Human Physiology 19

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Human Physiology 19
2011-10-11 18:36:55
Human Physiology

Regulation of Metabolism
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  1. What must living organisms continuously have in order to overcome the second law of thermodynamics?
    energy and materials
  2. What molecule is the energy currency of all living systems?
    adenosine triphosphate (ATP)
  3. What three types of molecules provide energy to the body?
    • carbohydrates
    • proteins
    • fats
  4. What is the most common unit of measure of energy in food?
    the kilocalorie
  5. What is a calorie?
    the amount of energy required to raise the temperature of one gram of water one degree celius
  6. How many calories are in carbohydrates, proteins, and fats respectively?
    carbohydrates = 4 kcal/gm; proteins = 4 kcal/gm; fats = 9 kcal/gm
  7. What is the total rate of body metabolism, that is, the amount of O2 consumed by the body/minute?
    metabolic rate (MR)
  8. What is the metabolic rate of an awake, relaxed person 12-14 hours after eating and at a comfortable temperature?
    basal metabolic rate (BMR)
  9. List five factors that influence basal metabolic rate.
    • age
    • sex
    • body surface area
    • activity level
    • thyroid hormone levels
  10. What are all the chemical reactions in the body?
  11. In what type of metabolism do synthesis and energy storage reactions occur?
  12. In what type of metabolism do energy liberating reactions occur?
  13. What type of reactions synthesize DNA and RNA, proteins, fats, and carbohydrates?
    ababolic reactions
  14. What is the rate at which a molecule is broken down and resynthesized?
    turnover rate
  15. What are small organic molecules that serve as coenzymes in metabolism or have highly specific functions and must be obtained in diet because the body does not produce them, or does so in insufficient amounts?
  16. What are the two classes of vitamins?
    • fat-soluble
    • water-soluble
  17. List the four major fat-soluble vitamins.
    • A
    • D
    • E
    • K
  18. List the major water-soluble vitamins.
    • B vitamins
    • pantothenic acid
    • biotin
    • folic acid
    • vitamin C
  19. What group of nutrients are inorganic and are needed as cofactors for specific enzymes and other critical functions?
  20. What minerals are needed in relatively large amounts daily?
    • sodium
    • potassium
    • magnesium
    • calcium
    • phosphate
    • chloride
  21. What class of minerals are required in only relatively small amounts each day?
    trace elements
  22. List the eight trace elements.
    • iron
    • zinc
    • manganese
    • fluorine
    • copper
    • molybdenum
    • chromium
    • selenium
  23. What molecules have an unpaired electron in their outer orbital and are thus highly reactive and oxidize or reduce other atoms?
    free radicals
  24. What are the three important physiological functions of free radicals?
    They help to destroy bacteria, can produce vasodilation, and can stimulate cell proliferation.
  25. What is the general negative effect of free radicals?
    In excess they can exert oxidative stress thus contributing to disease states.
  26. How does the body protect itself from free radicals?
    It uses enzymatic and nonenzymatic (vit. C & E for example) means.
  27. What substances serve as energy reserves in the body?
    • glycogen
    • protein
    • fat
  28. What energy sources circulate in the blood?
    • glucose
    • lactic acid
    • fatty acids
    • glycerol
    • ketone bodies
    • amino acids
  29. How does the body appear to maintain a certain amount of adipose tissue?
    Through negative feedback loops involving hormones released by adipocytes and other tissues.
  30. The number of adipocytes increases greatly shortly after birth. What stimulates the mitotic division and differentiation of adipocytes?
    high levels of fatty acids
  31. Name the general group and give a specific example of hormones secreted by adipocytes.
    adipokines - example: leptin
  32. What is the general effect of the changes in the levels of adipokines that occur with the onset of obesity?
    reduced effectiveness of insulin thus contributing to the onset of diabetes mellitus type II
  33. What is the relationship between starvation or malnutrition and the resulting low levels of leptin and the immune system?
    Helper T cells have leptin receptors. Low leptin levels can lead to diminished immune function.
  34. How does obesity differ between child and adults?
    Childhood obesity involves increases in both size and number of adipocytes. Weight gain in adulthood is due mainly to increase in adipocyte size.
  35. What is the formula for body mass index (BMI)?
    BMI=(weight in kilograms)/(height in meters)2
  36. Healthy weight is in what range of BMI?
  37. In terms of BMI, what is obesity?
  38. In terms of BMI, what is overweight?
    greater than 25, less than 30
  39. What part of the brain is at least partially involved in the control of hunger?
    the hypothalamus
  40. What neurotransmitters promote overeating?
    endorphins and norepinephrine
  41. What neurotransmitter suppresses overeating?
  42. What digestive organs help to regulate hunger?
    the stomach and small intestine
  43. What hormone secreted by adipocytes increases as stored fat increases and acts to suppress hunger?
  44. What percentage of daily calorie expenditure is used to maintain the basal metabolic rate?
    up to 60%
  45. What percentage of daily caloric expenditure is normally use in response to temperature changes and for digestion?
    up to 10%
  46. In what three ways are calories used?
    • BMR
    • temperature regulation and digestion
    • physical activity
  47. What term refers to the 4-hour period after eating when energy substrates from digestion are used and deposited in storage forms?
