Tag: biology

Questions Related to biology

Function of SA node is to ensure

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Muscular pain

  2. Contraction of lungs

  3. Heart beat

  4. None of the above

Show answer
Correct Option: C
Explanation:

The entire heart is made of cardiac muscles. A specialized cardiac musculature called the nodal tissue is also distributed in the heart i.e sino-atrial node (SAN- A patch of this tissue is present in the right upper corner of the right atrium ). The nodal musculature has the ability to generate action potentials without any external stimuli, i.e., it is autoexcitable. Hence function of the SA node is to ensure heartbeat.

So, the correct answer is 'Heartbeat'.

Mark the correct match.

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Malleus - Anvil

  2. SA node - Pacemaker

  3. Leucocytes - Lymphocytes

  4. Haemophilia - Blood cancer

Show answer
Correct Option: B
Explanation:
A. Malleus is known as hammer bone and is the largest ear ossicles.
B. SA node is known as pacemaker. It initiates and maintains the rhythmic contraction of heart.
C. Leucocytes are white blood cells. Lymphocytes are agranular leucocytes i.e. white blood cells which do not contain granules. They are a type of white blood cells.
D. Haemophilia is a genetic disorder in which blood doesn't clot due to deficiency of coagulation factor. 
Hence, option B is a correct match.
So, the correct answer is 'SA node - Pacemaker'.

Pacemaker is situated in heart

cardiac cycle simple nutrients into cells the circulatory system biology

  1. In the wall of right atrium

  2. On interauricular septum

  3. On interventricular septum

  4. In the wall of left atrium

Show answer
Correct Option: A
Explanation:
Pace maker is Sinoatrial or SA node situated in the upper corner of wall of right atrium in heart. It initiates and maintains the rhythmic contraction of heart. Excitation waves begin in SA node due to which atria contract and the oxygenated and deoxygenated blood is forced into respective ventricles through atrioventricular valves. It acts as stimulus for the next wave of excitation and thus, maintains the frequency of heart beat.
So, the correct answer is 'In the wall of right atrium'.

State whether the following statements are true or false.
A  pacemaker is a tiny computerised electrical device that is implanted in -a patients body to regulate the brain activity.

cardiac cycle simple nutrients into cells the circulatory system biology

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

A pacemaker is a tiny battery run instrument placed near to the heart of a patient for generation impulses similar to the SA node for the rhythmic functioning of the heart

So, the correct answer is 'False'

Which of the following is the correct pathway for propagation of cardiac impulse?

cardiac cycle simple nutrients into cells the circulatory system biology

  1. SA node $\rightarrow$ AV node $\rightarrow$ Bundle of His $\rightarrow$ Purkinje fibres

  2. AV node $\rightarrow$ Bundle of His $\rightarrow$ SA node $\rightarrow$ Purkinje fibres

  3. SA node $\rightarrow$ Purkinje fibres $\rightarrow$ AV node $\rightarrow$ Bundle of His

  4. Purkinje fibres $\rightarrow$ AV node $\rightarrow$ SA node $\rightarrow$ Bundle of His.

Show answer
Correct Option: A
Explanation:

Cardiac impulse generates from SA node then it reaches to AV node, then to bundle of HIS and finally to Purkinje fibers, this is how the cardiac impulse is generated.

So, the correct option is 'SA node 
→→ AV node →→ Bundle of His →→ Purkinje fibers'.

What happens when the pacemaker becomes nonfunctional?

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Only auricles contract rhythmically

  2. Only ventricles contract rhythmically

  3. Cardiac muscles do not undergo co-ordinated rhythmic movements

  4. Auricles and ventricles contract rhythmically

Show answer
Correct Option: C

An artificial pacemaker is implanted subcutaneously and connected to the heart in patients

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Having 90% blockage of the three main coronary arteries

  2. Having a very high blood pressure

  3. With irregularity in the heart rhythm

  4. Suffering from arteriosclerosis

Show answer
Correct Option: C
Explanation:

Pacemaker serves to produce rhythmic impulses for the heart beat. The sinoatrial node (SA) node serves as a pacemaker and is a small mass of specialized cardiac muscle. It is present in the posterior wall of the right atrium near the opening of superior vena cava. 

When the natural pacemaker is defective, the heartbeat may be too fast, too slow or irregular. Artificial pacemakers are electronic devices that stimulate the heart with electrical impulses to maintain or restore a normal rhythm in people with slow heart rhythms. An artificial pacemaker provides an electrical impulse (discharge) that can stimulate the heart, thus restoring or maintaining a regular heartbeat. 
So, the correct answer is option C.

The 'cardiac pacemaker' in a patient fails to function normally. The doctors find that an 'artificial pacemaker' is to be grafted in him. It is likely that it will be grafted at the site 

cardiac cycle simple nutrients into cells the circulatory system biology

  1. Purkinje fibres

  2. Under the clavicle

  3. Atrioventricular node

  4. Bundle of His

Show answer
Correct Option: B
Explanation:
Sinoatrial (SA) node is the natural pacemaker of the heart. It generates the nerve impulses needed for heart contraction. When the SA node stops functioning, an artificial pacemaker should be implanted for proper conduction of impulse.
The artificial pacemaker is implanted inside the skin under the clavicle. In this, a vein is incised with the insertion of electrode lead through the valve of heart.
So, the correct answer is option B.

What is the amount of average price tag on nature's life support services determined by Robert Constanza and his colleagues?

biology water and air and their importance water management - case studies introduction to natural resources management of natural resources

  1. US $\$$ $3$ trillion a year

  2. US $\$$ $13$ trillion a year

  3. US $\$$ $23$ trillion a year

  4. US $\$$ $33$ trillion a year

Show answer
Correct Option: D
Explanation:

A small but growing chorus of ecological economists are saying that perhaps the best way to protect nature is to figure out just how much it’s worth — in cold, hard cash. In their quest to integrate Adam Smith with Rachel Carson, these proponents of “ecosystem valuation” are infuriating many of their colleagues: both economic evangelists preaching the gospel of the free market, and environmentalists who are horrified at the prospect of reducing the natural world to a cost-benefit analysis. At the epicenter of this maelstrom is Robert Costanza, director and founder of the Gund Institute for Ecological Economics at the University of Vermont, and cofounder of the International Society for Ecological Economics. In 1997, Costanza and his colleagues made news headlines around the world with a paper, published in the British journal Nature, that estimated the annual net worth of the biosphere: $33 trillion, a figure greater than the annual gross national products (GNP) of all the world’s economies combined.

So the correct option is 'US $ 33 trillion a year'.

Which is not an energy crop?

biology management of natural resources water management - case studies water and air and their importance introduction to natural resources

  1. Tapioca

  2. Sugarcane

  3. Calotropis

  4. Sugar beet

Show answer
Correct Option: C