Digestion All animals are heterotrophs Different modes of feeding evolved Modes of feeding (structure-function) can be used as an evolutionary evidence Compartmentalization Intracellular vs. Extracellular Intracellular- occurs within food vacuoles
E.g. food vacuoles in Paramecium, amoebocytes of sponge Extracellular- occurs within specialized compartments Incomplete vs. complete Incomplete A single opening is present for both
entrance of food and exit of wastes Gastrovascular cavity of Cnidarians Gastrodermis- has specialized cells that secrete digestive enzymes Hydrolysis of macromolecules is intracellular Incomplete
Obelia sp. Complete Opening of food is different from exit of waste materials Specialized regions of the alimentary canal Complexity varies in each phylum Extracellular hydrolysis of food
Complete Bos taurus Modes of feeding Herbivore Carnivore Omnivore
Connects the pharynx to the stomach Peristalsis Goblet cells- specialized cells that lines the esophagus Release mucus that covers the bolus Peristalsis Wave-like motion responsible for the
movement of digested food in the alimentary canal Stomach Stores and digests food Cardiac sphincter- prevents backflow Pyloric sphincter- regulates entrance of acidic chyme to the small intestine
Secretes digestive juice Mixed with food through churning of the stomach through smooth muscle contractions Stomach Chief cells- secretes pepsinogen Parietal cells- secrete HCl HCl- disrupts the extracellular matrix of plant and animal cell
Pepsin- active form of pepsinogen Hydrolyzes proteins Works best in an acidic environment Stomach Stomach lining is protected First, pepsinogen is only activated when secreted into the lumen due to the action of the acidic HCl (pepsinogen activation-positive
feedback) Secondly, presence of goblet cells that secrete mucus product- acid chyme Stomach Small Intestine
Major organ of digestion and absorption Longest section of the alimentary canal Divided into three sections:duodenum, jejunum, ileum Duodenum- site of mixing of acidic chyme and other digestive juices (digestion) Jejunum and Ileum- absorption Small Intestine
Carbohydrate digestion Protein Digestion Nucleic Acid Digestion Fatty Acid Digestion
Carbohydrate digestion Starch, glycogen and other polysaccharides that were digested in the mouth is further digested Pancreatic amylase Maltase- splits maltose into its glucose units Disaccharides- absorbed by intestinal
epithelium Protein digestion Trypsin and Chymotrypsin- breakdown large polypeptide chain like pepsin Dipeptidase- split small peptides Carboxypeptidase- breakdown polypeptides in its carboxyl end Aminopeptidase- breakdown peptidase in
its nitrogenous end Enteropeptidase- activates pancreatic enzymes Protein digestion Intestinal enzymes- aminopeptidase, enteropeptidase Pancreatic enzymes- Trypsinogen, Procarboxypeptidase, Chymotrypsinogen
within Other enzymes hydrolyze the nucleotides into its components Fatty acid digestion Bile salts- emulsify undigested fats in the duodenum Emulsification- inc SA of fat molecules
Lipase- digests fat molecules Absorption Villus- folds found in the small intestine Microvillus- microscopic fingerlike projections that increases the absorption of materials
Each villus is connected to a capillary (BV) network and lacteals(Lymphatic system) Transport of nutrients Passive Diffusion Active transport Nutrients that were absorbed are transformed
into what the body needs Chylomicron- small globule that is a combination of fats, cholesterol, coated with proteins Hormones that regulate digestion Gastrin-stimulated by gastric juices Inhibited by low pH stimulates secretion of gastric juice
Enterogastrones- group of enzymes found in the duodenum Cholecystokinin (CCK)- stimulated by fats and amino acids Stimulates gall bladder to release bile Secretin- stimulated by the acidic chyme Stimulates pancreas to release bicarbonates
If chyme is rich in fats, it stimulates the duodenum to release other enzymes to slows down digestion in the stomach Large Intestine
Also called the colon Cecum small pouch that has different fxns Appendix- small cecum found in man Rectum- portion of the large intestine that temporarily stores feces Main fxn of colon is to reabsorb water Feces- waste that was formed after digestion Compactness depends on water that was reabsorbed
Large Intestine Intestinal Bacteriacommon example is E. coli Have mutualistic relationship with host Generate methane or hydrogen sulfide Some produce vitamins that are
needed by the body Nutrition Nutritionally adequate diet composed of: fuel (chemical energy) organic raw materials (carbon skeletons) essential nutrients (substances the
animal cannot make) Balancing the fuel Homeostatic mechanism balances the animals fuel ATPs that were produced are budgeted depending on the energy requirements Fats have the highest amount of ATP Glucose conversion is an example of
Information Governance Maturity ModelARMA International. Review: The Principle and Maturity Model Levels Principle . of Accountability - An organization shall assign a senior executive who will oversee a recordkeeping program and delegate program responsibility to appropriate individuals, adopt policies and...
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Cyclone Impact Terra 2008/122 05/01/08 04:35 UTC Cyclone Impact - Conclusions The data sets are immediately laid out on the PO.DAAC site. Deciding on which data set to use requires reading the data guides (is this surprising?).
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Epinephrine is the only medication that a teacher may administer by syringe because it is an auto-injector and only to a student with a known allergic reaction and appropriate licensed provider order and medication administration /parent consent form. ... Show...