gastrointestinal system imari attaway, olivia dicapua riley dinneen, stephanie tyrrell
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Gastrointestinal SystemImari Attaway, Olivia DiCapua Riley Dinneen, Stephanie Tyrrell
GI Tract: MouthSalivary glandsPharynx and EsophagusStomachPancreasLiverSmall intestineLarge intestine
GI SystemDigestive system Mechanical and chemical breakdown of food into smaller components that allow it to be absorbed into the blood stream.
MouthTwo types of digestion: 1. Chemical 2. Mechanical
Mechanical=Chewing and swallowing
Salivary GlandsLocated under tongue and near lower jawOnce mouth is chewing salvia gets released from glands and begins breaking down food. Moistens foodEnzymes Amylase: A digestive enzyme in the saliva that breaks down carbohydrates.
PharynxConnects nasal and oral cavities with the larynx and esophagus.Aides in swallowing.3 structures:1. Nasopharynx2. Oropharynx3. Larynopharynx
Esophagus25 centimeter long passageway for food. Pharynx --> stomach.Along the esophagus are mucus glands which moisten passageway. (food goes smoothly)Lower esophageal sphincter: area above where esophagus meets stomach. Contains smooth muscle fibers which can contract to close the entrance of the stomach and prevent food from going back into esophagus.
StomachA j-shaped pouch-like organHangs inferior to the diaphragm in upper left portion of abdominal cavity.capacity=1liter+Receives food from esophagus>mixes with gastric juice>initiates digestion>carries on absorption>moves into small intestine
Parts of StomachDivided into 4 regions: cardiacfundusbodypyloric
Stomach SecretionsMucous membrane of stomach is thick, studded with many small openings called gastric pits that are at the ends of tubular gastric glands.Gastric glands generally have 3 types of secretory cells:Mucous Cells- in the necks of the glands near the openings of the gastric pitsChief Cells- in the deeper part of the glands, secrete digestive enzymesParietal Cells- in the deeper part of the glands, cellsrelease hydrochloric acid.Together they form Gastric Juice.
Components of gastric juice:
ComponentSourceFunctionPepsinogenChief cells of the gastric glandsInactive for of pepsinPepsinFormed from pepsinogen in the presence of hydrochloric acidA protein-splitting enzyme that digests nearly all types of dietary proteinHydrochloric AcidParietal cells of the gastric glandsProvides the acid eniviornment needed for the conversion of pepsinogen into pepsin and for the action of pepsinMucusMucous CellsProvides a viscous, alkaline protective layer on the inside stomach wallIntrinsic FactorParietal cells of the gastric glandsAids in vitamin B12 absorption
PancreasExtends horizontally across the posterior abdominal wall in the C-shaped curve of the duodenumPancreatic Actinar-cells that produce pancreatic juice, make up the bulk of the pancreas. Smaller tubes unite to form larger ones, Panceratic duct, extending the length of the pancreas.Hepatopancreatic spincher- controls movement of pancreatic juices into the duodenum(the first segment of the small intestine).Makes insulin, secreting it directly into the bloodstream.Insulin is the chief hormone for metabolizing sugar.
Reddish-Brown color-well supplied by blood vessels.Covered by fibrous capsule and connective tissue
Divided into two lobes (large right lobe and small left lobe.) Hepatic lobes: Each of the two lobes are separated into many smaller ones. These are the functional units of the liver.Gallbladder: pear-shaped sac off the liver that store bile in between meals.
Liver (physiology)Breaks down food Stores important substancesContains MacrophagesHelp lipid metabolism (food-->fats):Converts portions of carbs and protein molecules into fat moleculesoxidizes fatty acidsSynthesizes lipoproteins.Helps protein metabolism (food -->protein): synthesizing plasma proteins and converting certain amino acids to other amino acids.
Small intestineTubular organRuns between stomach and large intestineFills most of abdominal cavityMade up of 3 parts:Duodenum-25cmJejunum-2/5 of peritoneal cavityIleum-remainder of peritoneal cavity
Small intestine (cont.)Wall of the small intestine:Lined with villi (part of mucus membrane)-increase surface area and aid in mixing and absorptionIntestinal gland-located between villiSecretions and Absorptions: Mucus secreting goblet cellsDigestive enzymes (peptidases, sucrase, maltase, and lactase)Movement:Segmentation (major mixing)Peristalsis (when irritated)
Large intestineBegins in lower right side of abdominal cavity1.5 meters long4 parts:CecumColonRectumAnal cord
Large intestine (cont.)Large intestine wall: similar to other walls in alimentary canalunique layer of longitudinal, banded muscle fibersFunctions: secretes mucusabsorbs water and electrolytesforms and stores fecesMovement:similar to small intestinemass movements 2-3 times a daydefecation reflex: stimulates waste elimination
Diseases and Disorders involvedCrohns disease (aka iletis or enteritis) what is it- inflammation of any area of the digestive tract. Most commonly affects the lower part of the small intestinecauses- pain, empties intestines resulting in diarrheamost common age is 20-30Jewish have increased risk-Blacks have decreased Symptoms-pain, diarrheaDiagnosis-thorough physical exam and a series of testsTreatment- drugs, nutrition supplements and/or surgery
Diseases and Disorders (cont.)Appendicitiswhat it is- an irritation, inflammation, and infection of the appendix. occurs when inside becomes filled with mucus, stool, or parasites (causes swelling)causes- pain, no purpose but if goes untreated it can burst and lead to infectionsymptoms- stomach ache on right sidediagnosis-blood and urine testmost occur between ages 10 and 30treatment: removal
Diseases andDisorders (cont.)lactose intolerancewhat it is-the bodys inability to break down lactose (sugar found in milk)causes pain, digestive diseases, injury to small intestinesymptoms-pain 30min-2hrs after eating, diarrhea, bloating, gasdiagnoses- lactose intolerance testtreatment- diet, oral pill