Nutrition Ch. 3

Lower Esophageal Sphincter (LES)

A circular band of muscle between the esophagus and the stomach that opens and closes to allow food to enter the stomach.

Pepsin

A digestive enzyme produced in the stomach that breaks down a protein.

Gastrin

A digestive hormone produced in the stomach that stimulates digestive activities and increases motility and emptying .

gallbladder

A pear shaped organ located behind the liver. The gallbladder stores bile produced by the liver and secretes the bile through a bile duct into the small intestine.

segmentation

A sloshing motion that thoroughly mixes chyme with the chemical secretions of the intestine

Pancreas

Accessory organ of digestion that produces hormones and enzymes. ITs connected to the duodenum via the bile duct.

Hydrochloric Acid

Activates enzyme pepsin, enhances absorption of minerals, breaks down connective tissue of meat, protects against invaders (mucus protects stomach lining from damage)

Crohn's disease

An inflammatory bowel disease involving inflammation and selling of intestines

Hormones

Chemical substances that regulate, initiate or direct cellular activity.

Mechanical Digestion

Chewing, grinding food to aid swallowing

Gastrointestinal Tract (GI Tract)

Consists of mouth, esophagus, stomach, SMALL INTESTINE(majority of digestion and absorption), and large intestine. Main role is to break down food into small components, absorb nutrients and prevent microorganism from entering body. Nearly 30 ft. long

Chemical digestion:

Digestive juices and enzymes break down food into absorbable nutrients.

Passive Diffusion

Due to concentration gradient. When concentration in GI tract exceeds that of intestinal cell, nutrient is forced across cell membrane.

ileocecal sphincter

Gateway between the end of the small intestine and the beginning of the large intestine. The sphincter prevents back flow of fecal contents from LI to SI

Rectum

Lowest pare of the large intestine, continuous with the sigmoid colon and anus

Small Intestine

Majority of digestion and absorption of nutrients. THREE SEGMENTS: duodenum, Jejunum, Ileum

Large Intestine

Most nutrients absorbed by the time it reaches large intestine, three sections: cecum, colon, and rectum. Absorbs water and electrolytes, chem. digestion done by bacteria. bacteria in colon produces vitamin k and biotin and breaks down remaining fibers and carbohydrates.

Active transport

Nutrients absorbed from low to high concentration, requiring both carrier and energy.

Digestion

Process of breaking down foods into absorbable components using mechanical and chemical means in the Gastrointestinal (GI) tract

Villi

Projections on the walls of the small intestine that increase the surface are over which nutrients can be absorbed.

Facilitated Diffusion

Similar to passive method, but requires a specialized protein to carry nutrients.

Gallstones

Small hard structures formed in gallbladder due to unusual thick bile

Peptic Ulcers

Sores, erosions, or breaks in the mucosal lining of the stomach

Pyloric Sphincter

Sphincter in the bottom of the stomach that separates the pylorus from the duodenum of the small intestine.

Gastroesophageal Reflux disease (GERD)

The backward flow of stomach contents past the lower esophageal sphincter into the esophagus

Peristalsis

The forward rhythmic muscular contraction that moves food through the GI tract

Liver

The largest gland in the body. It aids in digestive activity and is responsible for metabolism of nutrients, detoxification of alcohol and some nutrient storage.

Chyme

The semiliquid partially digested food mass that leaves the stomach and enters the small intestine.

Pharynx

The throat. Passageway for the respiratory and digestive tracts

Microvilli

Tiny projections on the vili in the small intestine that increase the surface area even more.

peddler movement

a constrictive wave that involves both forward and reverse movements of chyme and enhances nutrient absorption.

Enzymes

break down food into absorbable nutrient components

heart burn

burning sensation in esophagus. caused by reflux of gastric contents from stomach to esophagus. Can lead to Gastroesophageal Reflux disease (GERD)

bolus

chewed masses of food

dysphagia

difficult swallowing

epiglottis

flap of tissue that protects the trachea while swallowing.

gastroenteritis

formal term for stomach flu. Caused by a virus or bacteria and results in inflammation of the stomach and/or intestines

lumen

the interior of the digestive tract, through which food passes

bile

yellowish green fluid made in the liver, stored in gallbladder