Functions of the Digestive system

Mouth

Oral/Buccal cavity

Vestibule

Space between the lips and the gums/teeth

Hard palate

Separates the nasal and oral cavity, hard surface to form the bolus

Soft palate

closes off the nasopharynx during swallowing

Uvula

closes off the nasopharynx during swallowing

Tonsils

Part of mucosa associated lymphatic tissue

Palatine Tonsils

Captures ingested microbes

Lingual tonsils

Captures ingested microbes

Pharyngeal Tonsil

captures inhaled microbes

Tongue

Forms bolus, mechanical digestion, houses tastebuds

Extrinsic muscles

Alters tongue position in mouth, elevates tongue for swallowing

Intrinsic muscle

Alters shape of tongue for speech, swallowing and eating

Filiform papillae

Creates friction to grab food

Fungiform papillae

mushroom shaped, contains taste buds

vallate papillae

contains tastebuds (back of the tongue) V shape

Foliate papillae

lateral ridges of the tongue with taste buds, especially in children

Frenulum

Anchors tongue, limits anterior/posterior movement

Alveoli

Pockets within mandible and maxillary one to house teeth roots

Gingivae

forms a seal between the teeth and bone

periodontal membrane

connective tissue that attaches the tooth to the alveoli

Crown

exposed part of the tooth for chewing and mastication

Root

portion of the tooth embedded within bones

Dentin

calcified layer beneath enamel which contributes to tooth hardness

Enamel

Hardest substance in the body to resist compressive forces of chewing

Cementum

Calcified layer that attaches the periodontal membrane to bone

Pulp

living portion of the tooth containing blood vessels, nerves, and lymphatics

Root canal

Passageway with tooth root for blood vessels, nerves, and lymphatics

Apical foramen

Opening at the tip of each teeth root

Neck

Tooth region between the root and crown

Dental formula

Describes one quadrant of adult teeth ( 2 incisors, 1 canine, 2 pre-molars, 3 molars)

Incisors

involved in cutting and chopping

canines

involved in tearing esp. meat

Premolars

involved in grinding and mashing

Molars

involved in grinding and mashing

salivary glands and ducts

example of an exocrine gland

Parotid gland

produces a more serous secretion containing salivary amylase and lingual lipase

Submandibular gland

produces a mixed serous and mucous saliva

Sublingual gland

produces a mucous saliva for lubrication of mouth

Pharynx

no fxn

Oropharynx

passageway for food, air, and liquid

Laryngopharynx

shared passageway; things get rerouted (anterior→ air) (posterior→food)

Nasopharynx

Air passageway

Esophagus

Transports bolus from laryngopharynx to the cardiac sphincter

Stomach

Continues mechanical and chemical digestion; limited absorption

Muscle layers

for mechanical digestion of food

Esophageal hiatus

location where the esophagus passes through diaphragm (location of potential hiatal hernia)

Cardiac sphincter

allows bolus to pass into the stomach and prevents regurgitation of acid chyme back into the esophagus

Pyloric sphincter

regulated the passage of acid chyme into the duodenum

49,50

anatomical structures

Body

area of active digestion

fundus

upper portion of the stomach associated with storage

pyloric region

lower region of the stomach associated with active chemical digestion

rugae

allows for expansion of stomach for larger food volumes

small intestines

major location for chemical digestion

Plicae circulares (circular folds)

increases surface area in small intestines for food absorption

Villi

folds on the plicae circulares increasing surface area for food absorption

Duodenum

receives secretions from pancreas, liver, and gallbladder; area of high chemical/enzymatic activity

duodenal papilla

projection-like bump in duodenum containing ampulla of vater

Ampulla of vater

collects secretions from the common bile duct and pancreatic duct

sphincter of odi

muscle; regulates flow of secretions from the ampulla of vater

Jejunum

involved in chemical breakdown of food and absorption

Ileum

involved mainly with food absorption

Ileocecal valve

regulates flow of alkaline chyme from the intestines to large intestines

pancreas

dual organ with exocrine function (production of pancreatic enzymes and bicarbonate)

endocrine function (prod. insulin and glucagon)

head

contains principal pancreatic duct just before union with common bile duct

67-69

anatomical structures

principal pancreatic duct

main duct that drains enzymes and bicarbonate from pancreas and joins common bile duct

Accessory pancreatic duct

pressure release if principal pancreatic duct is backed up

liver

multiple functions

major metabolic organ

RBC recycling

bile production

deamination

production of clotting proteins

73

anatomical

falciform ligament

attaches/anchors liver to the ventral body wall

ligamentum teres

remanent of umbilical vein

hepatic artery

delivers O2 rich blood to the liver

hepatic vein

drains blood from the liver to the inferior vena cava

hepatic portal vein

delivers blood from many abdominal organs to the liver for filtering and metabolic processing

Right and Left hepatic ducts

drains bile from the right and left lobes of the liver

Common hepatic duct

union of the right and left hepatic ducts

cystic duct

drains bile from the gallbladder

common bile duct

drains bile from common hepatic duct and cystic duct

gallbladder

stores, concentrates, and releases bile

large intestines

reabsorbs water, houses beneficial bacteria; compacts, stores and eliminates feces

haustra

fill with chyme and then contract to move chyme to next haustrum

taenia coli

longitudinal strips of muscle along colon that can contract to adjust the length of colon

cecum

first portion of the colon

vermiform appendix

contains MALT, houses beneficial bacteria

89-92

Anatomical

sigmoid

stores feces

rectum

final, straight portion of the colon

rectal columns

contains rectal veins and can stretch for rectal expansion

rectal valves

allows flatulation without defecation

internal anal sphincter

contains smooth muscle for involuntary regulation of BM

external anal sphincter

contains skeletal muscles for voluntary regulation of BM

hemorrhoidal veins

anatomical

Anus

external opening of colon

parietal peritoneum

produces serous fluid to reduce friction between GI organs (lines the abdominal body wall)

visceral peritoneum

produces serous fluid to reduce friction between GI organs (on the outside surface of most abdominal organs)

retroperitoneal space

behind the peritoneal cavity containing: pancreas, duodenum, kidneys, adrenal glands, aorta, and IVC

intraperitoneal space

within the peritoneal cavity

mesenteries of the gut

made up of serous membranes

greater omentum

stores fat, lymphatic, and endocrine functions