Brain: Parts and Functions

Central Nervous System: Brain 4 brain regions Cerebral hemisphere Diencephalon Brainstem Cerebellum

Cerebral Hemispheres Most superior part of brain Covered with: Gyri: ridges Sulci: grooves 2 hemispheres are separated by a longitudinal fissure Each lobe is separated by small fissures

Brain Lobes

Frontal Lobe Decision making area: choice Problem solving Personality Behaviors

Parietal Lobe Sensory input Motor output

Somatic Sensory Area Located posterior to the central fissure in the parietal lobe. Impulses traveling from the body’s sensory receptors are localized and interpreted in this area (not special senses; eye, ear, taste, smell) Recognize pain/Coldness/Light touch Lips and fingertips

Occipital Lobe Vision Center

Temporal Lobe Auditory area (hearing) Olfactory area (smell) Understanding speech

Cerebral Cortex Broca’s area (ability to speak) Vocalize words Usually on the left hemisphere only of the frontal cortex Higher intellectual reasoning Anterior portion of frontal cortex Memory Stored in frontal and temporal lobes Speech Area (sound out words) Junction of temporal, parietal and occipital lobes Language comprehension (word meanings) Frontal lobe Corpus callosum Connects the cerebral hemispheres

2. Diencephalon: Interbrain Enclosed by the cortex Thalamus Relay station for sensory nerve impulses to pass to cortex Can determine if sensation is pleasant or unpleasant Epithalamus Contains pineal body (endocrine gland) Choroid plexus Forms cerebral spinal fluid

Diencephalon: Interbrain Hypothalamus (under thalamus) Regulation of many functions Temperature, water balance, metabolism Regulates the pituitary gland Center for many “drives” and emotions (part of limbic system) Thirst, appetite, sex, pain, pleasure

3. Brain Stem Midbrain Reflex centers for vision and hearing Pons Relay station for cortex Medulla oblongata Controls vital functions Heart rate Breathing Blood pressure Swallowing vomiting

4. Cerebellum 2 hemispheres Provides the precise timing for skeletal muscle activity Controls balance Body movements are smooth and coordinated Equilibrium Receives messages from the inner ear Monitors body position Touch your finger to your nose with your eyes shut

Protection of the CNS Bones: skull and vertebrae Membranes: Meninges Dura mater: outer most double layer Outer: attaches to inner surface of skull (Periosteum) Inner: forms the outer-most covering of the brain Arachnoid mater (“spider”) Pia mater (“gentle mother”) Clings to the surface of the brain Subarachnoid space (between arachnoid and pia mater) Filled with CSF Meningitis inflammation of the meninges encephalitis inflammation of the brain

Protection of the CNS Cerebral spinal fluid Watery cushion Moves continuously inside the brain Circulates in ventricles (reservoirs) Contains, glucose, proteins and sodium chloride Lumbar spinal tap Draw CSF for testing Meningitis MS Tumors

Spinal Cord 17 inches long Continuation of the brain stem 2 way conduction pathway to and from the brain Major reflex pathway 31 pairs of spinal nerves exit