3.3 Changes in Structure and Function in Old Age Flashcards
What can be causative factors of problems in Old Age?
Genetics Lifestyle Cell damage Disease Social Factors
What is FEV1?
Forced Expiratory Volume in 1 second - the volume of air which can be forcibly be blown out after one full inspiration
What happens to FEV1 with old age?
Men have a higher FEV1 , but overall for both men and women the FEV1 decreases - begins at around the age of 30
How are lung and chest functions affected?
Decreased elastic recoil
Increased chest wall stiffness
Decreased respiratory muscle strength
Decreased intervertebral space
How is gas exchange affected by old age?
Decrease lung elastic recoil
Decreased pulmonary capillary volume
Decreased dispensability of arteries
Decreased Lung surface
How is ventilatory control affected by old age?
Decreased responsiveness to hypoxia/hypercapnia
Decreased sensitivity to elastic and resistive loads
Decreased protective reflexes in the airways
What is part of the prognostic score for pneumonia?
Confusion, Increased urea, increased respiratory rate and decreased blood pressure, age over 65
Why does diastolic pressure not change?
Distal blood vessels don’t show any changes - resting peripheral resistance doesn’t change - diastolic doesn’t change
What other cardiac changes are present in old age?
Decreased beta adrenergic stimulation
Left ventricular enlargement - stiffening of main arteries
Ejection fraction at rest remain the same
Decreased response in exercise to cardiac output and heart rate
“STRESS” reveals changes
What do these cardiac changes result in?
Symptoms worse on exercise
Greater sensitivity on hypertension, postural hypertension, iischemic heart disease and heart failure
What is carotid sinus syndrome?
An exaggerated response to baroreceptor stimulation, causes a drop in blood pressure
What happens to blood pressure in old age?
Systolic blood pressure rises steadily with age - This is because larger, elastic, artery walls become thicker and stiffer with increasing age.
Which GI functions change in old age?
Less teeth Less taste buds Less saliva Less HCL production Less gut motility Less liver size
How do nutritional requirements change?
Malnutrition and nutrient deficiencies are common, usually due to insufficient intake rather than poor absorption
How is the glucose absorption altered?
Same amount of insulin is released but it is delayed - higher and longer peak of glucose - meaning that insulin sensitivity has been decreased - less affective packing of glucose into cells, - increased risk of diabetes
What other endocrine changes are there?
Osmoregulation
Decreased sensation of thirst
Poorer response to water dehydration - risk of dehydration
What happens to bioavailability in old age?
Decreased first pass metabolism - decreased liver size and blood flow
Change in distribution volume - low body water, high fat
What other changes in drug metabolism are seen?
Increased passage across blood brain barrier
Increased tissue sensitivity
Decreased renal and hepatic clearance
Give examples of drugs which can be dangerous in elderly….
• Digoxin • Morphine • Sedatives (e.g. temazepam, haloperidol) • Antihypertensives Warfarin
What immune changes are seen in the elderly….
Reduction in number of t helper lymphocytes
Reduction in size and function of thymus gland by 60
Reduction in antibody production by B cells
Reduction in mucosal immunity
Less IgE production - less allergies
What do the immune changes result in clinically?
Higher risk of infection - lower cell mediated immunity
Poorer response of infections
What is the risk of shingles of people aged between 45 - 85 ?
Five times greater risk of shingles resurfacing due to lowered immunity
How does renal function change with age?
Decreased kidney size Decreased BF Decreased GFR Decreased renin and aldosterone High levels of variability between people
How is renal function measured and how does it change with age?
Serum creatinine measured
Creatinine levels reduced due to less muscle
Creatinine clearence varies between individuals
What is the Cockcroft and Gault equation?
(140 –age) x body weight (kg) serum creatinine (umol/l)
What changes in vision and the eye can be seen in the elderly?
Ciliary muscles are weaker
Decreased lens elasticity but increased size - can’t focus
Increased force required to focus at above 40 years
Pupil size decreases - less light
Some retina and optic pathway loss - less detail and contrast
What presbyopia?
After age 50
Difficulty with near vision
Reading glasses needed
How is hearing affected by old age?
Degeneration of cochlear cells
Dry impacted wax
Changes in articular cartilage
Degeneration of hair cells and lining cells
What is presbycusis?
Loss of high frequency hearing with old age
What are the changes seen in the brain?
Loss of neurones and neuronal connections
Reduced cerebral blood flow
Decreased brain size - bigger ventricles
Which aspects of memory are more affected?
Working and episodic memory decline
Semantic/procedural memory are less affected
What is dementia?
Progressive decline in intellectual function
Interferes with daily activities
How does old age impact on bone?
Peak bone mass - age 25-30
Decreased bone mass accelerated by menopause in women - also smoking, diet, exercise drugs
What is WHO definition of osteoporosis?
Bone mineral density greater than -2.5 standard deviations from the mean of a healthy young adult
How is muscle affected by old age?
Loss of muscle strength
Loss of muscle mass
Changes in gait pattern
Increased risk of falls
Are age associated changes inevitable?
Training can prolong health, so they can be prevented or reversed
How is the nervous system altered in old age?
Decreased cortical cell count,
Decreased nerve conduction velocity
Decreased sleep duration
Slower psychomotor response
