Class 10th Science Gujarat Board Solution
Exercise- Which of the following structures is responsible for transportation of water in higher…
- The kidneys in human being are a part of the system for:A. Respiration B. Transportation…
- How many chambers are present in human heart?A. 2 B. 3 C. 4 D. 6
- Where is tricuspid valve found in human heart?A. Between two atria B. Between two…
- What is the excretory unit in human being?A. Bowman’s capsule B. Nephron C. Urinary…
- In which part of the body blood gets purified (Becomes oxygenated) ?A. Heart B. Lungs C.…
- In plants, food and other substances are transported through .....A. Tracheids B. Vessels…
- Mention the color of blood and lymph.
- Define Transpiration.
- What is transported through phloem?
- Define Ultafiltration.
- Name the organs of excretory system in human being.
- Name the components of circulatory system of human being.
- Differentiate between arteries and veins.
- Why the wall of artery is thick and elastic?
- What is the advantage of four chambered heart?
- Define Excretion.
- Explain the excretory system of human being.
- Explain the structure of human heart.
- Explain the process of urine formation.
- Describe the structure of nephron.
- Write a note on lymphatic system.
- Which of the following structures is responsible for transportation of water in higher…
- The kidneys in human being are a part of the system for:A. Respiration B. Transportation…
- How many chambers are present in human heart?A. 2 B. 3 C. 4 D. 6
- Where is tricuspid valve found in human heart?A. Between two atria B. Between two…
- What is the excretory unit in human being?A. Bowman’s capsule B. Nephron C. Urinary…
- In which part of the body blood gets purified (Becomes oxygenated) ?A. Heart B. Lungs C.…
- In plants, food and other substances are transported through .....A. Tracheids B. Vessels…
- Mention the color of blood and lymph.
- Define Transpiration.
- What is transported through phloem?
- Define Ultafiltration.
- Name the organs of excretory system in human being.
- Name the components of circulatory system of human being.
- Differentiate between arteries and veins.
- Why the wall of artery is thick and elastic?
- What is the advantage of four chambered heart?
- Define Excretion.
- Explain the excretory system of human being.
- Explain the structure of human heart.
- Explain the process of urine formation.
- Describe the structure of nephron.
- Write a note on lymphatic system.
Exercise
Question 1.Which of the following structures is responsible for transportation of water in higher plants:
A. Sieve tube
B. Sieve Cell
C. Vessel
D. Companion cell
Answer:•Xylem is the component which is responsible for transportation of water. Xylem consists of Tracheids and Vessels which help higher plants to transport water.
•Phloem is the component which is responsible for transportation of food to different parts of plants. It consists of Sieve tubes, companion cells, sieve tubes.
•Since, in the given options vessel is the only option which is a component of xylem tissue which transports water and all other options given are components of phloem which are responsible for transportation of food.
Therefore, (C) Vessel is the correct answer.
Following picture depicts part of xylem and phloem and functions of xylem and phloem:
Question 2.The kidneys in human being are a part of the system for:
A. Respiration
B. Transportation
C. Excretion
D. Nutrition
Answer:A Pair of kidneys is consist by our excretory system. All other processes like respiration, transportation and nutrition do not consist kidneys in their system. Following picture illustrate that our excretory system consists of a pair of kidneys.
Question 3.How many chambers are present in human heart?
A. 2
B. 3
C. 4
D. 6
Answer:Human heart consists of 4 chambers- Right atrium, Right ventricle, Left atrium and Left ventricle.
Following picture illustrate four chambered heart in human beings:
Figure: Human heart
Question 4.Where is tricuspid valve found in human heart?
A. Between two atria
B. Between two ventricles
C. Between right atrium and right ventricle
D. Between left atrium and left ventricle.
Answer:Tricuspid valve is present between right atrium and right ventricle to prevent backflow of blood.
Between left atrium and left ventricle bicuspid valve is present to prevent backflow of food.
No valve is present between two atria and ventricles.
Therefore, correct option is (C).
Mitral valve is other name for bicuspid valves.
Question 5.What is the excretory unit in human being?
