Endocrine System

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Endocrine System
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Review of Structure and Function
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Review of Structure and Function
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Feedback Regulation
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Age Related Changes
Pituitary Changes - must consider hypothalamus
as well Secretion of RH does not change
signif. Despite Decrease Blood Supply Increase
connective tissue Blood levels of TSH, GH and
ACTH only decline slightly to age
60 Importance of Receptor Density and
Function Exercise may help maintain GH
responsiveness LH and FSH increase in blood in
postmenopausal women lack of negative feedback
by estrogen
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Age Related Changes
Thyroid Gland - Thyroid deficiency shows similar
functional changes with aging A cause of
aging?? Atrophy - loss of follicles, dec.
size Blood T4 does not dec. signif. with
age Feedback Regulation Correlation with
metabolism ? Cause and effect ?
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Age Related Changes
Adrenals - connective tissue replaces
degenerating tissue age-related decline in
cortical secretions glucocorticoids decline in
aldosterone over 50 no apparent effect on salt
and water balance medullary hormones actually
increase epinephrine
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Age Related Changes
Pancreas - not under hypothal./ pituitary
control directly regulated by blood
glucose pancreatic function greatly affected by
age some atrophy of Islet Cells decreased
insulin sensitivity ? Reduced response to
glucose tolerance test 50 of over
60 increased time to return to normal insulin
levels similar to young people
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Age Related Dysfunctions
Diabetes Mellitus - Type I - juvenile
onset Type II - adult onset insulin resistance
(elevated levels) gradual onset Risk Factors
- obesity, sedentary life style,
age Consequence - AGEs, retinopathy,
neuropathy gangrene, slow wound healing,
ketosis, glaucoma, cataracts, heart disease
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Age Related Dysfunctions
Hypothyroidism - 5 over 65 decreased
metabolism TRH ?, TSH?, Autoimmune ? Fatique,
depression, cold sensitive Treatment - T4
(synthroid) Stress Response - hypothal/
pituitary / adrenal cortex help cope with
stress hyperactive in older people feedback
control