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BIO 151 A&P II > Unit 2: Ch 26 Nutrition (v2) > Flashcards

Unit 2: Ch 26 Nutrition (v2) Flashcards

1
Q

Amino acid conversion processes

A
  1. Deamination: removal of an amino group (−NH2)
  2. Amination: addition of an amino group (−NH2)
  3. Transamination: transfer of amino group (−NH2) from one molecule to another
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2
Q

Arcuate nucleus of hypothalamus (appetite)

  • Description
A
  • All five chemical signals of short and long-term appetite regulators present
    • 2 neural networks involved in hunger
      • Neuropeptide Y (NPY); appetite stimulant
        • stimulated by gherlin
        • inhibited by insulin, PYY, and leptin
      • Melanocortin; appetite inhibitor
        • stimulated by leptin
        • inhibited by endocannabinoids (appetite stimulants)
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3
Q

Vitamin B

  • Soluability
  • Function
A
  • Water soluable
  • Function as coenzymes
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4
Q

Mechanisms for high body temperature

  • Describe
A
  • When heat-loss center senses that the blood temperature is too high it activates heat-losing mechanism
    • Cutaneous vasodilation
      • Increases blood flow close to the body’s surface and promotes heat loss
      • Triggers sweating which inhibits heat-promoting center
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5
Q

Mechanisms for low body temperature

  • Describe
A
  • When heat-promoting center senses that the blood temperature is too low it activates mechanisms to conserve heat or generate more
    • Cutaneous vasoconstriction
      • By way of the sympathetic nervous system warm blood is retained deeper in the body and less heat is lost through the skin
    • Shivering thermogenesis
      • involves a spinal reflex that causes alternating contractions of antagonistic muscle pairs
        • every muscle contraction releases heat from ATP consumption
        • can increase the body’s heat production up to fourfold
    • Non-shivering thermogenesis: long-term mechanism for generating heat
      • sympathetic nervous system and thyroid hormone increase metabolic rate
      • More nutrients burned as fuel, increased heat production, and we consume more calories
    • Behavioral thermoregulation: behaviors that raise or lower the body’s heat gains and losses—adding or removing clothing
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6
Q

Body mass index (BMI)

A
  • Indication of being overweight or obese
    • BMI = W/H2 (W = weight in kg; H = height in meters)
      • 20 > 25 = optimal
      • Over 27 = overweight
      • Above 30 = obese
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7
Q

Sources of carbohydrate forms

  • List & describe
A
  • Nearly all dietary carbohydrates come from plants
    • Fructose - fruits and corn syrup
    • Lactose - cow’s milk
    • Maltose - cereal grains
    • Sucrose - sugarcane and sugar beets
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8
Q

Carbohydrate forms

  • List & describe
A
  • Disaccharides
    • sucrose, maltose, lactose
  • Monosaccharides
    • glucose, galactose, fructose
      • arise from digestion of starch and disaccharides
      • SI and liver convert galactose and fructose to glucose
      • outside hepatic portal system, only blood sugar is glucose
  • Polysaccharides (complex carbohydrates)
    • starch, glycogen, and cellulose
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9
Q

Glucose catabolism

  • Describe
  • Formula
A
  • All oxidative carbohydrate consumption is glucose catabolism
    • C<u>6</u>H<u>12</u>O<u>6</u> + 6 O<u>2</u> ⇢ 6 CO<u>2</u> + 6 H<u>2</u>O
    • transfers energy from glucose to ATP
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10
Q

Carbohydrates

  • General description
A
  • Fuel source; burned as fuel within hours of absorption
  • Oxidized source of chemical energy
    • Most cells meet energy needs by a combination of carbohydrates and fats
    • Neurons and erythrocytes depend solely on carbohydrates
  • Deficiency can lead to hypoglycemia
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11
Q

Blood glucose concentration

  • Interplay of ___ and ___
  • Regulate’s balance between ___ and ___
A
  • Blood glucose concentration is carefully regulated
    • Interplay of insulin and glucagon
    • Regulate balance between glycogen and free glucose
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12
Q

Cholecystokinin (CCK)

