Subscribe For Free Updates!

We'll not spam mate! We promise.

2012-05-11

Shorts Question Answers – Homeostasis | HSC Part-II – Biology Notes


Chapter 1
Shorts Question Answers – Homeostasis

Q.1. Why more water is required for the excretion of ammonia.
Ans. It is highly soluble in water and rapidly diffuse across the plasma membrane. Ammonia is toxic for the organism. Its toxicity is reduced when diluted with large quantities of water due to this reason more water is required for excretion.

Q.2. Where urea is produces and why ATP is required for the process?
Ans. Urea is produced in the liver. NH3 combines with CO2 during this process ATP is required. Mammals, amphibians, shark and some bony fishes also excreted urea.

Q.3. Why water is not required for the excretion of uric acid?
Ans. It has extremely low solubility in water due to this water is not required for the excretion of uric acid. Formation of uric acid requires ATP.

Q.4. In which form the uric acid is excretion out of the body?
Ans. The suspension of uric acid is discharged in the form of thick paste or solid pellets. Uric acid is excreted by insects reptiles and bird.

Q.5. How much urea is less soluble than ammonia in water?
Ans. Urea is relatively less soluble in water 100,000 times less toxic than NH3.

Q.6. Give the route of excretion from the soft bodied animals and fishes?
Ans. In soft bodied animal ammonia is excreted from the body surface. In fish, most of the ammonia is excreted through gills as ammonium ions.

Q.7. What are the excretory organs of earthworm?
Ans. The excretory organs of earthworm are metanephridia which are arranged segmentally.

Q.8. What is metanephridium?
Ans. Each metanphridiumus coiled tube which is surrounded by capillaries. One end of metanephridium open in coemolic fluid where as other end opens on body surface through nephridiopore. Waste materials along with water are absorbed from the coemolic fluid passes through coiled part reabsorption of water takes place and remaining part is excreted through nephridiopore to outside the body.

Q.9. What is liver?
Ans. Liver is large reddish brown exocrine gland located in abdomen just below the diaphragm. Liver has bladder like gall bladder which stores bile and pour this bile into duodenum by the help of bile duct.

Q.10. What is the role of the liver for the metabolism of carbohydrates?
Ans. Liver maintain the level of glucose in blood. If blood contains excess glucose then glucose is stored in liver in the form of glycogen. If blood contains less glucose then stored glycogen is converted in glucose and release in blood. If glycogen is unavailable then liver converts amino acid or lipids into glucose and release in ton blood. Liver also converts lipids into fats and stores it.

Q.11. What is deamination and in which cycle the ammonia is converted into urea?
Ans. In liver break down of amino acids takes place. First amino group (NH4) is separated from amino acids and this process is called diamination then CO2 reacts with ammonia in ornithine cycle and converted into urea. This urea is released in blood circulation and excreted through kidneys.

Q.12. Describe the detoxification role of liver?
Ans. Liver also neutralizes many toxic substance such as hydrogen peroxide which is produced during metabolism is broken down into H2O and O2 by the help of enzyme catalase.

Q.13. How gall stones are formed?
Ans. Liver synthesizes cholesterol in excess amount forms gall stones in gall bladder.

Q.14. How liver help in the maintenance of body temperature for homeostatis?
Ans. Due to high metabolic are in liver heat is produced which helps in maintaining body temperature.

Q.15. For which vitamins the liver act as a reservoir?
Ans. Liver also stores many vitamins such as A, B and D.

Q.16. What is ultrafiltration and where it occurs?
Ans. During this process when blood passes through glomerulous, its plasma filters and diffuses into Bowman’s capsule. Filtration occurs due to high hydrostatic pressure in glomerulous is called ultrafiltration. This filtrate contains all molecules except plasma, proteins and blood cells.

Q.17. From where the reabsorption of glucose, amino acid, water and salt occur in the nephron?
Ans. When filtrate passes through proximal convoluted tubule, glucose, amino acids, water and salts are reabsorbed in per tubular network.

Q.18. Compare the role of ascending and descending limb of henel?
Ans.
Ascending Limb Of Loop Of Henle
In ascending limb of loop of Henle active absorption of sodium and chloride ions takes place. Sodium and chloride ions move out from filtrate into interstitial fluid and then taking up by the blood.

