Kerala SSLC Class 9 Solutions for biology – Circulatory Pathways (English Medium)
Page No. 23:
Question 1:
How do the food particles from the small intestine reach each cell?
Solution:
Food particles from the small intestine are absorbed into the blood by microvilli present on the wall of the small intestine.
Page No. 24:
Question 1:
What is the advantage of the increased length of the small intestine?
Solution:
Advantages of increased length of the small intestine include:
- Slow movement of food particles through the small intestine
- Uniform digestion of food
- Proper and complete absorption of nutrients from the small intestine
Question 2:
What is the advantage of having large surface area of absorption?
Solution:
A large surface area of absorption in the small intestine is due to the presence of villi. Villi provide a large surface area for absorption, ensuring the complete absorption of nutrients into the blood.
Question 3:
To what extent is the structure of the villi suitable for the absorption of food particles?
Solution:
The structure of the villi is completely suitable for the absorption of food particles.
The villi are one-cell thick, thus making the absorption of nutrients and its transport into the blood easy.
Arterioles which spread in the wall of the small intestine enter the villi and further divide into capillaries.
Capillaries unite to join small veins or venules.
A small branch of the lymph vessel is also present in villi.
When the absorption of food takes place, glucose and amino acids are absorbed by blood capillaries in the villi, while fatty acids and glycerol are absorbed into the lymph vessel.
Page No. 25:
Question 1:
You have already studied about some processes that help water and salts to enter the tissues. What are they? List them.
Solution:
Processes which help water and salts to enter the tissues:
- Osmosis
- Diffusion
- Active transport
- Passive transport
- Carrier-mediated transport
- Vesicle-mediated transport
Page No. 26:
Question 1:
Complete the flow chart.
Solution:
Page No. 27:
Question 1:
We have seen earlier that some of the food particles after digestion are, absorbed by the lymph through lacteals. How are these particles transported?
Solution:
- Lymph is a colourless tissue fluid which enters lymph capillaries.
- It is devoid of RBCs and platelets.
- Many proteins and minerals which are present in the plasma are also seen in the lymph.
- However, the quantity of these proteins and minerals is less in the lymph as compared to the plasma.
- Lipid and lipid-soluble proteins are transported through the lymph.
- Lymph capillaries of lacteals which arise from tissues carry these nutrients and pass through different blood vessels, ultimately transporting them to the vena cava.
- From the vena cava, nutrients are transported to the heart along with the blood and then to the rest of the body.
Question 2:
Prepare a note on the transport of materials through the lymph.
Solution:
- Lymph is a colourless tissue fluid which enters lymph capillaries.
- It is devoid of RBCs and platelets.
- Many proteins and minerals which are present in the plasma are also seen in the lymph.
- However, the quantity of these proteins and minerals is less in the lymph as compared to the plasma.
- Lipid and lipid-soluble proteins are transported through the lymph.
- Lymph capillaries of lacteals which arise from tissues carry these nutrients and pass through different blood vessels, ultimately transporting them to the vena cava.
- From the vena cava, nutrients are transported to the heart along with the blood and then to the rest of the body.
Page No. 28:
Question 1:
Where do the food particles that flow through blood and lymph go to?
Solution:
- Food particles which flow through the blood and lymph are first transported to the heart through different vessels.
- These particles are then transported from the heart to the different parts of the body.
Question 2:
Observe the illustration that shows the path of the food particles from the villus and complete it.
Solution:
Question 3:
Analyse the illustration given and find out how the nutrients reach the heart.
Solution:
Nutrients take the following route to reach the heart:
- Simple sugars and amino acids which are formed as products of digestion get absorbed in the blood capillaries through the villi.
- From the capillaries, these nutrients flow through small veins along with blood and reach the liver.
- The quantity of sugars and amino acids in the blood is regulated in the liver, and then this blood with optimum concentration of sugars and amino acids flows through the vena cava to the heart.
- Glycerol and fatty acids formed by the digestion of lipids get transported through the lymph.
- Lymph from tissues flows through the lacteals, small lymph vessels, large lymph vessels and vena cava to reach the heart, thus carrying glycerol and fatty acids to the heart through the same path.
- From the heart, all absorbed nutrients are then transported to the different parts of the body.
