Digestion - WordPress.com

Digestion - WordPress.com

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

Dentition Alimentary canal Modes of Feeding Suspension feeders Substrate feeders Fluid feeders Bulk feeders

Modes of Feeding Symbiotic Relationship Vertebrates acquired symbiotic relationship with microscopic organisms in processing food E.g. Ruminants, Humans, termites Four Main Stages of Food

Processing Ingestion Large oral cavity Digestion Mechanical vs. Chemical Absorption Elimination

Digestion in Humans Primary organs of digestion Mouth, pharynx, esophagus, stomach, small intestine, large intestine

Accessory glands of digestion Salivary glands, pancreas, liver, gall bladder Digestion in Humans Mouth- functions: ingestion and digestion Digestion begins in the Oral Cavity

Mechanical and Chemical digestion Salivary amylase- breaks down polysaccharide and glycogen Saliva- also fxns as antibacterial agent and neutralizes acidity of foods Pharynx

Upper portion of the throat Where air and digested food meet Digested ball (bolus) of food enters Epiglottis- acts as a seal to prevent food from entering the air passages

Esophagus Upper portion- striated muscle Lower portion- smooth muscle

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

Enteropeptidase- activates Trypsinogen Trypsin- activates Procarboxypeptidase, Chymotrypsinogen Nucleic Acid Digestion Nucleases- hydrolyze nucleic acids Exonucleases- hydrolyze nucleic acids on its terminal Endonucleases- hydrolyze nucleic acids

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

homeostatic mechanism Caloric Imbalance Undernourishment Calorie deficiency Overnourishment Excessive calorie intake- results to obesity

Malnourishment Deficient in any essential nutrients Essential Nutrients

Essential Amino Acids Essential Fatty Acids Vitamins Minerals Essential Amino Acids Tryptophan, methionine, Valine, Threonine, Phenylalanine, Leucine, Isoleucine, Lysine, Histidine (infants)

Deficiency in one of these may result into protein deficiency Essential Fatty Acids Essential Fatty Acids belong to the unsaturated fatty acid groups An example is linoleic acid Deficiencies are rare

Vitamins Organic molecules that are required relatively in small amount Two types: Water-soluble B vits, C Fat-soluble A, D, E, K

Minerals Inorganic nutrients that are required in small amounts E.g. Calcium, Phosphorous, Sodium, etc.

Balance diet what enters= what leaves It is easier to take in calories in the body than to burn it The food pyramid serves as a guide in the kind of foods that should be taken in

Recently Viewed Presentations

  • Maximizing the Value of Information Applying RIM Principles ...

    Maximizing the Value of Information Applying RIM Principles ...

    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...
  • Vectors Scalars: a physical quantity described by a

    Vectors Scalars: a physical quantity described by a

    is the angle between the vectors Right hand rule: A´B = C A - thumb B - pointer C - middle Cartesian Unit vectors C = AB sin f = B sinf A is the portion of B perpendicular A...
  • "Appointment with Love" By S. I. Kishor

    "Appointment with Love" By S. I. Kishor

    Location: Grand Central Station. Blandford will finally meet his Hollis. 2nd Time! 2nd Time! 2nd Time!? 2nd Time!? 2nd Time! Blandford will finally meet his Hollis? Blandford will finally meet his Hollis? Blandford will finally meet his Hollis?
  • Cyclone Impact - National Snow and Ice Data Center

    Cyclone Impact - National Snow and Ice Data Center

    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?).
  • Estilo De Vida Y Actividades Del Remanente

    Estilo De Vida Y Actividades Del Remanente

    Seguir este estilo de vida ayuda a prevenir enfermedades como los males coronarios, controla la hipertensión y la diabetes, la osteoporosis y el asma bronquial". "A grandes rasgos se podría decir que las personas vegetarianas corren menor riesgo de sufrir...
  • Medication Delegation Role and Responsibility of the Teacher

    Medication Delegation Role and Responsibility of the Teacher

    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...
  • 1-5 Angle Relationships

    1-5 Angle Relationships

    Examples. 1. Name a linear pair. 2. Name 2 acute adjacent angles. 3. Name an angle supplementary to <EKH. 4. The measure of the supplement of an angle is 36 less than the measure of the angle.
  • P14311: PCB Isolation Router System Detailed Design Review

    P14311: PCB Isolation Router System Detailed Design Review

    Shinano dual shaft NEMA 17 stepper motors. Router Assembly. Variable Speed Router Kit. Basic Description: Variable Speed Router Kit. Materials: Plastic body with cast aluminum base. Size. Router dimensions: 3.75" diameter, 3.3 lb weight. Collet Size.