A. Bowman’s capsule
B. Nephron
C. Urinary bladder
D. Kidney
Answer:Nephron is known as excretory unit because it is responsible for the process of urine formation in our body and thus helps our body to get rid of waste materials.
Kidney consists of many nephrons and since they do the major function- Nephron is known as excretory unit.
Therefore, correct option is B. Nephron.
Question 6.In which part of the body blood gets purified (Becomes oxygenated) ?
A. Heart
B. Lungs
C. Atrium
D. Ventricle
Answer:Heart (Right atrium) receives deoxygenated blood from different parts of body and then from right ventricle through pulmonary artery deoxygenated blood is transferred to lungs. In the lungs blood gets purified where deoxygenated blood is converted into oxygenated blood and then through pulmonary vein oxygenated blood is again transferred back to heart (left atrium) and then through aorta oxygenated blood is supplied to all parts of body.
Since, purification of blood i.e. conversion of deoxygenated blood to oxygenated blood takes place in lungs. Therefore, correct option is B. Lungs
Following picture depicts the complete process:
Question 7.In plants, food and other substances are transported through .....
A. Tracheids
B. Vessels
C. Ultrafiltration
D. None of them
Answer:In plants, food and other substances are transported through phloem and its components.
Tracheids and vessels are elements of xylem which are involved in transportation of water.
Ultrafiltration in no way is related to transportation of food in plants.
Therefore, correct option is D. None of them.
Question 8.Mention the color of blood and lymph.
Answer:Color of Blood= Red
It is due to the presence of haemoglobin pigment in our blood. Due to presence of this pigment, our blood appears red.
Color of Lymph- Lymph is colorless as it has no haemoglobin into it. It is the fluid which is present in intercellular spaces and comes from the leakage of blood capillaries and vessels.
Question 9.Define Transpiration.
Answer:Transpiration is the process of loss of water from the stomata of leaves in the form of water vapour. This process takes place when adequate water is present in plants. This process helps in regulation of temperature of plants.
Following picture also illustrate the process of transpiration:
Question 10.What is transported through phloem?
Answer:Transportation of photosynthetic products like carbohydrates takes place through the phloem. Photosynthesis takes place in the leaves and food formed is translocated to all other parts of plants. Transportation of food through the phloem is called translocation.
Question 11.Define Ultafiltration.
Answer:In kidneys, excretory unit is present which is known as nephron. Basic structure of nephron is as follows:
In this there is a cup shaped Bowman’s capsule in which bunch of blood capillaries is present which is known as glomerulus. To this glomerulus the blood having waste material is brought by afferent arteriole. Now since glomerulus consists of capillaries blood brought to glomerulus is under pressure and is thus filtered and is passed to Bowman’s capsule. This process of filtering blood through glomerulus is called Ultrafiltration.
Following picture also depict this process of ultrafiltration:
Question 12.Name the organs of excretory system in human being.
Answer:Following are the organs of excretory system:
•Kidneys: A pair of bean shaped kidneys is present in the abdomen on the dorsal surface of body.
•Ureters: A pair of ureters arises from each kidney.
•Urinary bladder: In this bladder urine is stored.
•Urethra: This opens by a small opening which helps in excretion of urine from the body.
Following picture also depicts the organs associated with excretory system:
Question 13.Name the components of circulatory system of human being.
Answer:Following are the components of circulatory system in human beings:
•Blood: This is the fluid which transports nutrients, waste materials, hormones, gases like oxygen, carbondioxide etc.
•Lymph: This is the fluid which transports nutrients, waste materials, hormones, gases like oxygen, carbondioxide etc.
•Heart: It is an organ which takes deoxygenated blood from the complete body and pumps oxygenated blood to the complete body.
•Lungs: Lungs also form a component of circulatory system as purification of blood takes place in lungs only.
•Blood vessels: Blood vessels carry blood into them and transfer it to different organs. There are two types of blood vessels:
a) Arteries: They carry oxygenated blood from heart to different parts of body.
b) Veins: They carry deoxygenated blood from different parts of the body to the heart.
