Nervous System

    Nervous System
    Which of the following substances CANNOT cross the blood-brain barrier?
    The BBB protects the brain from these substances. The substances in the other choices can all cross the BBB.
    Author: rikazzz Comment
    Nervous System
    One of the functions of the prefrontal cortex is:
    The prefrontal cortex (of frontal lobe) performs abstract intellectual functions such as predicting the consequences of actions or events. Hence it helps us make conscious decisions.
    Author: rikazzz Comment
    Nervous System
    What is the gap between the plasma membranes of a neuron that conducts an incoming signal and the cell that is going to receive the signal called?
    The gap between cells at a synapse is called a synaptic cleft. A neuromuscular junction is one type of synapse.
    Author: rikazzz Comment
    Nervous System
    Which cells of the retina are responsible for detecting light in scotopic (i.e. low light) conditions?
    Rods and cones are the light sensitive cells. Rods are used for viewing in low light (dim) or night-time conditions.
    Author: rikazzz Comment
    Nervous System
    Accommodation refers to the eye’s ability to focus light from objects whatever their distance from the eye. How is this achieved?
    The eye lens is flexible. If stretched by the zonules, it adopts a flattened and thin biconvex shape; if it is allowed to recoil into its relaxed more spherical shape, it can focus on objects very close to the eye (such as a page of writing).
    Author: rikazzz Comment
    Nervous System
    Which of the following structures together make up the brainstem?
    The cerebellum, thalamus and pineal gland are not part of the brainstem.
    Author: rikazzz Comment
    Nervous System
    What structure(s) does a neurotransmitter molecule cross?
    A neurotransmitter is released from the synaptic knob of the presynaptic neuron so must get out of the neuron by crossing its plasma membrane, the synaptic cleft, before lodging in the receptor on the postsynaptic membrane.
    Author: rikazzz Comment
    Nervous System
    The central sulcus of the brain lies between which two lobes?
    The central sulcus separates the frontal lobe from the left and right parietal lobes.
    Author: rikazzz Comment
    Nervous System
    What is the function of the “corpora quadrigemina”?
    The two superior colliculi receive visual sensation, while the two inferior colliculi receive auditory sensations. Choice A refers to the thalamic nuclei. Choice B refers to the hypothalamus. Choice D refers to the mammillary bodies.
    Author: rikazzz Comment
    Nervous System
    Which statement about refraction of light in the human eye is correct?
    The cornea is also a lens; hence, light is refracted as it enters the cornea from air. As the difference between air and corneal tissue is greater than the difference between aqueous humour and the lens, more refraction occurs in the cornea than in the “lens”.
    Author: rikazzz Comment