Gastrointestinal System

what organs secrete substances used in the gastrointestinal process

• gastrointestinal tract

• pancreas

• gallbladder

• salivary glands

intestine function

mixes the meal with secretions and moves everything to the intestinal tract

what do salivary glands produce

enzyme salivary a-amylase

what activates salivary glands

Cl-

what does salivary a-amylase (produced by salivary glands) digest?

starch

what is the mechanism of action for enzyme salivary a-amylase

• hydrolyzes 1:4a linkages

• produces a-limit dextrins (matotriose and maltose)

incisors

• chisel like

• for cutting and incising

canine teeth

• wedge like

• cutting and tearing

premolars

• 2 projections

• tearing and grinding

molars

• multiple projections

• grinding

epiglottis

• flap of cartilage on top of the glottis

• closes trachea (windpipe) when swallowing

• prevents food from entering the larynx

• food will then travel down the esophagus

peristalsis

involuntary muscle contractions to move food along

3 layers of smooth muscle of the stomach

1. outer longitudinal

2. middle circular

3. inner oblique muscles

what does the body of the stomach secrete

• mucus

• pepsinogen

• HCL

what does the antrum of the stomach secrete

• mucus

• pepsinogen

• gastrin

what cells make up the gastric gland

1. surface mucus cells

2. parietal cells aka oxyntic cells

3. ECL cells

4. chief cells

5. G-cells

what do surface mucus cells of the gastric gland secrete

• produce and secrete mucus

• mucus contains HCO3- and peptides that helps to protect the stomach from gastric acid

what do parietal aka oxyntic cells of the gastric gland secrete

• secrete HCL (gastric acids)

• intrinsic factor (necessary for vitamin B12 absorption)

what do ECL cells of the gastric gland secrete

• histamine

what do chief cells of the gastric gland secrete

• pepsinogen (will be activated to become pepsin0 from acid in the stomach

• gastric lipase

what do G-cells of the gastric gland secrete

• gastrin (peptide hormone, stimulates secretion of HCL by parietal cells)