  • Description
  • What does it stimulate?
  • Secreted by?
A
  • Short-term appetite regulator
    • Stimulates
      • secretion of bile and pancreatic enzymes
      • brain and sensory fibers of the vagus nerve suppressing appetite
  • Secreted by enteroendocrine cells in duodenum and jejunum
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13
Q

Cholesterol & exercise

A
  • Vigorous exercise lowers blood cholesterol
    • Sensitivity of right atrium to blood pressure is reduced
    • Heart secretes less atrial natriuretic peptide and thus kidneys excrete less sodium and water
    • Raises blood volume
    • Dilution of blood lipoproteins causes adipocytes to produce more lipoprotein lipase
    • Adipocytes consume more blood triglycerides
    • VLDL particles shed some cholesterol which is picked up by HDL and removed by the liver
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14
Q

T/F

Most of the body’s cholesterol is endogenous - internally synthesized rather than dietary?

A

True

  • Body compensates for variation in intake
  • High dietary intake lowers liver cholesterol production
  • Low dietary intake raises liver production
  • Lowering dietary cholesterol lowers level by no more than 5%
  • Certain saturated fatty acids (SFAs) raise serum cholesterol level
    • Moderate reduction in SFAs can lower blood cholesterol by 15% to 20%
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15
Q

Chylomicrons

A
  • Lipoprotein
    • Produced in enterocytes from dietary lipids (fatty acids and cholesterol)
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16
Q

Macronutrients & micronutrients

  • Compare
A
  • Macronutrients
    • Must be consumed in relatively large quantities
    • Water, carbohydrates, lipids, and proteins
  • Micronutrients
    • Only small quantities are required
    • Vitamins and minerals
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17
Q

Core body temperature

A
  • Temperature of organs in cranial, thoracic, and abdominal cavities
  • Rectal temperature is an estimate of core temperature
  • Adult temperature varies normally from 99.0° to 99.7°F
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18
Q

Define thermoregulation

A

The balance between heat production and loss

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19
Q

Dietary fiber

  • Describe
  • List types
A
  • All fibrous material of plant and animal origin that resists digestion
  • Cellulose, pectin, gums, and lignins
  • Fiber is important to diet (RDA is 30 g/day)
  • Types
    • water-soluable
    • water-insoluable
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20
Q

Essential nutrients

A
  • Nutrients that cannot be synthesized in body
  • Must be consumed in diet
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21
Q

Hypothermia

A
  • Core body temperature drops below 91°F
  • Notes
    • Metabolic rate drops so low that heat production cannot keep pace with heat loss
    • Death from cardiac fibrillation may occur below 90°F
    • Below 74°F is usually fatal
    • Dangerous to give alcohol to someone in hypothermia, as it accelerates heat loss by dilating cutaneous vessels
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22
Q

Impact of exposure to excessive heat

A
  • Heat cramps
    • muscle spasms due to electrolyte imbalance from excessive sweating
    • occur especially when a person begins to relax after strenuous exertion and heavy sweating
  • Heat exhaustion
    • from severe water and electrolyte loss
    • Hypotension, dizziness, vomiting, and sometimes fainting
  • Heat stroke (sunstroke)
    • core body temperature is over 104°F
    • brought about by prolonged heat wave with high humidity
    • skin is hot and dry
    • nervous system dysfunctions: delirium, convulsions, or coma
    • tachycardia, hyperventilation, inflammation and multi-organ dysfunction, death
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23
Q

Fat-soluble vitamins

  • List & describe
A
  • Incorporated into lipid micelles in the small intestine and absorbed with dietary lipids
    • Vitamin A
      • Component of visual pigments
      • Promotes proteoglycan synthesis and epithelial maintenance
      • Antioxidant (ascorbic acid)
    • Vitamin D
      • Promotes calcium absorption and bone mineralization
    • Vitamin E
      • Antioxidant
    • Vitamin K
      • Essential for prothrombin synthesis and blood clotting
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24
Q

Fever

A
  • Normal protective mechanism that should be allowed to run its course if it is not excessively high
  • Above 108° to 110°F can be very dangerous
    • Elevates the metabolic rate
    • Body generates heat faster than heat-losing mechanisms can disperse it
    • Causes dangerous positive feedback loop
    • Core temperatures of 111° to 113°F promote metabolic dysfunction, neurological damage, and death
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25
Q

