1. The Brain

2. The Brain ~35 billion neurons
Adult brain contains almost 98% of neural tissue in the body
Weighs about 1.4 kg (3lbs)
Volume of 1200 cc (71 in3)
No correlation between brain size and intelligence

3. Three Main Structures
1. Cerebrum
2. Cerebellum
3. Brain Stem

4. The Cerebrum Conscious thought and intellectual function originate
B. Outer Surface composed of:
a. Gyri- elevated ridges (increase surface area)
b. Sulci- shallow depressions
c. Fissures- deep grooves
C. Two Cerebral Hemispheres covered by a cerebral cortex
1. Right Hemisphere
2. Left Hemisphere
~Hemispheres are united by a corpus callosum
- major route of communication between the hemispheres.

5. The Cerebrum

6. Hemisphere Control Right Side judging the position of things in space
knowing body position
understanding and remembering things we do and see
putting bits of information together to make an entire picture
controls the left side of the body
Left Side
understanding and use of language (listening, reading, speaking and writing)
memory for spoken and written messages
detailed analysis of information
controls the right side of the body

7. LEFT BRAIN DAMAGE Problems seen on the right side of the body.
RIGHT BRAIN DAMAGE Problems seen on the left side of the body.
                                                                                         
                                                                                           

8. Cerebral Hemispheres
Separated by a deep longitudinal fissure (central sulcus extends laterally)
Divided into lobes named for bones of the skull:
Frontal Lobe
Temporal Lobe
Parietal Lobe
Occipital Lobe

9. Frontal Lobe Primary Motor Cortex: - voluntary motor function
problem solving
Spontaneity
Memory
Language
Judgment
impulse control
Personality
Vulnerable to injury

10. Parietal Lobe Primary Sensory Cortex: - sensory somatic information
Location for visual attention.
Location for touch perception.
Goal directed voluntary movements.
Manipulation of objects.
Integration of different senses that allows for understanding a single concept.

11. Temporal Lobe Hearing ability Memory acquisition
Some visual perceptions
Categorization of objects
Auditory Cortex- hearing
Olfactory Cortex- smelling

12. Occipital Lobe Visual Cortex - Vision
~not particularly vulnerable to injury because of their location at the back of the brain
~although any significant trauma to the brain could produce subtle changes to our visual-perceptual system

13. The Limbic System
Contains several cerebral nuclei, gyri, and tracts that border the cerebrum and the diencephalon.
Contains cerebral centers concerned with:
1. sense of smell
2. long-term memory storage- Hippocampus
3. emotional states (flight and fight)- Amygdaloid
4. control of reflex movements that can be consciously activated

14. Diencephalon (Forebrain)
Central Core of the forebrain
Switching and relay centers that integrate the conscious and unconscious sensory and motor pathways.
Composed of the:
1. Thalamus
2. Hypothalamus
3. Epithalamus

16. Thalamus Constitutes the top of the brain stem
Paired egg shaped masses
Afferent impulses from all senses converge and synapse in the thalamus
Impulses are sorted out, edited, and relayed as a group
Coordination of voluntary and involuntary motor commands
Plays an important role in mediating sensation, motor activities, learning and memory.

18. Hypothalamus Located between the thalamus
Contains centers associated with emotions of rage, pleasure, pain, thirst, hunger, and sexual arousal
1. Adjusts and coordinates the activities of autonomic centers in the pons and medula oblongata
2. Coordinates neural and endocrine activities
3. Produces a variety of hormones including antidiuretic hormone (ADH) and oxytocin
4. Coordinates voluntary and autonomic functions
5. Maintains normal body temperature
6. Regulates sleep, sleep cycle, hunger, blood pressure, heart rate, breathing depth

20. Epithalamus
Pineal gland: extends from the posterior border and secretes melatonin- involved in sleep regulation, and mood
Choroid plexus- structure that secretes CSF (cerebrospinal fluid)

21. Midbrain Located between the diencephalon and the pons
Midbrain structures include:
1. various nuclei and buncles of ascending and descending nerve fibers.
2. control involuntary motor reflexes to sudden visual and auditory stimuli (loud noise, bright light)
Reticular Formation- network of interconnected nuclei that extend the length of the brain stem.
- regulation of involuntary functions
-maintains position and posture

23. Pons (Hindbrain)
Bulging brainstem region between the midbrain and the medulla oblongata
Fibers of the pons:
Connect higher brain centers and the spinal cord
Relay impulses between the motor cortex and the cerebellum

25. Medulla Oblongata Most inferior part of the brain stem
Physically connects the brain with the spinal cord
Cardiovascular control center- adjusts force and rate of heart contraction.
Respiratory centers- control rate and depth of breathing

27. Cerebellum
Makes rapid adjustments to muscle tone and position to maintain balance and equilibrium
Programs and fine-tunes voluntary and involuntary movements
Plays a role in language and problem solving
Recognizes and predicts sequences of events
Maybe permanently damaged by stroke or temporarily affected by alcohol

28. Gray Matter Adjusts the postural muscles of the body:
Coordinates rapid automatic adjustments to maintain balance and equilibrium
Programs and “fine-tunes” voluntary and involuntary movements
- refines learned movements patterns

29. White Matter
Arbor Vitae- (tree of life) which links Cerebellar cortex (gray matter) to the-
1. Cerebellar Peduncles-
which link the cerebellum to the
mesencephalon
diencephalon
cerebrum
Transverse fibers
Like the commissural fibers in the cerebrum
- link the cerebellar hemispheres and extend into the pons and medulla oblongata.