Class - 7, Science, Chapter:- 11 Transportation in Animals & Plants Notes, NCERT Solutions & Frequently Asked Questions

 Science

Class:-7, Chapter:- 11

Transportation in Animals & Plants 

Notes, NCERT Solutions & Frequently Asked Questions

-- Notes --

⭐ Transportation in Animals :- 

⭐ Circulatory System :- The organ system of the body that is responsible for the transport of material throughout the body is called the circulatory system.

• The materials transported are nutrients, oxygen, carbon dioxide, cells, etc

• The medium of transportation is blood.

• The primary parts of the circulatory system are heart, arteries and veins.

⭐Blood :- Blood is a fluid tissue that transports nutrients and oxygen to the cells and carries away carbon dioxide and other waste products in our body.

• The fluid part of blood is called plasma and has various salts and nutrients dissolved in it.

• Blood cells are suspended in plasma and they are Red Blood Cells (RBCs), White Blood Cells (WBCs) and Platelets.

a) Plasma :- Plasma is the liquid component of the blood in which most of the blood cells are suspended.

• It is mostly made up of water (up to 95%) and contains dissolved nutrients, carbon dioxide and oxygen.

b) RBC :- Red blood cells (RBC) present in the blood are responsible for the transport of oxygen throughout the body.

• They contain a red pigment called haemoglobin, which binds with the oxygen.

• The reddish colour of the blood is due to haemoglobin.

c) WBC :- The blood contains White blood cells (WBC), which are part of the immune system.

• They are like soldiers, which fight and kill germs that may enter the body.

d) Blood Platelets :- Platelets are the smallest cells in the blood.

• By clumping together, they form a blood clot, preventing loss of blood due to bleeding.

• They prevent excessive damage to the blood vessels by binding together at the site of damage.

⭐ Functions of Blood :- Various functions of blood are :- 

• It transports substances like digested food from the small intestine to the other parts of the body.

• It carries water to all the parts of the body.

• It carries oxygen and C0₂ during circulation.

• It carries waste products like urea from liver to kidney for excretion in urine.

• It protects the body from disease.

⭐ Blood Groups :- The blood group of an individual human being always remains unchanged throughout their life. 

• Karl Landsteiner described that human blood can be divided into four groups, i.e. A, B, AB and O. 

• If a person gets injured and heavy blood loss occurs, there is a need to give blood of other people to the patient. 

• The person who gives the blood is called a donor while the person who receives the blood is called the recipient. 

⭐ Blood Vessels :- Blood vessels are tubes that carry blood all over the body.

• Arteries, veins and capillaries are collectively called as blood vessels.

a) Arteries :- Arteries are blood vessels that carry oxygenated blood (Oxygen rich blood) to the cells and tissues of our body.

• They carry blood from the heart to the tissues.

➽ Note :- The arteries normally carry oxygenated blood from the heart but pulmonary artery carries deoxygenated blood from the heart to lungs.

b) Veins :- Veins are blood vessels that carry away deoxygenated blood (Carbon dioxide rich blood) from the cells and tissues of our body.

• They carry blood from tissues to the heart.

➽ Note :- The Veins carry deoxygenated blood but pulmonary vein carries oxygenated blood from the lungs to the heart.

⭐ Difference between arteries & veins :- 

c) Capillaries :- Capillaries are the smallest of the body’s blood vessels.

• It serves the most important task of the circulatory system: exchange of material between circulation and cells.

• The fine network makes it easy for the process of diffusion of materials due to the increase in surface area.

⭐ Heart :- The heart is a muscular organ in animals that pumps blood through blood vessels to all the parts of the body.

• The heart consists of four chambers that prevent the oxygenated and deoxygenated blood from mixing.

• The upper chambers are called as atria and the lower chambers are called as ventricles.

⭐ Location of Heart :- The heart is located in the chest cavity slightly towards the left side. 

• It lies between the two lungs and above the diaphragm. 

• The heart is made up of special muscles called cardiac muscles that do not fatigue and are not the solid muscle. 

• The heart is hollow from inside.

⭐ Structure of Heart :- The heart has four compartments called as chambers.

•  The upper two chambers of heart are called atria (singular -  atrium) and the lower two chambers of heart are called ventricles. 

• On the left side of heart are left atrium and left ventricle and on the right side of the heart are right atrium and right ventricle.

⭐ Heartbeat :- The rhythmic contraction and relaxation of heart muscles that produce a specific sound of lubb-dubb is called heartbeat. 

• The average heartbeat of an adult person is 72-80 beats per minute at resting but the number increases during and after a physical exercise. 

• During fast beating of heart, the blood is pumped more rapidly to the organs to supply more oxygen to the body cells. 

