Chapter 8 Gastrointestinal System

Digestion vs absorption

Digestion: Breaking food into smaller molecules
Absorption: Taken into bloodstream

Biggest organ in digestive system

Small intestine

What surrounds the digestive system organs

Smooth muscle

Forward motion generated by digestive muscles

Peristalsis

Oral cavity

Mouth

First step of digestion

Mechanical digestion by teeth

First step of chemical digestion

Salivary enzymes

How many sets of salivary glands?

3

Salivary gland names

Sublingual: under tongue
Submandibular: Under jaw
Parotid gland: Ears

What must be present for taste receptor to detect flavor?

Moisture

Enzyme that breaks down carbohydrates in oral cavity

Salivary amylase

What transports food from mouth to stomach

Esophagus

What occurs after breakdown in oral cavity

Passes pharynx, enters esophagus

What does the esophagus do?

Secretes mucus to pass food to stomach

Length of esphoagus

25 cm

What prevents backwards flow of food from throat to stomach

Sphincter (open = movement, contracted = no movement)

Stomach description

J-shaped organ in left region of abdominal cavity

How much food can the stomach hold

1 Liter

Where does food go after being partially digested in the stomach

Small intestine

Muscle between stomach and small intestine

Pyloric sphingter

Stomach’s secretoroy cells

Mucous cells, chief cells, parietal cells

Mucous cells

Secrete mucous as lubricant and buffer

Chief cells

Release pepsinogen, helps with digestionP

Parietal cells

Releases HCl, turning pepsinogen into pepsin

Allows for absorption of Vitamin B12 (RBC production)

Pancreas

C-shaped organ underneath the stomach

Pancreas functions

Endocrine: Releases insulin and glucagon
Exocrine: Release pancreatic juice (breaks down proteins, carbs, lipids)

What cell in the pancreas is responsible for releasing pancreatic juice

Acinar cells

What is released in the pancreas to counteract stomach acidity

Bicarbonate

Liver

Located in upper-right abdominal cavityL

Liver functions

1. Produce bile (emulsification)

2. Absorption of lipid molecules and fat-soluble vitaminds

Small intestine

Cylindrical organ in middle of abdominal cavityS

Small intestine function

Where digestion ends and absorption begins

Enzymes in small intestine

Aminopeptidase - turns peptides into amino acids

Maltase,sucrase,lactase - Turns disaccharides into monosaccharides

Enterokinase - activates proteolytic enzymes

How long for food to cross the small intestine

6 to 8 hours

Large intestine

Cecum, colon, rectum, anal canal

What occurs in the large intestine

Feces passes through, intestinal flora degrade fiber/vitamins

GERD

Gastroesophageal reflux disease - consistent heartburn (more then twice a week)

Where do ulcers usually occur

Stomach, duodenum

Celiac disease

Destruction of mucus lining in small intestine, causes malnutrition

Crohn’s Disease

Inflammation in small intestine ileum

Ulcerative Colities

Inflammation of colon mucus lining, blood in stool