Tag: biology

Questions Related to biology

Making of small check dams across the flooded gullies is important because they

management of water uses and limitations of dams air, water and soil management of natural resources biology

  1. hold water and prevent soil erosion

  2. recharge ground water

  3. help stagnate water

  4. hold water for irrigational purpose

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Correct Option: A,C

In our country, there are attempts to increase the height of several existing dams like Tehri and Almati, dams across Narmada. Choose the correct statements among the following that are a consequence of raising the height of dams.

management of water uses and limitations of dams air, water and soil management of natural resources biology

  1. Terrestrial flora and fauna of the area is destroyed completely

  2. Dislocation of people and domestic animals living in the area

  3. Valuable agricultural land may be permanently lost

  4. It will generate permanent employment for people

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Correct Option: A,B,C

The problems for criticism about large dams are that they

management of water uses and limitations of dams air, water and soil management of natural resources biology

  1. displace large number of peasants and triables without proper rehabilitation

  2. swallow up huge amounts of public money withrout the generation of proportionate benefits

  3. contribute enormously to deforestation and the loss of biological diversity

  4. all of the above

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Correct Option: C

Pacemaker is situated in the

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Wall of right atrium

  2. Interauricular septum

  3. Interventricular septum

  4. Wall of left atrium

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Correct Option: A
Explanation:
The actual structure that serves as the heart's primary pacemaker is called the sinoatrial node (SA node). The SA node is a little bundle of cells located in the wall of the right atrium, the small upper chamber on the right side of the heart.
Thus, the correct answer is 'Wall of right atrium.'

The pacemaker of heart is

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Foramen ovale

  2. Sinoatrial node

  3. Ductus arteriosus

  4. Bundle of His

  5. Vagus nerve

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Correct Option: B
Explanation:

Electrical impulses from the heart muscle cause your heart to beat (contract). This electrical signal begins in the sinoatrial (SA) node, located at the top of the heart's upper-right chamber (the right atrium). The SA node is sometimes called the heart's“natural pacemaker.”

So, the correct option is 'Sino-atrial node'.

Rate of heart beat is determined by

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Purkinje fibres

  2. Papillary muscles

  3. AV-node

  4. SA-node

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Correct Option: D

The heart beat is initiated and regulated by nodal tissue made of specialised cardiac muscles called

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Spongy tissue

  2. Purkinje tissue

  3. Alveolar tissue

  4. None of these

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Correct Option: B
Explanation:

Purkinje tissue is influenced by electrical discharge from the sinoatrial node. During the ventricular contraction portion of the cardiac cycle, the Purkinje fibres carry the contraction impulse from both the left and right bundle branch to the myocardium of the ventricles. In this way these fibres control and initiate heart beat.

So, the correct option is B. ( Purkinje tissue )

The action potential is conducted from the atria to ventricles by:

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Purkinje fibre

  2. SA node and AVN

  3. Bundle of his and SAN

  4. All of the above

Show answer
Correct Option: B
Explanation:
  • Sino-atrial node (SA node) is located the right upper corner of the right atrium and AVN(AV node) is located in the lower-left corner of the right atrium close to the atrioventricular septum.
  • The SAN can generate the maximum number of action potentials, i.e., $70-75 min^{–1}$, and is responsible for initiating and maintaining the rhythmic contractile activity of the heart. Therefore, it is called the pacemaker. From the SA node, the action potential is conducted from the atria to ventricles by AVN.
  • Hence the action potential is conducted from the atria to ventricles via SA node and AVN.
  • So, the correct answer is 'SA node and AVN'.

Sinoatrial node (SAN) is located at

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Right upper corner of right atrium

  2. Right Lower lower corner of right atrium

  3. Right upper corner of left atrium

  4. Left upper corner of right atrium

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Correct Option: A
Explanation:

The sinoatrial node is present at the right upper corner of the right atrium. The node is present below the Vena Cava. It initiates the autonomous contraction of the heart muscles.

So, the correct option is 'Right upper corner of right atrium'.

Give these structure of the conduction system of the heart :
1. It is Atrioventricular bundle
2. AV node
3. Bundle branches
4. Purkinje fibres 
 5. SA node
Choose the arrangement that lists the structures in an order of an action potential passes through them.
cardiac cycle simple nutrients into cells the circulatory system biology

  1. $2,5,3,1,4$

  2. $5,2,1,3,4$

  3. $2,5,1,3,4$

  4. $5,2,4,1,3$

Show answer
Correct Option: B
Explanation:

The correct series is 

5.SA node
2.AV node
1.It is atrioventricular bundle
3.Bundle branches
4. Purkinje fibers
So, the correct answer is '5,2,1,3,4'