerulus, acting as vasodilator on the afferent glomerular arterioles and as a vasoconstrictor on efferent arterioles.
It decreases aldosterone release from the adrenal cortex and decreases release of renin, thereby decreasing angiotensin-II. ANF acts antagonistically to the renin-angiotensin system, aldosterone and vasopressin.
Question 20.
Write a short note on urinary tract infection?
Answer:
Female's urethra is very short and its external opening is close to the anal opening, hence improper toilet habits can easily carry faecal bacteria into the urethra. The urethral mucosa is continuous with the urinary tract and the inflammation of the urethra (urethritis) can ascend the tract to cause bladder inflammation (cystitis) or even renal inflammation (pyelitis or pyelonephritis).
Symptoms include dysuria (painful urination), urinary urgency, fever and sometimes cloudy or blood tinged urine. When the kidneys are inflammed, back pain and severe headache often occur. Most urinary tract infections can be treated by antibiotics.
Question 21.
Write a short note on Renal Failure or Kidney Failure?

Answer:
Failure of the kidneys to excrete wastes may lead to accumulation of urea with marked reduction in the urine output. Renal failure are of two types, acute and chronic renal failure.
In acute renal failure the kidney stops its function abruptly, but there are chances for recovery of kidney functions. In chronic renal failure there is a progressive loss of function of the nephrons which gradually decreases the function of kidneys.
Question 22.
Write a short note on Uremia?
Answer:
Uremia is characterized by increase in urea and other non-protein nitrogenous substances like uric acid and creatinine in blood. Normal urea level in human blood is about $17-30 \mathrm{mg} / 100 \mathrm{~mL}$ of blood. The urea concentration rises as 10 times of normal levels during chronic renal failure.
Question 23.
Write a short note on Renal calculi?
Answer:
Renal calculi, also called renal stone or nephrolithiasis, is the formation of hard stone like masses in the renal tubules of renal pelvis. It is mainly due to the accumulation of soluble crystals of salts of sodium oxalates and certain phosphates. This result in severe pain called "renal colic pain" and can cause scars in the kidneys. Renal stones can be removed by techniques like pyleothotomy or lithotripsy.

Question 24.
Write a short note on Glomerulonephritis?
Answer:
Glomerulonephritis is also called Bright's disease and is characterized by inflammation of the glomeruli of both kidneys and is usually due to poststreptococcal infection that occurs in children. Symptoms are haematuria, proteinuria, salt and water retention, oligouria, hypertension and pulmonary oedema.
Question 25.
Write a short note on Haemodialysis?
Answer:
Malfunction of the kidneys can lead to accumulation of urea and other toxic substances, leading to kidney failure. In such patients toxic urea can be removed from the blood by a process called haemodialysis. A dialyzing machine or an artificial kidney is connected to the patient's body. A dialyzing machine consists of a long cellulose tube surrounded by the dialysing fluid in a water bath.

The patient's blood is drawn from a convenient artery and pumped into the dialysing unit after adding an anticoagulant like heparin. The tiny pores in the
dialysis tube allows small molecules such as glucose, salts and urea to enter into the water bath, whereas blood cells and protein molecules do not enter these pores.

This stage is similar to the filtration process in the glomerulus. The dialysing liquid in the water bath consists of solution of salt and sugar in correct proportion in order to prevent loss of glucose and essential salts from the blood. The cleared blood is then pumped back to the body through a vein.
Question 26.
Write a short note on Kidney Transplantation?
Answer:
Kidney Transplantation is the ultimate method for correction of acute renal failures. This involves transfer of healthy kidney from one person (donor) to another person with kidney failure.
The donated kidney may be taken from a healthy person who is declared brain dead or from sibling or close relatives to minimise the chances of rejection by the immune system of the host. Immunosuppressive drugs are usually administered to the patient to avoid tissue rejection.