senescence

Question 1

primary ageing

Answer 1

intrinsic changes occurring with age, unrelated to disease or environmental influences

Question 2

secondary gang

Answer 2

changes caused by the interaction of primary aging with environmental influences or disease provcess

Question 3

wear and tear

Answer 3

free radicals, DNA damage, aggregation of proteins which aren’t cleared, dysfunctional proteins not cleared

Question 4

processes that cause aging

Answer 4

1. damage caused by oxidative stress
2. inadequate repair of damage
3. dysregulation of cell number

Question 5

ROS

Answer 5

reactive oxygen species 
oxidative stress 
- susceptibility of sugars - glycation 
- susceptibility of mitochondria 
- susceptibility of DNA (somatic mutations, may kill the cell or cause problems)

Question 6

repair mechanisms

Answer 6

DNA - repair, telomeres
protein turnover - ubiquitin, autophagy
membranes - lipid peroxidation

Question 7

cell number homeostasis

Answer 7

limitations to cell division - senescence - hay flick limit, telomeres
cell removal by - necrosis, apoptosis

Question 8

cellular senescence

Answer 8

cels in senescence response to damage/replication
- arresting growth of old/dmagaed/dysfunctional cells
- beneficial early in life, may contribute to aging later - altered secretion of proteases, cytokines, growth factors
accumulation og senescent cells predicts lifespan

Question 9

changes in body composition

Answer 9

decrease in lean body mass, muscular and skeletal mass, decrease in total body water, increase in adipose tissue

Question 10

cellular changes in aging

Answer 10

increase in DNA damage and decrease in DNA repair capacity
decrease if oxidative capacity
accelerated cell senescences
increase in fibrosis, lipofuscin accumulation (oxidised protein/lipid lysosomes)

Question 11

sarcopaenia

Answer 11

loss of muscle mass
predominantly type 2 (fast) muscle loss (shift to type 1)
cause of death may be myogenic or neurogenic
muscle fibre may die to to inactivity or MN loss (cannot survive without being innervated by a motor neurone)

Question 12

two ways muscle fibres die

Answer 12

myogenic - lost due to inactivity

neurogenic - loss due to loss of MN innervation

Question 13

MN loss

Answer 13

loss of myofibres and loss of fine motor control

cannot be improved with strength training

Question 14

bone and joints

Answer 14

bone remodelling - Osteoclasts start to win where resoprtion>formation, progressive mass loss, menopause accelerates loss

Question 15

osteoporosis

Answer 15

decrease in bone mineral density

heightened risk of bone fractures

Question 16

synovial joints

Answer 16

joint flexibility declines, articular cartilage thins, and decrease in tensile stiffness, fatigue resistance and strength
increase in glycosylation and collagen cross linking, loss of proteoglycans
loss of elasticityy tendency toward osteoarthritis

Question 17

CNS ageing effect

Answer 17

atrophy
aggressive accumulation
decrease in neurotransmission

Question 18

PNS aging effect

Answer 18

reduced regenerative response
demyelination/axonal atrophy/electrophysiology
damped signal transduction
loss of responsiveness of autonomic nervous system
less homeostatic ally adaptive

Question 19

sensory functions

Answer 19

deteriorate
touch, vibration, spatial distinction, proprioception, vestibular function
hearing loss - especially high frequency - loss of organ of Corti hair cells and auditory nerve neurones, decrease in cochlear blood supply

Question 20

vision in aging

Answer 20

progressive loss of accomodation - presbyopia
decreased ability to alter pupil size in response to light intensity
decreased number of retinal rods and cones

Question 21

central processing deficit

Answer 21

difficulty distinguishing words from background noise

Question 22

cognitive functions

Answer 22

intelligence, memory and learning decline is not marked in the baseness of dementia
may reflect slowing of central processing
decrease ability to solve novel problems
learn less quickly

Question 23

vascular

Answer 23

decrease in arterial compliance and distensibility

Question 24

cardiac

Answer 24

increase after load due to decrease arterial compliance
decrease ejection fraction, decrease diastolic relaxation
decrease intrinsic and maximum heart rate
increase in atrioventricular conduction time
blunted baroreflex

Question 25

pulmonary function

Answer 25

decrease respiratory muscle strength and endurance lung volumes decrease gradually decrease in lung elasticity (compliance)

Question 26

exercise capacity

Answer 26

Max O2 uptake declines decrease muscle mass, CV/pulm function all contribute elderly CV system - heart less responsive to adrenergics decrease in response physical conditional

Question 27

kidney and urinary

Answer 27

RBF and GFR falls wit h age decrease in renal mass and tubular transport function lose responsiveness - changes in Na load decreased bladder capacity number of uninhibited contractions increases

Question 28

minor GIT

Answer 28

loss of skeletal muscle at both ends of GIT - minor less of function (chewing, swallowing, faecal continence) atrophy of secretory systems - decrease of exocrine secretion decrease in liver mass and hepatic blood flow

Question 29

endocrine function

Answer 29

increase in insulin resistance and decrease in glucose tolerance decrease in hypothalamus induce rhythm increase in ADH release in response to osmolar stimuli adrenal cortex - cortisol and aldosterone secretion well preserved thyroid glands - increased incidence of abnormalities, increased PTH levels associated with osteoporosis

Question 30

growth hormones

Answer 30

``` significant decline GH and IGF-1 adrenal steroids menopause - abrupt cessation andropause - progressive decline ```

Question 31

mechanism of loss of GH

Answer 31

decrease in peak pulsatility of the hypothalamus | GnRH release no longer pulsitile, decrease in plasma GH and IGF-1

Question 32

adrenal steroids mechanism of reduction

Answer 32

age related decline in zona reticularis cell number

Question 33

gonads

Answer 33

reduction in hypothalamus stimuli - GnRH reduction in cell number of gonad secretory cells - decrease in ovarian reserve, decrease in oestrogen and progesterone leydig/Sertoli cell atrophy cause decrease in testosterone

Question 34

decrease in ovarian reserve

Answer 34

decrease in oestrogen decrease in negative feedback increase In LH and FSH increase in follicular recruitment/atresia reduction in ovarian reserve ceasing oestrogen production menopause