CHSE Odisha Class 11 Biology Solutions Chapter 19 Excretory Products and Their Elimination

Odisha State Board CHSE Odisha Class 11 Biology Solutions Chapter 19 Excretory Products and Their Elimination Textbook Questions and Answers.

CHSE Odisha 11th Class Biology Chapter 19 Question Answer Excretory Products and Their Elimination

Excretory Products and Their Elimination Class 11 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Multiple Choices Questions

Question 1.
The organs of excretion in the cockroach are
(a) Flame cells
(b) Green gland
(c) Nephridia
(d) Malpighian tubules
Answer:
(d) Malpighian tubules

Question 2.
Birds eliminate their nitrogenous wastes in the form of
(a) ammonia
(b) urea
(c) uric acid
(d) amino acids
Answer:
(c) uric acid

Question 3.
Ornithine cycle occurs in
(a) liver
(b) kidney
(c) brain
(d) skin
Answer:
(a) liver

Question 4.
Ornithine cycles synthesises
(a) ammonia
(b) urea
(c) uric acid
(d) xanthine
Answer:
(b) urea

Question 5.
What is the main nitrogenous waste product in reptile?
(a) ammonia
(b) urea
(c) uric acid
(d) hippuric acid
Answer:
(c) uric acid

Question 6.
Urea is formed from the breakdown of
(a) carbohydrates
(b) proteins
(c) fats
(d) nucleic acids
Answer:
(b) proteins

Question 7.
In man, uric acid is formed from the break down of
(a) carbonydrates
(b) proteins
(c) fats
(d) nucleic acids
Answer:
(d) nucleic acids

Question 8.
Desert mammals have in their nephrons.
(a) long loops of Henle
(b) long proximal convoluted tubules
(c) long distal convolutions
(d) long collecting ducts
Answer:
(a) long loops of Henle

Question 9.
ADH exercises its action on part of the nephron.
(a) PCT
(b) Henle’s loop
(c) DCT
(d) glomerulus
Answer:
(c) DCT

Question 10.
Most aquatic animals are
(a) ammonotelic
(b) ureotelic
(c) ureotelic
(d) aminotelic
Answer:
(a) ammonotelic

Question 11.
What is diabetes insipidus due to?
(a) loss of glucose by the urine
(b) deficiency of ADH
(c) deficiency of insulin
(d) All of the above
Answer:
(b) deficiency of ADH

Question 12.
Which hormone is secreted from juxtaglomerular apparatus of kidney?
(a) renin
(b) angiotensin
(c) adrenalin
(d) calcitrol
Answer:
(a) renin

Question 13.
Reabsorption of sodium and chloride occurs in
(a) Ascending limb of Henle’s loop
(b) Proximal convoluted tubule
(c) Descending limb of Henle’s loop
(d) Distal convoluted tubule
Answer:
(b) Proximal convoluted tubule

Question 14.
Human kidney is
(a) pronephric
(b) mesonephric
(c) metanephric
(d) opisthonephric
Answer:
(b) mesonephric

Question 15.
Longer loop of Henle is meant primarily for increased absorption of
(a) glucose
(b) water
(c) potassium
(d) amino acids
Answer:
(b) water

Short Answer Type Questions

Write briefly on the following (within 50 words each)

Question1.
Ammonotelism
Answer:
Ammonia is the most toxic form of nitrogenous waste, it requires large amount of water for its elimination. The organisms that excrete ammonia are called ammonotelic and this process of eliminating ammonia is known as ammonotelism. Examples of ammonotelic animals are bony fishes, aquatic amphibians and aquatic insects. Since, ammonia, is readily soluble in water and is generally excreted by diffusion across body surfaces or through gill surfaces (in fish) as ammonium ions the ammonotelism is commonly found in aquatic animals.

Question 2.
Ureotelism
Answer:
The process of excreting urea is called ureotelism. Animals, which do not live in high abundance of water convert ammonia produced in the body into urea (in the liver) and release it into the blood, which is filtered and excreted out as urine by the kidneys.
Examples of ureotelic animals are mammals, many terrestrial amphibians and marine fishes.