Gastric peristalsis

A
  • When mild hunger contractions begin after stomach is empty
    • Increase in intensity over a period of hours
    • Do not affect the amount of food consumed
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26
Q

Ghrelin

A
  • Short-term appetite regulator
  • Signal that begins a meal; produces sensation of hunger
    • Secreted from parietal cells in fundus of empty stomach
    • Stimulates the hypothalamus to secrete growth hormone–releasing hormon & neuropeptide Y
    • Secretion ceases within an hour of eating
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27
Q

Glucose catabolism pathways

  • List & describe
A
  • Aerobic respiration
    • Occurs in the presence of oxygen
    • Completely oxidizes pyruvic acid to CO2 and H2O
  • Anaerobic fermentation
    • Occurs in the absence of oxygen
    • Reduces pyruvic acid to lactic acid
  • Glycolysis
    • Glucose (6 C) split into two pyruvic acid molecules (3 C)
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28
Q

Gut-brain peptides

  • Describe
A

Act as chemical signals from the gastrointestinal tract to the brain

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29
Q

HDL

  • Function
  • Where is it produced
  • What does it produce
A
  • A lipoprotein that removes excess cholesterol from the body
  • Production begins in the liver; produces a collapsed protein shell
  • High level of HDL is beneficial
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30
Q

Heat production & loss

A
  • Most of the body’s heat comes from exergonic chemical reactions (energy releasing such as joint friction, blood flow, and other movements)
    • At rest
      • most heat is generated by the brain, heart, liver, and endocrine glands
        • Skeletal muscle contributes 20% - 30% of total resting heat
    • During vigorous exercise
      • muscles produce 30 - 40 times as much heat as the rest of the body
31
Q

3 ways the body loses heat

  • List & describe
A
  1. Conduction: Transfer of kinetic energy from molecule–molecule as they collide with one another
  2. Evaporation: The change from a liquid to a gaseous state. Forced convection
  3. Radiation: The emission of infrared (IR) rays by moving molecules
32
Q

Hypervitaminosis

A

Vitamin excess

33
Q

Hypoglycemia

A
  • Deficiency of blood glucose
  • Causes nervous system disturbances such as weakness and dizziness
34
Q

Hypoglycemia

  • Describe
A
  • Deficiency of blood glucose
  • Causes nervous system disturbances such as weakness and dizziness
35
Q

Hypothalamic thermostat

A
  • The preoptic area of the hypothalamus functions as the body’s thermostat
    • Monitors temperature of the blood
    • Receives signals from peripheral thermoreceptors in the skin
    • Sends appropriate signals to either the heat-loss center: a nucleus in the anterior hypothalamus or the heat-promoting center in a more posterior nucleus near the mammillary bodies of the brain
36
Q

Insulin

  • Describe
  • Secreted by?
A
  • Long-term appetite regulator
    • Stimulates glucose and amino acid uptake
    • Promotes glycogen and fat synthesis
    • Weaker effect on appetite than leptin
  • Secreted by pancreatic beta cells
37
Q

LDL

A
  • Absorbed by receptor-mediated endocytosis by cells in need of cholesterol for membrane repair or steroid synthesis
  • Digested by lysosomal enzymes to release the cholesterol for intracellular use
  • Levels of LDL
    • High LDL is a warning sign–Correlates with cholesterol deposition in arteries
    • Elevated by saturated fat intake, cigarette smoking, coffee, and stress
38
Q

Leptin

  • Describe
  • Secreted by?
A
  • Long-term appetite regulator
    • Informs brain on how much body fat we have
    • Level proportionate to one’s own fat stores
    • Obese people are more likely to have a receptor defect than hormone deficiency
  • Secreted by adipocytes throughout the body
39
Q

Lipid sources

A
  • Saturated fats
    • Animal origin: meat, egg yolks, dairy products
  • Unsaturated fats
    • Found in nuts, seeds, and most vegetable oils
  • Cholesterol
    • Found in egg yolks, cream, shellfish, organ meats, and other meats
    • Does not occur in foods of plant origin
40
Q

