1. The Nervous System
A network of billions of nerve cells linked together in a highly organized fashion to form the rapid control center of the body.
Functions include:
Integrating center for homeostasis, movement, and almost all other body functions.
The mysterious source of those traits that we think of as setting humans apart from animals

2. Upper motor neurones Lower motor neurones
Performance of normal voluntary movement,
the integrity of two sets of neurons is important
Upper motor neurones
Neurons originating in the cerebral cortex and the brain stem
Synapse directly or indirectly with the anterior horn cells or with the motor neurones of the cranial nerves
Grouped into pyramidal and extrapyramidal systems
Lower motor neurones
Motor cranial nuclei and their axons, i.e. motor fibres of the cranial nerves (3rd, 4th, 5th, 6th, 7th, 9th, 10th, 11th and 12th)
In the spinal cord they include the anterior horn motor neurones and their axons, i.e. the motor nerves to skeletal muscles

3. Basic Functions of the Nervous System
Sensation
Monitors changes/events occurring in and outside the body. Such changes are known as stimuli and the cells that monitor them are receptors.
Integration
The parallel processing and interpretation of sensory information to determine the appropriate response
Reaction
Motor output.
The activation of muscles or glands (typically via the release of neurotransmitters (NTs))

4. Nervous vs. Endocrine System
Similarities:
They both monitor stimuli and react so as to maintain homeostasis.
Differences:
The NS is a rapid, fast-acting system whose effects do not always persevere.
The ES acts slower (via blood-borne chemical signals called H _ _ _ _ _ _ _) and its actions are usually much longer lasting.

5. Organization of the Nervous System
2 big initial divisions:
Central Nervous System
The brain + the spinal cord
The center of integration and control
Peripheral Nervous System
The nervous system outside of the brain and spinal cord
Consists of:
31 Spinal nerves
Carry info to and from the spinal cord
12 Cranial nerves
Carry info to and from the brain

6. Brain Regions
Cerebrum
Diencephalon
Brainstem
Cerebellum
Cerebellum

7. Cerebral Cortex 3 types of functional areas:
Motor  Control voluntary motor functions
Sensory  Allow for conscious recognition of stimuli
Association  Integration

8. Cortical Motor Areas Primary Motor Cortex Premotor Cortex Broca’s Area
Frontal Eye Field

9. 1.Primary motor cortex
2.Premotor cortex
4.Frontal Eye Field
3.Broca’s Area

10. Primary (Somatic) Motor Cortex
Located in the precentral gyrus of each cerebral hemisphere.
Contains large neurons (pyramidal cells) which project to SC neurons which eventually synapse on skeletal muscles
Allowing for voluntary motor control.
These pathways are known as the corticospinal tracts or pyramidal tracts.

11. Primary (Somatic) Motor Cortex
Somatotopy
The entire body is represented spatially in the primary motor cortex,
_ i.e., in one region we have neurons controlling hand movements and in another region leg movements, etc.
What does it mean to say that motor innervation is contralateral?

13. Sensory Areas Found in the parietal, occipital, and temporal lobes.
Primary somatosensory cortex
Somatosensory association cortex
Visual areas
Auditory areas
Olfactory cortex
Gustatory cortex
Vestibular cortex

14. Primary Somatosensory Cortex
Found in the postcentral gyrus.
Neurons in this cortical area receive info from sensory neurons in the skin
and from proprioceptors which monitor joint position.
Contralateral input.

16. Somatosensory Association Cortex
Found posterior to the primary somatosensory cortex and is neurally tied to it.
Synthesizes multiple sensory inputs to create a complete comprehension of the object being felt.
How would damage to this area differ from damage to the primary somatosensory cortex ?

17. Basal Nuclei
Info arrives at the caudate nucleus and the putamen from sensory, motor, and association areas of the cortex.
Processing and integration occurs w/i the nuclei and then info is sent from the globus pallidus to the motor cortex via the thalamus.
The basal nuclei alter motor commands issued by the cerebral cortex via this feedback loop.

18. Parkinson’s Disease
Each side of the midbrain contains a nucleus called the substantia nigra.
Neurons in the substantia nigra inhibit the activity of basal nuclei by releasing dopamine.
Appearance of symptoms of Parkinson’s disease: tremor, slow movement, inability to move, rigid gait, reduced facial expression
Damage to SN neurons
Decrease in dopamine secretion
Gradual increase in muscle tone
Increased activity of basal nuclei

19. Diencephalon Forms the central core of the forebrain
3 paired structures:
Thalamus
Hypothalamus
Epithalamus
All 3 are gray matter