Ageing Flashcards
Changes in heart and lungs associated with ageing (3)
Increased blood pressure
Decreased lung capacity
Decreased oxygen uptake
Changes in body composition and metabolism associated with ageing (3)
Greater body fat
Raised blood lipids
Impaired glucose tolerance
Changes in reproductive function associated with ageing (2)
Menopause
Male infertility
Changes in musculo-skeletal function associated with ageing (3)
Muscle wasting
Reducing muscle tone and strength
Bone mineral declining
Changes in immune function associated with ageing
Declining cellular and passive immunity
Changes in digestive tract associated with ageing (5)
Loss of teeth Salivary flow reduced Reduced gastric secretions Reduced colonic motility Malabsorption of micronutrients
What are the two fates of cells during the ageing process (2)
Cell death
Quiescence
Necrosis (4)
Cell death due to external factors abnormal Cell death due to inflammation, injury or infection
Involves breakdown of cell and organelle membranes
Lysomal destruction of cell components
Apoptosis (3)
Programmed cell death
Occurs on activation of caspases
Coordinated recruitment of systems to destroy genetic material and proteins
Cellular quiescence (4)
Cells become quiescent during as we age
Which is altered patterns of gene expression
Quiescent cells may be replaced by stem cells
Ageing begins to impact on function if rate of senescence exceeds rate of replacement
What is p53?(2)
Tumour suppressor protein
Is a regulator of the G1/S checkpoint in the cell cycle
What regulates p53 concentration?
Hdm2 (mdm2)
What happens when p53 is activated through DNA damage/mutation?(2)
Results in either:
Senescence
Or triggers apoptosis
There is a _________ correlation between ____ and lifespan
Negative
BMR
Changes in nervous system associated with ageing (4)
Sensory impairments
Memory loss
Slower reflexes
Slower mental function
Oxidative senescence
DNA vulnerable to oxidative damage
Lose capacity to prevent oxidation
Damage to mitochondrial DNA promotes excessive ROS generation
Unrepaired DNA damage activates p53 expression
What does p53 activation lead to?(2)
Apoptosis
Cell cycle arrest
What are telomeres?
Repeating sequences of linear chromosomes
What happens to telomere length as we age?(3)
Shortens
Below critical length p53 is activated
And apoptosis or senescence occurs
Purpose of telomeres (2)
Prevent chromosome fusing together
Therefore preventing development of genetic defects
What is the second mechanism causing telomeres to shorten?
Oxidation
Calorie restriction mechanisms (6)
Generates negative energy balance Lower fat mass Reduced insulin production Less inflammation Enhanced protein synthesis Reduced mitochondrial respiration and production of ROS
Hazards associated with CR (6)
Excessive weight loss Infertility Osteoporosis Reduced wound healing Reduced immune function More psychological disorders
Outcomes associated with with early life exposure to CR
More chronic diseases
Potential hazard of high amounts of antioxidants (2)
Down regulation of oxidative repair
And antioxidant enzyme repair
Oxidative senescence pathway (5)
ROS
DNA damage
DNA damage repaired
Or
p53 activation
Apoptosis or cell cycle mass
Hayflick limit (4)
Cells divide a certain amount of times before they die or become quiescent
Cells from short lived animals divide fewer times than those from longer lives animals
Cells from older animals divide fewer times than those from young animals
This may have evolved to protect against cancer
INK4a pathway (5)
Ink4a and ARF are tumour suppressor proteins produces from a single gene
Promotes ageing through inhibition of stem cell differentiation
And prevention of cell division
Expressions of proteins increases with ageing
Ink4a can override the telomere clock
Example of long term calorie restriction in humans (5)
Okinawa has greatest density of centurions
Low CVD and cancer rates
Nutrient-dense diet with much less energy than western diet
However long life may be due to health foods rather then calorie restriction
Or may be due to genetics
Antioxidants and ageing (6)
May restrict oxidative senescence
And slow ageing
Some studies have shown protective effects of ascorbate
Resveratrol extends life in simple organism
But no benefit of complex organisms
High dosage may also suppress other beneficial elements