Descending Limb Of Loop Of Henle
When filtrate passes through descending limbs of loop of Henle reabsorption of water and sodium takes place.

Q.19. What is the function of distil convoluted tubule of nephron?
Ans. In distal convoluted tubule concentration of various salts in adjusted under influence of hormones. The filtrate now almost urine and collected in collecting dust.

Q.20. How many types of counter current mechanism are there?
Ans. There are two counter current system are operating.
1. One of the counter current is termed as counter current multiplier loops of Henle.
2. The other counter current system is consists of those blood vessels which run parallel to loop of Henle and are called Vasa Recta.

Q.21. How counter current multiplier perform its responsibilities?
Ans. In counter current multiplier loops of Henle the filtrate passes through descending limbs of loop of Henle, reabsorption of water takes place from filtrate and it becomes hypertonic then the interstitial fluid. In ascending limb of loop of henle, sodium and chloride ions are actively reabsorbed from the filtrate and it becomes hypotonic. Sodium and chloride ions removed from ascending limbs slowly diffuse bact to descending limbs.

Q.22. What is the role of vasa recta?
Ans. The outer counter current system is consists of those blood vessels which run parallel to loop of Henle and are called Vasa Recta. The blood supply to vasa recta provides oxygen and nourishments to the tissues of medulla it also takes away water absorbed from the filtrate.

Q.23. What are the adaptations of kidneys for the conservation of water?
Ans. Kidneys are adapted for the conservation of water. For this purpose two types of nephrons are found in kidneys. Such as cortical nephrons which have sorter lop of henle where the reabsorption of water is lower and Juxtamedullary nephrons which have longer loop of henle which extend up to medulla. In these nephrons reabsorption of water is higher. If kidney has larger number of Juxtamendullary nephrons there is greater conservation of water.

Q.24. How many types of nephrons are there?
Ans. There are two types of nephrons.
1. Cortical Nephrons: Which have shorter loop of Henle where the reabsorption of water is lower.
2. Juxtamedullary Nephrons: Which have longer loop of Henle which extend up to medulla. In these nephrons reabsorption of water is higher.

Q.25. How ADH increase the reabsorption of water?
Ans. A hormone ADH (Antidiuretic hormone) or vasopressin which increases the permeability of collecting duct in this way reabsorption of water increases.

Q.26. Which hormones are responsible for the reabsorption of sodium ions and calcium ions?
Ans. Another hormone Aldosterone which is secreted from adrenal gland increases the reabsorption of sodium ions Parathormone secreted from parathyroid glands maintains the level of calcium after increasing reabsorption of calcium ions.

Q.27. What is the percentage of infective renal stones and what is their biochemical compositions?
Ans. About 20% of calcium are termed as infective stones. Such calculi consists of combination of calcium, magnesium and ammonium phosphate. Some stones about 5% are formed by uric acid.

Q.28. What is lithotripsy?
Ans. It is the advance method of removing stones from kidneys and urinary bladders. In this method shock waves and ultra sonic waves are used for breaking stones in the body. After being broken small broken fragments of are passed in urine.

Q.29. What is renal failure and what are their major signs and symptoms?
Ans. It is the condition in which kidney are unable to filter blood to remove waste materials. In this way waste materials accumulate in blood, which leads to symptoms such as nausea, vomiting loss of appetite, weakness, breathlessness etc. In severe cases coma and death.

Q.30. What is haemodialysis?
Ans. Haemodialysis means “cleaning the blood”. In this procedure blood is circulated through a machine which contains a fluid dialyzer whose composition is mentioned.

Q.31. How many types of dialysis are there?
Ans. There are two types of dialysis
1. Haemodialysis
2. Peritoneal dialysis

Q.32. How haemodialysis is carried out?
Ans. Dialyzer has two spaces separated by their semipermeable membrane. Blood passes from one side of the membrane and dialyzer on the other side. The wastes and excess water pass from the blood through the membrane into the dialyzer. There after the blood is returned to circulation.