    absorptive state
  48. What term refers to the condition following the absorptive state?
    postabsorptive or fasting state
  49. What two cell types involved in energy homeostasis occur in the pancreatic islets?
    alpha and beta cells
  50. What two hormones are secreted by the pancreas?
    glucagon and insulin
  51. What is the effect of glucagon on blood glucose levels?
    It increases blood glucose
  52. What is the effect of insulin on blood glucose?
    It decreases it
  53. What type of pancreatic islet cell secretes glucagon?
  54. What type of pancreatic islet cell secretes insulin?
    beta cells
  55. What is the normal fasting glucose level?
    65-105 milligrams/decaliter
  56. Insulin normally prevents blood glucose from rising above what level?
  57. Glucagon normally prevents blood glucose from falling below what level?
  58. What is the overall effect of insulin?
    It promotes anabolism
  59. What does an oral glucose tolerance test assess?
    The ability of beta cells to secrete insulin and insulin's ability to lower blood glucose
  60. How does glucagon maintain blood glucose above 50 mg/dl?
    It stimulates glycogenolysis in the liver and stimulates gluconeogenesis, lipolysis, and ketogenesis
  61. What is the effect of the parasympathetic division of the ANS on insulin secretion?
    It stimulates it
  62. What is the effect of the sympathetic division of the ANS on pancreatic islet cells?
    It stimulates the secretion of glucagon and inhibits the secretion of insulin
  63. Why might blood glucose levels initially fall as a meal is ingested?
    The small intestine secretes hormones that stimulate the release of insulin in anticipation of a rise in blood glucose levels
  64. What is the main characteristic of diabetes mellitus?
    chronic high blood glucose levels
  65. What form of diabetes mellitus is an autoimmune disease in which pancreatic islet cells are destroyed resulting in insufficient insulin secretion?
    type I
  66. What form of diabetes mellitus is due to lack of effect insulin?
    type II
  67. What form of diabetes mellitus is most common?
    type II
  68. In diabetes lipolysis leads to the release of fatty acids which then converted to ketone bodies. An excess of ketone bodies may lead to what condition?
  69. What type of diabetes mellitus is slow to develop, has a multigene inheritance pattern, involves insulin resistance, is usually accompanied by normal to high insulin levels, is not usually accompanied by ketoacidosis, and is treatable by exercise and diet?
    type II
  70. What is the effect of exercise that may help treat diabetes mellitus type II?
    Exercise increases the insertion of GLUT4s into skeletal muscle
  71. What condition results from an oversecretion of insulin due to an exaggerated response of beta cells to a rise in glucose?
    reactive hypoglycemia
  72. What condition results in tremors, hunger, weakness, blurred vision, and confusion due to low blood glucose?
  73. What two hormones are similar to glucagon in their effects in that they stimulate glycogenolysis and lipolysis?
    epinephrine and norepinephrine
  74. What hormone supports the effects of glucagon and is secreted in response to ACTH as a result of stress including fasting and exercise?
  75. What hormone sets BMR, is necessary for growth and develpment, and increases metabolic heat?
  76. What hormone of the anterior pituitary stimulates growth in children and adolescents and has important metabolic effects in adults?
    growth hormone
  77. Excess growth hormone secretion in children produces what condition?
  78. Inadequate secretion of growth hormone during childhood produces what condition?
  79. Excess growth hormone secretion in adults, after epiphyseal discs are ossified, results in what condition?
  80. What condition causes the growth of soft tissue resulting in the elongation of the jaw, deformities in the hands, feet, and bones of the face, but no increase in height?
  81. What part of the body acts as a storage for calcium and phosphate?
    the skeleton
  82. What type of bone cells form bone?
  83. What type of bone cells reabsorb bone?
  84. What type of bone cells are most active during skeletal growth?
  85. What type of bone cells are most active during osteoporosis?
  86. What opposing actions within the skeletal system allow the position of teeth to be shifted through the use of braces?
    bone deposition and reabsorption
  87. What hormone is most important in the control of blood calcium levels, is released in response to low blood calcium, stimulates osteoclasts to reabsorb bone, stimulates the kidneys to reabsorb calcium from the filtrate, and promotes the formation of vitamin D?
    parathyroid hormone
  88. What hormone is the antagonist to parathyroid hormone?
  89. What hormone works to reduce blood calcium?
  90. What endocrine gland makes calcitonin?
    the thyroid
  91. What substance is synthesized in the skin when a cholesterol derivative is converted to it by sunlight?
    vitamin D
  92. What substance simulates intestinal absorption of Ca2+ and PO43-, directly stimulates bone
    reabsorption by promoting formation of osteoclasts, stimulates kidney to reabsorb Ca2+ and PO43 while simultaneously raising Ca2+ and PO43- resulting in increased tendency of these to
    precipitate as hydroxyapatite, and is stimulated by PTH?
    vitamin D
  93. Inadequate vit D in the diet and body can cause what two conditions related to loss of bone calcification?
    osteomalacia and rickets