What do you already know Complete the Digestive System Handout to the best of your ability without looking in any text or your notes You may work in groups Do not complete the bottom overview ID: 612621
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Slide1
The Human Digestive System
What do you already know?
Complete the Digestive System Handout to the best of your ability without looking in any text or your notes.
You may work in groups.
Do not complete the bottom overview.Slide2
The Human Digestive System
Video OverviewSlide3
When you eat foods such as bread, meat, and vegetables, they are not in a form that the body can use.
Food and drink consumed must be broken down into smaller
molecules so that they can be absorbed into the body.
Why do we need a Digestive System?Slide4
Components of the Digestive System?
The Digestive Tract is a series of hollow organs joined in a long, twisted tube from the mouth to the anus.
Organs involved:
Mouth
Esophagus
Stomach
Liver
PancreasSmall IntestineLarge IntestineRectum
Oral Cavity (mouth)
Small Intestine
EsophagusSlide5
Components of the Digestive System?
The entire length of the digestive tract is lined with
epithelial tissue
.
Contains lots of
goblet cells
which secrete mucus. The mucus does two things
Protects tract from digestive enzymesMoves materials along the tubeSlide6
Digestive Enzymes
Digestive Enzymes help to break food
into smaller pieces so that it is easier to digest
Digestive Enzymes VideoSlide7
The Mouth
Digestion begins in the oral cavity (mouth) where 2 types of digestion take place:
Mechanical Digestion
Chemical DigestionSlide8
Mechanical Digestion
Chewing breaks up large pieces of food into smaller onesSlide9
Chemical Digestion
The Human Body releases 1 – 1.5L of saliva per day from glands in your cheeks (salivary glands)
Saliva converts Carbohydrates into simple sugars like Glucose.
GlucoseSlide10
Chemical Digestion
Saliva also contains mucus and water which makes food easier to swallow. Slide11
Chewing Crackers Activity – Part 1
Put a regular cracker into your mouth and chew
What did it taste like?
Sweet? Plain? Record your observationsSlide12
Chewing Crackers Part 2 – Record your observations
What it feels like initially in your mouth
- Is it sweet/bland?
What is feels like after 1 min. in your mouth
- Is it sweet/bland?
What it feels like after 1.5 min. in your mouth
What it feels like when you chew it
Place a cracker in your mouth and let it sit for 1.5 min. before chewingSlide13
What was the main texture (feeling) difference in your mouth between chewing right away and waiting 1.5 minutes before chowing down?
When the cracker is in your mouth your saliva starts to break it down
get’s softer
Chewing Crackers
DiscussionSlide14
Food enters the esophagus which is a narrow, muscular tube about
25 centimeters long
.
Food is swallowed by voluntary action (you control) of the tongue.
Grab a ruler and have a look
EsophagusSlide15
The Trachea (
Wind Pipe
) and Esophagus are connected: – Why does food not go into lungs?
There is a small flap consisting of
connective tissue which prevents food from entering the trachea when swallowing (Epiglottis).
Esophagus
TracheaSlide16
The wall of the esophagus is made up of two layers of
smooth muscles which push the food down into the stomach
If a person were to swallow while being upside down you could see the muscles in action
.
EsophagusSlide17
Place
your hand over your throat then swallow
- What do you feel?
2
) Turn
to someone next to you.
Have your partner tilt their head up
Watch their neck as they swallow – reverse rolesDemoSlide18
The stomach acts as a
storage place for food as well as a place
of digestion.
It is also described as an elastic “bag” made
of muscle which expands.- It can hold up to 4 L of food!!
StomachSlide19
Chemical Digestion
:
Stomach cells produce acid (
HCl
) which helps break down proteinsThe stomach cells also secrete mucus to protect its lining from the acid.
Sometimes this acid exits the stomach and enter the esophagus
Can lead to heart
burn - Video
StomachSlide20
Mechanical Digestion
: The muscles of the stomach wall contract and expand to
churn food and move it towards the small intestine.
The growling sound you sometimes here is your stomach moving.
This is smooth muscle
StomachSlide21
Bread in bag experiment:
Take 1 piece of bread per two students. Rip in half so each student has ½ of a slice
Obtain a small sandwich bag from the front of the room
Tear your ½ slice of bread into smaller pieces and place it into your sandwich bag
(What does this represent?)
Your teacher will come around now and pour a small amount of juice into the bag
Close your bag and squish the bread with your fingers until all of the pieces are really small
(What does this represent?)Put all of the contents of the bag into the garbage (What does this represent?)Slide22
The small intestine further splits food into smaller pieces.
Most of the nutrients we take in are absorbed in the small intestine.
Small Intestine Video
Blood
Small IntestineSlide23
Receives many digestive enzymes from the pancreas and
liver to help break down food
Moves
food
using
smooth muscle cell contraction
The lining of the intestine secretes protective mucus to protect it from the enzymes Is about 7 m (22 feet 6 inches) long, 2.5 cm (1 inch) in diameter and has a surface area of 250 square meters (2,700 square feet) – the size of a tennis court!
Small IntestineSlide24
Sometimes
called the
Colon.
Its function is to
absorb water and vitamins from the remaining
food.
Also stores
the remains of the food that cannot be absorbed (wastes) before they are flushed from the body. About 1.5 m (5 feet) long and 6.5 cm (2.5 inches) in diameter
Called the large intestine because it
has a much larger
diameter than the small intestine
Large IntestineSlide25
The rectum
acts as a temporary storage facility for feces
before it is excreted from the body.
Uranus
RectumSlide26
The Liver, Pancreas, and Gall Bladder all help with the digestion by
supplying digestive enzymes.
The Liver also produces
bile which helps digest fats
These substances are delivered into the
Small Intestine
Accessory OrgansSlide27
Produces
bile which is stored in the gall bladder.
Bile
is then sent to the small intestine to break down fats.
Gall Bladder
LiverSlide28
Is involved
in supplying enzymes required for digestion directly into the small
intestine.
Secretes
a hormone called insulin directly into the blood stream.
Insulin causes most of the body's cells to
take up circulating glucose (cell food) from the blood
. If insulin is not used effectively, diabetes can result.
Insulin Video
PancreasSlide29
Review and Revisit
Name that Digestive System Organ
1)
Liver
2) Esophagus 3) Stomach 4) Pancreas
5)
Small Intestine
6) Large Intestine 7) Rectum 1
2
3
7
5
6
4Slide30
The Human Digestive System Handout Revisited
What do you already know?
Complete the Digestive System Handout to the best of your ability without looking in any text or your notes.
Complete the bottom section using information from this Power PointSlide31
Excellent Digestive System Interactive Activities – Please Click to Visit