Ageing

Question 1

New Zealand population structure

Answer 1

Increasing number of older people (65+). Mean life expectancy expected to increase.

Question 2

Survival curves, aging kicks in when?

Answer 2

At about 20 (physiology similar), probability of dying increases. Every 8 years chance doubles

• % survival, slight dip at 100% due to perinatal mortality
• Mean life span at 50%

Question 3

Ageing characteristics?

Answer 3

Progressive; universal and irreversible

Question 4

Diseases: 1) that are part of the ageing process; 2) show increasing incidence with age; 3) more serious consequences with increasing age; 4) Generally PUI but not necessarily fatal or age related

Answer 4

1) Hypertension, atherosclerosis. (PUI?)
2) Neoplasms, Not PUI
3) Resp infections, incidents. Not PUI
4) Osteoarthritis, emphysema, osteroporosis

Question 5

Physiological changes with age

Answer 5

Increases to ages 20-30, then steady decrease

Max breathing capacity, vital capacity, Renal plasma flow, GFR, BMR

Question 6

Two theories of ageing

Answer 6

Programmatic: ageing due to inherent genetic programming
Stochastic: Ageing results form environmental damage

Question 7

Programmatic theories

Answer 7

• Rate of living theory: Level of BMR determines life span and weight (humans low, live longer). When corrected for body mass, not so convincing
• Temperature: Cold blooded animals at hiher latitudes live longer, mice core temp decreased, live 20% longer, , hibernation

Question 8

Stochastic Theories

Answer 8

-Free radical theory: Free radicals causing alterations to proteins. As a result of breathing O2.
Actions of them: increased collagen cross linking (stop nutrient diffusion); inactivate enzymes, break DNA; oxidised protein turned over quicker.
However we have protective mechansims: Superoxide dismutase, catalase, glutathione, Vit E, Vit C
-Calorie restriction: No evidence that it works on humans. By doing it by about 30%, decrease blood glucose, temp etc. Related to Sir2, a transcriptional silencing gene that maintains telomeres

Question 9

ECM and ageing

Answer 9

Collagen: Increased cross linking, reduced tissue flexibility, and diffusion

Elastin: loss with age, more fragmented, reduced recoil, especially lung and arteries

Proteoglycans: Increase in sulphated PG’s, increase in lipid binding in vessels, decreased hyaluronan, reduced water content in tissue