Transcript 3.2 Organs and Systems

3.2 ORGANS AND ORGAN
SYSTEMS
AGENDA
 Hook
Video on Bicycle Riding
 From
Cells to Tissues to Organs
 Types
 The
of Organ systems
Digestive Organ System
FROM CELLS TO TISSUES AND ORGANS



Human stem cells differentiate into epithelial,
muscle, nervous, and connective cells. These
accumulate to become tissues.
These tissues are organized to form organs,
which are designed to perform a specific function.
The organs are used to form organ systems
which together provide everything necessary to
keep the organism (human) alive.
HIERARCHY OF ANIMAL
SYSTEMS
Organ Systems (Circulatory, Digestive,
Respiratory, etc.)
Organs (Heart, Liver, Intestine,
Blood Vessel, etc.)
Tissues (Connective,
Muscular, etc.)
Specialized Cells
(Blood, Heart,
Bone, etc)
Stem
Cells
T-P-S: NAME THE ORGAN
SYSTEMS
ORGAN SYSTEMS IDENTIFIED
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
Muscular
Skeletal
Nervous System
Endocrine
Circulatory
Integumentary
Lymphatic
(Immune)
Respiratory
Digestive
Excretory
Reproductive
DIGESTIVE SYSTEM
The digestive system has 4 primary
functions:

Ingestion

Digestion

Absorption

Egestion
INGESTION & EGESTION
 Ingestion
refers to
the consumption of a
substance (1st step).
 Egestion
refers to the
removal of unwanted
materials from the
body. (Last step)
DIGESTION
 Digestion
is the mechanical and chemical
breakdown of food into smaller
components. (2nd step)

It is the breakdown of large food molecules into
smaller ones.
ABSORPTION (FIG. 3.16)

Absorption is the process by which digested food
nutrients and water are taken from the intestine
and moved throughout the body. (3rd step)
Body (Through Blood Vessels)
Body (Through Blood Vessels)
DIGESTIVE SYSTEM LABELLED
Gallbladder
Pancreas
LABEL THE DIGESTIVE SYSTEM
COMPONENTS
SCENARIO: EATING A BURGER

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The burger enters the oral cavity
(i.e. the mouth)
A bite is taken out of the burger and
chewing proceeds (mechanical
digestion)
The salivary glands secrete amylase
to breakdown the carbohydrates.
(chemical digestion)
Once the food has been broken down
into small enough pieces, the food is
swallowed.
DOWN THE OESOPHAGUS TO THE
STOMACH
 The
partly digested food travels through the
pharynx down the oesophagus through
peristaltic contractions.
DIGESTION IN THE STOMACH
 The
food passes through a sphincter into the
stomach where gastric juices surround the
food.

Hydrochloric acid and the enzyme pepsin break
down most of the protein. (chemical digestion)

The stomach then covers the food in mucus and
sends the food down to the small intestine
(duodenum)
THE SMALL INTESTINE


The pancreas, liver, and gall
bladder release chemicals to
help break down the food
further.
The small intestine contains
millions of tiny folds called
villi and microvilli


Provides increased area for
absorption
Nutrients and water can be
reabsorbed into the bloodstream
THE LARGE INTESTINE
 Includes
the colon, rectum, and anus
 Mainly absorbs water


Also absorbs vitamins and various salts
Undigested food leaves as feces (E.g. Corn)
VIDEO/MULTIMEDIA TOOL

http://kitses.com/animation/swfs/digestion.swf