©2005 texas trade and industrial education1 cosmetology digestive & excretory systems

©2005 Texas Trade and Industrial Education 1

Cosmetology

Digestive & Excretory Systems

©2005 Texas Trade and Industrial Education Cosmetology I: Digestive & Excretory Systems 2

Performance Objectives

Upon completion of this lesson, the student will be able to identify and describe the key functions and processes of the digestive and excretory systems. The student will demonstrate these competencies by completing a written test with a minimum of 80 percent accuracy.


Specific Objectives• Identify the key responsibility of the digestive system• Describe the digestive process• List and describe the five basic activities the digestive

system performs to prepare food for use by cells• Identify the parts of the digestive tract and their main

functions• Identify the key responsibility of the excretory system• Name the key organs that play a role in the excretory

system and their functions


Key Responsibility of the Digestive System Responsible for changing food into

nutrients and waste Allows the body’s cells to convert food into

high-energy molecules that run the cell’s machinery


The Digestive Process

Digestive enzymes are chemicals that change certain kinds of food into a form that can be used by the body

Once the food is in a soluble form, it is transported by the bloodstream and used by the body’s cells and tissues

The entire digestive process takes about nine hours to complete


The 5 Basic Activities the Digestive System Performs

Ingestion - taking food into the body Peristalsis - the physical movement or

pushing of food along the digestive track Digestion - the breakdown of food Absorption - the passage of digested food

from the digestive tract into the cardiovascular and lymphatic systems for distribution to the body’s cells

Defecation - the elimination from the body of those substances that are indigestible and cannot be absorbed


Digestive Tract:Parts and FunctionsMouth, or oral cavity: Teeth bite off and chew food

into a soft pulp that is easy to swallow

Chewing mixes the food with watery saliva to make it moist and slippery

Pharynx: Begins the process of

swallowing, moving the food from the mouth


Digestive Tract:Parts and Functions (2)Esophagus: A collapsible, muscular tube that secretes

mucus and transports food from the throat to the stomach

Stomach: Begins the digestion of proteins

(carbohydrates begin to digest in the mouth), mashes the food into soupy consistency and passes the contents to the small intestine

The stomach also produces digestive juices that attack the food and dissolve its nutrients


Digestive Tract:Parts and Functions (3)

Small intestine: Approximately 21 feet in length and 1 inch in

diameter, the small intestine performs the major portion of the absorption and digestion

Enzymes continue the chemical attack on the food, and finally the nutrients are small enough to pass through the lining of the small intestine and into the blood

The nutrients are carried away to the liver and other body parts to be processed, stored, and distributed


Digestive Tract:Parts and Functions (4)

Large intestine: Approximately 5 feet in length and 2.5 inches

in diameter Absorbs spare water and minerals through

the walls of the large intestine, back into the blood

Forms feces and removes it from the body


Key Responsibility of the Excretory System A group of organs responsible for purifying the

body by eliminating waste matter The metabolism of body cells forms various

toxic substances that, if retained, could poison the body


Key Organs of theExcretory System

Kidneys: The most important organ in the excretory

system Kidneys clean the body’s blood 40 times a

day The waste from the blood creates urine


Key Organs of theExcretory System (2)

Liver: Largest internal organ in the body Functions as part of the digestive,

excretory, and circulatory systems Produces bile and discharges it to gall

bladder, and then passes to the small intestine where it breaks down molecules


Key Organs of theExcretory System (3)

Skin: Eliminates waste through perspirationLarge intestine: Eliminates decomposed and undigested

food as described in the digestive system section

Lungs: Exhale carbon dioxide


Summary

The digestive and excretory systems perform important functions for the body. They also work with the other systems to maintain homeostasis (maintaining the body’s internal environment).

©2005 texas trade and industrial education1 cosmetology digestive & excretory systems

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