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Digestive/Excretory System
Life Science Unit 3
Lesson 6
Attendance link: http://goo.gl/forms/42Y0JINUAL
Objectives
Describe the functions of organs and other
structures in the digestive and excretory
systems.
 Compare the digestive and excretory systems
of animals and plants.
 Describe the function of the digestive and
excretory systems in organisms.
 Identify the structure of the digestive and
excretory systems and organs within these
systems.

Parts of the Digestive System
 Mouth
 Pharynx
 Esophagus
 stomach
 small intestine
 large intestine
 Colon-rectum
 anus
Accessory Parts
Accessory
Salivary
Organs
Glands
Pancreas
Liver and Gallbladder
Process--Mouth
Food
enters the mouth (mechanical
digestion)
Teeth
grind, tear and chop food
Saliva moistens it
Amylase begins to break down carbs in
food
Soft mass of chewed food--BOLUS
Swallowing
Swallowing--muscles
in the tongue and
mouth push food into…..
Esophagus--epiglottis keeps most food out
of the windpipe
Connects to the stomach at the pyloric
valve
Peristalsis
forces food into stomach
Stomach
Stomach--churns
and mixes food with
acids and enzymes
Three mechanical/chemical tasks
Storage
Mix
food, liquid and digestive juices
Soup
Empty
like mass called CHYME
contents slowly into small intestine
Do all animals have a stomach?
No
What
do birds have to help them
break down food?
It
is a gizzard.
Small Intestine
Pyloric
sphincter allows chyme into
duodenum
Bile
from pancreas added
Digestion continues
Absorption begins
Villi--finger
like projections
Role of Accessory Organs
Liver--produces
bile to help absorb
fat; processes nutrients
Gallbladder--stores bile
Pancreas--produces enzymes;
neutralizes stomach acids
Large Intestine
Main
function--remove water from
undigested matter and form solid
wastes
Colon--solid wastes are stored until
expelled through the rectum
What best describes the function of
the digestive system?
The
function of the digestive system
is to break down food into nutrients.
Incomplete vs complete
digestive systems
Incomplete
Takes
place in a
saclike cavity with
a single opening.
 Any
food not digestive
gets pushed back out
through the same
opening.
Complete
Takes
place in a
series of tubes.
With one entrance
and one exit.
Undigested food is
expelled in this
one-way flow.
For both incomplete and
complete digestive system…
Digestion
begins outside the cells.
Code word:
Urea
Urinary System
Contains organs that remove waste
products from your blood
Three body systems have a role in
excretion: integumentary, respiratory,
and finally the urinary system.
Kidneys
Located
on either side of backbone
Filters waste from other body
systems
Makes sugar available as fuel and
sends it to tissues
Removes toxic chemicals in the
bloodstream
Kidneys
Blood
circulates collecting waste
Enters kidneys
Reaches NEPHRONS--filtering units
Remove
excess water, salt and urea from blood
Material left in nephron is urine
Passes into 2 tubes called URETERS which
connect to urinary bladder
Urine passes through URETHRA--and out
Urinary System Problems
Bacterial
infections: infections can
get into the bladder, and cause
painful infections
Kidney stones: salts and wastes
collect inside the kidneys and form
kidney stones
Urinary System Problems
Kidney
disease: damage to nephrons
prevent normal kidney functioning, a
person will end up on dialysis to help
filter the blood.
Which of the two organs below are
part of the excretory system?
A.
B.
C.
D.
Gizzard, beak
Stomach, esophagus
Large intestine, small intestine
Kidney, bladder
What is the name of the organ that
is responsible for storing urine?
Bladder
Assessment
OLS
Online
assessment 6 questions
Offline assessment 1 question
Make
sure that you are mastering each
lesson! That is the only way it counts!