Human Body and Organ system

Question 1:

Find out my partner.

Group 'A'	Group 'B'
1. Heart beats	a. 350 ml
2. RBC	b. 7.4
3 WBC	c. 37∘C
4 Blood donation	d. 72
5 Normal body Temperature	e. 50-60 lakh/mm3
6 pH of oxygenated blood	f. 5000-6000 per mm3

ANSWER:

Group 'A'	Group 'B'
1. Heart beats	d. 72
2. RBC	e. 50-60 lakh/mm3
3 WBC	f. 5000-6000 per mm3
4 Blood donation	a. 350 ml
5 Normal body Temperature	c. 37∘C
6 pH of oxygenated blood	b. 7.4

Question 2:

Complete the following table.

Organ system	Organs	Functions
1. Respiratory
2. Circulatory system

ANSWER:

 

Organ system	Organs	Functions
1. Respiratory	Nose Pharynx Wind pipe Lungs	Traps dust particles and microbes and prevents their entry in the respiratory system. Acts as a passage for the entry of air into the wind pipe. Acts as a passage through which air passes into the lungs. Exchange of gases occurs in lungs.
2. Circulatory        system	Heart Blood vessels	The main organ from where circulation of blood to different body parts occurs. Closed system of vessels which help in circulation of blood.

Question 3:

Draw neat and labeled diagrams.
a. Respiratory system
b. Internal structure of heart.

ANSWER:

a. Respiratory system




b. Internal structure of heart

Question 4:

Explain with reasons.
a. Human blood is red colured.
b. Upward and downward movement of diaphragm occurs consecutively.
c. Blood donation is considered to be superior of all donations.
d. person with 'O' blood group is considered as 'universal donor'
e. Food must have limited amount of salts.
 

ANSWER:

a. Human blood is red in colour due to the presence of the respiratory pigment haemoglobin. Haemoglobin is a pigment which is red in colour and thus imparts red colour to the blood.

b. Diaphragm is a muscular partition which is present between the thoracic cavity and abdominal cavity. During the process of breathing, the upward and downward movement of diaphragm occurs simultaneuosly. When we inhale, the ribs rise up while the diaphragm lowers down simulatenously causing a decrease in pressure on lungs. This results in the moving of air into lungs through nose. As the ribs return to their original position, diaphragm rises up leading to the increase in pressure inside the lungs. This results in moving of the air outside the nose.

c. Blood donation is considered superior of all donations because it can save someome's life. Most of the lives are lost due to blood loss during surgeries, accidents or cases where regular blood transfusion is required. These lives can be saved, if adequate amount of blood is available.

d. Person with 'O' blood group is considered as 'universal donor' because such an indivisual can donate blood to a person having any other blood group.

e. Food must have limited amount of salts as we require limited amounts of these in our body. Excessive salts in food can lead to accumulation of water in different parts of the body such as arms, legs etc. and lead to edema. Too much salt leads to increase in the blood pressure as well.

Question 5:

Answer the follwing questions in your own words.
a.Explain the functional correlation of circulatory system with respiratory, digestive and excretory system.
b.Explain the structure and function of human blood.
c.Explain the importance and need of blood donation.
 

ANSWER:

a. The functional corelation between circulatory system with respiratory, digestive and excretory system is as follows:

We already know that during respiration exchange of gases occurs in the lungs. The respiratory system causes the diffusion of oxygen into the blood and the diffusion of CO₂ out of the blood. The oxygen is then transported to cells of the body via the circulatory system. 
The digestive system is responsible for producing nutrients by breaking complex molecules into simpler ones. The circulatory system then tranports these nutrients to different cells and tissues. 
The excretory system is responsible for the elmination of waste products from the body. These waste products are transported by blood to the excretory system.


b. Blood is a fluid connective tissue that flows in blood vessels. It is composed of two components- plasma and blood cells. 

Plasma is a yellowish colour fluid, made up of water (~90%) and some dissolved nutrients, proteins, hormones and waste products. 

