Chapter 3 Chapter 3

THE NERVOUS SYSTEM


KEY POINTS
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(1) Age-related changes in the central and peripheral nervous sys(CNS and PNS) are responsible for many of the physioloand behavioural changes commonly associated with advancing age and senility.
(2) Many of the age-related degenerative CNS changes reported to occur in humans are believed by veterinary neurologists to occur in dogs and cats but they have been poorly documented.
(3) In decision making about treatment and prognosis it is important to relate observed neurological changes to the site of the underlesion. For example, it is important to differentiate upper motor neuron deficits from lower motor neuron deficits in patients with locomotor disease.
(4) The onset of seizures in old animals should promote a search for extracranial causes (e.g. hepatic disease) and for structural lesions in the CNS (e.g. brain tumours).
(5) Old patients requiring anticonvulsant therapy for seizures should be screened for liver disease and should be monitored for early detection of hepatotoxicity.
(6) Neuroendocrine disorders are probably much more common in old animals than is currently recognised clinically.
(7) The process of ageing may be a manifestation of a failure to regulate neuroendocrine function or ageing may be dependent upon neuroendocrine regulation running in parallel with other temporal factors the so-called genetic 'programming', 'clock' or pacemaker' theory.
(8) Regular exercise is an important stimulator of neuroendocrine function and should be maintained throughout old age.

3.1 INTRODUCTION

3.2 AGE-RELATED TISSUE CHANGES

3.3 FUNCTIONAL CHANGES

3.4 NEUROLOGICAL DISEASES OF OLD AGE CHRONIC 'OLD DOG' ENCEPHALITIS

REFERENCES AND FURTHER READING