Lipid constitution in males/females

A
  • Males = 15% body fat
  • Females = 25% body fat

Note: Well-nourished adult meets 80% to 90% of resting energy needs from fat

41
Q

Lipoprotein complexes

  • Function
  • Composition
A
  • Transport lipids in plasma
  • Coated with protein and phospholipids
    • Coating allows lipid to be suspended in blood
    • Also serves as a recognition marker for cells that absorb them
  • Contain cholesterol and triglycerides
42
Q

Long-term appetite regulators

  • List
A
  • Insulin
  • Leptin
43
Q

Megavitamins

A
  • Doses 10 to 1,000 times the RDA
  • Show no effect on performance
44
Q

Metabolic rate

  • Describe
  • How is it measured
A
  • The amount of energy liberated in the body in a given period of time (kcal/hr or kcal/day)
    • Calorimeter: a closed chamber with water-filled walls that absorb the heat given off by the body
    • Measured indirectly with a spirometer by measuring the amount of oxygen a person consumes
  • Metabolic rate depends on physical activity, mental state, absorptive or postabsorptive status, thyroid hormone, and other hormones
45
Q

Metabolic states & rate

  • Describe
  • List and describe states
A
  • Metabolism changes from hour to hour
    • Depending on how long since your last meal
  • Absorptive (fed) state
    • About 4 hours during and after a meal
    • Nutrients are being absorbed
    • Nutrients may be used immediately to meet energy and other needs
  • Postabsorptive (fasting) state
    • Prevails in the late morning, late afternoon, and overnight
    • Stomach and intestines are empty
    • Body’s energy needs are met from stored fuels
46
Q

What is metabolism

A

The chemical change that lies at the foundation of form and function

47
Q

Minerals & vitamins

A
  • Minerals
    • inorganic elements that plants extract from the soil or water and introduce into the food web
  • Vitamins
    • small dietary organic compounds that are necessary to metabolism
  • Neither is used as fuel
  • Both are essential to our ability to use other nutrients
48
Q

Negative nitrogen balance

A
  • Excretion exceeds ingestion of protein
    • Body proteins being broken down for fuel; muscle atrophy
      • Muscles and liver proteins are more easily broken down than others
      • Carbohydrate and fat intake is insufficient to meet body’s energy needs
    • Glucocorticoids promote protein catabolism in states of stress
49
Q

Neurotransmitters

  • Describe
  • What stimulates desire for what
A
  • Stimulate desire for different types of food
    • Endorphins: protein
    • Galanin: fats
    • Norepinephrine: carbohydrates
50
Q

Normal body temperature variations

A

Varies about 1.8°F in a 24-hour cycle

Low in morning and high in late afternoon

51
Q

Obesity

A
  • Weight > 20% above recommended norm for one’s age, sex, and height (US)
    • 30% obese
    • 35% overweight
52
Q

Peptide YY (PYY)

A
  • Short-term appetite regulator
    • Signal that ends a meal
    • Secreted by enteroendocrine cells of ileum and colon
53
Q

Positive nitrogen balance

  • Who experiences it?
A
  • Occurs in
    • athletes in resistance training
    • children because they ingest more than they excrete retaining protein for tissue growth
    • pregnant women
54
Q

Protein amino acids

  • Essential & inessential amino acids
A
  • 8 essential amino acids that cannot be synthesized by the body
    • Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine
  • 12 inessential amino acids synthesized by the body if the diet does not supply them
  • Cells do not store surplus amino acids for later use
    • When a protein is synthesized, all amino acids must be present at once
    • If one is missing, the protein cannot be synthesized
55
Q

Protein types

  • List & describe
A
  • Complete proteins
    • high-quality dietary proteins that provide all of the essential amino acids in the necessary proportions for human tissue growth, maintenance, and nitrogen balance
  • Incomplete proteins
    • lower quality because they lack one or more essential amino acids
56
Q

Protein

  • Body constitution
  • Functions
  • Components
A
  • 12% - 15% of total body mass; 65% in skeletal muscle
  • Functions
    • Muscle contraction
    • Motility of cilia and flagella
  • Components
    • Cellular membranes: receptors, pumps, ion channels, and cell-identity markers
    • Fibrous proteins: collagen, elastin, and keratin make up much of the structure of bone, cartilage, tendons, ligaments, skin, hair, and nails
57
Q

Recommended daily allowances (RDA)

