The Remarkable Body Flashcards

1
Q

The Body’s Cells

A
  • Cells need energy, oxygen, water, and nutrients to do their work
  • Genes determine nature of cells’ work
    • Affect how nutrients are handled
      • Cells → Tissues → Organs → Body System
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2
Q

Transport of Nutrients
(Body fluids supply tissues with nutrients)

A
  • Blood
    • Carries water-soluble nutrients
    • Goes from small intestine to liver to heart
    • Cardiovascular System
  • Lymph
    • Carries fat-soluble nutrients
    • Goes from small intestine via the lymphatic system to the thoracic duct where lymph enters the bloodstream near the heart (“mixing oil with water”)
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3
Q

Transport of Nutrients
(Arteries carry oxygen and nutrients to the tissues)

A
  • Blood circulates among cells by capillaries
  • Exchange of materials between the cell fluid and the extracellular fluid
    • How the Body Fluids Circulate Around Cells
    • Delivery of oxygen an nutrients
    • picks up carbon dioxide and wastes
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4
Q

Transport of Nutrients
(Blood returns to the heart via veins)

A
  • Carbon dioxide is removed by the lungs in exchange for oxygen
  • Blood circulates to the kidneys where wastes are removed (filtered by nephrons) and excreted in the urine
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5
Q

Regulation
(Communication between organs and cells)

A
  • Hormones
    • e.g insulin and glucagon regulate blood glucose
  • Nervous System
    • e.g responds to need for food (hunger), regulates digestion (gastric juices)
  • Combination of hormones and nervous system
    • e.g. fight or flight reaction: epinephrine (hormone) and body responses/movements
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6
Q

Digestion

A
  • Breakdown of nutrients into their smallest subunits for absorption into the body
    • CHO: monosaccharides
    • Protein: Amino Acids
    • Fat: fatty acids and glycerides
  • Digestive System
  • Summary of Chemical digestion
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7
Q

Digestion
(Mouth)

A
  • Taste buds guide food acceptability
  • Mechanical digestion: chew and mix food with saliva (mucus and enzymes)
  • Chemical digestion: saliva contains salivary amylase enzyme to begin breakdown of CHO
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8
Q

Digestion
(Esophagus)

A
  • Passes food to the stomach via peristalsis (wave-like muscular squeezing along digestive tract)
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9
Q

Digestion
(Stomach)

A
  • Mechanical digestion: churns and mixes food to a liquid mass (chyme)
  • Movement within stomach aided by 3 layers of muscle
  • Movement of food along GI tract controlled by
    • Cardiac sphincter (into stomach)
    • Pyloric Valve (into small intestine)
      • Heartburn
      • Antacids for temporary heartburn relief
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9
Q

Heartburn

A

Burning sensation in the chest caused by backflow of stomach acid into the esophagus

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10
Q

Digestion
(Stomach - 2)

A
  • Chemical digestion: adds hydrochloric acid and enzymes (pepsin to breakdown proteins), and fluids (gastric juice)
    • Gastric juice is pH ~2
      • Denatures proteins
      • Kills microorganisms
      • Mucus protects the stomach wall
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11
Q

Digestion
(Small Intestine)

A
  • Major site of digestions
  • 20 feet long
  • Pancreas secretes bicarbonate that neutralizes the acidic contents from the stomach
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12
Q

Digestion
(Small Intestine - 2)

A
  • Chemical digestion: enzymes from pancreas and small intestine digest CHO, protein and fat
    • Pancreatic amylase (CHO); pancreatic lipase (fat); trypsin and chymotrypsin (protein)
    • Enzymes enter via pancreas → Pancreatic duct → small intestine
  • Mechanical digestion: segmentation
  • Hormones from pancreas: insulin and glucagon
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13
Q

Digestion
(Small Intestine - 3)

A
  • Bile emulsifies fat to assist digestion
    • Synthesized in the liver
    • Stored in the gall bladder
    • Enters small intestine via bile duct
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14
Q

Microbes in the Digestive Tract

A
  • A healthy digestive tract contains trillions of microbes (microbiota)
  • These bacteria do many activities within our digestive tract, and can effect our bodies in many ways
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15
Q

Absorption

A
  • Movement of nutrients from small intestine into the blood (water-soluble nutrients) or lymph (fat-soluble nutrients)
  • Large absorptive area created by folds of villi and smaller projections of microvilli
  • What is not absorbed (e.g., fibre) stays in small intestine and passes into the large intestine (colon)
16
Q

Lower GI Tract

A
  • Large Intestine
    • Reabsorbs water and minerals
    • Passes wastes (fibre, bacteria, any unabsorbed nutrients) and some water to rectum
  • Rectum
    • Stores wastes (feces) prior to elimination
17
Q

