ATI TEAS Digestive System

Digestive system

Organ system that breaks down food, absorbs nutrients, and eliminates waste

What is the main function of the digestive system?

To break down food for nutrient absorption and distribute nutrients to the body

Mechanical digestion

Physical breakdown of food into smaller pieces

Chemical digestion

Enzymatic breakdown of food into simple molecules

What is the difference between mechanical and chemical digestion?

Mechanical breaks food physically, chemical uses enzymes to break molecules

Mouth

Entry point of food where digestion begins

What happens in the mouth?

Food is chewed and mixed with saliva to begin digestion

Saliva

Fluid that lubricates food and contains digestive enzymes

Amylase

Enzyme in saliva that breaks down starch

Lipase

Enzyme that begins breakdown of lipids

Bolus

Ball of chewed food ready to be swallowed

Deglutition

Process of swallowing

Epiglottis

Structure that prevents food from entering the trachea

Esophagus

Tube that carries food from mouth to stomach

Peristalsis

Wave-like muscle contractions that move food through the digestive tract

What does peristalsis do?

Moves food through the esophagus and intestines

Stomach

Muscular sac that continues digestion

What happens in the stomach?

Food is mixed and broken down into chyme

Chyme

Semi-liquid mixture of partially digested food

Hydrochloric acid

Acid in stomach that creates low pH for digestion

Pepsin

Enzyme that breaks down proteins in the stomach

Why is mucus important in the stomach?

It protects the stomach lining from acid

Small intestine

Organ where most digestion and absorption occur

Duodenum

First part of small intestine where chyme is neutralized

What happens in the duodenum?

Chyme mixes with bile and pancreatic secretions

Bile

Substance that helps break down fats (lipids)

Where is bile produced and stored?

Produced in liver and stored in gallbladder

Brush border enzymes

Enzymes in small intestine that complete digestion

Villi

Finger-like projections that increase surface area for absorption

Microvilli

Smaller projections on villi that further increase absorption

What structure absorbs nutrients in the small intestine?

Villi and microvilli

What happens to nutrients after absorption?

They enter the blood and go to the liver

Liver

Organ that processes nutrients, detoxifies substances, and stores glycogen

What is the role of the liver in digestion?

Processes absorbed nutrients and removes toxins

Large intestine

Organ that absorbs water and forms feces

What happens in the large intestine?

Water and salts are absorbed and bacteria break down waste

Cecum

First part of large intestine

Appendix

Small projection from cecum with immune function

Rectum

Stores waste before elimination

Anus

Opening where waste exits the body

What is eliminated from the body?

Undigested food and waste

Enzyme

Protein that speeds up chemical reactions in digestion

Why are enzymes important in digestion?

They break down food into absorbable molecules

What role do bacteria play in digestion?

Help break down waste and produce vitamins like vitamin K

Hormone

Chemical messenger that regulates body processes

Ghrelin

Hormone that stimulates hunger

Leptin

Hormone that signals fullness

Insulin

Hormone that allows cells to take in glucose

Glucagon

Hormone that increases blood glucose levels

What is the role of hormones in digestion?

They regulate appetite, digestion, and nutrient use

What happens to carbohydrates during digestion?

Broken down into simple sugars for absorption

What happens to proteins during digestion?

Broken into amino acids

What happens to lipids during digestion?

Broken into fatty acids and glycerol

What is the role of bile in digestion?

Emulsifies fats to aid in their breakdown

Where does protein digestion begin?

In the stomach with pepsin

Where does carbohydrate digestion begin?

In the mouth with amylase

Where does most nutrient absorption occur?

Small intestine

What happens if the small intestine is damaged?

Nutrient absorption decreases

What is the purpose of increasing surface area in digestion?

To improve absorption efficiency

How does the digestive system interact with the circulatory system?

Nutrients enter the blood and are transported throughout the body