The Brain

The brain has 4 major regions Cerebral hemispheres Cerebellum Diencephalon Brain stem

– Cerebrum – largest, superior portion of the brain, divided into two hemispheres (right and left)

Cerebral lobes Frontal lobe – higher intellectual reasoning, complex memories, language comprehension Primary motor area – allows voluntary movement of skeletal muscles Broca’s area – speech Parietal lobe – numerical relationships, manipulation of objects Somatic sensory area – interprets impulses from sensory receptors

Cerebral lobes Occipital lobe – interprets visual impulses from eyes Temporal lobe – interprets auditory impulses (from the ears) and olfactory impulses (from the nose) Corpus Callosum – large bundle of nerve fibers that connects the right and left hemispheres

Cerebellum Two hemispheres, controls balance, equilibrium, and precise timing for skeletal muscle activity

Diencephalon Sits on top of the brainstem and is enclosed by the cerebral hemispheres, and has three major regions. Thalamus – relay station for sensory impulses from the sensory receptors to the brain, controls sleep and awake states of consciousness Hypothalamus – autonomic nervous system (regulates body temperature, water balance, metabolism, thirst, appetite, pain, pleasure) and produces hormones to regulate these activities

Diencephalon Epithalamus – furthest posterior portion, contains two important structures Pineal body – converts nervous system signals into endocrine system signals, secretes melatonin Choroid plexus – makes the cerebrospinal fluid

Brain stem Midbrain – reflex centers for vision and hearing Pons – control of breathing Medulla oblongata – motor control of the visceral organs