28 The effect of ageing on the nervous system

Question 1

what is Alzheimer’s Disease?

Answer 1

{a form of dementia}

a reduction in cognitive ability associated with gradual brain cell death

Question 2

what is familial AD?

Answer 2

a family history of AD attributed to susceptibility

some alleles cause early onset

~ 0.1 % of cases are autosomal dominant inheritance

Question 3

what are the three alleles that tend to AD mutations?

Answer 3

amyloid precursor protein

presenilin 1

presenilin 2

Question 4

what are causes of sporadic AD?

Answer 4

other genetic differences (e.g. APOEe4 –> incr. rate of deposition in plaques)

severe/repeated head injury

stroke

low levels of intellectual stimulants

Question 5

what are some cardiovascular diseases that can contribute to development of AD?

Answer 5

hypertension

smoking + its attributed diseases

high blood cholesterol

Question 6

what are symptoms of AD in brain scans?

Answer 6

shrivelled/fewer brain cells

shorter/fewer dendrites

Tau inside cells

Question 7

outline the early stage of AD

Answer 7

cognitive deficits are accounted for ∴ person continues to function independently

basic memory loss; poor judgement; mood changes

Question 8

outline the mid-stage of AD

Answer 8

personality changes

physical problems

lack of awareness of forgetting

aphasia; disorientation; aggression

Question 9

outline the late stage of AD

Answer 9

severe and distressing

loss of control of bodily functions –> complete dependency on carer

loss of language and dysphagia

Question 10

what are Tau proteins?

Answer 10

proteins that stabilise microtubules

abundant in CNS neurones

Question 11

how do Tau proteins contribute to development of AD?

Answer 11

neurofibrillary tangles of Tau

hyperphosphorylation of Tau –> build up inside the neurone causing them to disintegrate

abnormal breakdown of Tau –> B-amyloid proteins –> accumulates and forms plaque on outside of axons and dendrites

Question 12

how does a loss of neurones and synapses contribute to development of AD?

Answer 12

in cerebral cortex and subcortical regions

gross atrophy of temporal/parietal lobes + parts of frontal cortex

Question 13

how does herpes simplex type 1 contribute to development of AD?

Answer 13

causative of APOEe4

causes damage to CNS

Question 14

outline the inflammatory processes that contribute to development of AD

Answer 14

derivatives of B-amyloid-derived diffusible ligands

kill a range of neurones

bind to surface receptors on the neurones and change the structure of a synapse –> disruption to neuronal communication

Question 15

how could a vaccine prevent AD?

Answer 15

stimulates B cells

antigen is abnormal part of B-amyloid

immune system acts against the body protein

specific antibodies attach to B-amyloid

removed by white blood cells

Question 16

what is the difference between age-related memory loss and dementia?

Answer 16

dementia is disruptive to normal functioning

Question 17

how can memory loss be reduced?

Answer 17

regular exercise

social interaction

fruit/veg/antioxidants

managing stress

sufficient sleep

not smoking

Question 18

what is presbycusis?

Answer 18

age-related hearing loss due to the damage and death of hair cells in the cochlea and neurones in the auditory nerve

Question 19

what is visual impairment?

Answer 19

a severe reduction in vision that cannot be corrected with standard glasses or contact lenses and reduces a person’s ability to function at certain or all tasks

Question 20

what is age-related macular degeneration (ARMD)?

Answer 20

a loss of central vision that results from a loss of effective function in the macular

Question 21

what is dry ARMD?

Answer 21

cellular debris (drusen) accumulates between retina and choroid causing the retina to detach

Question 22

what is wet ARMD?

Answer 22

{neovascular}

abnormal blood vessel growth in the choroid causing leaking of fluid into retina –> scarring of macular

retina can detach from choroid

Question 23

how is wet ARMD treated?

Answer 23

laser coagulation surgery

medication to inhibit blood vessel growth

Question 24

how do eyedrops cause the pupil to dilate?

Answer 24

circular and radial muscles = antagonistics

drops act like NAdr (symp.)

∴ radial muscles contract

drug also blocks ACh (para.)

∴ circular muscles not stimulated to contract

Question 25

what is cataracts?

Answer 25

a loss of transparency of the lens, resulting in cloudy vision

Question 26

what are the four categories of cataracts?

Answer 26

partial/complete

stationary/progressive

hard/soft

partly/completely opaque

Question 27

what are the three types of cataracts?

Answer 27

nuclear (colour differentiation more difficult)

cortical (problems with glare)

subcapsular (poor vision in daylight)

Question 28

name three factors that contribute towards cataract development

Answer 28

diabetes

smoking

alcohol

Question 29

how is cataracts treated?

Answer 29

cloudy lens removed and replaced by a plastic one

Question 30

what is glaucoma?

Answer 30

damage of the optic nerve due to increased pressure from a lack of drainage

Question 31

what is chronic open-angle glaucoma?

Answer 31

blockage of drainage from aqueous humour

Question 32

what is primary angle-closure glaucoma?

Answer 32

touching of iris and cornea blocks drainage channels

Question 33

what is secondary glaucoma?

Answer 33

glaucoma following another eye condition

Question 34

what is congenital glaucoma?

Answer 34

develops just after birth

Question 35

name the two factors that contribute to glaucoma

Answer 35

age

ethnicity

Question 36

how is glaucoma treated?

Answer 36

eye drops

laser surgery