1. 1011 multipolar neurons and countless fibers
THE BRAIN
1011 multipolar neurons and countless fibers

2. Portions of the brain
Cerebrum
Cerebellum
Brain stem

3. Cerebrum
Split in half—cerebral hemispheres—separated by a layer of dura mater
Corpus callosum connects the two hemispheres
Ridges called convolutions
Sulcus—shallow groove
Fissure—deep groove
Lobes of brain named after bones around them
Frontal lobe, Parietal lobe, Temporal lobe, Occipital lobe

4. Cerebral Cortex Surrounds the outside of cerebrum (gray matter)
75% of active neurons in brain
Beneath is a mass of white matter that connects to the rest of nervous system

5. Functions of Cerebrum
Centers for interpreting sensory impulses, initiating voluntary movements, memory, ability to reason, general intelligence and personality stem from cerebrum
Functional areas broken down into motor areas, sensory areas, and association areas (Figure 9.24)
Hemisphere dominance
Ventricles
Diencephalon

6. Cerebellum
Large mass of tissue below the occipital lobes of the cerebrum
Two hemispheres and a cortex
Functions
Coordination and skeletal muscle movements
Helps maintain posture
Brings information on position of limbs and joints
Communicates with cerebrum to move parts to desired positions
Sends out impulses to midbrain to move the body

7. Brain Stem Three portions Midbrain Pons Medulla Oblongata
Joins lower parts with higher parts
Contains reflex centers for vision and hearing
Pons
Relays impulses from different parts of the brain and sensory impulses from PNS to cerebrum
Small function in breathing rate
Medulla Oblongata
Three major activity centers: Cardiac, Vasomotor, and Respiratory
Also centers for coughing, sneezing, swallowing, and vomiting

8. Throughout all of the brain stem is a complex network of fibers and gray matter called the reticular formation. It joins the hypothalamus with the rest of the brain and helps control sleep and wakefulness

9. Diencephalon
Found between cerebral hemispheres—surrounds third ventricle
Thalamus bulges into third ventricle
Receives all sensory impulses going to brain and channels them to appropriate locations
Hypothalamus—regions below the thalamus
Regulates: heart rate/blood pressure, body temp., water/electrolyte balance, control of hunger, control of movements and glandular secretions, sleep and wakefulness
Limbic System controls emotional experience and expression

10. Brain