Anatomy and Physiology MCQs

Cells and Tissues

The cell membrane’s resting potential (about −70 mV inside with respect to the outside) is due mainly to which of the following mechanisms?

The sodium-potassium pump

The diffusion of cations and anions through the membrane along their concentration gradients

The diffusion of sodium and potassium across the cell membrane

The presence inside the cell of anions too large to passively cross the cell membrane

The ATPase pump shifts 3 Na+ out of the cell and 2 K+ into the cell. This disparity in positive charge is the major influence on the resting potential.

Author: rikazzz Comment

Cells and Tissues

What is the function of phospholipids in the plasma membrane?

To maintain the intracellular fluid at a similar composition to that of the interstitial fluid

To form channels to selectively allow passage of small molecules

To act as receptors for signalling chemicals

To present a barrier to the passage of water-soluble molecules

Molecules that are soluble in water cannot pass through lipid (fat). So the phospholipids are a barrier. The functions described by B and C are performed by other molecules in the plasma membrane.

Author: rikazzz Comment

Body Temperature, Energy and Heat Loss

The Système International (Standard International) unit of power is the watt. This unit is the same as which one of the following?

Electronvolt

Joule

Joule per second

Kilojoule

Power is the rate of doing work or of converting energy from one form to another. The unit of power = J/s is renamed the watt in honour of James Watt. All the other choices are units of energy.

Author: rikazzz Comment

Nervous System

Which of the following substances is prevented from entering the brain by the blood-brain barrier?

Glucose

Nicotine

Pharmaceuticals

Alcohol

Many pharmaceuticals are unable to cross the BBB.

Author: rikazzz Comment

Cardiovascular System

Which of the following is not a type of white blood cell?

Leucocyte