Question 3.
Uricotelism
Answer:
The process of excreting uric acid is called uricotelism. Uric acid, being the least toxic nitrogenous waste can be removed with a minimum loss of water from the animal body.
Thus, it is excreted in the form of pellet or paste (i.e., semisolid form). Normally, the animals which live in desert exhibit uricotelism.
Examples of uricotelic animals are reptiles, birds, land snails and insects.

Question 4.
Role of the Malpighian tubule in the excretion in cockroach.
Answer:
Malpighian tubules are principle excretory organs of a cockroach. These tubules consists of two distinct regions, i. e. the distal half (secretory) and the proximal portion (absorptive in function).
The distal region is alkaline, concerned with the secretion of urates of potassium and sodium extracted from the surrounding haemolymph.
The proximal region is acidic due to CO₂ secretion.
The uric acid is therefore precipitated while sodium and potassium Eire reabsorbed as bicarbonates to be used again. The urine passes to ileum, excreted via rectum along with the faeces where excess water is absorbed from them.

Question 5.
Structure of the mammalian nephron
Answer:
The LS of a mammalian kidney shows differentiation into outer cortex and inner medulla.

LS of kidney

Inside the kidney, the ureter is expanded as a funnel-shaped cavity called pelvis. The free end of pelvis has number of cup-like cavities called major calyces (sing, calyx) and minor calyces.
Medulla projects into the calyces as conical processes, called renal pyramids or medullary pyramids. The tip of pyramids are called renal papillae. The cortex spreads in between medullary pyramids as renal columns called columns of Bertini.

Microscopic Structure
Each kidney is composed of numerous (nearly one million) complex tubular structures called nephrons. These are the functional units of kidney.
Structure of Nephron or Uriniferous Tubule
Each nephron consists of two parts, i.e., the Malpighian body or renal corpuscle and the renal tubule.
(i) Malpighian Body or Renal Corpuscle Glomerulus along with Bowman’s capsule is called the Malpighian body or renal corpuscle which filters out large solutes from the blood and delivers small solutes to the renal tubule for modification.

Malpighian body (renal corpuscle)

Question 6.
Ultrafiltration
Answer:
Ultrafiltration or Glomerular Filtration
The first step of urine formation is the filtration of blood. It is carried out by the glomerulus. That is why this step is called glomerular filtration.
Kidneys filter about 1100-1200 mL of blood per minute, which constitute roughly 1/5th of the blood pumped out by each ventricle of the heart in a minute.
The glomerular capillary blood pressure causes filtration of blood through three layers, i.e.,
(i) the endothelium of glomerular blood vessels.
(ii) the epithelium of Bowman’s capsule.
(iii) a basement membrane (present between the above mentioned two layers).
The podocytes (epithelial cells of Bowman’s capsule) are arranged in such a manner, so that some minute spaces called filtration slits or slit pores occur between them.

Diagram representing the path taken by fluid (glomerular filtrate) during its passage from the plasma in a glomerular capillary of the lumen of a renal capsule

Question 7.
Selective reabsorption
Answer:
2. Selective Reabsorption
This is the second step in the formation of urine from filtrate. The urine released is 1.5 L as compared to the volume of the filtrate formed per day (180 L). It suggests that as much as 99% of the material in the filtrate is reabsorbed by the renal tubules. Thus, the process is called reabsorption. Depending upon the types of molecules being reabsorbed, movements into and out of epithelial cells in different segments of nephron occur either by passive transport or active transport.
These are described as follows
(i) Water and urea, are reabsorbed by passive transport (i.e., water is reabsorbed by osmosis and urea by simple diffusion).
(ii) Glucose and amino acids are reabsorbed by activi transport.
(iii) The reabsorption of Na⁺, occurs both by passive and active transport.

Question 8.
Henle’s loop
Answer:
(ii) Henle’s Loop
Reabsorption in Henle’s loop is minimum, besides this, it plays an important role in maintaining the high osmolarity of medullary interstitial fluid. Two portions of Henle’s loop, play different role in osmoregulation. These are as follows
1. Descending Limb of Loop of Henle Water is reabsorbed here due to increasing osmolarity of interstitial fluid but, sodium and other electrolytes are not reabsorbed here. This concentrates the filtrate as it moves down.

