Digestion 4

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Digestion 4

• Digestive organs review
• Accessory organs
• Nutrition
• Vitamins and Minerals

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Digestion Absorption
Intestinal lunen
Materials remain in the small intestine for a
period of 5-6 hours
Epithelial cell
Blood capillary
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Large Intestine

• No chemical digestion
• Digestion and absorption near complete by time
  chyme reaches large intestine
• Formation of feces and conservation of water
• About 90 of water in chyme is absorbed
• Resident bacteria give off valuable by-products
  we could not produce alone
• (ex.) vitamin K (blood clotting)

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Large Intestine

• Absorption of water formation and storage of
  feces (5 foot long)
• Remains in the LI for 12-24 hours
• 4 parts
• Caecum-
• short pouch that receives chyme from SI
• movement controlled by one-way valve
• appendix-function unknown

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Large Intestine

• Colon
• resident bacteria digest material in chyme that
  was not digested by SI
• Vitamin K and some B complex vitamins are
  produced by bacteria
• Rectum
• stores feces
• Anus
• feces expelled through anal canal and out anus

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FYI Total volume of food and water 2 liters

• Body adds 7 liters of its own fluids
• 1.5 liters salivary enzymes
• 2.0 liters of gastric secretions
• 1.5 liters of pancreatic secretions
• 0.5 liters of bile
• 1.5 liters of intestinal secretions

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Nearly all fluids and solids are absorbed

• 8.5 liters reabsorbed into small intestine
• 350 millimeters reabsorbed in the large intestine
• Only 50 grams of solids and 100 milliliters of
  liquid leave as feces
• Fluid absorption efficiency 99

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Large Intestine Troubles

• Colon Polyps Colon Cancer
• Diarrhea
• Constipation
• Hemorrhoids

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Accessory Organs of the digestive tract

• Products released via ducts into duodenum

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Liver

• Largest gland in the body
• Removes poisonous substances and detoxifies them
• Maintain homeostasis of the bloods nutrients
  stores iron and fat soluble vitamins
• Makes plasma proteins from amino acids
• Regulates the quantity of cholesterol

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Liver continued

• Produces and secretes bile
• involved in processing of fats
• stores and breaks down glycogen
• Produces urea after breaking down amino acids
• Removes bilirubin, a breakdown product of
  hemoglobin from the blood, excretes it in bile

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Liver Disorders

• Jaundice
• Hemolytic and Obstructive
• Hepatitis Inflammation of liver
• A, B and C
• Cirrhosis

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Liver and gall bladderProduces bile stores bile
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Gall bladder

• Stores bile from liver until needed
• Connected via duct to duodenum
• Gall stones
• Develop when excess cholesterol in bile
  precipitates out and traps calcium and salts

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Bile duct
Cholesterol deposit
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Pancreas

• Exocrine and endocrine gland
• Endocrine function insulin and glucagon
• Exocrine functions
• Sodium bicarbonate to neutralize stomach acid
• Enzymes to chemically digest food

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PancreasEnzymes and sodium bicarbonate
Acini
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Digestive Enzymes (Recap)

• CHO Amylases (Salivary and Pancreatic)
  Maltase, Sucrase and Lactase
• Proteins Pepsin, Trypsin, Chymotrypsin,
  Peptidases (Carboxy and Amino)
• Lipids Lipases

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Nutrition

• Vitamins and minerals

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Nutrients

• Macronutrients CHO, Proteins and Fats
• Micronutrients Vitamins and Minerals
• Micronutrient deficiency cause of more clinical
  problems

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Vitamins

• Most vitamins are not produced by the body and
  must be obtained from the diet
• Needed only in small amounts
• Essential for enzymatic reactions
• most vitamins serve as co-enzymes to promote
  enzyme activity
• Classified as water soluble or fat soluble

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Fat Soluble Vitamins

• Vitamins A, D, E and K
• Dissolve in fat
• Absorbed with fat in small intestine
• Excess stored in liver

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Fat soluble Vitamin A (Retinol)

• Precursor Beta carotene in dark green and
  yellow fruits, and vegetables also in fortified
  milk, egg yolk and fish liver
• Uses
• Synthesis of visual pigments,
• Development of bone and teeth
• Deficiency leads to
• Xeropthalmia, damage to the cornea of the eye
• Night blindness
• Too much of Vitamin A leads to
• birth defects
• liver abnormalities
• reduced bone mineral density that may result in
  osteoporosis

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Fat soluble Vitamin D (Calciferol)

• Can be produced by skin cells when exposed to sun
• Kidney and liver convert it into its active
  hormone form
• Formed in skin and in egg yolk, fish liver oils,
  fortified milk
• Uses
• Promotes bone growth and mineralization
• Enhances calcium and phosphorus absorption
• Maintains normal blood levels of calcium and
  phosphorus
• Deficiency causes
• Rickets in children
• Osteomalacia in adults

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Fat soluble Vitamin E (Tocopherol)

• Whole grains, dark green vegetables and vegetable
  oils
• Inhibits effects of free radicals, helps maintain
  cell membranes, blocks breakdown of vitamins A
  C
• Deficiency rare, occurs in people who cannot
  absorb fatty acids
• Anemia
• Degenerative nerve disorders
• Cancer caused by presence of excess free radicals

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Fat soluble Vitamin K (Phylloquinone)

• Source is mainly colon bacteria, also found in
  meat and green leafy vegetables
• Associated with Anemia
• Deficiency causes
• abnormal bleeding as it contains anticoagulant
  chemicals

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Water Soluble Vitamins

• Vitamin B1, B2, B6, B12, Niacin, Vitamin C,
  Pantothenic Acid, Biotin and Folic Acid
• Dissolved in water and absorbed with water in
  small intestine
• Only small amount can be stored Excess is
  excreted in the urine
• All should be eaten daily
• Body can synthesize niacin

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Water Soluble Vitamin B1 (Thiamin)

• Found in meats, grains, eggs, legumes
• Uses
• Required to metabolize carbohydrates
• Helps manufacture Hydrochloric acid
• Required to maintain health of nervous system
• Deficiency causes Beriberi
• Damage to heart tissue, nerve damage which can
  lead to paralysis

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Water Soluble Vitamin B2 (Riboflavin)

• Manufactured by Intestinal flora
• Uses
• Cellular respiration
• Metabolism of proteins and lipids
• Helps to create Niacin
• red blood cell formation
• antibody production
• Deficiency leads to Dermatitis and Cheilosis

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Water Soluble Vitamin B3 (Niacin (a.k.a)
Nicotinic acid)

• Manufactured by the body
• Uses
• Cell respiration and in the release of energy
• Metabolism of carbohydrates, fats, and proteins
• Proper circulation and healthy skin
• Functioning of the nervous system
• Normal secretion of bile and stomach fluids
• Synthesis of sex hormones
• Deficiency
• Pellagra

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Water soluble Vitamin B4 (Adenine)

• Cellular respiration and oxidation of fats
• deficiency causes Pellagra

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Water Soluble Vitamin B5 (Pantothenic acid)

• Anti-stress vitamin
• Manufactured in the body by the intestinal flora
• Uses
• Secretion of adrenal hormones that aid metabolism
• Helps fight allergies
• Maintenance of healthy skin, muscles and nerves 
• Deficiency
• Sleep disturbances and neurological disorders
• Abnormal sensation such as "burning feet"
  syndrome

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Water Soluble Vitamin B6 (Pyridoxine)

• Brewer's yeast, eggs, chicken, carrots, fish,
  liver, kidneys, peas, wheat germ, walnuts
• Uses
• Required for the balancing of hormonal changes in
  women
• Assisting the immune system and the growth of new
  cells
• Processing and metabolism of proteins, fats and
  carbohydrates
• Assists in controlling your mood as well as your
  behavior
• Promotes red blood cell production
• Fights the formation of the toxic chemical
  homocysteine, which is detrimental to the heart
  muscle
• Manufacture of Vitamin B3

• Deficiency
• PMS and menstrual cramps
• Nausea during early pregnancy
• Loss of sex drive

Too much of B6 causes Insomnia and Nightmares
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Water Soluble Vitamin B9 (Folic acid)

• Manufactured by the body and stored in the liver
• Uses
• Required for DNA synthesis and cell growth
• Essential for creating heme, and hence Oxygen
  transport
• Important for red blood cell formation
• Formation of amino acids
• Energy production
• Mental and emotional health maintenance
• Deficiency
• Anemia
• Osteoporosis
• Cancer of the bowel and cervix

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Water Soluble Vitamin B12 (Cyanocobalamin)

• Cannot be got from Plants, strictly animal
  product
• Present in liver, organ meat, muscle meat,
  shellfish, eggs, cheese, fish, and can be
  manufactured in the body
• Uses
• Manufacture and maintenance of red blood cells
• Stimulates appetite
• Promotes growth
• Provides energy boost
• Clears infections and protects against allergies
• Deficiency
• Pernicious Anemia
• Erosion of myelin sheath, the lining of nervous
  tissue
• Also blamed in depression

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Water Soluble Vitamin H (Biotin)

• Present in cheese, beef liver, cauliflower, eggs,
  mushrooms, chicken breasts, salmon, spinach,
  brewer's yeast, nuts
• Uses
• Cell growth
• Production of fatty acids,
• Metabolism of fats, and proteins
• Maintenance of healthy hair and skin, healthy
  sweat glands, nerve tissue, and bone marrow
• Helps with the transfer of carbon dioxide
• Maintenance of steady blood sugar level
• Deficiency
• Excess hair fall and thinning leading to baldness
• High cholesterol

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Water Soluble Vitamin C (Ascorbic acid)

• Green leafy vegetables, berries, citrus fruits,
  guavas, tomatoes, melons, papayas
• Uses
• Required for synthesis of Collagen,
  neurotransmitters, steroid hormones
• antioxidant that helps to protect the body
  against pollutants
• conversion of cholesterol to bile acids
• healthy cell development, normal tissue growth
  and repair
• proper calcium absorption
• prevention of blood clotting and bruising
• Deficiency
• Scurvy
• Bleeding gums, loose teeth, weak muscles, poor
  wound healing

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Problem of Free Radicals

• By - product of Cellular metabolism
• Weak bonds split and leaves a molecule requiring
  extra electrons (O2-) to stabilize themselves
• Nucleic acids, lipids and proteins found in the
  plasma membrane are targets to steal electrons
  from DANGER !!
• Generosity may lead to cancer

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Quick Chemistry Review

• Human Body -Cells -Molecules-Atoms-Elements
• Atoms - nucleus - neutrons -protons-electrons
• Number of protons () in the nucleus determines
  the number of electrons (-) surrounding the atom

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An atom will try to fill its outer shell. 1s-2,
2s8 etc.

• How does it accomplish this?
• Gaining or losing electrons
• Sharing by bonding with other atoms
• Important for stability for the molecule

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Health Protectors

• Vitamins C, E, and beta carotene are antioxidants
• Antioxidants
• chemicals that disarm cell damaging molecules
• neutralize free radicals by donating one of their
  own electrons
• The antioxidants do not become free radicals
  because they are stable in either form

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Normally a body can handle free radicals

• But if antioxidants are unavailable or free
  radical production is excessive, damage can occur
• Free radical damage accumulates with age
• Linked to degenerative disorders like Alzheimers

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WATER

• Contributes to 60-70 of body weight
• Solvent in which chemicals dissolve, transports
  chemicals through the body, provides a medium in
  which chemical reactions take place, important in
  temperature regulation
• Need 2-3 liters a day

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Minerals

• Chemicals needed by body to serve in a variety of
  cellular and body functions
• Ca, Na, K, Na, Cl, P, S, Mg
• The adult body contains 4.4 lbs of minerals
• 2 minerals make up the major portion of the those
  4.4 lbs -
• Calcium and Phosphorus the components of bone
  and teeth

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Calcium

• Blood clotting
• Muscle contraction
• Enzyme reactions
• Cellular communication
• Skin differentiation
• Provides strength to bones and teeth
• 95 of tooth enamel composed of calcium
• Deficiency causes rickets, osteoporosis or
  osteomalacia

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Phosphorus

• Carbohydrate metabolism
• Cell membrane structure and transport processes
• Muscle function
• Energy storage in the form of Adenosine
  triphosphate (ATP)
• Structural component of bones and teeth
• Buffer system to maintain the narrow pH range

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Magnesium

• Enzymes involved in Energy metabolism
• Protein synthesis
• Nucleic acid synthesis
• Regulation of Calcium levels
• Deficiency causes loss of appetite, irritability,
  disorientation, convulsions, and abnormal
  behavior
• (Can reduce migraines and PMS)

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Sodium
Potassium

• Maintains the normal hydration state of the
  bodily fluids
• Affects the movement of water in an out of cells

• Energy metabolism
• Glycogen and Protein synthesis
• Neuromuscular conduction
• Deficiency causes Cardiac arrhythmias, Muscle
  weakness and disruption of acid-base balance in
  the body

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Micromineral or Trace Mineral Iron Zinc

• Transportation of oxygen
• Cofactor for several enzymes involved in energy
  production
• Deficiency causes Anemic conditions
• Expression of genetic information
• regulation of bone calcification

• Growth, appetite, development of the testicles,
  skin integrity, mental activity, wound healing
  and proper functioning of the immune system

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Chromium
Iodine

• Regulation of basal metabolic rate (associated
  with energy production) in adults
• Growth and development in children
• Deficiency causes Goiter

• CHO, Fat, Nucleic acid metabolism
• Deficiency includes high blood sugar and
  abnormalities in stimulating nerves located in
  the extremities

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• Cobalt Vitamin B12 function
• Copper Enzymes to transport iron and maintaining
  connective tissue integrity
• Manganese Assists in activities of many enzymes
  in cellular metabolism
• Molybdenum molecular structural component of
  many enzymes
• Selenium Reducing Cancer risk and
  detoxification
• Flouride Prevents tooth decay