Chapter 26 (Nutrients & Metabolism) Study Guide Flashcards
1) What is the key factor that determines body weight?
2) How do you gain weight?
3) How do you lose weight?
1) Determined by the body’s energy balance: If energy intake and output are equal, body weight is stable
2) Gain weight if intake exceeds output
3) Lose weight if output exceeds intake
1) What percent of body weight variation is hereditary?
2) What two main environment factors make up the rest of the variation?
1) 30% to 50% of variation in human weight is hereditary
2) Eating and exercise habits account for the rest of the variation
1) What are gut-brain peptides?
2) What is the purpose of short term regulators of appetite?
3) Give 2 examples of short term regulators
1) Act as chemical signals from the gastrointestinal tract to the brain, influence appetite
2) Makes one feel hungry and begin eating and makes one feel satiated and end a meal
3) Ghrelin and cholecystokinin (CCK)
1) What cells secrete ghrelin?
2) Is ghrelin a short term or long term regulator of appetite?
3) After ghrelin has been released, what organ is stimulated in response to release of ghrelin? What hormone does that organ secrete and why?
1) Parietal cells in the fundus of an empty stomach
2) Short-term regulator
3) Stimulates hypothalamus to release growth-hormone releasing hormone (GhRH) to prime the body to take advantage of the nutrients about to be absorbed.
1) What cells secrete cholecystokinin (CCK)?
2) Is CCK a short term or long term regulator of appetite? 3) After CCK has been released, what does it cause secretion of?
4) What fibers does CCK stimulate?
5) What is the overall goal of CCK in response to appetite?
1) Enteroendocrine cells of the duodenum and jejunum
2) Short-term regulator
3) Stimulates secretion of bile and pancreatic enzymes
4) Sensory fibers of vagus nerve and the brain, suppressing appetite
5) Acts as a signal to stop eating
1) What is the purpose of long term regulators of appetite?
2) What are the two long term regulators of appetite? What is their overall goal, i.e., what do they help with?
3) What cells in the body secrete these long term regulators of appetite?
1) To govern caloric intake and energy expenditure over periods of weeks to years
2) Leptin and insulin inform the brain of how much adipose the body has, and activate mechanisms for adding or reducing fat
3) Leptin is secreted by adipocytes, insulin is secreted by beta pancreatic cells
Does gastric peristalsis stimulate or inhibit hunger?
Stimulate hunger
1) What are some causes of obesity?
2) What impact does this have on physical health and life expectancy?
1) Causes are diverse: heredity, overfeeding in infancy and childhood; evolution resulted in adaptations to store nutrients to cope with times of scarcity
2) Shortens life expectancy; increased risk of atherosclerosis, hypertension, diabetes mellitus, joint pain, kidney stones and gallstones, cancer of uterus, breast, and prostate, and sleep apnea
1) Can you define nutrient?
2) Name the 6 categories of nutrients. Include which are macronutrients and which are micronutrients.
3) Can you explain the difference between macronutrient and micronutrient?
1) Any ingested chemical used for growth, repair, or maintenance of the body
2) Water, carbohydrates, lipids, and proteins (macronutrients) and vitamins and minerals (micronutrients)
3) Macronutrients means we require large quantities; micronutrients means only small amounts are needed
1) Can you define/explain recommended daily allowance (RDA)?
2) Define essential nutrient.
3) Give examples of essential nutrients.
1) RDA: The safe estimate of daily intake that would meet the nutritional needs of most healthy people
2) Essential nutrients: Cannot be synthesized by the body
3) Minerals, most vitamins, eight amino acids, and one to three of the fatty acids must be consumed in diet
1) What two hormones regulate blood glucose levels, maintain proper balance between glucose and glycogen? 2) What gets used as fuel when low on glycogen and glucose?
3) Excess carbohydrate are converted to what organic substance?
1) Insulin and glucagon
2) Fats used as fuel when glucose and glycogen levels are low
3) Into fats
1) Why does the body need dietary fiber?
2) Where do we get this dietary fiber?
3) Does the human body digest fiber?
1) Decreases blood cholesterol and LDL levels; absorbs water in intestines, softens stool and increases its bulk, stretches colon, and stimulates peristalsis thereby quickening passage of feces
2) Cellulose, chitin (animal origin), pectin, gums, and lignins
3) Fiber is not digested
1) What is the purpose of fat?
2) What is glucose-sparing and protein-sparing?
3) What are some fat soluble vitamins? What do they depend on in order to be absorbed?
4) Which fat soluble vitamins are produced by gut bacteria?
1) Fat has glucose-sparing and protein-sparing effects when used for energy needs, and fat-soluble vitamins can only be absorbed with dietary fat
2) Fat is
3) A, D, E, K require fat to be absorbed
4) Vitamin K
1) How are lipids transported in the plasma?
2) What are high levels of LDL suggestive of?
3) What are high levels of HDL suggestive of?
4) Should the ratio of HDL to LDL be higher or lower and how are some ways this can be achieved?
1) Lipoproteins (like chylomicrons) transport lipids
2) High LDL levels: suggests cholesterol deposition in arteries
3) High level of HDL: indicates that cholesterol is being removed from arteries and transported to the liver for disposal; is beneficial
4) Higher HDL than LDL; regular aerobic exercise, avoid smoking, saturated fats, coffee, stress (all raise LDL levels)
1) When would dietary consumption of protein need to be increased?
2) What happens if excessive amounts of proteins are consumed?
1) Higher intake recommended under conditions of stress, infection, injury, and pregnancy
2) Excessive intake overloads the kidneys with nitrogenous waste and can cause kidney damage
1) In terms of proteins what is the difference between essential amino acids and inessential amino acids?
2) Do cells store surplus amino acids?
3) Can you synthesize a protein if you are only missing one amino acid?
1) Essential amino acids are not synthesized by the body, inessential ones are.
2) Cells do not store surplus amino acids for later use
3) When a protein is synthesized, all amino acids must be present at once; if one is missing, the protein cannot be synthesized
1) What are minerals?
2) What are vitamins?
3) Are these organic or inorganic? Are they used as fuel?
1) Minerals: inorganic elements that plants extract from soil or water and introduce into the food web
2) Vitamins: organic small dietary compounds that are necessary for metabolism
3) Neither is used as fuel, but both are essential to our ability to use other nutrients