Digestion Flashcards
What are nutrients
substances essential for growth and maintaining life
4 Main Functions of Digestive System
Ingestion: taking in food and liquids
Digestion: breakdown of food into smaller molecules that can be used and absorbed by the body
Absorption: molecules are absorbed through walls of small intestine
Elimination: feces eliminated out through intestines and anus
Macronutrients
-major nutrients required by body in large amounts to provide energy and support many phsyiological functions
-carbs, proteins, fats
Micronutrients
-required by bod in small quantities compared to macronutrients, play crucial role in many physiological processes
-vitamins and minerals
Essential Nutrients
-body requires for normal physiological functioning but cannot produce sufficient amounts or at all, so must be obtained from diet
-carbohydrates, proteins, fats, vitamins, minerals
What are essential amino acids
specific amino acids that cannot be synthesizes by the body and must be obtained from dietary sources
Essential vitamins
-vitamins that the body requires for various metabolic functions
-13 total
What are Essential fatty acids
specific fatty acids (omeage-3 and omega-6) that are required for normal body function but cannot be produced y the body in sufficient amounts
Monnosaccharides
simple sugars that cant be broken down further (hydrolyzed)
-glucose, fructose, galactose
Disaccharides
-carbohydrates composed of 2 monosaccharide units joined by glycosidic bond
-sucrose, lactose, maltose, trehalose
Polysaccharides
-complex carbohydrates made up of multiple monosaccharide units linked together by glycosidic bonds
-starch, glycogen, cellulose
Proteins and Absorbable units
Proteins are macromolecules made of amino acids linked together by peptide bonds
Amino acids are building blocks and play essential roles in many processes
-nonpolar, uncharged polar, charged polar
Nonpolar essential acids (6)
Leucine, Isoleucine, Valine, Phenylalanine, Tryptophan, Methionine
Uncharged Polar Essential Acids (2)
Histidine, Threonine
Charged Polar Essential Acids
Lysine, Arginine, Histidine
Fats
-(lipids)- essential macronutrient plays important tools in energy storage, insulation, cellular structure, hormone synthesis
-broken down into absorbable units
Monoglycerides
-lipid molecule that consist of one glycerol molecule attached to one fatty acid molecule
Fatty Acids
-building block of fats and are classified on their chain length and degree of saturation
Nucleotides
Composed of 3 thins: Nitrogenous base (guanine, thymine, adenine, cytosine
Pentose Sugar -5 carbon sugar
Phosphate Group: phosphorus and oxygen atoms that link nucleotides together
Nucleosides
2 components; Nitrogenous Base: acgt
Pentose sugar: ribose or deoxyribose
-same as nucleotides just np phosphate group
What are Calories
-measurement used to quantify the energy content of food and the energy expenditure of the body
Intracellular Digestion
cells take in food particles by endocytosis
-surrounds food with cell membrane
-very simple creatures
Extracellular Digestion
- takes place in a tube enclosed in body but outside body cells -digestive tract
-occurs in compartments that are continuous with the outside of the animals body
-food is ingested, digestive tract breaks it down outside of cell walls
-more efficient + complex creatures
4 types of feeders
Herbivores: plant based materials
Carnivores: other animals (meat only)
Omnivores: plant based and meat
Filters Feeders: feed by straining suspended particles or small organisms from water
GI tract of Earthworm
-simple but efficient in processing soil
-mouth ingests at anterior end
-food goes into pharynx + crop
-from crop, into gizzard with thick walls with grit that aid in mechanical digestion
-intestine -absorption and digestion
-undigested out through anus
GI Tract of Insects
-plant material, other insects
-mouth parts vary, but usually something to chew+ grind
-enters stomodaeum -mouth, pharynx, esophagus, crop
-mesenteron -digestion and absorption
-proctodaeum absorbs water and salts, waste out through anus
GI Tract of Pigeon
-more complex -higher metabolic demands and diverse diet
-mouth- beak to grasp and manipulate food
-food down esophagus into crop- stored and moistened
-gizzard -grit to grind food
-small intestine (duodenum, jejunum, ileum) -digestion and absorption
-colon absorbs water + electrolytes, waste out anus+ cloaca
Monogastric Digestive System
simple, single chambered stomach that performs majority of digestion
-pigs, dogs, cats, human
-mouth, esophagus, stomach, small intestine, large intestine, out anus
Ruminant Digestive System
-complex, multi chambered stomach allows them to digest plant material
-cattle, sheep, goats
-mouth, rumen (breaks down cellulose and plant fibers), reticulum (regurgitate and rechew partially digested food), abomasum -digestion occurs, small intestine, large intestine out the anus
Human Digestive System: Mouth
-entry point of food
-ingestion of food, mechanical digestion (chewing), chemical digestion (salivary enzymes break down starches)
Human Digestive System: Pharynx
-muscular tube that connect mouth to esophagus
-passage of chewed food (bolus) from mouth to esophagus
Human Digestive System: Esophagus
-muscular tube that carries food from pharynx to stomach
-peristaltic contractions propel food downwards to stomach
Human Digestive System: Stomach
-storage of food, mechanical digestion (mixing and churning), and chemical digestion (gastric juices break down proteins)
Human Digestive System: Small Intestine -3 parts
-long coiled tube where most digestion and absorption of nutrients occur
Duodenum: receives digestive enzymes from pancreas and bile from liver to further break down food
Jejunum and Ileum: absorb nutrients (carbs, proteins fats) into bloodstream
Human Digestive System: Large Intestine (colon)
-wider tube for formation f feces, absorption of water and electrolytes, eliminated of feces
Cecum, colon, rectum, anus
Accessory Structures of Human Digestive System: Liver
-produces bile which emulsifies fats for digestion and absorption
-detoxification of harmful substances, storage of glycogen and synthesis of proteins
Accessory Structures of Human Digestive System: Gallbladder
-stores and concentrates bile produced by liver
-releases bile into duodenum to aid in fat digestion
Accessory Structures of Human Digestive System: Pancreas
-secretes pancreatic enzymes (amylase, lipase) into duodenum to digest carbs, fats, proteins
-regulates blood sugar levels by producing insulin and glucagon
Accessory Structures of Human Digestive System: Salivary Glands
-produce saliva containing enzymes that begin digestion of carbs in the mouth
-moistens food, facilitates swallowing, initiates carbohydrate digestion
Accessory Structures of Human Digestive System: Appendix
-a small, finger like pouch attached to cecum of large intestine
-contains immune tissue that may play a role in immune defense
Layers of the Gastrointestinal Tract: Mucosa
Mucosa: innermost where food passes through
-has epithelium-absorption, secretion, protection
-lamina propria-loose connective tissue has blood and lymphatic vessels -supports epithelium
-muscularis mucosa-smooth muscle cells create folds and movement in mucosa- aids in absorption and secretion
Layers of GI tract: Submucosa
-dense connective tissue beneath mucosa
-blood vessels and nerve that supply nutrients to surrounding tissues + regulate digestive functions
-submucosal plexus control secretion of glands
layers of GI Tract: Muscularis Externa
-responsible for peristalsis and segmentation -propel good along Gi tract and mix with digestive enzymes
Layers of GI Tract: Serosa
-outermost layer
-connective tissue anchors GI tract t surrounding structures
-mesothelium covers serosa and secretes fluid to reduce friction between organs in abdominal cavity
