Digestion of Carbs, etc.pdf - Mrs Stovel

Figure B-59 THE DIGESTION OF CARBOHYDRATES
polysaccharides
salivary
amylase
breaks up long
chain starch
molecules
small
intestine +
pancreatic
enzymes
maltase
maltose sucrose lactose
disaccharides
I
00 00 00
glucose glucose glucose fructose glucose galactose
CH,OH
O
OH
OH
-
CH,OH
I
ON
O
dehydration
synthesis
maltase
OH hydrolysis
OH
CH2OH
CH,OH
OH
OH
glucose + glucose

Figure B-61 THE DIGESTION OF PROTEINS
pepsin pepsin
polypeptides
peptone
protease
pepsin breaks complex protein chains into shorter lengths called peptones and proteoses
1small intestine
!yn
trypsin
7
chymotrypsin
dipeptides
eatic
_
trypsin and other peptidases break peptones and proteoses into single or double amino acid units'
Lend products
for absorption
Q

Figure B-60 THE DIGESTION OF FATS
liver
produces bile
emulsification
fat droplets
rpancreas
produces
lipase
H2O
glycerol
fat molecules
end products
of digestion
glycerol and fatty acids
H
H--C Q^ h_BO----`CQ Ca7Hac
// dehydration
synthesis
H -C^ ------%-C„H, lipase
H--,C H _ _C-C,7H, hydrolysis
H -Cf 0 -`^- C C, 7 a, + H,0
1 //
H--C---0-C© C17H, ± H2O
//
H-C--Q C- ----C,H,5 + Hr0
H
glycerol -3-stearic acid tristearin

Figure 13.11.
The liver, gall bladder,
pancreas, small intestines, and
the ducts which deliver bile and
pancreatic juices to the
duodenum.
Small
^tfst(1
Figure 24.16 Fat Digestion:
Emulsification , Fat Absorption,
Bile Salt Recycling. This diagram
shows how a fat globule
floating along in the small intestine
after a meal is emulsified by
bile salts. Bile salts are produced
in the liver, stored in the
gallbladder, and passed down
the bile duct. From fat globules,
bile salts help remove small
groups of lipid molecules. which
in turn pass into cells lining the
intestinal wall. The small group
of lipid molecules becomes
coated with protein and enters
the lymph and eventually the
blood circulation, and the bile
salts are recycled and stored
once again in the gallbladder.
rats to
lymph to
E arty use

a 12.21 The action of some
major pancreatic enzymes
Nuftiem k Product of
Psrtleie Enzyme D19*01on
t --- --- ws
Maltose
o-a
Dextrin
i►a
Pancreatic Arnytase
Sucrose
Lactose
Trypsin or Chymotrypsin
A ^Ik1A A
Proteose
Protein
Peptone
sAA
Proteose
Ot
*4,4,,k
Peptone
Trypntn or Chymatrypsin
A
Dipeptide
Key
i
Pancreatic Lipase
E and n
n
r Monosacr haride
A Amino Acid
Emulsified Fat
Glycerol
Fatty
Acids
E Gtycsro€
• Fatty Acid

Nutrient
lntermec€iate Products of Digestion
Key
• Monosaccharide
A Ammo Acid
E
Glycerol
8 Fatty Acid
Final Products
of Cigestion
Polysaccharide
Salivary
Amylase
and
Pancreatic
Amylase
r-i
Intestinal
Maltase
• •
Maltose Intestinal Glucose Glucose
Sucrose
Sucrose Intestinal Glucose Fructose
Lactase
ems---+ --+ • •
Lactose
Glucose Galactose
Disaccrtarides
Monosaccharides
Protein
PepsineR
Pancreatic
Enzymes
Proteossa
A
Eaeotones
Pancreatic
Enzymes
Dipeatide
Pancreatic
And Intestinal
Enzymes
A
Amino Acids
Ell
0
Bile
(Phys4cal Emulsification
into Smaller Particles)
Pancreatic Lipase
Glycerol
Fatty
Rcids
Fat
Figure 2.7
Chemical digestion of major nutrients into absorbable end products.

3. ABSORPTION
There are 2 types of absorption that occur in the digestive system. One is the absorption of
nutrients (the small molecular end-products of digestion, as well as vitamins, minerals and water)
which occurs in the small intestine and the other is the absorption of the large quantities of water
that is part of the leftover food/waste material which occurs in the large intestine.
A. ABSORPTION IN THE SMALL INTESTINE
Once all of the food material has been broken down into small absorbable molecules, it can be sent
to the blood stream and the blood will deliver the nutrients to all body cells.
The increased amount of surface area (in the lumen, or interior lining of the SI) that is created by
the villi and microvilli means that the amount of surface which has the ability to absorb the
nutrients will also be increased.
More absorptive surface means that nutrient uptake by the blood will occur faster.
Each villus (singular of villi) contains: (also refer to the diagrams)
• A capillary network - these are very small blood vessels which are able to absorb
monosaccharides, amino acids and nucleotides.
• A lacteal - these are small lymph vessels which absorb fatty acids and glycerol
• Mucus cells - these provide lubricant to the lumen(interior cavity) of the SI.
• Microvilli -- these are microscopic finger-like projections which further increase the
surface area for greater absorptive capacity
Most, but not all, nutrients are absorbed as they pass through the Si.
ABSORPTION IN THE LARGE INTESTINE (COLON)
"Leftovers" (undigested food) from the ST enter the LI through the ileocaecal sphincter.
There are 3 sections: ascending cold
ansverse colon and descending colon.
The main. function of the LI/colon is to re-absorb water from the leftovers. This is an effort to
conserve water and compact the now "waste" material so that it can be stored in the lowest and
last portion of the LI, called the rectum.
Waste food materials are called FECES. Feces are excreted from the rectum through the anal
sphincter (anus) by a process known as defecation.

