Term
| In the digestive system, organs are divided: |
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Definition
into two groups
The alimentary canal:
1. mouth, pharynx, esophagus
2. Stomach, small and large intestine |
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Term
| What are the accessroy digestive organs? |
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Definition
teeth, tongue
gallbladder salivary glands liver and pancreas |
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Term
| What is the histology of the alimentary canal wall? |
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Definition
same 4 layers from esophagus to anus
1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa |
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Term
| What is the mucosa layer? |
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Definition
the innermost layer
consists of:
-epithelium
-lamina propria: loose CT
-muscularis mucosae: think layer of smooth muscle |
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Term
| Where is the muscularis mucosae? What does it do? |
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Definition
throughout the mucosa layer in the digestive tract except in mouth and pharynx
Localized movements of the mucosa |
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Term
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Definition
external to the mucosa
contains blood and lymphatic vessels, nerve fibers |
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Term
| What is the Muscularis externa? |
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Definition
external to the submucosa
has two layers of smooth musclue
-circular muscularis is inner
-longitudinal muscularis is outer
It moves and mixes ingested food |
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Term
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Definition
the outermost layer
The visceral peritoneum- Mesothelium is simple squamous epithelium +thin CT |
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Term
| In the serosa layer, for organs outside of the peritoneal cavity, they have: |
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Definition
| an adventitia- ordinary fibrous CT |
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Term
| Types of glands in the GI? |
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Definition
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Term
What are intrinsic glands?
Where?
What secretions? |
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Definition
entirely w/in wall of alimentary canal
-mucosal/submucosal glands
they are continous w/epithelial lining
Secrete: mucus, gastric acid, proteolytic enzyme and bicarbonate |
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Term
| What are extrinsic glands? |
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Definition
outside of alimentary canal; connect via long ducts
-Salivary glands
-Pancreas: secretes most digestive enzymes
-Liver: bile salts to aid in digestion of fat |
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Term
| Nerve plexuses in GI contain? |
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Definition
| Autonomic and visceral sensory nerves |
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Term
| Types of nerve plexuses in GI? |
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Definition
| Myenteric and Submucosal nerve plexus |
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Term
What is the Myenteric Nerve plexus?
Job? |
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Definition
aka auerbach's plexus
-in muscularis externa, between circular and longitudinal layers
-Both parasymp and symp control the contractions of the muscularis externa |
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Term
| What is the submucusal Nerve Plexus? |
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Definition
aka Meissner's plexus
-within submucosa
-both para and symp control of localized movement of muscularis mucosa and gland secretion |
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Term
Where is the enteric Nervous system?
What dose it do? |
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Definition
entirely w/in wall of alimentary canal
Part of myenteric and submucosal plexuses
Seperate from autonomic nerves, but receives autonomic input
Form reflex arcs that control many digestive processes (short sensory neurons, short visceral motor neurons, interneuorn-like neurons) |
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Term
| How many neurons in the enteric nervous system? |
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Definition
| 100 million- as many as entire spinal cord |
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Term
| What are the processes of the digestive? |
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Definition
ingestion
propulsion
mechanical digestion
chemical digestion
absorption
defecation |
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Term
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Definition
a serous membrane
-Visceral and Parietal peritoneum |
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Term
| What is the visceral peritoneum? |
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Definition
| surrounds digestive organs |
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Term
| What is the parietal peritoneum? |
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Definition
| lines the body wall, peritoneal cavity a slit like potential space |
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Term
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Definition
a double layer of peritoneum
Holds organs in place; attaches dorsal and ventral abdominal wall
-sites for fat storage
-provides a route for circulatory vessels and nerves |
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Term
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Definition
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Term
| What are dorsal mesenteries? |
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Definition
connect to posterior wall
Majority of mesenteries |
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Term
| What is the largest dorsal mesentery? |
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Definition
Greater omentum
extends from greated curvature of stomach to posterior abdominal wall, extends forward and drapes over transverse colon and some small intestine |
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Term
| What are ventral mesenteries? Includes? |
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Definition
connec to anterior wall
Includes: lesser omentum |
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Term
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Definition
| lesser omentum- extends from liver to less curvature of stomach indirectly connected to anterior abdominal wall |
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Term
| What are secondarily retroperitoneal organs? |
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Definition
some organs of the alimentary canal loose their mesenteries during embyonic development
-they lie outside of the peritoneum
-mesenteries reabsorbed |
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Term
| Name the secondarily retroperitoneal organs? |
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Definition
| duodenum, ascending colon, descending colon, rectum, pancreas |
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Term
| Where are the retroperitoneal organs? What are peritoneal organs? |
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Definition
behind the peritoneum
digestive orgnas that keep their mesentery |
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Term
| Embryonic development of the primitive gut? |
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Definition
primitive gut: folds into tube
Endoderm-> epithelium +secretory cells of glands
Splanchnic mesoderm_> remainder of the wall |
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Term
| What are the initial 3 segments of the gut in embryos? |
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Definition
1. Forgut
2. Midgut
3. Hindgut |
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Term
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Definition
pharynx to 1st part of duodenum
supplied by celiac artery and its branches |
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Term
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Definition
distal duodenum to last third of colon
supplied by superior mesenteric artery |
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Term
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Definition
last third of colon to anus
supplied by inferior mesenteric artery |
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Term
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Definition
stomach rotates right 90 degrees and tilts slightly up
Part of colon rotates up (transverse)
Small intestine grows into medial space surrounded by colon |
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