GI Tract - TEAS prep

gastrointestinal

• the organs that take in food & liquids & breaks them down into substances that the body can use for energy, growth, & tissue repair

• 4 basic functions include:

  • ingestion

  • digestion

  • absorption

  • elimination

ingestion

• taking in of food (eating)

digestion

• biomolecule polymers break down into building blocks

• components:

  • mechanical

  • chemical

  • epiglottis

  • persistalsis

  • stomach

  • lower esophageal

  • pyloric sphincter

mechanical

• physically breaking down food into smaller particles

• churning of the stomach, bathes contents in gastric juices → chyme

chyme

• pulpy acidic fluid which passes from the stomach into the small intestine

chemical

• enzymes break down nutrients into smaller molecules (saliva)

• hydrochloric acid (HCl)

• pepsin

hydrochloric acid

• strong acidic solution of the gas hydrogen chloride in water

pepsin

• chief digestive enzyme in the stomach that breaks down proteins into polypeptides

epiglottis

• flap that covers the trachea during swallowing so food doesn’t enter the lungs

persistalsis

• involuntary construction & relaxation

  • creating wave like movements to push contents down the canal to the stomach

stomach

• can store approximately 2 liters of food & liquid

lower esophageal sphincter

• separates the esophagus from the stomach

• prevents heart burn & gastroesophagal reflux (aka gird)

pyloric sphincter

• separates the stomach from the small intestines (duodenum)

• control passage digested food into our small intestine

• helps prevent back flow of intestinal contents into the stomach

absorption

• absorbs nutrients to be delivered to cells

• small intestines

  • duodenum

  • jejunum

  • ileum

  • digestive juices intake

duodenum

• shortest segment of small intestine

• chemical digestion of chyme

• breaks down fats, proteins, & carbohydrates

• absorbs iron & other minerals

jejunum

• middle segment of small intestines

• absorption of nutrients

• carbohydrates & proteins are absorbed into the bloodstream

• wall composed of villi

villi

• tiny hair-like projections that line the intestines and help with absorption into the blood stream

ileum

• final segment of small intestine

• absorption of nutrients

• vitamin b12, bile salts, & products of digestion are absorbed

large intestines

• ascending colon

• transverse colon

• descending colon

ascending colon

• first segment of large intestine

• absorbs water & salts

• solidify waste into formed stool

transverse colon

• longest most mobile part of large intestine

• storage site for digested food

• more absorption for water & salts

descending colon

• descending segment of large intestine

• carries solid waste toward the rectum

• more absorption of water & minerals

• store feces until defecation

elimination

• waste is removed

• rectum

rectum

• final segment of large intestine

• stores feces until they are expelled through the anus

liver

• carbohydrate & protein metabolism

• creates bile to help with the breakdown of lipids in small intestine

• largest internal organ

gallbladder

• store the bile produced by the liver, releasing it when needed for digestion

pancreas

• produces pancreatic juices to help neutralize chyme

gastrin

• found in the G cells of the stomach

• stimulate gastric glands to secrete pepsinogen (precursor for pepsin) & HCl

cholecystokinin

• found in the I (mucus) cells of the duodenum & jejunum

• digesting fats & proteins & stimulating the gallbladder to release contract bile

secretin

• found in the s cells of the duodenum

• regulates pH by inhibiting gastric acid secretion & stimulation bicarb production

insulin

• found in the beta cells of pancreas

• glucose metabolism & stores glucose as glycogen

glucagon

• found in the alpha cells of pancreas

• raises blood glucose levels

bile

• produced by liver stored in gallbladder

• emulsifies fats