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Maintenance of Homeostasis _ Associated Disorders

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Maintenance of Homeostasis _ Associated Disorders Powered By Docstoc
					ENDOCRINE SYSYEM
    Disorders
 Normal Endocrine function can be
  disrupted, and symptoms can range from
  mild discomfort to potentially life-
  threatening complications.

 Treatments of disorders include hormone
  replacement therapy, other medications
  and changes in diet or behaviour.
  Possible means of disruption
            includes:
 medical problems such as tumours,
  infection, auto-immune diseases and
  physical injury
 Genetic disorders
 Industrial pollutants
 Food additives
     Ex 1: Glucagon + Insulin
 Insulin: secreted by β-cells in pancreas
   Stimulates the uptake of glucose  glycogen
   Anabolic
   Decreases blood sugar
 Glucagon: secreted by α-cells in pancreas
   Stimulates conversion of glycogen to glucose
   Catabolic
   Increases blood sugar
                                     See page 378
Hormones: Glucagon + Insulin
      Disorder 1: Hypoglycemia
 The disease associated with LOW blood sugar
  levels
 principal problems arise from an inadequate
  supply of glucose to the brain, resulting in
  impairment of function from mild dysphoria to
  more serious issues such as seizures,
  unconsciousness, and (rarely) permanent brain
  damage or death.
 true hypoglycemia usually occurs in patients
  being treated for diabetes (type 1 and type 2).
Disorder 2: DIABETES MELLITUS
 Type 1: inability to make insulin
   Genetic
   Requires injections of insulin with each meal
 Type 2: insulin resistance or insensitivity
   May be genetic or due to lifestyle/overweight
   Higher prevalence
   Too much blood sugar (overstimulation)
      Inadequate release of insulin (B-cell exhaustion)
      Receptors no longer respond to insulin
DIABETES
Diabetes on the rise….
     Ex. 2: Ghrelin and Leptin
 GHRELIN:
 Gut hormone produced by stomach and
  pancreas
 Stimulates hunger
 High before a meal
 Low after a meal
 Amounts are inversely proportional to
  hours of sleep (may be connected to obesity)
   e.g. less sleep  more hungry  overweight
       Ex 2: Ghrelin and Leptin
   LEPTIN:
   Gut hormone produced by adipose tissue
   Feeling of satiation (feeling full)
   Low before a meal
   High after a meal
    Disorder 3: Hormone induced
               Obesity
   Excess of ghrelin
   Deficiency of leptin
   Leptin resistance (loss of sensitivity)
   Many other genetic factors are involved
   Anti-obesity vaccine
    stimulates the body to
    make antibodies
    against ghrelin
                  Knockout Mice




Both mice have a defective leptin gene (knockout)
LEFT: no leptin injection  ate uncontrollably  obese
RIGHT: daily leptin injections  normal appetite  normal
weight
             OBESITY STATS
   10-25% of teenagers have weight problems
   20%-50% of adults have weight problems
   80% of diabetes patients are obese
   1/4 - 1/5 adults are obese in Canada
   1/3 adults are obese in U.S.
   1Billion overweight adults globally (WHO)
   300,000 deaths per year
   Obesity in children is on the rise!
                                 (Library of Parliament)
BMI CHART
OBESITY RATES (Statistics Canada)
                 Ex 3: TSH
 TRH: Thyroid Releasing Hormone
   Hypothalamus produced to signal Pituitary
 TSH: Thyroid Stimulating Hormone
   Anterior Pituitary produced to signal Thyroid
 T3: tri-iodothyronine and T4: Thyroxin
   Thyroid Produced
 Requires iodine from diet
   Yogurt, milk, cheese, eggs, strawberries, salt
 Stimulates increase in metabolism
   Disorder 4: HYPERTHYROIDISM:
 speeds up the body
  -a.k.a Grave’s disease
  -Overproduction of hormones
  T3 and T4
  -Heart palpitations,
  sweating, anxiety, increased
  appetite, weight loss,
  diarrhea, impatience,
  irritability, increased blood
  pressure, hyperactivity
 Disorder 5: HYPOTHYROIDISM
 slows down the body
  -Deficiency of the hormones
  -Usually due to iodine deficiency
  -Slow heart rate, weight gain, water
  retention, depression, muscle cramps,
  fatigue, constipation
Disorder 6: GOITER

 Due to lack of iodine in the diet, there is a decrease in T3
 and T4 production, resulting in the thyroid gland increasing
 in size
      Ex 4: Growth Hormone
 GHRH: Growth Hormone Releasing
  Hormone
   hypothalamus  GH (Growth Hormone) in
    Anterior Pit
 Stimulates cell division in a wide variety
  of target tissues including those involved
  in immune, bone, metabolism
 Anabolic
       Disorder 7: Gigantism
Excessive GH production
pre- puberty




                          7.9ft vs. 2.4ft
 Disorder 8: Acromegaly
Excess GH after puberty
-Enlarged digits
-thicker bones
-larger organs
-Joint paint,
-muscle weakness
Disorder 9: Dwarfism
          Deficiency in GH
Ex. 5 Parathyroid Hormone and
           Calcitonin
 PH produced by parathyroid gland;
  calcitonin in Thyroid
 Regulates calcium levels in the blood by
  signalling kidneys to reabsorb or
  decomposing bone
 Vitamin D is essential for PTH to function
Disorder 10: Hypoparathyroidism
Parathyroid glands do not secrete sufficient
  parathyroid hormone
 Hypocalcemia (low blood calcium):
  - spontaneous action potentials to muscles
  leads to twitching, and at very low
  concentrations of calcium, tetany
  (paralysis) develops
 High levels of phosphorus
Disorder 11: Hyperparathyroidism
Parathyroid glands secrete excessive parathyroid
  hormone
 Hypercalcemia (high blood calcium):
  - slow reflexes, irregular heartbeat, kidney
  stones, fatigue, poor appetite, nausea,
  constipation, frequent urination, bones are weak,
  brittle and painful,
  -high calcium levels also prevent normal
  repolarization in the brain, resulting in
  hallucinations or impaired thinking and memory
 Low levels of phosphorus
       Ex. 6 Glucocorticoids
 Produced by the
  Adrenal Cortex
 Cortisol (regulates
  inflammation) and
  aldosterone
  (regulates Na+
  absorption in
  kidneys)
Disorder 12: Cushing’s Disease
 Excess
  glucocorticoids
 High blood
  pressure
 High blood sugar
 Muscle weakness
 edema
  Disorder 13: Addison’s Disease
 Hyposecretion of
  glucocorticoids and
  mineralocorticoids
 Low blood pressure
 Low blood sugar
                            Thomas Addison
 Suffer from weight loss
 Weakness
 Loss of resistance to
  stress
                 REMINDER
 Many more disorders than what are
  mentioned here.
 Most hormones have a multitude of effects –
  often they are not related and function in
  different parts of the body
   e.g. sleep, appetite, growth, immune,
    electrolyte balance, memory and learning
 The endocrine system is extremely complex
  and poorly understood
 The brain is even more complex and even
  less understood
               …HOMEWORK
 OPTIONAL:
  Make a review sheet –
  Guidelines:
   No sentences – only key words
   Covers all relevant lessons, readings and hw
   Obvious information is omitted
   Info related to types of questions to expect, things
    to focus on, areas of difficulty, diagrams to expect…
   Handwritten
   Maximum two pages one sided

				
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posted:4/20/2011
language:English
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