digested The nutrients are then absorbed into the bloodstream and taken to the cells where they can be used Four Digestion processes Ingestion Digestion Absorption Egestion Overview ID: 574350
Download Presentation The PPT/PDF document "Before the body can make use of the food..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Before the body can make use of the food you eat, the food has to be broken down to release the nutrients (digested).The nutrients are then absorbed into the bloodstream and taken to the cells where they can be used.Four Digestion processesIngestionDigestionAbsorptionEgestionSlide2
Overview!Slide3
Not All food needs digesting!Simple sugars, water, vitamins & minerals are small molecules and can be absorbed as they are – they do not need to be digested!Where & HOW does absorption take place…?Slide4
Food groupMechanical -Teeth / stomach…Specific enzymes do their bit…End product & absorbed where… ?Slide5
Main regions of the alimentary canal and associated organs
Mechanical
Digestion?
Chemical
Digestion?Slide6
Is the breaking-up of food into small soluble pieces.Food in the stomach is mixed up and stored (turned into a soup-like liquid)Stomach cells make enzymes (Pepsin) and hydrochloric acid
are released to aid digestion
Digestion
This acid also kills
bacteria present
in food.
Stomach – bag with lots of muscle in its walls…
Food held ~ 1-4 hours, liquids ~ a few minutesSlide7
Food is then slowly released into the
small intestine
(gut
) where
most of the digestion happens.
First part –
Duodenum
Where pancreas & bile fluids added joinsSlide8
Small intestine ~ 6 meters longSlide9
Gall bladder stores bile
In the
duodenum
(enzymes ~ amylase, trypsin, lipase)
from
the pancreas are added and
bile
which is made in the liver is also added.
The bile helps to
neutralize the acid
from the stomach and also helps to
break the fat
into little droplets.Slide10
Absorption: the movement of digested food molecules through the wall of the intestine into the blood Slide11
Is when food nutrients
pass
through
the gut wall and into the blood stream.
The lining of the small intestine is folded and has little finger-like projections called
villi
which increase the area for absorption.
Absorption
The
surface is
only one cell thick
which speeds up the absorption of nutrients
.
Cells covering the villi make enzymes
eg
Lactase (breaks down lactose in milk)Slide12
Discussion
:
What is the
small intestine
for?
Why are there villi on the inner surface of the
small intestine
?
By this stage most carbs – broken to simple sugars, proteins
to amino acids and fats to fatty acids & glycerol Slide13
What about the Liver?Blood from the digestive system must first filter through the liver before it travels anywhere else in the body. The principal roles of the liver include removing toxins from the body, processing food nutrients and helping to regulate body
metabolism (how your body gets its energy). Also produces bile…Slide14
In the Large Intestine (colon & Rectum), water and any remaining minerals are absorbedWhat is left consists of remnants of fibre, other undigested material and bacteria.
Egestion
The remains are formed into solid wastes (
faeces
/
poo
) and stored in
rectum
.
They are removed from the body through the
anus
.Slide15