Ageing Flashcards
What is ageing?
A distinct and progressive decline in function which makes us more vulnerable to disease
Common processes seen in most ageing tissues:
- Decrease in amount of tissue
- Altered molecular composition
- Accumulation of degraded molecules
- Reduced efficiency of functional elements
- Reduced synthetic capacity of differentiated cells
- Decline in stem cells
- Altered levels of hormones, growth factors and cytokines or altered ability of cells to respond to them
Examples of functional decline as we age?
1) Cognitive functions
- Normal decline
- Increase risk of Dementia
2) Senses
- Visual: eyesight deteriorates
- Auditory: Poorer hearing
- Balance: Increased risk of falls
3) Continence
- Front and back
Body composition and homeostasis as we age?
- Decrease muscle mass
- Increase body fat
- Decrease in % water
- Changes volume of distribution
- Increased bone loss
- Impaired baroreceptor function
– Orthostatic hypotension
– Dizziness due to when a person’s blood pressure suddenly falls when they stands up - Impaired thermoregulation
Slide 6
Conclusions of the study titled “Effect of aging and physical activity on left ventricular compliance”?
A sedentary lifestyle during healthy aging is associated with decreased left ventricular compliance, leading to diminished diastolic performance. Prolonged, sustained endurance training preserves ventricular compliance with aging and may help to prevent heart failure in the elderly. (Circulation. 2004;110:1799-1805.)
Conclusions of the study titled “Refining patterns of left ventricular hypertrophy using cardiac MRI”?
“Left ventricular hypertrophy (LVH) is generally considered to be an adaptive response that allows for normal ejection fraction despite abnormal pressure and/or volume load. However, this adaptation is associated with increased cardiac morbidity and mortality, including acute myocardial infarction, heart failure, arrhythmia, and stroke.”
Effect of ageing on pulmonary?
- Decreased elastic recoil, airways collapse earlier
- Decreased forced vital capacity, functional residual capacity, residual volume, FEV1
- Decreased ventilatory response and chemoreceptor function
Affect of Decreased elastic recoil, airways collapse earlier?
Increases residual volume
Affect of Decreased forced vital capacity, functional residual capacity, residual volume, FEV1??
Can’t expel CO2 so efficiently
Affect of Decreased ventilatory response and chemoreceptor function?
Increased hypoxia and hypercapnia
How is renal affected by ageing?
- Decreased mass and number of glomeruli
- Increased glomerulosclerosis (Scarring of the glomeruli)
- Glumular Filtration Rate slowly decreases
- Decreased Na+ retention; decreased responsiveness to Arginine vasopressin (AVP)
- Less concentration of urine
- Decreased thirst and drink response
- Resulting in increased dehydration
How is endocrine system affected by ageing?
1) Decreased glucose tolerance (Fasting Glucose decreases 1 mg/dL/decade) (Independent of obesity and inactivity)
2) Increased insulin resistance
3) Decreased Growth hormone (GH) & Insulin-like Growth Factor (IGF-1)
(Give elderly men GH, increases lean body mass) (IGF-1 is important for growth in children and has anabolic effects in adults.)
Affect of ageing on immunosenescence?
- Decreased T-helper cell activity (CD4+)
- Increased Killer T-cell activity (CD8+)
- Decreased Ab response to foreign antigen
- Increased auto-antibodies
Conclusions of the study titled “Mechanisms of immunosenescence”?
“Alterations to the immune system in the older person are generally viewed as a deterioration of immunity, leading to the use of the catch-all term immunosenescence. Indeed, many immunological parameters are often markedly different in elderly compared to young people, and some, mostly circumstantial, evidence suggests that retained function of both innate and acquired immunity in the elderly is correlated with health status.”
Other Clinical Features of Normal Ageing?
- Loss of muscle mass
- Decreased musculoskeletal mobility
- Reduction in bone mass (osteoporosis)
- Thinning and reduced elasticity of skin (wrinkling)
- Slower wound repair
- Brain, liver, kidneys – a low amount of cellular loss and reduction in mass
A theories around ageing fall into 1 of 3 groups which are:
1) Biological clock
2) Non-reversible cellular changes
3) Cellular damage
Monozygotic twins have life spans that are …
…closer than dizyotic twins
Each species has its own …
… average longevity
Ageing is programmed into…
…each species
The most popular theory of ageing concerns …
…telomere shortening (mitotic division counter)
- Somatic cells have a limited number of divisions
Somatic cells have a limited number of…
…divisions
Slide 20
The limit was found to correlate with …
…telomere length – the more times a cell had replicated, the shorter its telomere
What cells are effected by the hayflick limit?
- The cells that are continuously dividing by mitosis
- Bone marrow, epithelium, fibroblast cells
- We know that the rates of division does decrease with age
What might happen to red and white blood cell production because of hayflick limit?
Red and white blood cell production slows
What might happen to immune system because of hayflick limit?
Immune system less responsive
Link between fibroblast cells, rats and colalgen?
In rats rates of collagen synthesis decrease ten-fold between 1-24 months (8 to 60 human years)
Affect of hayflick limit on the epithelium?
- Know that skin gets thinner as we age
- The GI tract becomes leaky
We can’t stop these cells dividing, but we can …
…slow the need for their replacement