• The heartbeat is equal to the number of pulse in a minute. 

⭐ Stethoscope :- The heartbeat can be heard by an instrument called as stethoscope. 

• It is used by doctor to amplify the sound of heart. It consists of a chest piece that carries a sensitive diaphragm, two earpieces & a tube joining both the parts. 

⭐ Valves :- Valves are present in the heart as well as in veins.

• In the heart, they are present between atria and ventricles and at the base of big vessels leaving the heart.

• Valves are responsible for the unidirectional flow of blood in the body.

• Opening and closing of the valves present in the heart is responsible for the lub-dub sound of the heart.

⭐ Pulmonary Circuit :- It is the network of arteries and veins connecting the heart and lungs.

• Deoxygenated blood is pumped from the blood to the lungs for oxygenation.

• The oxygenated blood returns to the heart to be pumped to the rest of the body.

⭐ Oxygenation of Blood :- Oxygenation of blood occurs at the alveoli in the lungs.

• The alveoli have blood vessels wrapped around it and the blood is oxygenated by diffusion.

⭐ Pulse :- The heart periodically expands and contracts to pump blood into the arteries, which also expands and contracts as the blood flows through them. This is called pulsation.

• This pulsation of the arteries can be felt at certain places of the body such as the wrist.

• Pulsation is measured as the number of heartbeats per minute, which is nothing but pulse rate. 

⭐ Excretory System :- The organ system of the body that is responsible for the removal of waste material from the body is called the Excretory system.

⭐ Excretion :- The process of removal of waste products from the cells of living organisms is called excretion.

• For human beings, the waste products are in the form of carbon dioxide, urine and faeces.

⭐ Kidneys :- Our body’s main excretory organs are the kidneys.

• There is a pair of kidneys present on either side of the spine.

• Each kidney is a bean-shaped organ, reddish in colour.

• It contains millions of tiny tubules that act as microscopic filters and filter out the useful and harmful substances from the blood.

• The useful substances are again reabsorbed back into the blood and only harmful substances are concentrated.

• These harmful substances are present in a dissolved state in water and now it is called as urine.

• Urine is excreted out of the body. Thus, kidneys act as filters of our body.

⭐ Ureters :- Urine is sent from the kidneys to the urinary bladder through tubes called ureters.

⭐ Urinary Bladder :- The urinary bladder is a muscular bag where urine is accumulated and excreted from the body through the urethra.

• It can hold about 300-500 mL urine for a while before the urge to empty occurs.

• The opening of urinary bladder is controlled by the ring of muscle called as bladder sphincter. 

• When the bladder becomes full with urine this bladder sphincter opens and allows the urine to flow out.

⭐ Urethra :- The urine is stored in the urinary bladder for some times and at regular intervals it, is removed through the opening at the end of the tube called urethra.

⭐ Dialysis :- Dialysis is the filtering of blood outside the human body using a machine, when both the kidneys fail.

⭐ Sweat :- It is the liquid waste of the body that is produced by the sweat glands present in our skin. 

• Sweat contains water, some unwanted salts and urea in a very small amount.

• During hot summer, we sweat a lot. This gets evaporated from our body. This helps to provide the cooling effect to the body.

⭐ Excretion in Other Animals :- Excretion in different animals differs based on the excretory material.

• Ammonia, urea and uric acid are the commonly excreted material.

⭐ Transportation in Plants :- 

⭐ Osmosis :- Osmosis is the movement of solvent molecules from a region of lower solute concentration to a region of higher solute concentration through a semi-permeable membrane.

⭐ Root Hair :- Root hairs are elongated extensions of the roots that are comparable to hairs on animals.

• They increase the surface area for increased exchange of water and minerals.

⭐ Phloem :- Phloem is the plant tissue that transports the soluble organic material created during photosynthesis from the leaves to the other parts of the plant.

⭐ Xylem :- Xylem is the plant tissue that transports the water and other nutrients from the roots to other parts of the plant.

⭐ Transpiration :- Transpiration is the loss of water in the form of water vapour from stomata present on leaves.

• This process also helps the plants absorb and distribute water through their roots.

• Transpiration exerts a straw-like effect and the water moves up against gravity in tubes made of xylem cells.

-- NCERT Solutions -- 

-- Exercise Questions --

Question 1.- Match structures given in Column I with functions given in Column II.

Solution:- 

Question 2.- Fill in the blanks.

(i) The blood from the heart is transported to all parts of the body by the _____________ .

(ii) Haemoglobin is present in _____________ cells.

(iii) Arteries and veins are joined by a network of _____________ .

(iv) The rhythmic expansion and contraction of the heart is called _____________.

(v) The main excretory product in human beings is _____________.