Common Issues Affecting the Digestive Tract

A
  • Gas and Hiccups
  • Heartburn, GERD, Ulcer
  • Chocking, Dysphagia
  • Diarrhea
    • Frequent, watery bowel movements
    • If severe and prolonged, could lead to dehydration
  • Constipation
    • Infrequent and difficult bowel movements
    • Often caused by poor diet, inactivity, dehydration, or medication
    • Change diet slowly (more fibre and water); more physical activity
  • Foods and intestinal gas
  • IBS, IBD
18
Q

Storage Systems

A
  • Body’s energy stores of excess energy-containing nutrients:
    • Fat in fat cells/adipose tissue (large amount)
    • CHO as glycogen in liver and muscle (smaller amount)
    • Other nutrient stores in other tissues, e.g., bone: Ca, P, other minerals
19
Q

Controversy 3: Alcohol (1 - What is alcohol?)

A
  • Acts as lipid solvents
  • Easily penetrate cell’s outer lipid membrane
  • Denature cell’s protein structure
  • Alcohol in alcoholic beverages = ethanol
20
Q

Controversy 3: Alcohol (2 - What is a serving of alcohol)

A
  • Provides energy (7 cal/g) but it is not a nutrient
  • 12 oz beer = 150 cals (light beer = 100 cals)
  • 5 oz wine = 125 cals (dessert wine = 210 cals)
  • 1.5 oz hard liquior = 105 cals
    • (86 proof = 43% alcohol)
  • 8 oz soft drink = 100 cals
21
Q

Controversy 3: Alcohol (3 - Alcohol enters the body)

A
  • Alcohol diffuses through stomach wall into bloodstream
  • Food delays diffusion and stomach emptying
  • Vomiting protects against high dose of toxin
  • Alcohol absorbed rapidly in small intestine (regardless of food or not)
22
Q

Controversy 3: Alcohol (4 - Physical Effects)

A
  • Increases urine output
  • Mineral loss
  • Slow drinker: alcohol collected by liver and processed
  • Rapid drinker: some alcohol flows through rest of body and brain
23
Q

Controversy 3: Alcohol (5 - Alcohol and the Brain)

A
  • A depressant (not stimulant)
  • Sedates nerve cells :
    • 1st: judgment and reasoning
    • 2nd: voluntary muscle control
    • Last: respiration and heart action
    • “Passing out” helps protect against consumption of lethal dose
24
Q

Controversy 3: Alcohol (6 - Alcohol and the Liver (1))

A
  • Liver detoxifies (metabolizes)
    • 80% alcohol dehydrogenase (ADH)
    • 10% MEOS system (inducible)
    • 10% excreted through breath and in urine
  • Blood alcohol is proportional to breath alcohol
  • Some ADH in stomach; females have less
  • Alcohol Doses and Average Blood Level Percentages
25
Q

Controversy 3: Alcohol (7 - Alcohol and the Liver (2))

A
  • Alcohol stimulates fat synthesis in the liver, both acutely and chronically
  • Liver deterioration:
    • Fatty liver → fibrosis (scar tissue) → cirrhosis (loss of function)
26
Q

Controversy 3: Alcohol (8 - Alcohol and the Body (1))

A
  • About 1.5 h metabolize 1 drink
  • Walking, caffeine, etc. do not detoxify
    • Myths and Truths concerning Alcohol
  • Alcohol is preferentially used for energy, thus more fat is stored, especially abdominal region
27
Q

Controversy 3: Alcohol (9 - Alcohol and the Body (2))

A
  • Hangover:
    • Toxic effects of congeners (other substances in alcoholic beverages)
    • Dehydration and rehydration of the brain
    • Accumulation of formaldehyde (preferentially ethanol → acetaldehyde)
    • Toxic to cells and increases risk for many diseases
28
Q

Controversy 3: Alcohol (10 - Longterm Effects of Alcohol)

A
  • Liver cells - amino acid metabolism
  • Synthesis of blood lipids increases
  • Toxic to muscle
  • Increased BP
  • Increased risk of dementia
  • Increased risk of cancer (mouth, esophagus, larynx, pharynx, liver, breast)
  • Younger people: increased risk of death from any case
  • Who Should Not Drink Alcohol?
29
Q

Controversy 3: Alcohol (11 - Alcohol and Nutrition)

A
  • Alcohol abuse can lead to malnutrition
    • Inadequate food intake
    • Impaired nutrient absorption and metabolism
    • Thiamin deficiency (Wernicke-Korsakoff syndrome)
30
Q

Controversy 3: Alcohol (12 - Can Moderate Alcohol Use Provide benefits?)

A

Recent evidence shows limited benefits and risks for negative outcomes even with small amount of alcohol

31
Q

Controversy 3: Alcohol (13 - Alcohol and Appetite)

A
  • Usually reduces appetite
  • In older adults, small doses of wine may improve appetite