Biology For Class X - Chapter No. 2 - Homeostasis - Review Exercise From Text Book

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CHAPTER 2: HOMEOSTASIS
Review Exercise From Text Book

By Mrs. Ayesha Arif
Vice Principal
(Jauhar Progressive School)

A. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:
i) The internal condition of an organism is referred as:
(a) Homeostasis
(b) Internal environment ✓
(c) Internal metabolism
(d) Feedback mechanism

ii) A set of metabolism reaction which maintain internal environment is:
(a) Positive feedback
(b) Negative feedback
(c) Osmoregulation
(d) Homeostasis ✓

iii) Removal of extra liquid water is:
(a) Exudation
(b) Guttation ✓
(c) Respiration
(d) Transpiration

iv) Plant grow near coastal area called:
(a) Xerophyte
(b) Halophyte ✓
(c) Epiphyte
(d) Hygrophyte

v) Organ of human body which is considered on the largest organ is:
(a) Skin ✓
(b) Digestive tract
(c) Liver
(d) Brain

vi) The maintenance of body temperature with in suitable limit is called
(a) Homeotherm
(b) Thermoregulation ✓
(c) Osmoregulation
(d) Heterotherm

vii) The kidney is enclosed in a membrane called
(a) Pericardium
(b) Peritoneum ✓
(c) Pleural membrane
(d) Plumule

viii) The network of blood capillaries present in the layer of skin:
(a) Epidermis
(b) Dermis ✓
(c) Hypodermis
(d) Endodermis

ix) Selective reabsorption in nephron takes place at
(a) Glomerulus
(b) Malpighian body
(c) Convulated tubules
(d) Loop of Henle's ✓

x) The hormone ADH release from
(a) Pituitary gland ✓
(b) Kidneys
(c) Liver
(d) Lungs

B. SHORT QUESTIONS ANSWERS
i) Why homeostasis is required?
Ans: Homeo means same and stasis means state. So Homeostasis is the regulatory mechanism which maintained the internal environment of an organism within suitable limits. It is required to maintain osmoregulation, thermoregulation and also excrete toxic waste from body.
Homeostasis is responsible to maintain optimal conditions for enzyme action throughout the body, as well as all cell functions despite changes in internal and external conditions.

ii) Why plants remove liquid water instead of water vapours?
Ans: The plants remove liquid water in the form of droplet instead of water vapours when there is high atmospheric humidity and less or no transpiration. This process is called guttation. It only occurs at night when water pressure is high in leaves and low temperature environment is present.

iii) How plant survive in Saltish water?
Ans: Some plants grow in sea marshes, oceans or in saltish water. In salty condition water moves outside the cell which is not suitable for plants. To survive in saltish water and to move water from outside to inside the plant develop the following characters.

1. They develop salt glands where they store salts by taking it through active transport.
2. Plants oppose salt to move outside from vacuole.
3. Some salt is accumulated at surface of leaf which attracts water from air.

iv) Why skin is considered as excretory organ?
Ans: Skin is considered as an excretory organ because it plays a very important role in excretion through the production of sweat by sweat glands. It excretes water, salt, and urea from the body through sweat. It is the largest organ of the body, which basically functions as a protective organ but it also works and acts as an excretory organ.

v) What type of structures are present in dermis to perform different functions?
Ans: Dermis is the layer present between epidermis and hypodermis, it contains many different structures. They are as follows:

1. Dermis has nerves ending receptors to detect temperature change, pain, pressure etc.
2. It also contains sweat glands which secrete sweat on the surface to maintain temperature and also secrete urea, water and salt.
3. A network of arterioles is also present in the form of network, which are involved in temperature regulation.
4. The dermis also contains hair follicle and sebaceous glands which secrete oily sebum.

vi) Draw a neat and labelled diagram of nephron.
Ans: NEPHRONS

OR

vii) What is kidney stone?
Ans: A kidney stone is a solid mass that forms from the crystals of calcium oxalate or Calcium Carbonate. Sometimes uric acid and cysteine are also present in it. These molecules separate from urine, precipitate in kidney and deposit in the form of stone. Sometimes these stones are not hard therefore they break into sand like crystals which can pass out of the body with urine without pain. The large size stone however damages the kidney tissues, they may stuck anywhere in urinary tract and cause renal failure with pain.

viii) How human skin maintains temperature in cold conditions?
Ans: The skin is the organ which helps in regulating body temperature. The receptors in skin send nerve impulse to brain in case of increase or decrease in temperature. In cold condition when the body temperature starts decreasing the skin maintains the temperature by following actions:

1. Erection of hairs:
   The muscles contract pulling the hairs upright and trapping a layer of insulating air next to skin.
   