•Lymphatic system: This lymphatic system is present all over the body and helps in transportation of lymph which helps in transportation of various things like nutrients, hormones, gases etc.
Question 14.Differentiate between arteries and veins.
Answer:
Question 15.Why the wall of artery is thick and elastic?
Answer:The walls of arteries are thick and elastic because blood in the arteries is pumped from heart and is under high pressure. To bear and deal with that high pressure in order to avoid bursting walls of arteries are thick and elastic.
Question 16.What is the advantage of four chambered heart?
Answer:Human heart consists of four chambers i.e. Right atrium, Right ventricle, Left atrium and Left ventricle.
Advantage of these four chambered hearts-
•Oxygenated blood remains separated from deoxygenated blood and mixing of deoxygenated and oxygenated blood is prevented.
Question 17.Define Excretion.
Answer:Excretion is the process of removal of waste products which are formed in our body during different biochemical reactions as these waste products can cause harm to our body.
Question 18.Explain the excretory system of human being.
Answer:Excretory system of the human helps him/her in the process of Excretion. Excretion is an essential life process in which waste products formed during different biochemical reactions in our body are removed. Excretory system of a human being consists of following organs:
•Kidneys: A pair of bean shaped kidneys is present in the abdomen on the dorsal surface of body. The kidney remains divided into two portions – Cortex and Medulla.
They consist of the nephrons which are the excretory units.
•Ureters: A pair of ureters arises from each kidney. They carry the urine formed to the urinary bladder
•Urinary bladder: In this bladder urine is stored for some period of time.
•Urethra: This opens by a small opening which helps in excretion of urine from the body.
Following picture also depicts the organs associated with excretory system:
Now as told above that kidney comprises of excretory units known as nephron. Structure of nephron is explained below:
•Bowman’s capsule: This is a double walled cup in which filtrate of the blood comes. It comprises of a bunch of capillaries which helps in the ultrafiltration process.
•Glomerulus: It is a bunch of capillaries present in the Bowman’s capsule. Through this capillaries blood is filtered as blood remains under pressure here and is filtered out in Bowman’s capsule.
•Proximal convoluted tubule: This is the narrow and coiled part of the tubule.
•Loop of Henle: This is a loop consisting of one thin limb known as ascending limb and one thick limb known as descending limb. In these tubular parts absorptions of necessary elements like water, certain ions and amino acids take place.
•Collecting duct: This is a duct in which various nephrons open and urine formed is collected into this duct and further is transferred to ureters.
Following is the structure of nephron:
Question 19.Explain the structure of human heart.
Answer:Human heart is an essential component of circulatory system. It plays important role of pumping blood to all the parts of body and circulation of blood is quite necessary for our body in order to transport different nutrients, hormones etc.
It consist of four chambers which are as follows:
•Right atrium: It receives deoxygenated blood from inferior and superior vena cava from all parts of the body.
•Right ventricle: It receives deoxygenated blood from right atrium and then transfer this deoxygenated blood to lungs through pulmonary artery for purification.
•Left atrium: It receives oxygenated blood through pulmonary vein which carries purified blood from lungs.
•Left ventricle: It receives oxygenated blood form left atrium and then transfer it the aorta which pumps this blood to all arteries and in result oxygenated blood is circulated among all the body parts.
Valves are also present in our hearts which are as follows:
•Tricuspid valve: This valve is present between right atrium and right ventricle. This valve prevents the backflow of blood from right ventricle to right atrium.
•Bicuspid valve: This valve is present between left atrium and left ventricle. This valve prevents the backflow of blood form left ventricle to left atrium.
There are certain important arteries and veins which are present in heart and are as follows:
•Inferior vena cava: It brings deoxygenated blood from lower part of the body to the right atrium.
•Superior vena cava: It brings deoxygenated blood from upper part of the body to the right atrium.
•Pulmonary artery: Right ventricle pumps deoxygenated blood into pulmonary artery and this artery carries this deoxygenated blood to the lungs for purification.
•Pulmonary vein: It carries oxygenated blood from lungs and transfers it to left atrium.
