Hello Students: DAY- 28 Evening Coffee with NEET



9.Why auricles have thinner walls than the ventricles?

= Auricles have thinner walls in comparison to ventricles because the major function of auricles is to receive blood and pump it to the respective ventricles.While the major function of ventricles is pump the blood out of the heart ,i.e.to lungs and to the body parts which requires a great force.

10.The wall of left ventricle is thicker than right ventricle.Why ?

= The left ventricle is thicker than the right ventricle because the left ventricle pumps oxygenated blood around the entire body through the Aorta while the right ventricle only pumps blood to the lungs through Pulmonary artery which is much shorter distance.

11.Why artery have thick elastic wall ?

= Arteries carry oxygenated blood from the heart to the different body parts.Blood emerges from the heart under high pressure.In order to withstand this pressure , arteries have thick and elastic walls.

12.Why valves are present in the veins?

= Unlike arteries veins contain valves that ensure blood flows in only one direction.But, Arteries don't require valves because pressure from the heart is so strong that blood is only able to flow in one direction.Valves also help blood travel back to the heart against the force of gravity.

13.Why  lichens are called as  bioindicator of air pollution?

= Lichens are very sensitive to Sulphur dioxide pollution in the air.So in the clean environment Lichens will grow abundantly.In polluted environment with SO2 ,lichens are absent .

14.What is an Intestinal infection due to E.coli ?

= E.coli is a type of bacteria that normally live in the intestines of people and animals.However ,some types of E.coli , particularly E.coli O157:H7,can cause Intestinal infection by Shiga Toxin.

15.How blood is stored in blood bank?

= Blood is collected into a plastic bag which contains anticoagulant Citrate -Phosphate Dextrose(CPD),Acid - Citrate Dextrose (ACD) with other preservative,additive  solutions like SAGM( Saline, Adenine,Glucose,Mannitol).
 Red cells are stored in refrigerators at 6°C for up to 42 days . Platelets are stored at room temperature in agitators for up to five days .Plasma is stored in freezers for up to one year.

Mr.R.Soundarapandian, MSc, MEd, MPhil, 
PG Asst Zoology 
SIR MCTM Boys Higher Secondary School, 

Purasawalkam Chennai-84.

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