   
2. Vasoconstraction:
   Narrowing of blood arterioles of dermis occur which reduces the blood flow in capillaries of skin so less heat is lost.
   
   
3. Decrease in sweat production:
   The sweat gland stops to produce and secrete sweat, in order to prevent energy loss.
   
   
4. Increase in metabolic rate:
   In cold conditions the rate of metabolism in the organs increases generating more heat which is distributed around the body in the blood stream. It prevents loss through the adipose tissue in hypodermis which work as an insulation layer.

ix) When dialysis is required?
Ans: The patients of kidney failure require dialysis when the donor is not available for kidney transplant. A dialysis machine performs the function of a kidney. It helps to clean the patient's blood from metabolic waste products and toxics. For effective treatment the patient needs to undergo dialysis 2 - 3 times a week. Each session lasts about 3-5 hours depending on the patient's body size and medical condition.

x) Why filtration at Para tabular capillaries called ultra filtration?
Ans: Filtration at Para tabular capillaries i.e. Malpighian tubules is referred to as Ultra filtration because most of the blood plasma is forced out of the glomerulus blood capillaries into Bowman's capsule without any selection. This is a Process of non-selective filtration. Blood is filtered very finely through all the membranes in such a way that all the components of blood passed except proteins.

C. EXTENSIVE RESPONSE QUESTIONS:
i) How skin works as thermoregulatory organ?
Skin Works As Thermoregulatory Organ:
The skin is the organ which help in regulating body temperature .when the receptors in skin detects change in body temperature from set point (set point of human is 37 ℃) i.e. increase or decrease, and then Receptor send nerve impulse to brain. It occurs by feedback mechanism to correct the temperature.

If Body Temperature Start Rise:

1. Production of sweat:
   The sweat gland starts to produce and secrete sweat. The sweat accumulates at the surface of skin and evaporates with heat energy so the body feeling cool.
   
   
2. Laying down of hairs:
   In hot condition, muscles which are attached with hair relax. It allows the hair to lie flat against surface of the skin.
   
   
3. Vasodilation:
   Arterioles found in the form of network in dermis, dilate (become wide) which increasing the flow of blood as well as it brings the blood vessels near the surface of skin which allows more heat loss. This process of vessel dilation is called vasodilation.

In Cold Condition When Body Temperature Starts Decreasing:
In cold condition when the body temperature starts decreasing the skin maintains the temperature by following actions:

1. Erection of hairs:
   The muscles contract pulling the hairs upright and trapping a layer of insulating air next to skin. Now it is not very much effective in human.
   
   
2. Vasocontraction:
   Narrowing of blood arterioles of dermis occurs which reduces the blood flow in capillaries of skin so less heat is lost.
   
   
3. Decrease in sweat production:
   The sweat gland stops to produce and secrete sweat, so it prevent from energy loss.
   
   
4. Increase in metabolic rate:
   In cold conditions the rate of metabolism in the organs increases generating more heat which is distributed around the body in the blood stream. It prevents loss through the adipose tissue in hypodermic which work as an insulation layer.

ii) Describe the urinary system of man with the help of diagram?
Ans: Urinary System In Man
Urinary system of man consist of:

1. A pair of kidney
2. A pair of ureters
3. A urinary bladder
4. A urethra

Kidneys:

• Kidneys are reddish-brown bean shaped organs, situated at the dorsal side of the abdominal cavity on either side of the vertebral column.
• The kidneys lie above the waistline.
• Each kidney has an area in the center of concave surface which faces the vertebral column; this area is called hillus.
• The renal artery, renal vein, nerve and ureter are connected to each kidney at the hillus.
• They are covered by a membrane are called peritoneum.

Ureter:

• The ureter is a narrow tube which connects the kidney to the urinary bladder.
• Urine passes through ureter to the urinary bladder.

Urinary Bladder:

• The urinary bladder is a thin walled muscular pear shaped bag situated towards the bottom of abdominal cavity in front of the rectum which stores urine.

Urethra:

• The urethra is a tube which comes out from the urinary bladder, runs down and opens outside the body through urinary opening (Anus).
• It passes urine from bladder to outside the body.

OR

iii) Describe the structure of Nephron? OR Describe the structure of nephron within the L.S of kidney. 
Ans: Structure Of Nephron:
The structural and functional unit of kidney is called Nephron. Each kidney contains more than one million nephrons, which are microscopic urinary tubules.