(vi) Sweat contains water and _____________ .

(vii) Kidneys eliminate the waste materials in the liquid form called _____________ .

(viii) Water reaches great heights in the trees because of suction pull caused by _____________ .

Solution:-

(i) arteries

(ii) red blood

(iii) capillaries

(iv) heartbeat

(v) urea

(vi) salts

(vii) urine

(viii) transpiration

Question 3.- Choose the correct option:-

(a) In plants, water is transported through

           i) xylem

          ii) phloem

          iii) stomata

    

          iv) root hair

(b) Water absorption through roots can be increased by keeping the plants

           i) in the shade

           ii) in dim light

           iii) under the fan

           iv) covered with a polythene bag

Solution:-

a) i) Xylem

b) iii) under the fan

Question 4.- Why is transport of materials necessary in a plant or in an animal? Explain.

Solution:- Transport of materials is necessary in both plants and animals as every cell needs regular supply of nutrients and oxygen for releasing energy through respiration.

The food that we eat is broken down into smaller components to be absorbed by cells. The oxygen we inhale also has to be transported to all the cells of the body. Our body also requires constant removal of waste materials such as carbon dioxide.

For the transport of all these materials (nutrients, oxygen and waste products) our body has a specialised transport system. 

Similarly, in plants, the transport of water and food is accomplished with help of vascular tissues (xylem and the phloem). 

Question 5.- What will happen if there are no platelets in the blood?

Solution:- If there are no platelets, then blood will not clot as platelets release blood clotting factor at the site of injury and stops further bleeding.

Question 6.- What are stomata? Give two functions of stomata.

Solution:- Tiny pores present on the leaf surface are known as stomata. Stomata helps in exchange of gases & evaporation of water through leaves occurs due to stomata.

Question 7.- Does transpiration serve any useful function in the plants? Explain.

Solution:- Transpiration serves the following functions in plants :- 

• It helps in lowering temperature of plants, thus preventing heat injury of plants.

• Helps in transpiration pull, which helps in raining water in higher plants.

• It also causes loss of water absorbed by plants.

Question 8.- What are the components of blood?

Solution:- Red blood cells, white blood cells, platelets and plasma.

Question 9.- Why is blood needed by all the parts of a body?

Solution:- Blood is a significant part of transport system in our body, and we need blood for the following reasons:-

• For the transport of oxygen to all parts of our body

• To expel out carbon dioxide from our body

• To transmit heat thus helping in the regulation of body temperature.

• It is required to fight out infections and diseases.

Question 10.- What makes the blood look red?

Solution:- The presence of a red pigment called haemoglobin in red blood cells (RBC) makes the blood appear red.

Question 11.- Describe the function of the heart.

Solution:- The heart is an organ which beats continuously to act as a pump for the transport of blood, which carries other substances with it. The heart has four chambers. The two upper chambers are called the atria (singular: atrium), and the two lower chambers are called the ventricles. The partition between the chambers helps to avoid mixing up of blood-rich in oxygen with the blood-rich in carbon dioxide. Blood flow from the heart to the lungs and back to the heart from where it is pumped to the rest of the body.

Question 12.- Why is it necessary to excrete waste products?

Solution:- When our cells perform their functions, certain waste products are released. These are toxic and hence need to be removed from the body.

Question 13.- Draw a diagram of the human excretory system and label the various parts.

Solution:- 

-- Frequently Asked Questions --

Question 1.- What are the functions of transpiration in Plants?

Solution:- The functions of transpiration in Plants are :-

• The temperature is lowered in plants which prevent heat injury.

• Transpiration pull occurs where the rainwater is stored in higher plants.

• It also causes loss of water which is absorbed by plants.

Question 2.- What is the function of the heart?

Solution:- The heart is an organ of the human body which acts as a pump to transport blood and other substances. There are four chambers where the upper two chambers are called the atria and the lower two chambers are called the ventricles. There is a partition between them which helps to avoid mixing up of blood containing oxygen and carbon dioxide. Blood flow occurs from the heart to the lungs and back to the heart from where it is supplied to all the parts of the body.

Question 3.- What are the components of blood?

Solution:- The components of blood are :-

• Red Blood Cells (RBC)

• White Blood Cells (WBC)

• Platelets

• Plasma

Question 4.- What is the human ‘Circulatory system’?

Solution:- The circulatory system pumps blood from the heart to the lungs to get oxygen. The heart then sends oxygenated blood through arteries to the rest of the body.

Question 6.- What are ‘Capillaries’?

Solution:- Capillaries are very tiny blood vessels and they help to connect the arteries and veins in addition to facilitating the exchange of certain elements between blood and tissues.

- By Durgesh Pandey