The Human Brain Option A.2 Pt. II

The cerebral cortex forms a larger part of the brain and is more highly developed in humans than other animals. Cerebral cortex- outer layer of the cerebral hemispheres. a.Two to four mm thick. b.Up to six different layers of neurons. c.Only found in mammals. d.In humans it is a larger proportion of the brain than any other mammal.

The human cerebral cortex has become enlarged principally by an increase in total area with extensive folding to accommodate it in the cranium. Most of the surface area in the human cerebral cortex is in the folds. a. Mice and rats have unfolded cerebral cortex.

The cerebral hemispheres are responsible for higher order functions. Lobes of the brain: a. Frontal- reasoning, planning, problem- solving. b. Parietal- stimuli such as touch and pain c. Temporal- perception of auditory stimuli and memory. d. Occipital- visual

Sensory inputs to the cerebral hemispheres The left hemisphere receives input from the right side of the body and the right receives input from the left side of the body. a. Ex. Impulses from the right field of vision pass to the visual cortex in the left hemisphere of the occipital lobe. Left hemisphere controls muscle movement in the right side of the body and the right controls the left. a. Brain damage to the right side will cause paralysis on the left side of the body.

Brain metabolism requires large energy inputs Human brains use over 20% of energy consumed in metabolism compared to about 10% in other vertebrates.