Organ Systems of the Human Body

Digestive

Respiratory

Circulatory

Excretory

Nervous

The Big 5

In order for your body to get energy the food we eat must pass through the digestive system

It is in charge of breaking down food into small enough parts to be used by cells

3.1-- Digestive System

ITS EXPERIMENT TIME!!!

NO LAB REPORT!!!

Take the crackers you have in front of you and chew them up well..BUT DO NOT SWALLOW THEM!!!!

Hold them in your mouth for 5 minutes….starting….

Answer the questions as you go.

A Taste of Digestion Experiment

How did the crackers taste as you first chewed them?

Question #1

Describe how the taste changed as you neared the 5-minute mark?

Question #2

What do you think caused the any changes you experienced?

Question 3

Mechanical – the physical breakdown of food into very small pieces

Chemical – breakdown of large particles into smaller particles using ENZYMES.

Types of Digestion

The digestive system is merely a pathway where food follows long tubes with a few compartments

It starts at the mouth and finishes in the rectum

The Digestive Path

This is the first stage of digestion that occurs in this pathway

Mechanical digestion occurs with the chewing of the food using teeth

Saliva in the mouth moistens food and adds an enzyme called salivary amylase.

#1. Mouth and Esophagus

When your food is fully chewed your tongue pushes it to the back of your throat

Swallowing pushes the food down your throat into your esophagus

The food is pushed towards your stomach by wave-like movement called Peristalsis

They are caused by the contracting and relaxing of muscle tissue around the esophagus

Esophagus

Deals with the arriving food with a few processes;

◦ The muscular stomach wall churns food back and forth

◦ This mixes the food with the secretions from the wall of the stomach, called GASTRIC JUICE

Stop #2 -- The Stomach

Gastric Juice is made up of ◦ Mucus◦ Hydrochloric Acid◦ Water ◦ Digestive Enzymes

Gastric Juice

The Hydrochloric Acid and enzymes help chemically breakdown the larger particles

The mucus helps prevent the gastric juices from digesting the stomach itself

The stomach slowly releases the food, which is now a liquid, into the small intestines

The average length of an adult human male is about 22 feet 6 inches or 6.9 meters

In women it is 23 feet 4 inches or 7.1 meters

Fun Fact

Chemical digestion continues in the small intestines

The PANCREAS sends in more digestive enzymes to further help the breakdown

The small intestines itself releases more enzymes to assist the pancreas

Stop #3 --Small Intestines, Pancreas, Liver and Gall Bladder

Once the food has been broken up the small intestines absorbs as much as it can

To catch as much as possible the intestines use VILLI – finger like projections that absorb nutrients

The absorbed nutrients go directly into the blood stream

The liver produces BILE

Bile is stored in the GALL BLADDER

The gall bladder sends bile into the small intestines to assist in more chemical digestion

Liver and Gall Bladder

When food reaches large intestines mechanical and chemical digestion is complete

They absorb water, vitamins and minerals

Whatever is left forms into feces and is stored in the rectum

Stop #4 – Large Intestines