Digestive System

Front 1

Mucosa

Back 1

inner-most layer lining the lumen of the digestive tract.

Front 2

Epithelial lining

Back 2

mostly simple columnar epithliem--except where stressed, then lined with stratified squamous epithileum. May be grandular. This lining may be thrown into folds, which increases surface area.

Front 3

Lamina Propria

Back 3

underlies the epithelium; layer of loose connective tissue with blood vessels, nerve endings, lymphatic vessels, lymphoid elements.

Front 4

Musculosa Mucosae

Back 4

thin layer of smooth muscle that produces local movements of the mucosa.

Front 5

Submucosa

Back 5

layer of dense connective tissue that surrounds the muscularis mucosae. Contains larger blood vessels and lymphatic vessels, lymph nodules, & nerve fibers.

Front 6

Muscularis Externa

Back 6

smooth muscle layer usually arranged in inner circular & outer longitudinal layer. It is responsible for the muscle contractions that produces segmentation & peristalsis. The circular layer thickens in several places to form sphincters, which act as valves to control food passage. Nerve ganglion are located between the smooth muscle layers to control local reflexes within the muscular wall of the digestive system.

Front 7

Visceral Peritoneum

Back 7

serous membrane, which covers the organs. (is next to the organs)

Front 8

Parietal Peritoneum

Back 8

serous membrane, which lines the inner surface of the body wall. (against stomach & back wall)

Front 9

Mesentery

Back 9

serous membranes which connect the parietal & visceral peritoneum; portions of the digestive tract are suspended within them. They are double layers of peritoneum that extend to the digestive organs from the body wall. They provide an access route for nerves, blood, & lymphatic vessels. It also holds organs in place & stores fat.

Front 10

Lesser Omentum

Back 10

between the stomach & liver; stabilizes the stomach.

Front 11

Falciform Ligament

Back 11

between liver & superior abdominal wall; stabilizes liver.

Front 12

Greater Omentum

Back 12

enormous pouch that extends inferiorly from the lateral & anterior walls of the stomach & attaches to the transverse colon. Provides protection, insulation from heat loss & acts as a fat reservoir across the anterior & lateral surfaces of the abdomen.

Front 13

Mesentary Proper

Back 13

supports most of the small intestines.

Front 14

Mesocolon

Back 14

supports a portion of the large intestine.

Front 15

Transverse Mesocolon

Back 15

supports the transverse colon.

Front 16

Sigmoid Mesocolon

Back 16

supports the sigmoid colon.

Front 17

Intraperitoneal

Back 17

organs located within the peritoneal cavity supported by mesenteries. The digestive organs include: stomach, jejunum, ileum, transverse colon, sigmoid colon, liver, & gall bladder.

Front 18

Retroperitoneal

Back 18

organs located outside of the peritoneal cavity. These organs are lined on the surface next to the body cavity by the parietal peritoneum, & on the opposite surface by an adventitia that blends with body musculature. The organs include: duodenum, pancreas, ascending colon, descending colon, rectum, & anal canal.

Front 19

Parotid Salivary Glands

Back 19

largest of the salivary glands. A pair located lateral & posterior to mandible. Secretions are entirely serous--produces 25% of total saliva volume.

Front 20

Submandibular Salivary Glands

Back 20

a pair of glands located in floor of mouth. Secretions are both serous (4/5th) & mucus (1/5th). 70% of total saliva volume.

Front 21

Sublingual Salivary Glands

Back 21

Located in floor of mouth. Secretions are entirely mucus--produces 5% of total saliva volume.

Front 22

Lesser Curvature

Back 22

mesial surface (approx. 4 inches) --not as much surface area.

Front 23

Greater Curvature

Back 23

lateral surface (approx. 16 inches)

Front 24

Cardia

Back 24

portion of the stomach within 1.2 inches of the esophagus; contains numerous mucous glands & esophageal lining from the acidic environment.

Front 25

Fundus

Back 25

stomach superior to the junction between the stomach & the esophagus; it contacts the inferior diaphragm.

Front 26

Body

Back 26

largest region; the fundus & this contain gastric glands, which secrete enzymes and acid involved in gastric digestion.

Front 27

Pylorus

Back 27

antrum (connected to the body); canal (connected to the duodenum); pyloric sphinctor (regulates release of chyme into the duodenum); glands in this secrete mucous & hormones (such as gastrin) responsible for activity of gastric glands.

Front 28

Rugae

Back 28

longitudinal, temporary folds in the stoamch mucosa which allow for stomach expansion; the stomach can hold up to 1-1.5 liters of material.

Front 29

Parietal Cells

Back 29

secrete intrinsic factor & hydrochloric acid.

Front 30

Chief Cells

Back 30

secrete pepsonogen, which is converted into pepsin in acid. Pepsin is a proteolytic(protein-digesting) enzyme.

Front 31

Mucus Cells

Back 31

produce alkaline mucous for stomach lining protection against acid & pepsin.

Front 32

Enteroendocrine Cells

Back 32

secrete hormones into the lumen of the stomach.

Front 33

Cephalic Phase

Back 33

begins with sight, smell, taste, & thought of food. Function: production of gastric juice in prepartion for the arrival of food. Duration: this phase is relatively short(minutes).

Front 34

Gastric Phase

Back 34

begins with arrival of food. Function: enhance secretion started in the cephalic phase. Homogenize & acidify chyme. Initiate digestion of proteins by pepsin. Duration: Hours

Front 35

Intestinal Phase

Back 35

begins when the chyme enters the small intestines. Function: control rate of chyme entry into the duodenum. Duration: hours.

Front 36

Cholescystokinin (CCK)

Back 36

inhibits gastric secretion of acids & enzymes. lipids & cards in the duodenum stimulate it.

Front 37

Gastric Inhibitory Peptide (GIP)

Back 37

targets the pancreas, inhibits gastric secretion & reduces rate & force of gastric contractions.

Front 38

Secretin

Back 38

a drop of pH below 4.5 in the duodenum stimulates this secretion. Inhibits chief & parietal cell activity in the stomach; targets pancreas to release buffers to protect the duodenum.