The Nervous System Part II-The Brain

I. Central Nervous System: The Brain Cerebrum –Largest part –Sensory & motor functions –Higher mental functions (memory, reasoning, etc) Brainstem –Connects the cerebrum to the spinal cord Cerebellum –Coordinates voluntary muscle movements Diencephalon –Processes sensory info

A. The Cerebrum Divided into right and left cerebral hemispheres Covered by folds called convolutions and grooves called sulci (little groves) and fissures (big grooves) Connected by the corpus callosum It has a cortex: an outer covering about 2 mm thick Gray matter vs. white matter The cerebral cortex is divided into LOBES which control various functions

1. Frontal Lobe (Brain 1 handout) –Control of voluntary muscles in the body –Motor speech (Broca’s area) –Voluntary eye movement –Concentration, planning, problem solving –Rational thought, intelligence

2. Parietal Lobe –Somatosensory area- touch, taste and other sensory info –understanding speech, using words (Wernicke’s) 3. Temporal Lobe –smell and hearing –interpretation of sensory experiences 4. Occipital Lobe – visual senses 5. Primary Motor Area (frontal) – movement of skeletal muscles

6. Pre-Motor Area (frontal) – learned motor skills 7. Motor Speech Area (Broca’s) (frontal) – controls mouth movement for speech 8. Somatosensory Area (parietal) – conscious awareness of sensations –interpretation of sensory experiences 9. Auditory area (temporal) –Hearing is processed 10. Visual Area (occipital) –Processes input from optic nerves

Cerebral Hemispheres Hemisphere = half of sphere (brain) The right side of the brain controls the left side of the body and vice versa Hemispheres connected by the Corpus callosum

B. The Cerebellum Processes sensory information about limbs, joints, and other body parts to determine desired positions. Balance, coordination of skeletal muscle, posture

C. Brainstem Brainstem: Connects the cerebrum to the spinal cord –Midbrain: visual and auditory reflex center –Pons: transfers nerve impulses from cerebrum to cerebellum –Medulla Oblongata: controls heart and breathing rates, controls blood pressure, vessel changes

D. Diencephalon Thalamus- Receives all sensory impulses and relays them to the appropriate region of the cerebral cortex -Produces awareness of sensation Hypothalamus – Links the nervous system to the endocrine system –Regulates heart rate, blood pressure, body temp, hunger, gland secretions, sleep etc. –Maintains homeostasis-links nervous to endocrine system

The limbic system is a collection of structures involved in emotional behavior and your feelings –Includes the thalamus, hypothalamus, amygdala and hippocampus (long term memory) –Fear, anger, pleasure, sorrow –Olfaction travels through the limbic system so scent is related to feelings.