2. Ascending Limb of Loop of Henle This segment is impermeable to water, but permeable to K⁺,Cl^– and Na⁺ and partially permeable to urea. Thus, in the thick ascending limb of the loop of Henle Na⁺, K⁺, Mg²⁺ and Cl are reabsorbed.
Therefore, as the concentrated filtrate pass upward, it gets diluted due to the passing out of electrolytes to the medullary fluid of kidney

Question 9.
Counter current mechanism
Answer:
Kidney of higher vertebrates (such as mammals, birds and man) has the ability of absorbing more and more water from tubular fdtrate to conserve water and make the urine more concentrated.
This can be achieved by a special mechanism known as counter current mechanism. The basic concept and this mechanism is as follows

Question 10.
Kidney as an endocrine organ
Answer:
Kidney as an endocrine glands The mammalian kidney performs many endocrine functions in the body. The kidney produces three hormones, i.e.
(a) Erythropoietin a peptide hormone which controls erythrocyte production in the body.
(b) Calcitriol the final activation of vitamin-D to active hormone calcitriol occurs in the kidneys.
(c) Renin is the part of the Renin-Angiotensin- Aldosterone System (RAAS). It controls the formation of angiotensin that influences blood pressure and sodium balance in the body.
Kidneys also synthesise prostaglandins, which Eiffect many processes occuring in the kidneys.

Question 11.
Secretion
Answer:
It is also an important step in urine formation. Certain chemicals in the blood that are not removed by filtration . from the glomerular capillaries are removed by this process of tubular secretion.
Acid base
It helps in the maintenance of ionic and acid-base balance of body fluids by removing chemicals like foreign bodies, ions (K⁺ , H⁺ , NH⁺₄) and molecules (medicines), etc., that are toxic at elevated levels.

Question 12.
Acid-base balance
Answer:
Acid base
It helps in the maintenance of ionic and acid-base balance of body fluids by removing chemicals like foreign bodies, ions (K⁺ , H⁺ , NH⁺₄) and molecules (medicines), etc., that are toxic at elevated levels.

Question 13.
Role of liver in excretion
Answer:
Role of Liver:
It changes the decomposed haemoglobin of the worn out red blood corpuscles into bile pigments, i.e., bilirubin and biliverdin. These pigments pass into the alimentary canal with the bile for elimination in the faeces. The liver ‘ also excretes cholesterol, steroid hormones, certain vitamins and drugs via bile.

Liver deaminates the excess and unwanted amino acids, producing ammonia, which is quickly combined with C02 to form urea in urea cycle or Ornithine cycle, which is further removed by the kidneys.

Question 14.
Orinithine cycle/Urea cycle
Answer:
Urea formation occurs in the liver by urea cycle or Ornithine or Kreb’s-Henseleit cycle. The excess amino acids in the body undergoes deamination in the liver and forms ammonia. Being highly toxic, ammonia is immediately converted to the less toxic urea by urea cycle. Urea cycle involves three amino acids, i.e. ornithine, citrulline and arginine.

Steps
(a) Ornithine reacts with ammonia and C02 forming citrulline and water.
(b) Citrulline combines with more ammonia forming arginine and water.
(c) Arginine then transforms into urea and ornithine in presence of enzyme arginase water.

Question 15.
Dialysis
Answer:
When the kidneys can no longer excrete water and ions at rates that maintain body balance of these substances nor they can excrete the wastes as fast as they are produces a technique called dialysis is used to cure kidney failure haemodialysis is carried out in which blood is filtered. Dialysis means separation of substances using a semi or a selectively permeable membrane.

Question 16.
Storage excretion in cockroach
Answer:
In cockroach, urate cells are found. These cells absorb and store uric acid throughout the life. This is called storage excretion as they remain stored in the cells of corpora adipose.

