1. Section 9.3:The Central Nervous System (CNS)
Pages

2. Recap Current in wire vs. Current in nerves Action Potentials
Depolarization, Repolarization
Sodium-potassium Pump  Active Transport
Synaptic Transmission

3. The Central Nervous System
Includes the brain and the spinal cord
The brain is a concentration of nervous tissue  acts as the coordinating centre of the nervous system

4. The Spinal Cord
Carries sensory nerve messages from receptors to the brain
Relays motor nerve messages from the brain to muscles, organs, and glands
A cross-section shows that the spinal cord consists of two types of nerve tissue – white matter and grey matter

5. The Spinal Cord
Core of the spinal cord: contains unmyelinated interneurons (grey matter)
Periphery of cord: both sensory and motor neurons are myelinated (white matter)
Interneurons consist of nerve tracts that connect the spinal cord with the brain
Dorsal nerve tracts: bring sensory information into the spinal cord
Ventral nerve tracts: carry motor information from the spinal cord to the muscles, organs, and glands

6. The Spinal Cord Carry sensory information to spinal cord
Carry motor information from spinal cord to muscles, organs and glands

7. The Brain Has Layers
The brain is covered by a three-layer protective membrane called the meninges
Outer layer: dura mater
Middle layer: arachnoid mater
Innermost layer: pia mater
These three membrane layers form the blood-brain barrier, which determines what chemicals will reach the brain

8. The Brain Our hearing, vision, and sense of smell is unimpressive
Our ability to conceptualize and reason is extremely unique
The human brain is made of 3 distinct regions: the forebrain, the midbrain, and the hindbrain

9. The Forebrain Contains olfactory lobes – sense smell
Cerebrum (forebrain) – coordinating centre where speech, reasoning, memory, and personality reside
Surface of the cerebrum is called the cerebral cortex – made of grey matter of many folds and fissures
The right side of the forebrain  visual patterns or spatial awareness
The left side of the brain  linked to verbal skills

10. The Forebrain
Your ability to learn is heavily dependent on the dominance of one of the hemispheres
Corpus callosum  allows both hemispheres to communicate
Each hemisphere can be further subdivided into 4 lobes: frontal, temporal, occipital, and parietal

12. Table 1. page 429

13. The Hindbrain Joins with the spinal cord
Consists of the cerebellum, pons, and medulla oblongata
Controls breathing movements, the diameter of blood vessels, and heart rate

14. The Hindbrain
Pons: relays information between the two regions of the cerebellum and between the cerebellum and the medulla
Cerebellum: controls limb movements, balance, and muscle tone
Medulla oblongata: connection between the peripheral and the central nervous system that controls involuntary muscle action

15. Human Brain Compared to Chordates

16. Human body drawn in proportion to how many motor nerves control it

17. Case Study: Phineas Gage
1948 – Thunderous explosion in Cavendish, Vermont
Gage accidently set off blasting caps
A meter long bar entered below the left eye and exited through the skull
Recovered and lived for an additional 12 years
Vision, hearing, balance all remained intact

19. One thing did change… Gage became irresponsible and short-tempered
One thing did change… Gage became irresponsible and short-tempered. He had spontaneous temper tantrums and would use profane language

20. Why might that be?

21. Any Questions?