Blood consists of three types of blood cells. These are

i. Red Blood Cells: They contain a red pigment called haemoglobin, which transports oxygen to all body cells.

ii. White Blood Cells: They fight against germs that enter the body. Thus, they protect the body from diseases.

iii. Platelets: When we get injured, bleeding stops after some time. This happens because of the activity of platelets, which help in the clotting of blood.

Functions of blood:

• It transports nutrients and oxygen to the different parts of the body.

• It also carries waste materials (from the different parts of the body) to be removed by the excretory organs.

• Chemical messengers like hormones are transported by the blood.

• Protects the body from disease carrying germs.

• Helps to maintain a constant body temperature.

c. Blood donation is one of the biggest donations of an inidivisual towards their society. Blood loss can occur under circumstances of accidents, during surgeries or in case of diseases which require blood transfusion. Adequate amount of available blood can save many lives. It does not harm or effect the body of the donor and the amount of blood which is donated is recovered within 24 hrs.
This donated blood can be stored and used as and when the requirement arises.

 

Question 6:

Explain the differences.
a. Arteries and veins.
b. External and internal respiration

ANSWER:

a. 

External respiration	Internal respiration
1. It occurs between the body and external environment.	It occurs at the cellular level.
2. It is a mechanical process.	It is a chemical  process.
3. It can be both- voluntary and involuntary action.	It is only an involuntary action.

​
b. 

Arteries	Veins
1. Carries blood towards organs and away from heart.	Carries blood towards heart and away from organs.
2. Carries fully oxygenated blood	Carries deoxygenated and CO2 enriched blood.
3. Blood flows with high pressure and jerks,.	Blood flows with low pressure and smoothly.
4. Have no valves	Have valves to prevent backflow of blood.
5. Walls are elastic.	Walls are non-elastic.
6. Are Deeply placed.	Are superficial.
7 Branched and decreases in size.	Unites and increases in size
8. Can constrict and dilate	Cannot constrict.
9. Have thick and muscular walls	Have thin and less muscular walls.
10. Smallest artery is called arteriole	Smallest vein is called Venules.

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Question 7:

Which health parameters of blood donor should be checked?
 

ANSWER:

The following parameters of blood donors have to be checked prior blood donation:
 

1. Age – There is a set age before which and after which blood donation can be done or not respectively.​
 

2. Weight – Weight of individuals is also an important factor as underweight indivisuals are not allowed to donate blood. In underweight indivisuals, the likelihood of having a reaction such as dizziness and fainting following donation are higher.

3. Heart, lung, and blood disease – Donors are enquired about any prior history of heart, lung, or blood diseases. People with heart disease, heart valve conditions, irregular heartbeat, disease of the blood vessels in the brain, heart failure, and certain lung conditions may be excluded from blood donation. Certain blood diseases such as iron deficiency anemia or chronic leukemia may also lead to exclusion.

4. Other medical conditions – Any other medical condition such as diabetes, hypertension, hypotension, fever etc. are also checked before blood donation.

5. Recent surgery – People with recent surgery are not allowed for donating blood. However, after an year of surgery they can donate blood but only if healing is complete and they have resumed full activity.

6. Pregnancy – Women who are pregnant are not permitted to donate blood during pregnancy and for six weeks after the pregnancy ends.

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Question 8:

Fill in the blanks using appropriant words given in the bracket.
( hemoglobin, alkaline, diaphragm, red bone marrow, acidic, voluntary, involuntary.)

a. RBCs of the blood conatin _________, an iron compound.

b. ____________ is present between thoracic and abdominal cavity.

c. Cardiac muscles are_______

d. pH of oxygenated blood is________

e. Production of RBCs occurs in__________

ANSWER:

​a. RBCs of the blood conatin hemoglobin, an iron compound.

b. Diaphragm is present between thoracic and abdominal cavity.

c. Cardiac muscles are involuntary.

d. pH of oxygenated blood is alkaline.

e. Production of RBCs occurs in red bone marrow.

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Question 9:

Find odd one out.
a. A, O, K, AB, B.
b. Blood plasma, platelets, blood transfusion, blood corpuscles.
c. Trachea, alveoli, diaphragam, capillaries.
d. Neutrophils, globulins, albumins, prothrombin.            