Question 17.
Renin-angiotensin system
Answer:
As blood pressure/glomerular blood flow /GFR decreases, the cells of the JGA release the enzyme renin.
Renin converts angiotensinogen in blood to Angiotensin I and Angiotensin II (active form). This mechanism is generally known as the Renin-angiotensin mechanism. Renin is the rate limiting factor in this system.

Summary of the renin angiotension aldosterone system

Question 18.
Obligatory water loss
Answer:
The minimal amount of fluid loss that can occur from the living body is known as the obligatory water loss.
Human kidney have the ability to produce a hyperosmotic urine that enables the body to survive without water for a long period. The human kidneys can produce a maximal urine concentration of 1400 m osmol/L., approx, five times the osmolarity of the blood plasma; which is 300 m osmol/L. Urea, sulfate, phosphate and other waste products and ions excreted each day amount to approximately 600 m osmol/L. The minimum volume of water in which the above quantity of solute can be dissolved and excreted in the urine is
= \(\frac{600 \mathrm{~m} \mathrm{Osmol} / \text { day }}{1400 \mathrm{~m} \mathrm{Osmol} / \mathrm{L}}\)
= 0.444 L/day
This volume of urine is referred to the ‘obligatory water loss’. The loss of this minimal volume of urine contributes to dehydration when a person goes without water for a long period.

G Explain the Following

Question 19.
Net filtration pressure
Answer:
Net Alteration pressure It is the pressure that helps to move filterate from the glomerulus into Bowman’s capsule. It is a combination of glomerular hydrostatic pressure, capsular hydrostatic pressure and osmotic colloid pressure.

Question 20.
Glomerular filtration rate
Answer:
Glomerular Filtration Rate:
The amount of the filtrate formed by the kidneys per minute is called Glomerular Filtration Rate (GFR). In a healthy person it was found approximately 125 mL /min, i. e., 180 L/day. GFR is regulated by one of the efficient mechanism carried out by Juxtaglomerular Apparatus (JGA).
JGA is a special sensitive region formed by cellular modifications in the distal convoluted tubule and the afferent arteriole at the location of their contact.
This apparatus includes
(i) granular juxtaglomerular cells in the afferent arteriole.
(ii) macula densa cells of DCT.
(iii) agranular lacis cells situated in between the above two.

Question 21.
Obligatory reabsorption of water
Answer:
Obligatory reabsorption of water Eighty five percent of the water reabsorption occurs irrespective of the body water balance and is called obligatory reabsorption of water. It takes place in proximal and distal tubules.

Question 22.
Role of ADH in water reabsorption
Answer:
Excessive loss of fluid from the body activates osmoreceptors present in blood vessels of hypothalamus, thus stimulating it to release ADH or vasopressin from the neurohypophysis. ADH release increases water reabsorption from DCT. An increase in body fluid volume switches off the osmoreceptors and suppresses the ADH release to complete the feedback. ADH also causes constrictory effects on blood vessels of glomerulus thus, increasing pressure for faster filtration.

Question 23.
Obligatory water loss
Answer:
The minimal amount of fluid loss that can occur from the living body is known as the obligatory water loss.
Human kidney have the ability to produce a hyperosmotic urine that enables the body to survive without water for a long period. The human kidneys can produce a maximal urine concentration of 1400 m osmol/L., approx, five times the osmolarity of the blood plasma; which is 300 m osmol/L. Urea, sulfate, phosphate and other waste products and ions excreted each day amount to approximately 600 m osmol/L. The minimum volume of water in which the above quantity of solute can be dissolved and excreted in the urine is
= \(\frac{600 \mathrm{~m} \mathrm{Osmol} / \text { day }}{1400 \mathrm{~m} \mathrm{Osmol} / \mathrm{L}}\)
= 0.444 L/day
This volume of urine is referred to the ‘obligatory water loss’. The loss of this minimal volume of urine contributes to dehydration when a person goes without water for a long period.

Question 24.
Functions of vasa recta
Answer:
Function of vasa recta
(i) Vasa recta plays an important role in counter-current mechanism.
(ii) Vasa recta also regulates the blood flow in kidney.