•Aorta: It receives oxygenated blood from the left ventricle and then transfers this blood to other arteries which circulate that oxygenated blood to all other body parts.
A separation also remains present between left and right portion of heart which we call as septum. This septum separates the left and right chambers of heart and thus prevents mixing of deoxygenated and oxygenated blood.
Following is the diagrammatic representation of heart which will provide a better understanding for the structure of heart:
Question 20.Explain the process of urine formation.
Answer:Process of urine formation includes following steps:
i. Blood along with the waste materials is brought to kidneys by the renal arteries.
ii. Ultrafiltration: There is a bunch of capillaries known as Glomerurlus is present in the Bowman’s capsule. As the blood passes through capillaries, it remains under pressure and is thus filtered out. This filtrate gets collected in the Bowman’s capsule.
iii. There are different tubular parts in the nephron like proximally convoluted tubule, Loop of Henle. In these tubules all the important substances like water, certain ions and amino acids are absorbed.
iv. After absorption of these necessary substances the remaining fluid only contains excretory substance and that fluid is known as urine. This urine is secreted back into tubular part which goes to collecting duct.
v. Several nephrons opens into a collecting duct into which they empties the urine which is further transferred to ureters and then to the urinary bladder.
In this way urine is formed in the human body. Following picture also depict the same mechanism:
Question 21.Describe the structure of nephron.
Answer:Structure of nephron is explained below:
•Bowman’s capsule: This is a double walled cup in which filtrate of the blood comes. It comprises of a bunch of capillaries which helps in the ultrafiltration process.
•Glomerulus: It is a bunch of capillaries present in the Bowman’s capsule. Through this capillaries blood is filtered as blood remains under pressure here and is filtered out in Bowman’s capsule.
•Proximal convoluted tubule: This is the narrow and coiled part of the tubule.
•Loop of Henle: This is a loop consisting of one thin limb known as ascending limb and one thick limb known as descending limb. In these tubular parts absorptions of necessary elements like water, certain ions and amino acids take place.
•Collecting duct: This is a duct in which various nephrons open and urine formed is collected into this duct and further is transferred to ureters.
Question 22.Write a note on lymphatic system.
Answer:Lymphatic system is related with the circulation of lymph. Lymph is also a fluid like blood which helps in transportation of various materials like nutrients, enzymes, hormones, waste materials from one part to another. Lymph is an intracellular fluid which is formed due to the leakage of blood cells, plasma, proteins from the capillaries. It is a colourless fluid.
For the transportation of lymph, lymphatic system consists of lymph capillaries, lymph vessels and lymphatic nodes.
The lymph first enters into lymphatic capillaries from intracellular fluid. Then, these capillaries open into large lymphatic vessels.
Following are the functions associated with the lymphatic system:
•It collects the intracellular fluid and then again returns it blood circulation.
•This system also helps in absorption and transportation of lipids. Several lymphatic vessels are also present in villi in small intestine. There lymphatic vessels absorb the lipids and further transport it.
•Lymphatic system also provides protection against diseases as they are a part of our immune system which protects us against several diseases.
Following is the diagrammatic representation of lymphatic system:
Which of the following structures is responsible for transportation of water in higher plants:
A. Sieve tube
B. Sieve Cell
C. Vessel
D. Companion cell
Answer:
•Xylem is the component which is responsible for transportation of water. Xylem consists of Tracheids and Vessels which help higher plants to transport water.
•Phloem is the component which is responsible for transportation of food to different parts of plants. It consists of Sieve tubes, companion cells, sieve tubes.
•Since, in the given options vessel is the only option which is a component of xylem tissue which transports water and all other options given are components of phloem which are responsible for transportation of food.
Therefore, (C) Vessel is the correct answer.
Following picture depicts part of xylem and phloem and functions of xylem and phloem:
Question 2.
The kidneys in human being are a part of the system for:
A. Respiration
B. Transportation
C. Excretion
D. Nutrition
Answer:
A Pair of kidneys is consist by our excretory system. All other processes like respiration, transportation and nutrition do not consist kidneys in their system. Following picture illustrate that our excretory system consists of a pair of kidneys.
