Transcript Digestive And Excretory Systems

Digestive
And
Excretory
Systems
Digestive
System
Functions of the Digestive System
• Digestion
• Waste Removal (solid)
• Conversion of food energy to energy
usable by the body
• Absorption of nutrients.
Organs of the Digestive System
•
•
•
•
•
•
•
•
Mouth
Salivary glands
Esophagus
Stomach
Small Intestine
Large Intestine
Liver
Pancreas
Digestive Process
In the mouth
• Food is chewed and swallowed
• Enzymes are added to food in this
process.
• Once swallowed, it moves down the
esophagus to the stomach
Enzymes
• Proteins that catalyze, or increase
the rates of chemical reactions.
Peristalsis
• Process where food is moved through
the digestive system by waves of
rhythmic muscular contractions.
In the stomach
• Strong acid and powerful enzymes
mix with the food and break down
the food into chyme.
• It is then moved to the small
intestine.
In the Small Intestine
• Secretions from the small intestine,
liver, and pancreas finish breaking
down the proteins, carbohydrates,
and fats
• Most of the absorption of nutrients
takes place in the small intestine
In the Large Intestine
• Vitamins, Minerals, and Water are
absorbed.
Role of the Liver in digestion
• Secretes chemicals that help digest
fats in the small intestine.
• Stores energy reserves.
Role of the Pancreas in digestion
• Secretes enzymes that break down
carbohydrates and proteins in the
small intestine.
Excretory System
Functions of the Excretory System
• Removes waste made by cells
• Maintains
– salt content
– water content
– blood pressure
– acid-base balance
Organs of the Excretory System
• Kidneys
• Lungs
• Skin
Kidneys
• Filter blood about 10 times a day.
(about 1 liter per hour)
Nephrons
• Blood filtering units in the kidney.
• Each kidney has millions of them.
• They remove salts, water, and cell waste
from the blood.
• 99% of the water removed by the nephrons
is reclaimed by the capillaries.
• Liquid waste is called urine.
Urinary Tract
• Ureter – tube that carries urine from the
kidney to the urinary bladder.
• Urinary Bladder – stores urine.
• Urethra – tube that runs from the urinary
bladder to the outside of the body.
Lungs
• Remove carbon dioxide (CO2) from the
blood and expels it from the body
Skin
• Excretes water, salts, small
amounts of hydrogen wastes,
and other substances such as
toxins in sweat