week 1 Flashcards
defne ageing
is the accumulation of changes in an organism or object over time.
define senescence
is the normal process of changes in the body over time.
also known as primary aging
what are the two main theories of aging
- Programmed Theory
* Error Theory (or Damage based Theory)
whats programmed theory
predetermined ageing includes programmmed longevity endocrine theory immunological theory
whats programmed longevity theory
where ageing is the result of certain genes being switched on or off, in sequence, over time.
whats endocrine theory
where the biological clock acts through hormones to control the rate of ageing.
whats immunological theory
where the immune system is programmed to decline over time. Leading to increased vulnerability to infectious diseases and death.
whats error theory
ageing is resulted for damage from biomechanical and environmental factors. includes: wear and tear thoery cross linking theory free radicals theroy somatic DNA damage theory
whats wear and tear theory
where cells and tissues simply wear out from repeated use.
whats cross linking theory
where accumulation of cross-linked proteins damages cells and tissues.
whats free radicals theory
where free radicals cause damage to macromolecular components of cells, causing accumulative damage, impaired functioning and cell ageing.
whats somatic DNA damage theory
Where accumulation of DNA damage to cells causes them to age. Telomeres have been shown to shorten with each successive cell division.
whats aging determined by
genetic factors, but also heavily influenced by environmental factors such as diet, exercise, exposure to micro-organisms, pollutants and radiation.
examples of primary aging (senescence)
- wrinked skill
- brain cells loss
- osteprosis
whats secondary aging
The degenerative diseases which become more common as we age
eg
atherosclerosis
caners
impacts to nervous system with aging
brain weights begins to define in 20s due to fluid loss and brain remodelling(strengthening connections we already have). reduction in blood supple
what has research shown that can improve memory
environmental factors
expectation on memory decline
what happens to the brain in dementia patients
neuronal loss may be less significant than changes in blood flow, receptor effectiveness and other changes in brain tissue.
what happens to neurones with ageing
- neurons are lost those remaining show increased plasticity with lengthening axons and the sprouting of new dendrites.
- allows new synapses to become established between adjacent cells compensating for some age related neuron loss.
- decline in the synthesis of many neurotransmitters with age plus a decline in their receptors.
- can slow reaction times, impair information processing and also increase the risk of depression.
changes in vision
lens: -thickens, • yellows, • clouds and • becomes less elastic cornea thickens pupil size reduced
changes in accomodation
change in shape of the lens
Presbyopia.
whats Presbyopia.
A form of hyperopia resulting from decreased elasticity of the lens.
what changes within the lens
- Thickening of the lens reduces the amount of light that can pass through the lens.
- yellowing of the lens more light is necessary to stimulate the light receptors of the retina.
- Night vision becomes impaired.
- ability to differentiate between shades of blue, green and violet becomes impaired,
define cataract
Clouding of the lens to any degree
Reduces & disperses light coming into the eye
changes to pupil
Pupil becomes less responsive and has decreased ability to change size
contributes to impaired night vision and poor visual acuity
two categories of hearing loss
conductive
sensory neural
whats conductive hearing loss
where conduction of sound waves through to the oval window is impaired. Causes: • Obstruction. Wax or foreign body. • Less pliable tympanic membrane. • Ossification of auditory ossicles
whatssensory neural hearing loss
where nervous system reception of sound is impaired Causes:
• Loss of stereocilia
• Loss of neurones in the auditory cortex
other changes with hearing
- high frequency hearing loss. Makes higher pitch harder to hear.
- balance impairment: Changes in the vestibular system include
• A progressive loss of hair cells
• Degeneration of otiliths
• A diminished number of vestibular nerve cells.
changes in the cellular immune system
- loss function cell medicated immunity
- increase in helper cells and decrease in supressor cells
- elderly less protected against mycobacterial and viral infections
changers to natural killler cells
decrease in number and/or effectiveness of NK cells
changes in cardiovascular system
- Contractility of heart muscle isn’t affected with ageing
- diastolic filling reduced
- reduction in ventricular distensibility
- Body responses less well when under stress such as exercise (heart rate)
whats atherosclerosis
- a disease process
- accumulation of macrophages and fibrous tissue causes damage to blood vessels
- affects vessel wall disensibilty, so contributes to peripheral resistance thereofore blood pressure and therefore cardiac output
- Atherosclerosis is not inevitable
bararoreceptor changes
Baroreceptor reflex less efficient= decrease in blood pressure to brain when standing up
changes to respiratory system
- gradual loss of elastic lung recoil. due to damage or loss of elastic fibres in the alveolar walls
- compliance reduces
changes to renal system
- Less able to deal with heat due to kidneys degeneration (dhydration)
- Prostati hyperplasia-can cause problems with urine flow or cancer problems
changes to gastrointestinal system
- food intake diminised due to decrease in energy requirements, slowing metabolism
- taste reduced
- smell reduced
- peristalsis of the gut slows leading to consitpation
- rise in the incidence of colon cancers
define sarcopenia
muscle atrophy and decrease in mass
changes in muscles as we age
Reduction in muscle fibre numbers and size
• Increased fat deposits at expense of dense muscle tissue
• Reduction in blood flow to major muscle groups
• Reduction in motor neuron numbers
• Decreased efficiency of mitochondria.
changes to skeletal system
- reduction of activity often seen in older people contributes to decreasing bone mass.
- stress of weight bearing exercises will continue to encourage osteoblasts to deposit calcium. So continued activity with age becomes very important.
factors contributing to bone loss
- Reduction of oestrogen levels in women
- Reduction of testosterone levels in men
- Reduction in levels of growth hormone
- Reduction in absorption of calcium and vitamin D
- Slight increases in parathyroid hormone
changes to joints
joints more prone to mechanical damage.
Flexibility of the joint decreases
changes to the integument
Reduced contact between epidermis and dermis results in an epidermis that separates easily from dermis by simple trauma (epidermis can be easily peeled off by simple trauma).
changes to reproductive system women
Menopause
• The cessation of the normal menstrual cycle
• Preceded by perimenopausal phase of varied duration.
• Usually occurs between the ages of 45 – 55yrs the average being 51yrs in women in Australia .
• Reduced oestrogen levels
- reduced bone density
- reduced vasomotor control (hot flushes).
changes to reproductive system male
Andropause • Collection of gradual changes thought to be caused by a gradual decline in levels of circulating testosterone - increased body fat - reduced muscle masss - reduced bone mass
regular exercise will improve
-muscle mass, strength and physical endurance
• coordination and balance
• joint flexibility and mobility
• cardiovascular and respiratory function
• bone strength
• body fat levels
• blood pressure
• susceptibility to mood disorders, such as anxiety and depression
• risk of various diseases including cardiovascular disease and stroke.
