1. INTRODUCTION TO NEUROLOGY
J.M.Stansbie
Warwick Medical School

2. Structural Units of the Nervous System
Neurone – an excitable cell specialised for the reception of a stimulus and the conduction of an impulse. Found in brain, spinal cord and ganglia. Communicate at synapses.

3. Structural Units of the Nervous System
Neurone – an excitable cell specialised for the reception of a stimulus and the conduction of an impulse. Found in brain, spinal cord and ganglia. Communicate at synapses.
Neuroglia – non-excitable cells in CNS.
i) Astrocytes – provide anatomical and functional supporting framework for nerve cells and fibres.
ii) Oligodendrocytes – form myelin sheaths of nerve axons.
iii) Microglia – involved in inflammatory response. Derived from macrophages outside nervous system.
iv) Ependyma – lines cavities in CNS. Involved in production and circulation of cerebrospinal fluid.

4. Structural Units of the Nervous System
Neurone – an excitable cell specialised for the reception of a stimulus and the conduction of an impulse. Found in brain, spinal cord and ganglia. Communicate at synapses.
Neuroglia – non-excitable cells in CNS.
i) Astrocytes – provide anatomical and functional supporting framework for nerve cells and fibres.
ii) Oligodendrocytes – form myelin sheaths of nerve axons.
iii) Microglia – involved in inflammatory response. Derived from macrophages outside nervous system.
iv) Ependyma – lines cavities in CNS. Involved in production and circulation of cerebrospinal fluid.
Schwann cells – peripheral nervous system equivalent of oligodendrocyte.

5. Peripheral nerve

6. Divisions of the Nervous System
Central
Peripheral
Somatic Visceral
Sensory Motor Sensory Motor
Sympathetic
Parasympathetic

7. Central and Peripheral Nervous Systems

8. CNS - Brain

9. CNS - Brain

10. CNS - Brain

11. CNS – Spinal cord

12. CNS – Meninges

13. PNS - Cranial Nerves
Rostral; Cranial; Anterior
Caudal; Posterior

14. PNS – Spinal nerves (1)

15. PNS – Spinal nerves (2)
Dermatome – area of skin supplied by a single spinal nerve.
Myotome – group of muscles supplied by a single spinal nerve.

16. Divisions of the Nervous System
Central
Peripheral
Somatic Visceral
Sensory Motor Sensory Motor
Sympathetic
Parasympathetic

17. Somatic Sensory System - modalities
General Special
Pain Olfaction (I)
Temperature Vision (II)
Touch(crude; two point) Taste (V,VII,IX)
Pressure Hearing (VIII)
Proprioception Balance (VIII)

18. Somatic Motor System
Cerebral cortex; limbic system; basal ganglia – planning, programming and initiation of movement.
Cerebellum - co-ordination; learning/memory.
Descending tracts (upper motorneurones) - influence reflexes and lower motorneurones.
Lower motorneurones - final common pathway.
Spinal cord – reflexes.

19. Motor Unit This is the basis of movement.
It comprises a single alpha-motorneurone and all the muscle fibres supplied by it.
Each muscle contains thousands of motor units.

20. Muscle Contraction
Results from the synchronous action of multiple motor units.
Muscle power depends on the number of motor units recruited(active) at any one time.
Motor units rotate their activity over time.
Is facilitated by reflex inhibition of antagonists through reciprocal innervation.

21. Muscle Tone (1) Is a state of partial contraction in resting muscle.
Is dependent on the stretch reflex involving muscle spindle receptors and alpha motorneurones.
Muscle spindles are rapidly responsive to the absolute length and rate of change of length of muscle and dynamically adjust their own muscle fibre length and tone as appropriate via reflexes involving gamma motorneurones.
The activity of gamma motorneurones, and therefore muscle tone, is influenced by the descending tracts.

22. Muscle Tone (2)
Golgi tendon organs are sensitive to tension and are involved in a reflex which protects muscle from damage due to excess tension but also provide the CNS with information which may influence voluntary muscle activity.
The assessment of clinical phenomena based on variations in muscle tone is an important component of the examination of the somatic motor system.

23. Visceral Sensory System - modalities
Pain
Stretch/pressure
Chemical
Osmotic pressure
Arterial pressure

24. Visceral Motor System Sympathetic Parasympathetic
Prepares body for emergency
Increases heart rate
Constricts arterioles of gut and skin
Dilates arterioles of muscle
Increases blood pressure
Dilates pupils
Relaxes bronchial smooth muscle
Closes sphincters
Stimulates sweating
Allows body to conserve energy
Reduces heart rate
Dilates arterioles of gut and skin
Reduces blood pressure
Constricts pupils
Constricts bronchial smooth muscle
Increases gut peristalsis
Relaxes sphincters
Stimulates glandular secretion

25. Visceral Motor System Sympathetic

26. Visceral Motor System Parasympathetic