G.I Flashcards
What are the layers of the GI tract walls?
Mucosa
Submucosa
Muscularis Externa
Serosa
What is the mucosa made up of?
Epithelial Cell
Lamina Propria
Muscularis Mucosa
What Governing Neurological system controls the GI?
Enteric Nervous system
What is the Enteric Nervous System divided into?
Myenteric System
Submucosal Plexus
What does the Myenteric System predominately control?
GI motility
What does the Submucosal predominately control?
Sensory information of the lumen
Control of blood flow to the GI
Secretions of the epithelial cells.
What is the average amount of saliva produced daily?
1000mL
What is the average amount of Gastric Secretion daily?
1500mL
What is the average amount of Small Intestinal secretion daily?
2000mL
What is the function of Saliva?
Anti-bacteria properties - antibodies, lysosomes
Beginning of Carbohydrate Digestion
Starts a limited role in fat digestion
Allows for taste to work
Without it, thirst results
Keeps mouth moistened, helping for speech
What is released in the Mouth that aid towards carbohydrate to break down? and what bonds does it break down?
Salivary Amylase
Alpha 1-4 glycosidic bonds
What is the function of Gastric Acid?
Breakdown of connective tissue
Denaturing of proteins
Activates Pepsin
Protection
Solublises calcium ions
What zymogens are secreted by the pancreas?
Trypsin
Chymotrypsin
Carboxypepidase
Elastase
Phospholipases
What enzymes are released from the pancreas?
Pancreatic Lipases
Lipase
Ribonuclease
Deoxyribonuclease
What does panceatic lipase break?
Breaks positions 1 & 3 fatty acids on glycerol
What stimulates the release of Alkaline from the pancreas?
CCK
What is the product of emulsification by the bile salts?
Micelles
What are the cells on the small intestine called that carry out the absorption?
Entrocytes
What enzymes are found on the brush border of the entrocytes?
Peptidases
Maltase
Lactase
Sucrase
What is Maltose made up of?
2 x Glucose
What is Lactose made up of?
Galactose and Glucose
What is sucrose made up of?
Fructose and Glucose
What are the broad processes of absorption?
Active
Facilitated
Passive
What lipoprotein is produced in the entrocyte and passed into the lymph system?
Chylomicrons
What happens to the non absorbed carbohydrate in the large intestines?
Fermentation by gut flora which releases fatty acids.
What branch of the aorta supplies the stomach, liver, pancreas, spleen, gall bladder and 1st 1/2 of duedonum
Cilieac branch
What does the super mesenteric artery supply?
2nd 1/2 of duedomum all the way to 1/2 transverse colon.
what does the inferior mesenteric artery supply?
2nd 1/2 transverse colon, down to anus
What are the folds in the stomach called?
Rugae
What are the endocrine secretions of the pancreas?
Insulin, Glucagon and Somatostatin
What makes the colon distinctive?
Taenia Coli - incompletely muscle
Haustra - Ring like circular muscles
What prevents Gastro reflux?
Lower Esophageal sphincter
What do the endocrine cells of the stomach produce and what is its function?
Gastrin.
Stimulates the release of:
- pepsinogen
- HCl
Activates gut motility
Where do pancreatic secretions enter the duodenum?
what sphincter controls this?
Duodenal Papilla through which the Ampulla of Vader secretes through
Sphincter of oddi
What epithelial tissue is present in the Small intestines?
Simple Columnar
What artery supplies the Gall bladder?
Cystic artery
What are the transporters of amino acids into the entrocytes called, and what drives there movement?
PepT1
Driven by swapping for H+ ions
What lipases are released to break triglycerides during fat metabolism, and where are they released?
Lingual Lipase - salivary glands
Gastric Lipase - stomach
Pancreas lipase - duodenum
Where are Brunner’s Glands found and what is their function?
Duedonum
Secrete alkaline solution to neutralise acid from the stomach
What bacteria is most likely to cause gastic ulceration?
Helicobacter pylori
What are Paneth cells?
The a granular cells in the small intestine that release enzymes
What is the main function of the duedonum?
Digestion
What is the main function of the Ilium?
Absorption
What are the enzymes on the brush border called that break down carbohydrates?
Lactase
Maltase
Isomaltase/ Sucrase
What enzyme in the duodeneum activates the trypsinogen to trypsin?
Enteropeptidase
What are the stages of digestion
Cephalic Phase
- Perpetration for food. Intiated by ACh release by the sight and smell of food.
- Vagus controls
Gastric phase
- longest phase
- gastrin ACh activate release of stomach enzymes
Intestinal Phase
- presence of chyme in the duodenum
- CCK production. Which also inhibits Gastric secretion
What protective measures are in place to prevent damage to the stomach from the acid and pepsin?
Mucus secretion from the neck cells
- prostaglandins stimulate production
Release of Bicarbonate near the surface of the mucus
- neutralises acid
- reduces the effectiveness of pepsin
Tight junctions around the gastric cells.
- restrict any movement