Question 3.
How many chambers are present in human heart?
A. 2
B. 3
C. 4
D. 6
Answer:
Human heart consists of 4 chambers- Right atrium, Right ventricle, Left atrium and Left ventricle.
Following picture illustrate four chambered heart in human beings:
Figure: Human heart
Question 4.
Where is tricuspid valve found in human heart?
A. Between two atria
B. Between two ventricles
C. Between right atrium and right ventricle
D. Between left atrium and left ventricle.
Answer:
Tricuspid valve is present between right atrium and right ventricle to prevent backflow of blood.
Between left atrium and left ventricle bicuspid valve is present to prevent backflow of food.
No valve is present between two atria and ventricles.
Therefore, correct option is (C).
Mitral valve is other name for bicuspid valves.
Question 5.
What is the excretory unit in human being?
A. Bowman’s capsule
B. Nephron
C. Urinary bladder
D. Kidney
Answer:
Nephron is known as excretory unit because it is responsible for the process of urine formation in our body and thus helps our body to get rid of waste materials.
Kidney consists of many nephrons and since they do the major function- Nephron is known as excretory unit.
Therefore, correct option is B. Nephron.
Question 6.
In which part of the body blood gets purified (Becomes oxygenated) ?
A. Heart
B. Lungs
C. Atrium
D. Ventricle
Answer:
Heart (Right atrium) receives deoxygenated blood from different parts of body and then from right ventricle through pulmonary artery deoxygenated blood is transferred to lungs. In the lungs blood gets purified where deoxygenated blood is converted into oxygenated blood and then through pulmonary vein oxygenated blood is again transferred back to heart (left atrium) and then through aorta oxygenated blood is supplied to all parts of body.
Since, purification of blood i.e. conversion of deoxygenated blood to oxygenated blood takes place in lungs. Therefore, correct option is B. Lungs
Following picture depicts the complete process:
Question 7.
In plants, food and other substances are transported through .....
A. Tracheids
B. Vessels
C. Ultrafiltration
D. None of them
Answer:
In plants, food and other substances are transported through phloem and its components.
Tracheids and vessels are elements of xylem which are involved in transportation of water.
Ultrafiltration in no way is related to transportation of food in plants.
Therefore, correct option is D. None of them.
Question 8.
Mention the color of blood and lymph.
Answer:
Color of Blood= Red
It is due to the presence of haemoglobin pigment in our blood. Due to presence of this pigment, our blood appears red.
Color of Lymph- Lymph is colorless as it has no haemoglobin into it. It is the fluid which is present in intercellular spaces and comes from the leakage of blood capillaries and vessels.
Question 9.
Define Transpiration.
Answer:
Transpiration is the process of loss of water from the stomata of leaves in the form of water vapour. This process takes place when adequate water is present in plants. This process helps in regulation of temperature of plants.
Following picture also illustrate the process of transpiration:
Question 10.
What is transported through phloem?
Answer:
Transportation of photosynthetic products like carbohydrates takes place through the phloem. Photosynthesis takes place in the leaves and food formed is translocated to all other parts of plants. Transportation of food through the phloem is called translocation.
Question 11.
Define Ultafiltration.
Answer:
In kidneys, excretory unit is present which is known as nephron. Basic structure of nephron is as follows:
In this there is a cup shaped Bowman’s capsule in which bunch of blood capillaries is present which is known as glomerulus. To this glomerulus the blood having waste material is brought by afferent arteriole. Now since glomerulus consists of capillaries blood brought to glomerulus is under pressure and is thus filtered and is passed to Bowman’s capsule. This process of filtering blood through glomerulus is called Ultrafiltration.
Following picture also depict this process of ultrafiltration:
Question 12.
Name the organs of excretory system in human being.
Answer:
Following are the organs of excretory system:
•Kidneys: A pair of bean shaped kidneys is present in the abdomen on the dorsal surface of body.
•Ureters: A pair of ureters arises from each kidney.
•Urinary bladder: In this bladder urine is stored.
