NOTES NI BEA

• Nutrition


  Any substance required for the growth and maintenance of an organism

  
• Types of organisms based on mode of nutrition


  • Autotrophs - organisms that obtain energy from sunlight & chemicals to produce their own food
  • Heterotrophs - organisms that cannot make their own food & obtain their energy from other organisms
• Autotrophs


  • plants, chemosynthetic bacteria
• Heterotrophs


  • fungi, animals, carcasses
• Carcass


  dead body
• Plant nutritional requirements


  • water, carbon dioxide, essential macro & micronutrients/elements
• Specialized absorptive structures in plants


  • root hairs, root nodules (where N-fixing bacteria thrive), mycorrhizae (a symbiotic interaction between a young root & a fungus)
• Nutritional adaptations in plants


  • symbiosis of plants & soil microbes, symbiosis of plants & fungi, parasitism, predation

  
• Animal nutritional requirements


  • carbohydrates, proteins, fats, essential nutrients (amino acids, fatty acids, vitamins, trace elements)
• Types of animal feeding mechanisms

  • substrate-feeders, filter feeders, fluid feeders, bulk-feeders

  
• Types of animal digestive compartments

  • food vacuoles, incomplete digestive tract, complete digestive tract

  
• Fat-soluble vitamins


  • VIT A, D, E, K
• Fat-soluble vitamins


  Linked to our lipids and brought to the different parts of the body via bloodstream
• Water-soluble vitamins


  • VIT C (Ascorbic Acid), VIT B/ VIT B Complex
• Digestion

  Breakdown of food into smaller, usable form

  
• Steps of digestion


  • Ingestion, Peristalsis, Digestion, Absorption, Defecation

  
• Mechanical digestion


  Ingested food is physically broken down into smaller pieces by chewing or mastication and peristalsis
• Chemical digestion


  Food is acted upon by catalytic enzymes to be broken down into its absorbable forms
• Catalyst


  Increase the rate of a chemical reactions, particularly digestion
• Parts of the digestive system

  • mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus, teeth, tongue, salivary glands, liver, gall bladder, pancreas

  
• Oral/Buccal Cavity or Mouth


  • Taste, Mechanical breakdown of food, Chemical digestion of carbohydrates, Ptyalin or salivary amylase in saliva secreted by 3 pairs of salivary glands
• Teeth


  For mechanical digestion thru biting, grinding, cutting
• 32 Complete Adult Teeth
• Tongue and Salivary Glands


  • Functions of tongue: Food manipulation, taste, speech, 3 pairs Salivary Glands: Parotid, Sublingual, Submandibular Glands
• Saliva


  Lubricates food and begins digestion, 99.5% H2O
• 5 Senses of Taste

  • Salty, Bitter, Sour, Sweet, Umami
• Pharynx


  Common passageway for food and air, where swallowing begins
• Esophagus


  • 25 cm or 10 in long, secrete mucus, transport food thru Peristalsis (smooth muscle contractions propel food thru a sphincter)
• Sphincter

  Made up of muscles that constrict and dilate, Prevent food from moving back to where it came from
• Stomach


  • Mixes & stores ingested food with HCl into chyme, Chemical and mechanical breakdown of food, Secretes hydrochloric acid & digestive juices that break down proteins and fats and may kill bacteria
• HCl (hydrochloric acid)


  Highly acidic
• Peristalsis


  Increases surface area of the stomach, Lines the inside of the stomach, Finger-like texture in the stomach
• Small Intestines


  • Where most enzymatic hydrolysis of macromolecules from food occurs and absorption of digested food by its villi, Divided into Duodenum, Jejunum, Ileum

  
• Duodenum


  25cm/10in, complete digestion of food by enzymes
• Jejunum


  8 ft, absorb H2O & products of digestion into bloodstream
• Ileum


  12 ft, absorption of end products, with villi & mirovilli
• Large Intestines/Colon


  • Concentrates & stores undigested matter by absorbing Na, Vit K & water, Doesn't have villi nor coils, Many bacteria live, thrive & process undigested material into feces, 1 meter long, Divided into Cecum, Ascending, Transverse, Descending, Sigmoid Colon
• Rectum


  Short extension of the large intestine, Final segment of the digestive tract, Where compacted undigested food from the colon are pushed via peristalsis, Distention triggers expulsion of feces
• Anus


  Terminal opening of the digestive system thru which feces are expelled, Controlled by internal and external sphincters

  
• E. Coli Bacteria/Escherichia Coli Bacteria are normal microflora present since birth and prevent other colonies of microbacteria