Age Related Changes Flashcards
Define aging
Progressive deterioration of functional properties of the body at the cellular, tissue and organ levels.
Why is it important to understand the physiological changes caused by age?
- to promote healthy aging
- to develop effective healthcare plans
- to improve quality of life
- to reduce the cost of healthcare
What are the three types of muscle fibers
Type I aerobic, slow twitch
Type IIa aerobic, fast twtich
Type IIb anaerobic, fast twitch
What is the main change in body composition due to aging ?
Muscle mass loss starting at the 4th decade
What is the percentage of muscle mass loss per year from 40 ?
0,5%
What is the percentage of muscle mass loss per year from 50?
1% to 2%
What is the muscle mass loss percentage per year from 60?
3%
Why is there a loss of muscle mass and strength with aging ?
Due to:
- decreased size and number of muscle fibers (mainly type II fibers)
- decreased neural activation
What are the different categories of older adults ?
Young-old from 65 to 74
Mid-old from 75 to 84
Old-old older than 85
What is the average life expectancy in Europe ?
75 years old
What are the visible signs of aging
- grey hair
- postural changes (flexion)
- muscle mass loss
- wrinkles
What are the signs of atrophy ?
- diminution in type II (fast twitch) muscle fibers
- increase in fat deposit around the muscle tissue
- increase in connective tissues around the muscle tissue
(Fat + connective-tissue being non-contractile tissues)
What is the result of type II muscle fibers loss ?
- reduction of muscle mass
- reduction of strength and velocity of muscle contraction
- reduction of aerobic capacity
What is the result of the increase of fat deposit around the muscle tissue?
- less toned muscles
- reduction of muscle cross sectional area
- loss of strength
What is the result of the increase of non-contractile structures (define) ?
Non contractile structures: fat and connective tissue
Result: decrease in muscle cross sectional area; reduction of potential strength
Which body parts decline faster due to aging ? Give an example
Lower limbs > Upper limbs
Extensors > Flexors
Ex: isometric knee extension between 55% and 76%
What causes decline in gait velocity in elderly people?
Decline in knee isometric extension
What are the effects of aging on connective tissue (define)
Connective tissue= fascia, cartilage, ligaments and tendons
Effects= increased number of cross-links in collagen fibers
—> makes them less extensible causing a decrease in AROM an PROM
—> as well as tendon stiffness
—> and reduced maximal force production
—> and slower transmission of forces.
What are the effects of aging on the cartilage ?
- reduced number of proteoglycans
- remaining proteoglycans become shorter and lose their ability to hold water
These factors cause a degeneration, thinning/ damage and loss of water content in the cartilage and leads to OA
What are the effects of aging on the MSK system ?
- decrease in bone density
- increase in cross links between collagen fibers
Both causing a higher risk of bone fracture - cartilage becomes less hydrated and thinner
This leads to possible degeneration
Risk of fall is an aggravating factor
What are the roles of the hypothalamus and pituitary gland complex ?
Command center of the endocrine system which secretes several hormones, some producing responses on targeted tissues, others regulating the synthesis and secretion of hormones of other glands.
What is the role of the pituitary gland ?
Controls other glands through release of hormones: growth hormone, prolactin, luteinizing hormone.
What is the role of the pineal gland?
Production of melatonin
What is the role of the thyroid gland ?
Controls metabolism through thyroid hormone
What is the role of the parathyroid ?
Controls calcium levels in blood
What is the role of the adrenal gland ?
Production of epinephrine, corticosteroids, aldosterone
What is the role (hormonal) of pancreas ?
Producing insulin and glucagon
What is the role of ovaries ? (Hormonal)
Production of estrogen
What is the role (hormonal) of testes ?
Production of testosterone which increases muscle protein synthesis
What are the effects of aging on the pituitary gland ?
It produces less growth hormone, reducing muscle mass and increasing deposition of adipose tissue.
What are the effects of aging on the pineal gland ?
It produces less melatonin, reducing the time of sleep and altering its pattern
What are the effects of aging on the parathyroid gland ?
It produces less parathyroid hormone leading to increased osteoclast activity and therefore a diminution in bone density.