•Urethra: This opens by a small opening which helps in excretion of urine from the body.
Following picture also depicts the organs associated with excretory system:
Question 13.
Name the components of circulatory system of human being.
Answer:
Following are the components of circulatory system in human beings:
•Blood: This is the fluid which transports nutrients, waste materials, hormones, gases like oxygen, carbondioxide etc.
•Lymph: This is the fluid which transports nutrients, waste materials, hormones, gases like oxygen, carbondioxide etc.
•Heart: It is an organ which takes deoxygenated blood from the complete body and pumps oxygenated blood to the complete body.
•Lungs: Lungs also form a component of circulatory system as purification of blood takes place in lungs only.
•Blood vessels: Blood vessels carry blood into them and transfer it to different organs. There are two types of blood vessels:
a) Arteries: They carry oxygenated blood from heart to different parts of body.
b) Veins: They carry deoxygenated blood from different parts of the body to the heart.
•Lymphatic system: This lymphatic system is present all over the body and helps in transportation of lymph which helps in transportation of various things like nutrients, hormones, gases etc.
Question 14.
Differentiate between arteries and veins.
Answer:
Question 15.
Why the wall of artery is thick and elastic?
Answer:
The walls of arteries are thick and elastic because blood in the arteries is pumped from heart and is under high pressure. To bear and deal with that high pressure in order to avoid bursting walls of arteries are thick and elastic.
Question 16.
What is the advantage of four chambered heart?
Answer:
Human heart consists of four chambers i.e. Right atrium, Right ventricle, Left atrium and Left ventricle.
Advantage of these four chambered hearts-
•Oxygenated blood remains separated from deoxygenated blood and mixing of deoxygenated and oxygenated blood is prevented.
Question 17.
Define Excretion.
Answer:
Excretion is the process of removal of waste products which are formed in our body during different biochemical reactions as these waste products can cause harm to our body.
Question 18.
Explain the excretory system of human being.
Answer:
Excretory system of the human helps him/her in the process of Excretion. Excretion is an essential life process in which waste products formed during different biochemical reactions in our body are removed. Excretory system of a human being consists of following organs:
•Kidneys: A pair of bean shaped kidneys is present in the abdomen on the dorsal surface of body. The kidney remains divided into two portions – Cortex and Medulla.
They consist of the nephrons which are the excretory units.
•Ureters: A pair of ureters arises from each kidney. They carry the urine formed to the urinary bladder
•Urinary bladder: In this bladder urine is stored for some period of time.
•Urethra: This opens by a small opening which helps in excretion of urine from the body.
Following picture also depicts the organs associated with excretory system:
Now as told above that kidney comprises of excretory units known as nephron. Structure of nephron is explained below:
•Bowman’s capsule: This is a double walled cup in which filtrate of the blood comes. It comprises of a bunch of capillaries which helps in the ultrafiltration process.
•Glomerulus: It is a bunch of capillaries present in the Bowman’s capsule. Through this capillaries blood is filtered as blood remains under pressure here and is filtered out in Bowman’s capsule.
•Proximal convoluted tubule: This is the narrow and coiled part of the tubule.
•Loop of Henle: This is a loop consisting of one thin limb known as ascending limb and one thick limb known as descending limb. In these tubular parts absorptions of necessary elements like water, certain ions and amino acids take place.
•Collecting duct: This is a duct in which various nephrons open and urine formed is collected into this duct and further is transferred to ureters.
Following is the structure of nephron:
Question 19.
Explain the structure of human heart.
Answer:
Human heart is an essential component of circulatory system. It plays important role of pumping blood to all the parts of body and circulation of blood is quite necessary for our body in order to transport different nutrients, hormones etc.
It consist of four chambers which are as follows:
•Right atrium: It receives deoxygenated blood from inferior and superior vena cava from all parts of the body.
•Right ventricle: It receives deoxygenated blood from right atrium and then transfer this deoxygenated blood to lungs through pulmonary artery for purification.
•Left atrium: It receives oxygenated blood through pulmonary vein which carries purified blood from lungs.