ANSWER:

a. A, O, K, AB, B - K is the odd one out because it is an inorganic ion while rest of the four are types of blood groups.
b. Blood plasma, platelets, blood transfusion, blood corpuscles- Blood transfusion is the odd one out because it is a techniques for transfer ing of blood from donor to repeient. Rest of the three are components of blood.
c. Trachea, alveoli, diaphragam, capillaries- Capillaries are the odd one out because they are a part of the circulatory system while rest of the three are parts of the respiratory system.
d. Neutrophils, globulins, albumins, prothrombin- Neutrophils are the odd one out because they are a type of blood cell. Rest of the three are components of the plasma.         

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Question 10:

Read the following paragraph and identify the disease.

Today, her child became one and half year old. However, that child does not seem to be healthy and happy. It was continuously crying and gradually becoming weak. It has shortness of breath. Its nails have become blue.

ANSWER:

From the above mentioned symptoms, it seams like the child is suffering from some kind of respiratory disorder/circulatory disorder. He has problem in breathing and his nails have become blue which means there is low level or lack of oxygen circulating in the red blood cells. It is known as cyanosis.
It occurs when enough oxygen is not present in blood, thus making the skin or membrane below the skin turn purplish-blue.

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Question 11:

Your neighboring uncle has been diagnosed with hypertension. what should he do to keep hsi blood pressure within normal range?

ANSWER:

The following methods can be adopted to keep the blood pressure within normal range:

• loose the extra weight
• exercise or do yoga regularly
• eat a healthy balanced diet containing fruits and vegetables
• reduce the amount or salt in food
• avoid alcohol and smoking
• reduce the amount of stress by indulging in your favourite activities
• regular monitoring of blood pressure 

Std.7 Ch. 12 Muscular system and Digestive system

Question 1:

Fill in the blanks with the right word from the brackets.
(a) The process of digestion starts from the ............. . (stomach / mouth)
(b) Eyelids have ............. muscles (voluntary / involuntary)
(c) ............ is not a function of the muscular system. (production of blood cells / Performing movements)
(d) Muscles of the heart are .............. (ordinary muscles / cardiac muscles)
(e) Pushing forward the food that has been chewed is the function of the ............. . (stomach / oesophagus).

ANSWER:

(a) The process of digestion starts from the mouth.
(b) Eyelids have voluntary muscles.
(c) Production of blood cells is not a function of the muscular system. 
(d) Muscles of the heart are cardiac muscles.
(e) Pushing forward the food that has been chewed is the function of the oesophagus.​
 

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Question 2:

Find a match for me.

Group 'A'	Group 'B'
(1) Cardiac muscles	(a) always function
(2) Are brought about by muscles	(b) we never feel tired.
(3) Pepsin	(c) uncontrolled and painful contraction of muscles.
(4) Cramps	(d) chewing movements of jaws.
(5) Skeletal muscles	(e) enzyme of the gastric juice.

ANSWER:

​

Group 'A'	Group 'B'
(1) Cardiac muscles	(b) we never feel tired.
(2) Are brought about by muscles	(d) chewing movements of jaws.
(3) Pepsin	(e) enzyme of the gastric juice.
(4) Cramps	(c) uncontrolled and painful contraction of muscles.
(5) Skeletal muscles	(a) always function

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Question 3:

Who is telling a lie ?

Organ	Statement
1. Tongue	My taste-buds can tell only a sweet taste.
2. Liver	I am the largest gland in the body.
3. Large intestine	I am 7.5 meter long.
4. Appendix	Digestion is impossible without me.
5. Lung	I play an important role in excretion.

ANSWER:

The tongue, large intestine, appendix and lungs are lying.

1. Tongue can taste salt, sweet and bitter tastes.
2. Large intestine is 1.5 meter long.
3. Appendix is not required for digestion.
4. Kidneys play an important role in excretion.

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Question 4:

Give reasons.
(1) Food becomes acidic in the stomach.
(2) Cardiac muscles are said to be involuntary muscles.
(3) Intoxicating substances should not be consumed.
(4) Your muscles should be strong and efficient.

