External Structures and Function of the Human Brain

Cerebral Hemispheres STRUCTURE -Largest part of the brain -Large paired structures, divided into left and right hemispheres. -The top layer is called the cerebral cortex, the rest is referred to as the cerebrum. -The cerebrum is divided up into 4 main lobes. Cerebral Hemispheres Cerebral cortex is part of the cerebrum, it’s the outer layer. Cerebral cortex is gray matter, while the cerebrum is both gray and white matter. Human cerebral cortex is made up of approximately 10 billion nerve cell bodies and their dendrites whereas the cerebrum has both cell bodies and nerve fibers. FUNCTION -Carries out higher thought processes involved with language, learning, memory, and voluntary body movements

Cerebellum STRUCTURE -Means “little brain” -Smaller structure under the base at the back of the brain  Also divided into two hemispheres Cerebellum FUNCTION -Responsible for balance and coordination 

Brain Stem STRUCTURE -Extends from the base of the brain -Continues into the spinal cord, made up of the pons and medulla oblongata  Brain Stem FUNCTION -Relays signals between the brain and spinal cord 

PONS PONS STRUCTURE -Top region of the brain stem FUNCTION -Relays signals between cerebrum and cerebellum -Helps control breathing rate  PONS

Medulla Oblongata STRUCTURE -Beneath the pons -Lower portion of the brainstem -Connects to the spinal cord  FUNCTION -Relays signals between the brain and the spinal cord -Helps control blood pressure, heart rate, and breathing rate Medulla Oblongata

Lobes of the Brain

Frontal Lobe Frontal FUNCTION Conscious thought, behavior, emotion, planning, personality, organizing, problem solving. Most uniquely human of all the brain structures. Front of the brain Frontal

Prefrontal Cortex! (PFC) This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior. Cognitive = knowing Frontal Eye Fields = Broodman’s area (voluntary eye movement)

Parietal Lobe FUNCTION Integrations of sensory information from primary sensory areas , perception, arithmetic, spelling, manipulation of objects. Middle top of the brain. 

Temporal Lobe FUNCTION Senses of smell and sound, as well as processing of complex stimuli like faces and scenes, memory, understanding language. Temple region. 

Occipital Lobe FUNCTION Sense of sight Extreme back of the brain

Internal Structures and Function of the Human Brain

Corpus Callosum LOCATION Beneath the cerebrum. About 10 cm long. Largest white matter structure. FUNCTION Allows for communication between the two cerebral hemispheres. About 200 million axons!

Thalamus LOCATION Beneath the Corpus Callosum, near the center of the brain. FUNCTION Acts as a gateway/relay of sensory information to the cerebral cortex.

Hypothalamus LOCATION Near the base of the cerebrum, below the thalamus. FUNCTION Connects the nervous system to the endocrine system. Communicates and directs the pituitary gland.

Pituitary Gland LOCATION A protrusion off of the hypothalamus. FUNCTION Part of the endocrine system. Responsible for regulation of other parts of the endocrine system as well as many of the body’s processes.

Hippocampus LOCATION In the temporal lobe, part of the limbic system FUNCTION Plays a role in the formation of new memories based upon experiences. Moves short term memories to long term memories. Hippocampus – Greek Hippos = horse Kampos = sea monster Limbic system  control functions necessary for self preservation and species preservation

Amygdala LOCATION In the temporal lobe, part of the limbic system FUNCTION Primary role in processing memory, storage of memories associated with emotions, and decision making Amygdala – Latin and Greek Almond

Amygdala = fear responses & pleasure Hippocampus = turns information into memory