Thursday, November 1, 2012

CBSE_NCERT_Transportation and Excretion 7th Biology

Transportation and Excretion 7th Biology


William Harvey was an English physician was the first to give the details of blood circulation, the properties of blood and the pumping of blood by the heart.
William Harvey was an English physician was the first to give the details of blood circulation, the properties of blood and the pumping of blood by the heart.

1. Q. Explain form and function of urinary system in man?


Urinary system consists of Kidney, The ureters, the urinary bladder and the urethra.
 The Functions of the Urinary System:
The kidneys regulate blood volume and composition, help to regulate blood pressure and pH, participate in red blood cell production and synthesis of vitamin D, and excrete waste products and foreign substances. The Nephron tubule is the functional unit of the kidney.
The ureters transport urine from the kidneys to the urinary bladder.
The urinary bladder stores urine and expels urine into the urethra,
The urethra discharges urine from the body.
2. Q. briefly describes the human circulatory system?

The circulatory system is made up of the Blood vessels, heart and Blood that help and control the flow of the blood around the body.


Heart pump blood around your body by alternate systole  and diastole.

Blood is the connective tissue that carries food, air, waste product and hormones. it contain fluid medium called plasma and three types of cell RBC,WBC and Platelets.

There are three distinct types of blood vessels, namely, arteries, veins and capillaries circulate blood around body.

3. Q. Describe composition of blood and explain function of its components?

The liquid component of blood is the plasma which is composed of water. it caries digested food,harmones CO2 etc.
RBC (Erythrocytes) caries oxygenated blood  WBC (Leukocytes) Fight against diseases. and platelets help in blood clotting.

4.Q. What is dialysis? Explain.

Dialysis is the artificial process of getting rid of waste and unwanted water from the blood by dialysis machines. 
Dialysis machines contain a tank with solution of water glucose and salt. Patient’s blood allowed passing through solution for removal of waste. the cleaned blood pumped to vein. The dialysis continues till all blood has been purified.

5. Q. What is another name for platelets?

Another name for platelets is thrombocytes 

Q. 21. Write the two functions of kidneys.


Ans. Osmoregulation and   excretion.

Q. 6. What are spiracles?

Ans The holes found on the lateral side of insect‘s body.

 Q. 7. Why do veins have thin walls compared to arteries?

Ans: Veins do not have thick walls because blood is no longer under pressure but blood emerges from the heart under high pressure. So arteries have thick walls

Q. 8. What do the following transport?
 a) xylem b phloem 
c) pulmonary vein
d) venacava

Ans. a) xylem-water and minerals
        b) Phloem- prepared food.
        c)  Pulmonary vein-oxygenated blood
       d) vena cava -deoxygenated blood

Q 9 .Write one function each of the following components of transport system in human beings.   
a) Arteries b) veins c) capillaries

Ans. a) Arteries- carry blood from heart to different parts of body
       b) veins-carry blood from different parts of body to the heart.
       c) Capillaries-exchange of material between blood and surrounding cells.

Q10. Differentiate between osmoregulation and excretion

Ans :  Excretion is the elimination of metabolic waste products from the body.
Osmoregulation is regulating osmotic pressure of the body fluids by controlling the amount of water and salts in the body

Q.11   Why is heart known as the pumping organ of the human body?

Ans Heart is the pumping organs of a human body as it continuously act as a pump for transporting blood to all body parts. Heart pumps carbon-dioxide rich blood to lungs and oxygen rich blood to rest of the body.

Q.12   What is the significance of dividing heart into different chambers?


 Ans. The division of heart into different chambers ensures that there is no intermixing of oxygenated and deoxygenated blood. This ensures a better efficiency of circulation and transportation of oxygen.

Q 13.  How do plants absorb water and minerals from soil?


Ans: Plants absorb water and minerals from soil by the roots. The root hair absorbs water and dissolved mineral nutrients from the soil. The roots remain in contact with underground water.

Q 14.  What do you mean by pulse and pulse rate?

Ans:  When blood flows in arteries, it gives throbbing sensation in arteries. This throbbing sensation is known as a pulse. The rate of heart beat or throbbing is known as pulse rate. A person has a pulse rate between 72 to 80 beats per minute. A stethoscope is an instrument used to measure the sound heart beat.

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