ANSWER:

a. Food becomes acidic in stomach because of the presence of hydrochloric acid in the stomach. As the food reaches the stomach, it gets mixed with the hydrochloric acid present there. The hydrochloric acid plays the following roles in digestion:

1. It initiates protein digestion by activating the conversion of pepsinogen to pepsin.

2. It provides acidic medium for the activity of pepsin and other enzymes present in gastric juice.

b. Cardiac muscles are said to be involuntary because they are not controlled by our will. These muscles are found in heart and are the only muscles which work throughout the life without getting tired or fatigue.

c. Intoxicating substances should not be consumed because they harm the body directly or indirectly. Substances such as alcohol cause damage to the nervous system and the digestive system as well. Liver is the main organ which is affected by alcohol. Tobacco is one of the leading causes of oral cancer. Smoking has a direct effect on the respiratory system of an individual and can lead to lung cancer as well.

d. Our muscles should be strong and efficient because they carry out various vital functions in our body. From helping us to breath, digest food to helping us in walking and lifting weights, muscles play an important role. If our muscles are not strong enough we would get tired easily and feel fatigue. It is required to keep them in a healthy state by regular exercising and taking proper diet. 

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Question 5:

Answer the following.
(a) How many types of muscles are there? Which are those types?
(b) What causes the problem of acidity? What is its effect on the body?
(c) Name the different types of teeth. What is the function of each type?

ANSWER:

a. There are 3 types of muscles:

• Skeletal muscle fibre: They are found attached to the skeletal bones and are voluntary. Skeletal muscle fibres are striated and are bundled together in a parallel manner by a sheath of tough connective tissues.

• Smooth muscle fibres: They are present in the walls of internal organs such as blood vessels, stomach, etc., and are involuntary. Smooth muscle fibres are fusiform (taper at both ends) and non- striated. They are held together by cell junctions and are bundled together in a sheath of connective tissues.

• Cardiac muscle fibres: This is the only type of muscle present in the heart. They are contractile in nature and are involuntary. Plasma membranes of cardiac cells are fused together by cell junctions, and hence, the cells stick together. Communication junctions present as intercalated discs facilitate the contraction of cardiac cells as a unit.

b. Stomach contains special cells called oxyntic or parietal cells which secrete hydrochloric acid in stomach. It plays two important roles like:

1. It initiates protein digestion by activating the conversion of pepsinogen to pepsin.

2. It provides acidic medium for the activity of pepsin and other enzymes present in gastric juice.

However, if the level of this HCl exceeds its normal levels, it results in acidity/acid reflux. Higher levels of HCl can result in the following effects on the body:

1. burning sensation in the stomach
2. burning sensation in the throat and heart
3. difficulty in swallowing
4. regurgitation
5. restlessness
6. belching
7. nausea
8. prolonged sour taste in the mouth
9. indigestion

Exposure to higher levels of HCl for longer durations can also result in the development of peptic ulcers/ulcers in the stomach. 


c. There are 4 types of teeth which are found in humans:

1. Incisors are the teeth present at the front portion of the mouth. There are four incisors in each jaw. They are used for biting and cutting food.
2. Canines are located next to the incisors. There are two canines in each jaw. They are used for tearing and piercing food.
3. Premolars lie next to the canines. There are four premolars in each jaw. They are used for chewing and grinding food.
4. Molars lie next to the premolars at the end of the jaw. There are six molars in each jaw. They are also used for chewing and grinding food.

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Question 6:

Sketch and label a diagram of the digestive system and describe it in your own words.

ANSWER:

Major constituent organs of the human digestive system are: buccal cavity, oesophagus, stomach, small intestine, large intestine, rectum and anus.

Buccal cavity − It includes the teeth, saliva and tongue. The teeth break down the food. Digestion of food begins in the mouth. The tongue helps in the chewing and swallowing of food.

Oesophagus − The food passes from the mouth, down the oesophagus, into the stomach, as a result of the movement of the walls of the oesophagus.

Stomach − It mixes the food received from the oesophagus with digestive juices.

Small intestine − The food from the stomach moves into the small intestine, which receives intestinal juices from two glands − liver and pancreas. These juices help in the further digestion of food.

Large intestine − Water is absorbed in the large intestine.

Rectum and anus − Undigested food particles are thrown out with the help of the rectum and anus.