Bio 2

• Autotrophs or Self-feeders


  Animals that consume organic molecules from other organisms for nutrition
• Dietary categories of animals

  • Autotrophs or Self-feeders
  • Heterotrophs
  • Herbivores
  • Carnivores
  • Omnivores
• Detritivores


  Also known as detritus feeders or eaters, they are heterotrophs that obtain nutrients from decaying bodies of plants and animal called detritus, usually by breaking them into smaller sizes before decomposers act on them
• Soil dwelling detritivores

  • earthworms
  • slugs
• Insects that are detritivores

  • dung beetles
  • flies
  • woodlice
  • springtails
• Aquatic detritivores

  • bottom dwellers like crabs, sea cucumber, sea stars
• Detritivores play an important role in breaking down organic matter
• Detritivores differ from scavengers, which eat large chunks of organic matter
• Intracellular digestion


  The digestion process which happens inside the cells through food vacuoles, common in single-celled organisms
• Phagocytosis


  The process where amoeba engulf their food in the form of bacteria, plant cells, and microscopic protozoa
• Extracellular digestion


  Food is broken down outside of cells, observed in animals with an incomplete or complete digestive system
• Incomplete digestive system or gastrovascular cavity


  Observed among simple animals like hydra, flatworms and coelenterates, with a single opening where food and waste pass through
• Feeding mechanisms in animals

  • Suspension feeding
  • Filter feeding
  • Substrate feeding
  • Fluid feeding
  • Bulk feeding
• Stages of food processing

  1. Ingestion

  2. Digestion

  3. Mechanical digestion

  4. Chemical digestion

  5. Absorption
• Esophagus


  Long tube connecting mouth and stomach
• Peristalsis


  Wavelike motion contraction that causes food to move from the esophagus down to the gut

  
• Stomach


  Folds when empty, expands when full, with thick muscular walls that mash food, and lining with gastric glands that secrete strong gastric juices
• Gastric glands


  Parietal cells secrete hydrochloric acid, Principal cells secrete pepsinogen
• Pepsinogen


  Weak enzyme then activated to become pepsin (stronger enzyme)
• Sphincters


  Ring like valves that regulate passage of food into and out of the stomach
• Chyme


  The result of stomach churning and mixing with Hydrochloric acid
• Pyloric sphincter


  Muscular valve controlling the passage of food to the small intestine
• Pancreas


  Controls glucose in the bloodstream and neutralizes the acidity of chyme
• Bile


  Yellowish green liquid that helps break down large fat particles
• Liver


  Makes bile
• Gallbladder


  Stores bile
• Villi


  Contain microvilli with capillaries that absorb nutrients into the bloodstream
• Colon


  Contains good bacteria which help further digest food but mainly functions to recycle water
• Digestion is a complex process involving ingestion, digestion, absorption, and elimination
• Ingestion starts in the mouth, where saliva and teeth begin the process of breaking down food
• The stomach is a major site of digestion, with gastric juices breaking down food chemically and mechanical churning helping to mix it with the juices
• The small intestine is where most nutrient absorption occurs, with its structure including villi and microvilli maximizing surface area for absorption

  
• The large intestine primarily reabsorbs water, preventing excessive loss and ensuring efficient digestion, and also houses beneficial bacteria
• Water


  A natural solvent that helps digest food, eliminate waste, regulate body temperature, maintain blood pH and volume, and keep skin and internal surfaces moist
• Carbohydrates


  Macromolecules that provide the main source of energy in the body, including simple sugars and complex starches
• Proteins


  Macromolecules essential for the growth of new protoplasm and repair of worn-out body cells and tissues, composed of amino acids
• Lipids


  Macromolecules that function for energy and structural support in cell membranes, as myelin sheaths in neurons, and in the production of certain hormones
• Fats


  Made up of long chains of fatty acids connected with glycerol molecules, can be saturated (solid at room temperature) or unsaturated (liquid at room temperature)
• Minerals


  Inorganic materials needed by the body to maintain homeostasis, such as calcium for bones and teeth, muscle function, nerve transmission, and blood clotting
• Vitamins


  Complex organic compounds not manufactured by the body, can be fat-soluble (A, E, D, K) or water-soluble (C, B)