Forebrain: Cerebrum - Practice Questions & MCQ

Forebrain: Cerebrum

• The cerebral hemispheres or cerebrum is the largest part of the brain occupying about two-thirds of the entire brain. 
• It consists of left and right hemispheres connected by a large bundle of myelinated fibres, the corpus callosum and other smaller fibre bundles.
• The outer portion of the cerebrum is called the cerebral cortex that makes up the grey matter of the cerebrum.
• The surface of the cortex is highly folded. 
• The upward folds are called gyri (sing. gyrus).
• They alternate with the downward grooves called or sulci (sing. sulcus).
• Below the grey matter millions of myelinated nerve fibres are present that connect the neurons of the cerebral cortex with those located elsewhere in the brain. 
• The large concentration of myelinated nerve fibres gives this tissue an opaque white appearance. Hence they are collectively called White matter.
• In each cerebral hemisphere, three types of functional areas can be seen as:

                       Sensory areas: They receive impulses from the receptors.
                       Association areas: They interpret the input, store the input and initiate a response in light of similar past experience.                             Thus the associated areas are involved in memory, learning and reasoning.
                       Motor areas: They transmit impulses to the effectors.

• Each cerebral hemisphere of the cerebrum is divided into four lobes: frontal, parietal, temporal and occipital lobes. 
• The central sulcus separates the frontal lobe from the parietal lobe. 
• The lateral sulcus separates the frontal lobe from the temporal lobe. 
• The parieto-occipital sulcus separates the parietal lobe from the occipital lobe