•Left ventricle: It receives oxygenated blood form left atrium and then transfer it the aorta which pumps this blood to all arteries and in result oxygenated blood is circulated among all the body parts.
Valves are also present in our hearts which are as follows:
•Tricuspid valve: This valve is present between right atrium and right ventricle. This valve prevents the backflow of blood from right ventricle to right atrium.
•Bicuspid valve: This valve is present between left atrium and left ventricle. This valve prevents the backflow of blood form left ventricle to left atrium.
There are certain important arteries and veins which are present in heart and are as follows:
•Inferior vena cava: It brings deoxygenated blood from lower part of the body to the right atrium.
•Superior vena cava: It brings deoxygenated blood from upper part of the body to the right atrium.
•Pulmonary artery: Right ventricle pumps deoxygenated blood into pulmonary artery and this artery carries this deoxygenated blood to the lungs for purification.
•Pulmonary vein: It carries oxygenated blood from lungs and transfers it to left atrium.
•Aorta: It receives oxygenated blood from the left ventricle and then transfers this blood to other arteries which circulate that oxygenated blood to all other body parts.
A separation also remains present between left and right portion of heart which we call as septum. This septum separates the left and right chambers of heart and thus prevents mixing of deoxygenated and oxygenated blood.
Following is the diagrammatic representation of heart which will provide a better understanding for the structure of heart:
Question 20.
Explain the process of urine formation.
Answer:
Process of urine formation includes following steps:
i. Blood along with the waste materials is brought to kidneys by the renal arteries.
ii. Ultrafiltration: There is a bunch of capillaries known as Glomerurlus is present in the Bowman’s capsule. As the blood passes through capillaries, it remains under pressure and is thus filtered out. This filtrate gets collected in the Bowman’s capsule.
iii. There are different tubular parts in the nephron like proximally convoluted tubule, Loop of Henle. In these tubules all the important substances like water, certain ions and amino acids are absorbed.
iv. After absorption of these necessary substances the remaining fluid only contains excretory substance and that fluid is known as urine. This urine is secreted back into tubular part which goes to collecting duct.
v. Several nephrons opens into a collecting duct into which they empties the urine which is further transferred to ureters and then to the urinary bladder.
In this way urine is formed in the human body. Following picture also depict the same mechanism:
Question 21.
Describe the structure of nephron.
Answer:
Structure of nephron is explained below:
•Bowman’s capsule: This is a double walled cup in which filtrate of the blood comes. It comprises of a bunch of capillaries which helps in the ultrafiltration process.
•Glomerulus: It is a bunch of capillaries present in the Bowman’s capsule. Through this capillaries blood is filtered as blood remains under pressure here and is filtered out in Bowman’s capsule.
•Proximal convoluted tubule: This is the narrow and coiled part of the tubule.
•Loop of Henle: This is a loop consisting of one thin limb known as ascending limb and one thick limb known as descending limb. In these tubular parts absorptions of necessary elements like water, certain ions and amino acids take place.
•Collecting duct: This is a duct in which various nephrons open and urine formed is collected into this duct and further is transferred to ureters.
Question 22.
Write a note on lymphatic system.
Answer:
Lymphatic system is related with the circulation of lymph. Lymph is also a fluid like blood which helps in transportation of various materials like nutrients, enzymes, hormones, waste materials from one part to another. Lymph is an intracellular fluid which is formed due to the leakage of blood cells, plasma, proteins from the capillaries. It is a colourless fluid.
For the transportation of lymph, lymphatic system consists of lymph capillaries, lymph vessels and lymphatic nodes.
The lymph first enters into lymphatic capillaries from intracellular fluid. Then, these capillaries open into large lymphatic vessels.
Following are the functions associated with the lymphatic system:
•It collects the intracellular fluid and then again returns it blood circulation.
•This system also helps in absorption and transportation of lipids. Several lymphatic vessels are also present in villi in small intestine. There lymphatic vessels absorb the lipids and further transport it.
•Lymphatic system also provides protection against diseases as they are a part of our immune system which protects us against several diseases.
Following is the diagrammatic representation of lymphatic system: