What are nutrients? Essential substances that your body needs in order to grow and stay healthy What...
-
date post
21-Dec-2015 -
Category
Documents
-
view
218 -
download
4
Transcript of What are nutrients? Essential substances that your body needs in order to grow and stay healthy What...
What are nutrients?• Essential substances that your body
needs in order to grow and stay healthy
What is a Nutrient?
Nutrients
• Some provide energy. • All help build cells and
tissues, regulate bodily processes such as breathing.
• No single food supplies all the nutrients the body needs to function.
Nutrients in the Human Diet
• Macronutrients– Water– Amino Acids and Proteins– Lipids– Carbohydrates
• Micronutrients– Vitamins– Minerals
Six categories of nutrients:
Healthy Diets Require:
• Water
• Carbs, Proteins, Lipids, Amino Acids
• Vitamins:
- water-soluble (thiamine, riboflavin, folic acid)
- fat-soluble (Vitamin A, D, E, K)
• Minerals (Fe, Ca, P, Na, K)
Water• Solvent in which the chemistry of life occurs
– cell chemistry occurs in an aqueous medium– water carries essential nutrients to cells– water carries metabolic wastes away from cells– hydrolysis & dehydration reaction– stabilizes body temp
Carbohydrates
• Energy Metabolism– catabolism of glucose during cellular
respiration yields ATP for energy-requiring activities
– glucose stored as glycogen in the liver and muscle cell fibers
Carbohydrates• Dietary Fiber
– water-insoluble fiber adds bulk to fecal matter facilitating its passage through and elimination from the digestive system
– water-soluble fiber may absorb dietary cholesterol, reducing its absorption by the digestion tract
Lipids• Triglycerides (Fats)
– energy storage molecules– protect and cushion delicate body organs– source of the raw materials for the
construction of phospholipids– unsaturated versus saturated fats
Lipids• Saturated Fats
– Solid at RT– Milk, cheese, meat– Not good for you
• Unsaturated Fats– Liquid at RT– Distorted double bounds– Canola, olive, peanut oil– Better choice
Lipids• Steroids (e.g., cholesterol)
– precursor molecules for steroid hormones, vitamin D, bile salts
– fundamental component of plasma membranes (influence membrane fluidity)
– HDL-cholesterol versus LDL-cholesterol
Proteins
• Enzymes • Structural proteins (shape and
form of cells and tissues)• Hormones• Immunoglobulins (antibodies)
Essential Amino Acids
• Tryptophan• Methionine• Valine• Threonine
• Phenylalanine• Leucine• Isoleucine• Lysine
• Histidine(infants)
Complete ProteinsVersus
Incomplete Proteins
• Vegetarian diet may result in protein deficiency
• Need essential amino acids– beans lysine – corn the methionine
Vitamins• Organic compounds needed by
the body in small, but essential amounts
• Cannot be synthesized by the body in sufficient amounts
• Function in a variety of ways in metabolic reactions
• Thirteen known vitamins
Water-Soluble Vitamins
vsWater-Insoluble
Vitamins
Water-Soluble Vitamins
Pantothenic acid
Biotin
B12 (cyanocobalamin)
Folic acid
C (ascorbic acid)
B1 (thiamin)
B2 (riboflavin)
Niacin
B6 (pyridoxine)
Water-Insoluble Vitamins
A (retinol)DEK
Minerals
• Essential inorganic elements• Involved in a variety of
metabolic processes• Major minerals versus trace
minerals
Major MineralsCalcium
PhosphorusMagnesiumSodiumPotassiumChlorine
Trace Minerals
IronIodineFluorideZincCopper
Manganese
Cobalt
Selenium
Chromium
• An animal whose diet is missing one or more essential nutrients.
Giraffe eats bone to get phosphorus nutrient
Malnourishment
Giraffe eats bone to get phosphorus nutrient
• Impaired cognitive development
• Won’t attain full height
• More susceptible to disease and infection
Malnourishment
• Healthy diets requires essential amino acids otherwise protein synthesis is retarded.
• Special adaptations during molting (non-feeding time)– uses their muscle proteins
as a source of amino acids to make new proteins
Feeding Types:
• Herbivores
• Carnivores
• Omnivores
• Detritivores
Some Feeding TypesSome Feeding TypesMany species don’t fit into convenient categories
• Algal Grazers and Browsers• Suspension Feeding• Filter Feeding• Deposit Feeding• Benthic Animal Predators• Plankton Pickers• Corallivores• Piscivores• Omnivores• Detritivores• Scavengers• Parasites• Cannibals• Ontogenetic dietary shifts
Fig. 41-6a
Humpback whale, a suspension feeder
Baleen
Fig. 41-6b
Leaf miner caterpillar,a substrate feeder
Caterpillar Feces
Fig. 41-6c
Mosquito, a fluid feeder
Fig. 41-6d
Rock python, a bulk feeder
Deep sea gulper
Large expandable stomach
Overview of Food Processing
The four main stages of food processing:
1. Ingestion
2. Digestion
3. Absorption
4. Elimination
Digestion occurs in specialized compartments
The simplest digestive compartments are food vacuoles; it is a process termed intracellular digestion
Gastrovascular cavity
Complete Digestive Tracts (Alimentary Canal)
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 41.13
Digestive ProcessDigestive Process
1.1. IngestionIngestion2.2. PropulsionPropulsion3.3. Mechanical DigestionMechanical Digestion
• MasticationMastication• Churning food in stomachChurning food in stomach
4.4. Chemical digestionChemical digestion5.5. AbsorptionAbsorption6.6. DefecationDefecation
incisors
cuspid
premolars
molars
TeethTeeth
enameldentinpulp cavity
root canal
bone
blood vessels
crown
neck
root
• Dentition, an animal’s assortment of teeth, is one example of structural variation reflecting diet.
Salivary GlandsSalivary Glands
Salivawatermucin
amylase
The Tongue
Taste BudsTaste Buds
Circumvallate Papilla
Filiformpapilla
Fungiformpapilla
Connective tissue Tongue epithelium
Salty- metallic ions
Sweet- sugarSweet- sugar
Sour- HSour- H++
Bitter- alkaloidBitter- alkaloid
Why are they important?
Umami- savory/meatyUmami- savory/meaty
Peristalsis
The Stomach
esophaguscardiac sphincter
pyloric sphincterduodenum
Stomach Secretions
Gastric Gland:Gastric Gland:Mucus cellsMucus cellsChief cellsChief cells
Parietal cellsParietal cells
Mucous neck cells- found in upper region of gastric glands produce• mucous
Parietal cells- in gastric gland of mucosa
produce• HCl – kills most bacteria• Intrinsic factor (required for absorption of vit. B12 in sm intestine, which is needed for producing mature erythrocytes)
Zymogenic (chief) cells-
produce• pepsinogen (inactive form of pepsin, which becomes active in presence of HCl) • rennin (milk digestion in children) protein digestion
Enteroendocrine cells in stomach mucosaproduces:
• Gastrin- regulates stomach secretions and mobility
• Histamine- activates parietal cells to release HCl• Endorphins- natural opiates• Serotonin- causes contraction of stomach
muscle• Cholecystokinin (CCK)- (in duodenal mucosa)
many functions and affects many organs• Somatostatin- (stomach and duodenal mucosa)
- inhibits gastrin, pancreatic secretions, inhibits GI blood flow in sm intestine…
Gastric ulcers- erosion of stomach wall; pain occurs 1-3 hrs after eating--- new research90% of recurrent ulcers due to bacterial infection (Helicobacter pylori), which destroys mucous protective barrier; use antibiotic therapy to kill bacteria
Pancreatic Enzymestrypsin
chemotrypsin
carboxypeptidase
amylase
phospholipase
lipase
nucleases
lumenmuscle layers
foldsvilli
Intestinal StructureIntestinal Structure
epithelial cells
capillaries
lacteal
Intestinal VillusIntestinal Villus
Intestinal Membrane Enzymes
disaccharidasesdisaccharidasesaminopeptidaseaminopeptidase
dipeptidasesdipeptidasesnucleotidasesnucleotidasesnucleosidasesnucleosidases
Figure 41.16 The duodenum
Bilebile saltsbile salts
bile pigmentsbile pigments
cecum appendix
ascending colon
transverse colon
descending
colon
sigmoidal
colon
rectum
internal anal sphincter external anal sphincter
anal canal
• The length of the vertebrate digestive system is also correlated with diet.
• Cellulose is difficult to digest• Termites have symbiotic
bacteria• Some bacteria and protists
have enzymes that hydrolyze cellulose
Symbiotic microorganisms aid in digestion
Moment of Zen