Nervous System

The sympathetic division “stirs you up” to get ready for action. The only choice consistent with vigorous activity is D.

Indeed, some organs (e.g. heart) are innervated by both divisions. In choices A and B, replace “sympathetic” with parasympathetic, and in choice C replace “parasympathetic” with sympathetic, to get a true statement.

The peripheral NS delivers sensory information to CNS as well as carrying motor commands from CNS to peripheral tissues. The somatic NS is part of the efferent division (carrying impulses away from the brain) of the peripheral NS. The autonomic (and parasympathetic division) carry efferent impulses.

The resting potential is negative, and the first ion movement is sodium ions into of the cell.

Motor neurons release acetylcholine.

A “postganglionic cholinergic fibre” runs from a ganglion to an effector organ (so choice A is wrong) and releases ACh (so choice C is wrong). Alpha and beta receptors are both adrenergic – that is, bind with epinephrine and norepinephrine (=adrenalin and noradrenalin) – so choice B is wrong.

The epidural space is above or on top of the dura and external to the spinal cord. It is between the spinal cord and the surrounding vertebrae.

Myopia is “short-sightedness” meaning that items that are close may be seen clearly but those far away cannot be seen. Myopic people need to be closer in order to see the item clearly. 3/6 vision means that from 3 m away, items may be seen that are normally clear from 6 m away. Choice B, 6/7 is a little myopic but not as much as 3/6.

The postsynaptic membrane is stimulated by a neurotransmitter, after it crosses the synaptic cleft, so has receptors for it. The postsynaptic membrane may be part of a muscle cell.

The precentral gyrus of the frontal lobe is the primary motor area. It controls voluntary movements of skeletal muscle.