Tag: cell membrane

Questions Related to cell membrane

Pneumotaxic centre occurs in.

  1. Cerebellum

  2. Cerebrum

  3. Medulla oblongata

  4. Pons varolii


Correct Option: D

The pneumotoxic and respiratory rhythm centres are respectively present in.

  1. Pons and medulla oblongata

  2. Corpus callosum and pons

  3. Medulla oblongata and hypothalamus

  4. Diencephalon and pons


Correct Option: A

Each $100$ml of human arterial blood carries 'P' ml of $O _2$ and 'Q' ml of $CO _2$ whereas each $100$ml of venous blood carries 'R' ml of $O _2$ and 'S' ml of $CO _2$. Choose the correct values of P, Q, R and S.

  1. P-$48$ml, Q-$19$ to $20$ml, R-$52$ml, S-$14$ to $15$ml

  2. P-$19$ to $20$ml, Q-$48$ml, R-$14$ to $15$ml, S-$52$ml

  3. P-$14$ to $15$ml, Q-$52$ml, R-$19$ml to $20$ml, S-$48$ml

  4. P-$52$ml, Q-$14$ to $15$ml, R-$48$ml, S-$19$ to $20$ml


Correct Option: B

What is $pO _2$ and $pCO _2$ in synthematic arteries?

  1. $pO _2$ $40$mm Hg, $pCO _2$ $45$mm Hg

  2. $pO _2$ $95$mm Hg, $pCO _2$ $104$mm Hg

  3. $pO _2$ $95$mm Hg, $pCO _2$ $40$mm Hg

  4. $pO _2$ $45$mm Hg, $pCO _2$ $40$mm Hg

  5. $pO _2$ $104$mm Hg, $pCO _2$ $159$mm Hg


Correct Option: C

Assertion :

Inspiration occurs due to muscular relaxation.



Reason : During

inspiration, ihe diaphragm and external iniercostal muscle contract

simultaneously






  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true


Correct Option: E
Explanation:

(e) Inspiration is the result of muscular contraction. The diaphragm and external intercostal muscle contracts simultaneously. The lateral thoracic wall moves outward and upward.





In response to $CO {2}$ and $H^{+}$ concentration, the chemosensitive area and, receptors associated with aortic arch and carotic artery, send necessary signals for remedial action to ______________.

  1. Pneumotaxic centre

  2. Apneustic centre

  3. Respiratory rhythm centre

  4. Both A and B


Correct Option: A

Listed below are four respiratory capacities (i-iv) and four jumbled respiratory volumes of a normal human adult.

Respiratory volumes and capacities Volume of air
(i)    Residual volume  2500 mL
(ii)   Vital capacity   3500 mL
(iii) Inspiratory reserve volume 1200 mL
 (iv) Inspiratory capacity  4500 mL

Which one of the following is the correct matching of two capacities and volumes?

  1. (ii) 2500 mL, (iii) 4500 mL

  2. (iii) 1200 mL, (iv) 2500 mL

  3. (iv)3500mL, (i) 1200 mL

  4. (i) 4500 mL; (ii) 3500 mL


Correct Option: C
Explanation:

Respiratory volumes and capacities Volume of air

Residual volume 1200 mL Vital capacity 4500 mL
Inspiratory reserve volume 2500 mL Inspiratory capacity 3500 mL.

Rate of breathing is controlled mainly by ________________.

  1. $CO _{2}$ level in blood

  2. pH in blood

  3. $O _{2}$ level in blood

  4. $O _{2}$ level and pH in blood.


Correct Option: A
Explanation:

Rate of breathing is mainly controlled by $CO _2$ level in the blood. Excess $CO _2$ decrease the pH of the blood and it mainly stimulate the respiratory centre of the brain (i.e., Medulla oblongata) and increase the inspiratory and expiratory signals to the respiratory muscles.

Rate of breathing is controlled mainly by

  1. $CO _2$ level in blood

  2. pH in blood

  3. $O _2$ level in blood

  4. $O _2$ level and pH in blood


Correct Option: A
Explanation:

The rate of breathing is controlled mainly by CO$ _2$ level in blood. The partial pressure of carbon dioxide (PCO$ _2$) controls the respiratory rate. The respiratory centre measures the levels of carbon dioxide, oxygen and acidosis in the arterial blood and sends message accordingly. If the carbon dioxide levels in the blood increases, the rate and depth of breathing increases.

Thus, the correct answer is 'CO$ _2$ level in blood.'

Which of the following is not a stimulus for breathing?

  1. Rising $CO _2$ levels

  2. Rising blood pressure

  3. Arterial $pO _2$ below $60$mm of Hg

  4. Change in pH of arterial blood


Correct Option: A
Explanation:

An increased concentration of carbon dioxide is the strongest stimulus to breathe more deeply and more frequently. When the carbon dioxide concentration in the blood is low, the brain decreases the frequency and depth of breath.

So the correct answer is 'Rising CO2 levels'.