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Flashcards in Ch 26 Digestion Deck (45)
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Functions of the Digestive System

Ingest food,
mix/move ingested materials,
add secretions to digest into smaller, usable components,
absorb nutrients into blood/lymph,
remove waste


What are the categories of organs in digestive system?

Organs in GI Tract,
Accessory digestive organs


What are the organs of GI tract

oral cavity, pharynx, esophagus, stomach, small intestine. large intestine, anal canal


What happens in GI tract organs

ingested food is broken down and absorbed along its length


What are the accessory digestive organs

Salivary glands, liver and pancreas
Teeth and tongue


What are the 4 tunics of the GI tract wall? What are their layers

Mucosa - inner most; has epithelium, lamina propria, muscularis mucosae

Submucosa- consist of submucosa and submucosal nerve plexus

Muscularis- outermost; consist of inner circular layer, myenteric nerve plexus, outer longitudinal layer

Adventitia or Serosa; outermost tunic


Difference between serosa and adventitia

Adventitia; composed of areolar connective tissue, w/dispersed collagen and elastic fibers

Serosa: same tissue; completely covered by serous membrane - visceral peritoneum


How are digestive process regulated by the Enteric Nervous System?

Neurons extend from esophagus to anus
Functions independently of CNS
Innervate = supply an organ with nerves
Innervates smooth muscle and glands of GI tract
Mediates the reflexes for mixing and propulsion of materials thru GI tract


How are digestive process regulated by the Autonomic Nervous System

GI tract wall innervated by PNS and SNS (of CNS)
Parasympathetic innervation: promotes GI activity, relaxes sphincters, stimulates GI motility

Sympathetic innervation: OPPOSE GI activity, contracts GI tract sphincters, inhibits GI motility, Vascoconstricts blood vessels within GI tract wall


How are digestive processes regulated by Nerve Reflexes?

ENS and ANS control GI Tract wall thru nerve reflexes


How are digestive process regulated by Hormonal Control?

Gastrin: released from stomach
Motilin released from small intestine


What is an intraperitoneal organ

organs in abdomen that are completely surrounded by visceral peritoneum; stomach, most of small intestine, parts of large intestine


What are retroperitoneal organs?

organs that lie directly outside of parietal peritoneum; directly against the posterior abdominal wall
Pancreas, esophagus, most of duodenum, parts of large intestine and rectum


What is the peritoneum?

serous membrane of the abdominopelvic cavity


what are the types of pertitoneum associated with the digestive system?

Parietal Peritoneum - line inner surface of abdominal wall

Visceral peritoneum- covers internal organs within the abdominopelvic cavity

Peritoneal cavity - potential space between the parietal and visceral peritoneum; contains serous fluid which lubricates organs reduces friction


What is mesentery?

a double later/fold of peritoneum that attaches organs to body wall


Mesentery: Greater Omentum

connects stomach to posterior abdominal wall; fatty apron; insulates organs and stores fat; covers most of abd organs


Mesentery: Lesser Omentum

connects stomach and duodenum to liver


Mesentery: Falciform ligament

attaches liver to internal surface of anterior abdominal wall


Mesentery: Mesentery proper

attaches small intestine to posterior abdominal wall


Mesentery: Mesocolon

attaches large intestine to posterior abdominal wall


What is the difference between long and short reflexes?

Short reflex = local and only involves ENS; coordinate small segments of GI tract to changse in stimuli
Long reflex= CNS; sensory input; sends digestive info to brain; secretory activity; coordinated muscle contractions


How is digestive system controlled thru endocrine system?

Hormonal control
- regulation of digestive processes
- Gastrin - increase force of contraction and release of secretion
- Secretin- decrease of secretory activity of stomach
- CCK - Cholecystokinin - causes decrease in stomach motility
-Motilin- controls pattern of smooth muscle contractions in upper GI


What happens in upper GI tract organs?

Initial mechanical and chemical process of ingested material takes place


What is bolus?

saliva mixed with ingested materials to form globular wet mass


What path does the bolus travel

Oral cavity and salivary gland > pharynx > esophagus >stomach


2 regions of oral cavity

Vestibule (buccal): space between gums/lips/cheeks

Oral Cavity proper: boudned laterall by cheeks and anteriorly by lips and teeth


Function of Buccinator muscle

compress cheeks against teeth to hold solids in place during mastication (chewing)


Function of Lips

formed by orbicularis oris muscle


Function of palate

forms roof of oral cavity; acts as barrier to separate oral from nasal cavity