OTHER THINGS TONOTE:
• E. coli bacteria living in the LI help breakdown and soften waste material
• E. coli also produce vitamin B and K from fibre (cellulose)
• Fibre is not a nutrient due to the fact that we do not possess the enzymes that are necessary for
its digestion.
Fibre is however, considered to be a very important component in our diet. Fibre acts like a
sponge in the LI, allowing the feces to hold on to some water and thus allow it to stay soft
(prevents constipation). Fibre also serves as a "scrub brush" to clean the intestines as its rough
surfaces pass along the lining of the intestines. This is thought to help prevent cancer. Also,
fibre adds bulk to the waste material both by its own presence and by the fact that it holds on
to water. This added bulk serves to raise the level of peristalsis that occurs in the intestines
and to "speed up" the conveyor belt. This means that materials can be moved to the site of
removal quicker and this is also thought to have a roll both in the prevention of constipation
and in the prevention of cancer.
• Exlax is a laxative. Laxatives are chemicals/drugs which increase the rate of peristalsis.
Increased peristaltic action means that materials pass through the digestive tract at a faster rate.
The faster rate prevents both digestion and absorption of both food and water from occurring
at their normal rates. As a result, the feces pass through the system in approximately the same
liquid state as chyme.
• Other chemicals/drugs can also affect the digestive process, as can environmental influences
such as stress, infections (flu viruses), and the quality of food and water (free from poisons or
pathogens).

Mesentery. A membrane
that supports the ---,
small intestine
and carries
blood vessels, etc. I I k %4 ►\ \ \\\^
The tube of the
small intestine
Mucosa . Muscle layers. Circular
Contains glands. and longitudinal muscles
contract to move the
Villi for absorption food along the tube
by peristalsis.
lining of small
j intestine
A SECTION THROUGH
THE SMALL INTESTINE
arteriole lymph vessel venule leaving
entering
villus
villus

Nutrition : small intestine
05.005
A Section of ileum
8 Part of ileum wall
showing villi
C Villus (vertical section)
1 Circular muscle
2 Ridge coverad with vitti
3 longitudinal muscle
4 Mucosa
% Thin muscle layer
Submucosa
7 Villas
$ Crypt of Lieberkuhn
Arterio4e
It Mucursecretinq cell
11 Epithelium
12 Network of blood
capillaries
13 Lacteal (carrying fatty
acids and gfyceroll
14 Vec uee (carrying amino
acids and
rnonosacchandes )

Organ
(Gland)
Name of the enzyme
that is produced there
Location of
enzyme action
Substrate that the
enzyme acts on
Product(s) that
is/are rode ed
Salivary
Glands 1 )
Gastric 1}
Glands
2 )
Crypts of 1)
Lieberkuhn
2)
3)
4)
5)
6)
7)
Pancreas 1)
2)
3}
4)
5}
6)
7)
8)-
9)
to }

Food group being digested
Name of an enzyme that
digests that type of food
I Where the enzyme is made
CARBOHYDRATES
1).
3)
FATS/LIPIDS I)
PROTEINS
I)-
2)
31
S)
6)
NUCLEIC ACIDS 1 1)

Biology. 30, --Digestion video
1. Crawfishes' teeth are located in their
2. The amoeba engulfs an entire food particle. It does
this by .
3. Humans eat everything; plants and meat. We are
called
4. All animals this in common--they must
5. Lipids break down into and
.
6. Digestion requires chemicals called
7. Lipases break down or
8. Egestion means
9. One organ of the digestive system is the
10. and control digestion.
1 1 . Saliva begins the chemical breakdown of
molecules in the mouth.
12. Food is chewed, pushed to the back of the mouth,
and down the .
13. Muscle contractions are also called
14. An is used to see what is going on in
the digestive system.

15. Pepsinogen, once activated by hydrochloric acid, is
called
16. Gastric juice dissolved a strip of beef in
0.25 h/0.50 h/1.0 h/1.5 h.
17. The stomach walls are protected from stomach acid
by a
lining.
18. Secretion of is controlled by nerves
and hormones.
19. Food is finished being digested in the
20. The small intestine is long.
21. stimulates the pancreas to release
pancreatic juice.
22. Bile emulsifies fat and is stored in the
23. The inner surface of the small intestine is lined
with
24. The small intestine is long.
25. The villi function to increase
.
26. Fat is absorbed the same way as proteins and
simple sugars; T/F
27. The blood carries food to the liver, which acts as a
28. live inside the colon.
29. Water is removed from/added to the colon.
30. The large intestine is long.