The Brain

1. The Brain • Four Major Regions • Cerebral hemispheres • Diencephalon • Brian stem • Cerebellum

2. Cerebral hemispheres • Collectively know as the cerebrum • Most superior part of the brain and covers the other parts • Gray matter of the cerebrum is known as the cerebralcortex and makes up the surface of the brain • The deeper cerebral white matter is made of tracts that carry impulses to and from the cortex. The tract that connects the two hemispheres is called the corpuscallosum • Basalnuclei (or basal ganglia) refers to gray matter that is buried deep within the white matter

3. Cerebral hemispheres • Also Contains • Gyri – elevated ridges of tissue • Sulci – shallow grooves • Fissures – deeper grooves that separate large areas of the brain • Lobes – areas of the brain that are named for the bone that covers them

4. Areas of the cerebrum • Somatic sensory area – area responsible for sensory receptor interpretation • The map of the areas of the somatic sensory area responsible for body areas is known as the sensoryhomunculus • It is upsidedown and crossed

5. The SensoryHomunculus • From Page 238

6. Primary motor area • Area that allows us to control our skeletal muscles is located in the frontal lobe right in front of the centralsulcus. • The body can also represented in a diagram called the motorhomunculus

7. Other Areas of the Cerebrum • Visual area – in the Occipital Lobe • Auditory and olfactory areas - Temporal Lobe • Broca’s area –involved in our ability to speak is found at the base of the precentralgyrus (raised area anterior to the central sulcus • Speech area – allows us to sound out words is found at the junction of the temporal, parietal, and occipital lobes • Higher intellectual reasoning and socially acceptable behavior are also believe to be part of the frontal lobe • Complex memories appear to be stored in the temporal and frontal lobes

8. Let’s label and color Figure 7.13 from Page 237

9. The Diencephalon • Also called the interbrain • Located just above the brainstem and is enclosed in the cerebralhemispheres • Made up of the thalamus, hypothalamus, and epithalamus

10. Thalamus • Encloses the 3rd ventricle (chamber) of the brain • Relay station for sensory impulses passing upward to the sensory cortexes • Allows for crude recognition of whether the sensation will be pleasant or unpleasant

11. Hypothalamus • Bottom part of diencephalon • Body’s homeostasis control center – controls temperature, metabolism, water balance • Center for many drives and emotions, which makes it the major part of the limbic system (emotional-visceral brain) • Regulates the pituitary gland and has mammillary bodies (reflex smell centers) bulge from the bottom of the hypothalamus

12. Epithalamus • Roof of the 3rd ventricle • Contains the pineal body (part of endocrine system) and the choroid plexus (knots of capillaries) of the third ventricle

13. Brain Stem • Small area (diameter of a thumb and 3 inches long, but contains the midbrain, pons, and medullaoblongata • Is responsible for vital activities like breathing and blood pressure

14. Cerebellum • Found under the occipital lobe of the cerebrum • Has two hemispheres and a complex surface with gray matter on the outside and white matter on the inside. • Provides the precise timing for skeletal muscle activity and controls our balance and equilibrium