aging and disease Flashcards
how much does the bone mass have to decrease for osteopenia and osteoporosis
- 1-2.5 `sd below the mean
-at least 2.5 sd below the mean
explain age risk factor for osteoporosis
-osteoblast
-osteoclast
imbalance between rates of rebasorbiton and formation lead to bone loss.
-reduced osteoblast number
cellular response and signalling reduced
as we get older we have reduced osteoblast number and cellular response and signals from other parts of the body are reduced
due to two main cells
osteoclast- breakdown of bone
osteoblast- build back up of bone matrix
wolfs law risk factor of osteoporosis
more physical activity increases bone density
calcium risk factor for osteoporosis
bone mineralised matrix of bone comprises of
organic portion= protein fibres (provides flexibility)
inorganic protion= calcium and phosphate salts (provides strength)
hormones risk factor for osteoporosis
women loose an average 2.5% of bone per year.
decrease in oestrogen production in menopause causes an increase in osteoclast activity.
Calcitonin and parathyroid hormone (PTH) regulate bone calcium.
- Age related increase in PTH
Glucocorticoids increase bone reabsorption
genetic factor risk for osteoporosis
40% of bone loss is due to your genetics
what is sarcopenia ?
age related loss of muscle mass and strength
what is osteoarthritis ?
cartilage thins and bones rub together.
-changes to collagen Makeup
-decrease in water
-cell chrondocytes go through senescence
difference between a normal heart and hypertrophied heart when aging
normal- thickening of left ventricle wall. too much causes hypertrophy.
hypertrophy- more collagen and less elastic heart so heart becomes less efficient to pump blood around the body
valve changes due to aging and the consequences
becomes thicker and less flexible.
consequences- can lead to aortic and mitral valve calcification. means valves don’t close properly.
-can lead to heart murmur as ventricles having to work harder to pump more blood out
conduction system changes as we age e.g. pace maker cells
and the consequences
- arrhythmia
-ischaemic event
decrease number of pacemaker cells in SA node. and increased fibrous tissue.
consequences- lead to arrhythmia (problem of heart beat rhythm).
these are more prone after an ischaemic event (blood flow restricted)
why is heart contraction lowered in the elderly ?
what cells does the heart contain
relies on cardiac muscle cells (cardiomyocytes)
calcium enters the cell and causes contraction.
what is the consequence of fluid transport imbalance in the rise in pulmonary hydrostatic pressure
pulmonary oedema
how is fluid transport determined by starling forces
fluid movements between blood and tissues are determined by differences in hydrostatic pressure forcing fluid out the arteriolar end and
colloid osmotic pressures drawing fluid back at venous end
what prevents pulmonary oedema ?
pulmonary hydrostatic pressure is lower than systemic pressure.
colloid pressures are equivalent