Q.33. What peritoneal dialysis?
Ans. During this method, there is inserted in the peritoneal cavity of abdomen after making an incision. Through this cathoter dialyze is filled in to the peritoneal cavity for several hours. As a consequen waste from the blood vessels lining the peritoneal cavity seep through peritoneal membrane into the cavity and mixes with dialyzer. The fluid is then drain out through the catheter.

Q.34. What is thermoregulation?
Ans. The regulation of body temperature within the stable normal constant limits of the body against the harsh fluctuating circumstances for the maintenance of homeostasis is called Thermoregulation.

Q.35. How many types of thermoregulation?
Ans. Thermoregulation among animals of two types.
1. Behavioral Thermoregulation
2. Physiological Thermoregulaton

Q.36. What is behavioural thermoregulation?
Ans. This regulation involves behavior of the animals in hot and cold weathers for e.g. animal increases or decreases heat loss by changing their locations. They will bask in the sun or in warm rock during winter and find wet cool area in summer.

Q.37. What is physiological thermoregulation?
Ans. Its involves the regulation of body temperature by some biological means. It is exhibited by the change in blood circulation, body metabolism, heat loss by evaporation of sweat.

Q.38. What are Poikilotherms?
Ans. Those animals which change their body temperature with respect to the change of temperature of surroundings. e.g. all invertebrates, fishes, amphibians and reptiles fall into this category.

Q.39. What are Homotherms?
Ans. Those animals which have constant body temperature which is independent to the changes in the temperature of surroundings.

Q.40. What are Ecotherms?
Ans. Those animals which maintain their body temperature by absorbing heat from the environment. E.g. Lizard basking in the sun.

Q.41. What are Endotherms?
Ans. Those animals which maintain their body temperature by generating heat in their bodies are called endotherms.

Q.42. What are Heterotherms?
Ans. Those animals which generate heat in their bodies to keep their body temperature to wider range. E.g. Bats, Humming Birds.

Q.43. How mammals control their body temperature physiological means during cold environment?
Ans. Thermoregulation in cold temperature.

Physiological Mechanism

(a) Non-Shivering Thermogenesis
i. Erection of Hairs: During cold weather hair of bodies becomes erect due the contraction in erector pilli muscles in skin. Vertical hair trap air near to skin which reduces heat loses from skin.
ii. Subcutaneous Fact Acelmulation: Mammals live in colder regions of world have thick layer of adipose tissues under their skin. These adipose tissues work as insulator and reduce head loss.
iii. Reduction in Blood Flow Through Skin: In cold temperature, arteries and veins in skin become narrow due to which blood circulation in skin decreases and heat loss is reduced due to radiation.

(b) Shivering Thermogenesis
In colder weather brain starts involuntary muscle movement called shivering which helps in generating heat to increase the body temperature.

Q.44. How mammals regulate their body temperature by behavioural means during cold environment?
Ans. Thermoregulation in Cold Temperature
Behavioural Mechanism.
In colder weather animals move towards warm places to maintain their body temperature.

Q.45. How mammals control their body temperature by physiological means during hot environment?
Ans. Thermoregulation in Hot Temp

Physiological Mechanism
i. Lowering of Hair: In hot weather animals lower their hair to reduce insulating effect.
ii. Increase in Blood Flow Towards Skin: Arteries and veins of skin become dilate due to which blood circulation increases in skin and heat loss occurs due to radiation.
iii. Sweating: In summer sweet glands secrete sweat, which when evaporates body looses heat.

Q.46. How mammals regulate their body temperature by behavioural means during hot environment?
Ans. Behavioral Mechanims:
Animal during summer move towards colder region to maintain their body temperature.

Q.48. How hypothalamus act as a Thermostate for the body.
Ans. Role of Brain in Temperature Regulation
Hypothalamus is the part of brain which regulates the body temperature. In this way this is called the most at of body. Hypothalamus receives messages from thermo receptor present in the skin. When any change in the temperature is detected by the hypothalamus, instructions are sent to the particular organ to bring the body temperature back to normal. For example in summer body promotes heat loss by evaporation of sweat from skin. But during winter body generates heat by different mechanism.

Socializer Widget By Funny And Amazing
SOCIALIZE IT →
FOLLOW US →
SHARE IT →

0 comments :

Post a Comment