GI Block One Flashcards
What does food equal
Chemical energy
What type of system is the GI system
Tubular, with close association to cardio
- Alimentary Nourishment Canal *
Length of GI when alive vs when cadaver
16-23 feet
23-29 feet
due to loss of muscular tone
Muscular alimentary canal main organs (5)
Esophagus Stomach Small Instestine Large Instestine Anus
Accessory digestive organs
Gallbladder
Liver
Pancreas
Six processes of digestion
Ingestion
Secretion
Mixing Propulsion
Digestion
Absorption
Defection
Largest serous membrane in the body and contents
Peritoneum
Simple squamous epithelium with parietal and visceral peritoneum
Organs retroperitoneal
Kidneys Ascending colon Descending colon Duodenum Pancreas
Where does the esophagus begin and end
Laryngopharynx to esophageal hiatus before the stomach
Muscular contents of the esophagus
Superior 1/3 = skeletal ; think UPPER ESOPHAGEAL SPHNICTER
Middle 1/3 = skeletal; and smooth
Inferior 1/3 = smooth ; think LOWER ESOPHAGEAL SPHINCTER
What is the esophageal ole in digestive enzyme production and reabsorption
It has NONE
serves as a mixing chamber and holding reservoir
Stomach
What do parietal cells secrete
Hydrochloric acid and Intrinsic Factor
What do chief cells secrete
Pepsinogen and gastric lipase
How often are peristaltic waves
15-20 seconds
- approximately 3mL of chyme is ejected into the duodenum each wave*
What are the parietal cells role in digestion?
Proton pumps (powered by H+/K+ ATPases) actively transport a H+ into lumen while bringing a K+ into the cell
What does the enzyme carbonic anhydride catalyze?
Formation of carbonic acid from water and co2
Providing a H+ source for proton pumps and bicarbonate
How can HCL be signaled to release from parietal cells (3)
Acetylcholine (ACh) released by parasympathetic neurons
Gastrin being secreted by G Cells
Histamine- paracrine substance released by local mast cells in lamina propria
Pancreatic duct (Duct of Wirsung) does what?
Joins common bile duct from liver and gallbladder then enters duodenum as the hepatopancreatic ampulla (also known as the ampulla of Vater)
Ampulla of Vater is regulated by the sphincter of Oddi
What do acini clusters secrete
Pancreatic juice
How much pancreatic juice is secreted daily
1200-1500mL
Contents of pancreatic juice
Sodium bicarbonate, water, salts, enzymes
What do pancreatic amylase secrete/trypsin?
PA = Starch digestion
Trypsin =Protein digestion
What are the active enzymes vs inactive
Active
Trypsin
Chymotrypsin
CArboxypeptidase
Inactive Trypsinogen Chymotryipsinogen Procarboxypepetidase Proelastase