Question

 Question 44

Which of the following statements is true about the resting membrane potential of a mammalian neuron? 

• The concentration of K⁺ is greater outside the cell than inside the cell 

• The sodium potassium pump maintain the Na' and K gradient in the resting membrane potential by moving those ions across the plasma membrane with the energy provided by ATP. 

• The inside of the cell is positively charged. 

• The concentration of Na⁺ is greater inside the cell than outside the cell.

• The resting membrane potential of a cell is Omv.

 Question 45 

The _______  is the amount of air that remains in the lungs after exhalation. 

• stroke volume 

• residual volume 

• pulse 

• vital capacity 

• tidal volume
  

Answer 1

44)Ion channels present on the plasma membrane of the animal cells are mainly responsible for regulating potential difference across .Resting membrane potential of a neuron or a cell is achieved due to the difference in concentrations of cations and anions especially Sodium and Potassium ,inside and outside the cells.The net concentration of K+ ion is higher inside the cell whereas Na+ concentration is higher in the outside environment at resting membrane potential.Potassium leaky channels are also responsible for an overall negative potential of the neurons at resting stage.The resting membrane potential of a neuron is -70mV.If the activity of Na+/K+ pump is inhibited, resting potential is disrupted and interferes with the generation of action potential.

45)Static Lung Volume is the volume of air present in the lungs under the specified static condition.These are of four types:

1)Tidal Volume- The amount of air that moves into the lungs with each inspiration or amount of air that moves out with each expiration during quite breathing.Normal Range=500ml

2)Inspiratory reserve volume-It is an additional volume of air that can be inspired forcefully after the end of normal inspiration.Normal Range=2000ml

3)Expiratory reserve volume-The volume of air expelled by an active expiratory effort(forcefully) after the passive expiration. Normal range=1000ml

4)Residual Volume-Volume of air remaining in the lung even after forceful expiration.Range=1300ml.As the lungs cannot be completely empty of air anytime,it can be said that residual volume is the air present in the lung at all times.

Vital capacity is the amount of air expired from fully inflated lungs(Tidal Volume+Inspiratory reserve volume) Normal Range(3500ml)

Stroke Volume is the amount of blood injected into a single beat by the left ventricle.