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Digestion & Nutrition

Evolutionary Importance and Development
  1. Digests food
  2. Breaks down food to cross plasma membrane
  3. absorbs nutrients
  4. eliminates waste remains
Adaptations of animals gave caused three different groups to develop
    1. herbiovores: plant-eating animal
    2. carnivores: meat-eating animal
    3. omnivores: plant and meat-eating animal
Over time animals have been adjusted to fit into these catagories based on their living environment and conditions. Organisms can contian intracellular digestion and extracellular digestion.
Maintaining Homestasis
Humans are ingestive heterotrophs, making the digestive system an important part of homeostasis. The digestive system probides a mechanism to provvide an outside source of nutrients and vitamins. These nutrients are then able to repair, build, and maintain tissues, which also enables chemical, mechanical, and enzymatic  processes to occur.
Structures & Functions
  • Mouth: chewing breaks down the food into particles that can be more easily digested, while saliva breaks down food for absroption.
  • Esophagus: from the mouth, the esophagus recieves food and then proveeds with the process of peristalsis, pushing the food towards the stomach
  • Stomach: the "container" that holds good for enzynes to break down into an absorbable and usable form
  • Small Intestine: consisting of the duodenum, jejunum, and ileum, it is a muscular tube that breaks down food by way of pancreas and liver as food passes through it
  • Pancreas: secretes enxymes in to first segment of small intestine, where it breaks down  proteins, fats, and carbohydrates
  • Liver: processes nutrients absorbed, while secreting bile which actively breaks down fats
  • Large Intestine: consisting of the cecum, ascending colon, transverse colon, descending colon, and sigmoid colon, it is used for processing waste material from digested food
  • Rectum: recieves stool from large intestine and stores the stool until the evacuation process begins
  • Anus: detects rectal contents and signals state of contents (solid, liquid, or gas), it also contains external sphincter which regulares release and control of rectal contents

Digestive system works with circulatory system because the absorbed nutrients are distributed through the body by the blood vessels. The endocrine system is involved because it controls the speed of digestion. Digestive system also works withexcretory system because they work together to control the amount of water in ones blood.
Major Concepts
Nutrition is the process of providing or obtaining the good necessary for health and growth in an organism
  • Vitamins: organic compounds bodies are unable to produce but needs for metabolic processes
    • Vitamin A: vision, hair, skin, bones, and sex organ health
    • Vitamin B: extract and utilize energy
    • Vitamin C: protect cell grom damage and repairs collagen
    • Vitamin D: health of bones and tooth enamel
    • Vitamin E: strengthening red blood cells
    • Vitamin K: bone metabolism and blood clotting


  • Minerals: a solid, inorganic substance of natural occurence
    • Calcium (Ca): muscle contraction; stong bones and teeth
    • Phosphorus (P): stong bones and teeth
    • Potassium (K): nerve conduction; muscle contraction
Diseases & Disorders
  • Gastroesophageal Reflux Disease: weakness's of valve between the esophagus and stomach, causes inflammation of esophagus that results in chest pain
  • Peritonitis: inflammation of lining in the abdominal cavity, which can often lead to appendicitis
Works Cited