Learning question: what conditions can arise from an aged NS? Title: The effects of aging on the nervous system Homework: You have your class test next week – study! 04 June 2016

Learning Objectives Candidates should be able to: (d) describe the effects of ageing on the peripheral nervous system, with reference to vision and hearing; (e) describe the symptoms, causes and treatment of cataracts, glaucoma and macular degeneration (HSW6a, 6b);

Key words Peripheral nervous system Accommodation Cataract Glaucoma Macular degeneration

Effects of aging on the brain Decrease in brain weight and volume Decrease in white matter Ventricular system enlarges Brain generates fewer neurotransmitters

Effects of aging on the brain Mental function and aging do not have a direct correlation – mental capacity does decrease in middle age (45) and there is a steeper drop after 65, but individual variation is great High percentage of older people that function normally Suggests a link to unhealthy diet, lack of mental stimulation and novel experience as well as a lack of social interactions

Effects of aging on PNS Peripheral nerves conduct much slower as we age Usually, effect is minimal, although peripheral nerves affect how quickly we respond to the external environment – Reflexes slower  injury likely If neuron is damaged but soma is intact, self repair can occur Minimal/incomplete and slower in older adults – Older people therefore more vulnerable to injury and disease

Effects of aging on PNS Notable changes to our senses as we get older Hearing problems – Ongoing hearing loss linked to changes in inner ear – Speech becomes difficult to understand, especially when there is background noise Sight problems – Cateracts – Glaucoma – Age-related macular degeneration (AMD)

Sight problems The lens in the eye begins to lose its elasticity as the proteins in the cells begin to denature This makes accommodation difficult

Cataract Clouding of lens in one or both eyes Symptoms: blurred vision, glare or light sensitivity, poor night vision, decreased vision, loss of colour perception, needing a brighter light to read Causes: incidence increases with age – 99% in those over 90. Smoking, sunlight exposure, diabetes and some BP lowering medications Treatment: surgically removing cloudy lens – replaced with artificial one. Normally day procedure and restores 85% of vision

Glaucoma Optic nerve becomes damaged – can lead to blindness Preventable if treated early 2 types – Open angle glaucoma – Closed angle glaucoma

Open angle glaucoma Most common form - aqueous fluid out of the eye is obstructed – results in painless, slow build up of pressure If untreated, can damage field of vision in eye Symptoms: no pain but can cause tunnel vision before eyesight is lost completely Treatment: reduce pressure in eyes using drops to reduce fluid produced in eye or opening up drainage channels. Laser treatment or an operation to open up channels may also be considered

Closed angle glaucoma Much less common – pressure in eye rises rapidly Edges of iris and the cornea come into contact. This prevents the fluid in the eye from reaching drainage channels Symptoms: eye becomes extremely red and painful, headaches, vomiting and blurred vision Treatment: medicine to reduce eye pressure and laser treatment or surgery. If treated quickly, can be almost complete and permanent recovery of vision

Glaucoma

Age-related macular degeneration Affects the central part of the vision and the peripheral vision is always left in tact. 2 types – wet and dry AMD

Dry AMD More common – affects 80% of sufferers with the condition Caused by degeneration of the macula of the retina due to hardening of arteries that supply oxygen and nutrients to the retina Results in gradual reduction of central vision Slow onset, but occurs in both eyes simultaneously Symptoms: ability to read and see fine detail is difficult. Treatment: user wears powerful spectacles, magnifying lens, bright lights and large print to read

Wet AMD Less common but more severe and with rapid effect on central vision area Symptoms: blood vessels grown in abnormal fashion around the macula area, causing them to leak or bleed. Results in rapid and significant reduction in central vision. Treatment: as well as lenses, laser treatment or injection of drugs into the back of the eye

Questions Complete questions 1 and 2 on page 267

Print out question 2 January 2012 page 7 - 9