Parts of Nephron:
Each nephron is sub-divided into four main parts:

1. Bowman's Capsule
2. Proximal convoluted tubule
3. Loop of Henle's
4. Distal convoluted tubule

1. Bowman's Capsule: 

• In each nephron inner end forms a cup-shaped swelling called Bowman's capsule.
• Each bowman's capsule have a ball of capillaries called glomerulus.
• Bowman's capsule with glomerulus are collectively called Malpighian body or Renal corpuscle.
  
  

2. Proximal Convoluted Tubule: 

• Bowman capsule leads into a short convoluted (coiled) tubule called Proximal Convoluted Tubule which passes into the medulla.
  
  

3. Loop of Henle: 

• The tubule enters into medulla, extends into renal pyramid and makes a U shaped structure called loop of Henle and it goes back into cortex.
  
  

4. Distal Convoluted Tubule:

• When tubule enters the cortex again, it becomes convoluted again.
  
  

Collecting Tubules:

• Number of nephrons opens into a tube called collecting duct.
  
  

Network Of Blood Vessels:

• Nephrons are surrounded by different blood vessels that are connected to the renal artery and renal vein.
  
  

iv) Describe the network of blood vessels found in nephron and their functions.
Ans: Network And Functions of Blood Vessels In Nephron:
Nephrons remove waste materials and excess water from blood and convert them into urine by the process of filtration, reabsorption, secretion and excretion. Nephrons are surrounded by different blood vessels that are connected to the renal artery and renal vein. The blood filter to produce urine in blood capillaries of nephrons as:

1. Afferent Arteriole:
   The renal artery when enters into kidney, it divides into millions of branches called afferent arteriole.
   Function: The blood enters the kidney through renal artery and goes into afferent arteriole.
   
   
2. Malpighian Body:
   Each afferent arteriole further divides into numerous blood capillaries in Bowman's capsule are collectively called glomerulus. The Bowman's capsule with glomerulus is called Malpighian body or renal corpuscles.
   Function: Ultrafiltration occurs at Malpighian body.
   
   
3. Efferent Arteriole:
   Blood leaving the glomerulus through efferent arteriole, enter in blood capillaries surrounding the nephrons.
   Function: these blood vessels carry away filtered blood from glomerulus.
   
   
4. Venule:
   Blood capillaries surround a loop of Henle's unite to form venule, which ultimately joins to form a branch of renal vein.
   Function: It carries filtered blood with less waste materials to the venous system.

v) Describe different disorders of kidney and their treatment?
Ans: Kidney Problems Or Disease:
When the kidneys do not function properly due to different reasons this is referred as Kidney problem or Kidney disease.
There are many problems of kidney:

1. Kidney Stone
2. Kidney Failure

Kidney Stone
A kidney stone is a solid mass that forms from the crystals of calcium oxalate or Calcium Carbonate. Sometimes uric acid and cysteine are also present in it. These molecules separate from urine, precipitate in kidney and deposit in the form of stone. Sometimes these stones are not hard therefore they break into sand like crystals which can pass out of the body with urine without pain. The little large size stone however damages the kidney tissues; it may stuck anywhere in urinary tract and cause renal failure with pain.
Treatment:

1. Lithotripsy:
   If the size of stone is comparatively small we can use the technique of lithotripsy to break stone by ultrasonic waves (sound waves). The broken rudiments drain out from kidney with urine.
2. Renal surgery:
   The large size stone cannot be broken by lithotripsy, so it is removed only by the process of renal surgery.

Prevention:
The large intake of water is the only measure to minimize the chances of formation of stone in kidney.

Kidney failure:
Sometimes the nephrons of kidney are badly damaged and stop working due to certain reason or infection and the kidneys are not able to filter the harmful nitrogenous substance it is called Renal failure Or Kidney failure.
It is mainly due to solute disbalance in blood and kidneys. The failure of kidneys allow urea and other waste materials to accumulate in blood. The amount of H₂O is not regulated also. This dis-balance of solutes causes death unless the patient is given treatment  to filter out wastes by machines.
Treatment of Kidney Failure:

1. Kidney Transplant:
   Patient of kidney failure may get a kidney transplant. In high degree renal failure the surgical transplantation of matching donor kidney is only the option left as the permanent treatment. A person with two healthy kidneys may donate one kidney and survive with one kidney.


2. Dialysis:
   Dialysis machine: A dialysis machine performs the function of a kidney. It helps to clean the patient's blood from metabolic waste products and toxic.
   If a donor is not available, the patient can be treated with dialysis using a dialysis machine. For effective treatment the patient needs to undergo dialysis 2-3 times a week. Each session lasts about 3-5 hours depending on the patient's body size and medical condition.

Source: Special Thanks To Sir Syed Arif Ali