Question 4:
The food particles that are absorbed from the small intestine reach the heart through the liver. Why do they go to the liver?
Solution:
Food particles which are absorbed from the small intestine go to the liver because the liver acts as a regulatory organ in the following manner:
- It helps in controlling the glucose concentration of blood.If there is excess amount of glucose in the blood, then the excess amount is converted to glycogen and stored in the liver.
- If the amount of glucose in the blood is less, then the glycogen in the liver is broken down to glucose and pumped into the blood stream.
- Excess amount of amino acids formed by digestion of proteins are converted to urea in the liver.
- Liver also decomposes poisonous substances and alcohol, thus rendering them harmless.
Question 5:
What is the part played by the heart in transporting the food particles absorbed by the blood to different parts of the body?
Solution:
The heart plays a key role in the transport of food particles absorbed by the blood to different parts of the body. It continuously pumps blood and keeps the blood moving thus helping in the transport of various food particles through the blood.
Question 6:
With the help of the figure given, try to understand the position, size and shape of the heart and note them down.
Solution:
- The heart is present posterior to the sternum in the thoracic cavity and behind the ribs. It rests on the diaphragm.
- The size of heart is roughly about a person’s clenched fist; approximately measuring 12 cm long and 9 cm wide.
- The shape of the heart is like an inverted cone, i.e. its upper end is broad and its lower end (called apex) is pointed. Its apex is slightly directed to the left.
Page No. 30:
Question 1:
Complete the table
Solution:
Page No. 31:
Question 1:
What other parts of the body tells you the pulse rate?
Solution:
Following parts of the body can tell the pulse rate:
- At the neck just above the collar bones
- Just below the jawbone at the corners of the mouth
- Just below the ears
- On the upper arm, at the folding of the elbow
- At the inner thighs, half way the length of the thigh
- On the knee
- At the ankle
- On the top side of the foot just in the centre
Page No. 32:
Question 1:
We have seen that blood enters the arteries due to the contraction of the heart. Where does the blood flow after this?
Solution:
- When the heart contracts, blood flows from the right ventricle through the pulmonary artery to the lungs.
- Blood simultaneously flows from the left ventricle through the aorta to the different parts of the body.
Question 2:
Why does the blood flow to the lungs?
Solution:
Blood which is pumped out of the right ventricle to pulmonary veins is deoxygenated.
It flows to the lungs to get oxygenated, and this oxygenated blood is then sent back to the left side of the heart.
Question 3:
Using the details in the figure, form an idea about the human circulatory system and complete the flowchart.
Give appropriate colouring to the picture to differentiate between oxygenated blood and deoxygenated blood.
Solution:
Question 4:
- Blood vessels that carry oxygenated blood.
- Blood vessels that carry deoxygenated blood.
- The heart chamber that receives deoxygenated blood.
- The heart chamber that receives oxygenated blood.
Solution:
- Blood vessels that carry oxygenated blood – Aorta, Pulmonary Veins
- Blood vessels that carry deoxygenated blood – Superior Venacava, Inferior Venacava, Pulmonary Arteries
- The heart chamber that receives deoxygenated blood – Right Atrium
- The heart chamber that receives oxygenated blood – Left Atrium, Left Ventricle
Page No. 33:
Question 1:
We know that microorganisms do not have blood or a circulatory system. Then how do the nutrients reach all parts of the body?
Solution:
Cytoplasmic streaming in a circular manner (called cyclosis) helps in the distribution of nutrients to all parts of the cell in microorganisms.
Page No. 34:
Question 1:
Do plants require any nutrients other than water and carbon dioxide? If they do, how these nutrients reach the leaves and other parts of the plant?
Solution:
- Apart from water and carbon dioxide, plants need nutrients which are classified as macronutrients and micronutrients.
- Macronutrients are nitrogen, phosphorus, potassium, sulphur and magnesium.
- Micronutrients are copper, zinc, chlorine and manganese.
- They are absorbed from the soil by the roots of the plant.
- These nutrients in the dissolved form in water are then transported to leaves and the other parts of the plant through special conducting tissue called xylem.
Question 2:
How does the food that is prepared in leaf by photosynthesis reach other parts of the plant?
Solution:
The food prepared by leaves reach other parts of the plant through a special conducting tissue called phloem.