A

Safe estimate of daily intake that would meet the nutritional needs of most healthy people

58
Q

Serum lipoproteins

  • List & describe classifications
A
  • Classified into 4 major categories by their density
    • Chylomicrons: 75–1,200 nm in diameter
    • Very low–density lipoproteins (VLDLs): 30–80 nm
    • Low-density lipoproteins (LDL): 18–25 nm
    • High-density lipoproteins (HDL): 5–12 nm
  • Differences are in composition and function
59
Q

Shell temperature

A
  • Temperature closer to the surface (oral cavity and skin)
    • Slightly lower that rectal temperature
    • Adult varies normally from 97.9° to 98.6°F
    • As high as 104°F during hard exercise
    • Fluctuates in response to processes that maintain stable core temperature
60
Q

Short-term regulators of appetite

  • Describe
  • List types
A
  • Makes one feel hungry and begin eating and satisfied at end of a meal; effects last minutes to hours
  • Types
    1. Cholecystokinin (CCK)
    2. Ghrelin
    3. Peptide YY (PYY)
61
Q

How is thermoregulation achieved?

A

Several negative feedback loops

62
Q

Vitamin C

  • Describe
A
  • Water soluable antioxidant that scavenges free radicals and possibly reduces the risk of cancer
  • Promotes hemoglobin synthesis, collagen synthesis, and sound connective tissue structure
  • Ascorbic acid
63
Q

Vitamin A

  • Symptoms of excess & deficiency
A
  • Vitamin A excess
    • anorexia, nausea and vomiting
    • headache and pain
    • fragility in the bones
    • hair loss
    • enlarged liver and spleen
    • birth defects
  • Vitamin A deficiency (most common vitamin deficiency)
    • night blindness
    • dry skin and hair
    • dry conjunctiva and cloudy cornea
    • increased incidence of urinary, digestive, and respiratory infections

Note: excess of vitamins B6, C, D & E can lead to toxic hypervitaminosis

64
Q

Vitamins from precursors (provitamins)

A
  • Body synthesizes some vitamins from precursors called provitamins
    • Niacin from amino acid tryptophan
    • Vitamin A from carotene
    • Vitamin D from cholesterol
    • Vitamin K, pantothenic acid, biotin, and folic acid are produced by bacteria of the large intestine
65
Q

Water-soluable vitamins

  • Describe
A
  • Vitamins C & B
    • Absorbed with water in small intestine
    • Quickly excreted by the kidneys, not stored, and seldom accumulate to excess
66
Q

VLDL

  • Describe
A
  • Produced by liver to transport lipids to adipose tissue for storage
  • Develop when triglycerides are removed from adipose tissue
  • Mostly comprised of cholesterol
67
Q

Water-insoluble fiber

  • List
  • General description
A
  • Cellulose, hemicellulose, lignin
  • Description
    • Absorbs water in intestines, softens stool, increases bulk 40% to 100%, stretches colon, and stimulates peristalsis thereby quickening passage of feces
    • Excessive intake can interfere with absorption of elements such as iron, calcium, magnesium, phosphorus, and other trace elements
  • No effect on cholesterol and LDL levels or colorectal cancer
68
Q

What briefly satisfies appetite?

A
  • Chewing
  • Swallowing
  • Stomach filling

Note: Lasting satiation depends upon nutrients entering blood

69
Q

What do growth hormones & sex steroids promote?

A

Protein synthesis and positive nitrogen balance in childhood

70
Q

What is a nutrient

A

Any ingested chemical used for growth, repair, or maintenance of the body

71
Q

What is nutrition

A
  • The starting point and the basis for all human form and function
    • Source of fuel that provides the energy for all biological work
    • Source of raw materials for replacement of worn-out biomolecules and cells
72
Q

What is the chief source of nitrogen

73
Q

Why is fat superior to carbs for energy storage?

A
  • Fats
    • contains almost no water, and is a more compact energy storage substance
    • Fat is less oxidized than carbohydrates and contains over twice as much energy (9 kcal/g)
  • Carbohydrates
    • hydrophilic, absorb water, and expand and occupy more space in the tissues
    • Contains less energy (4 kcal/g)

BIO 151 A&P II (8 decks)

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