Transcript Slide 1

Chapter 2: Nutrition
Food can divided into seven classes as follows:
Carbohydrates
proteins
fats
vitamins
minerals
fibre
water
Carbohydrate PMR 03 FOOD TEST
made up of
carbon, hydrogen
and oxygen.
•Carbohydrate supplies us with energy to
carry out daily activities such as walking,
breathing, and working.
Protein PMR 04
made up of carbon, hydrogen, oxygen, and nitrogen
•Proteins are required for building new cells for growth, to replace damaged tissue.
Protein @ carbohydrate
Fat
made up for carbon, hydrogen and oxygen but the ratio is different from that of carbohydrate
The function of fat include:
a.
supplying energy,
b.
as and insulator of heat to reduce heat loss from the body,
c.
protecting the internal organs such as the kidneys and the heart,
dissolving some vitamins in the body like vitamin A, D, E and K.
Vitamin
Vitamins are classified into two groups
1.vitamins soluble in water – vitamin B and C ,
2.vitamins soluble in fat- vitamin A, D, E and K.
Vitamin
A
B
Various types of vitamin
Main source
Egg, milk, cod liver, oil,
carrot, papaya
yeast, egg, milk, tomato,
liver, nuts
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-
C
D
E
K
lime, citrus fruits, tomato,
carrot , papaya, green
vegetables
egg, milk, cod liver oil
vegetable oil, palm oil, egg,
liver, milk
maize, sunflower seeds,
tomato, green vegetables
-
Function
for growth and to promote
healthy skin
for good vision
promotes the effective
functioning of the nervous
system
control the supply of
carbohydrates to the muscle
and nerve cells
increase immunity against
disease
promotes healthy skin
- helps in the absorption of
calcium and phosphorus in the
small intestines for the growth
of strong bones and teeth.
- maintains a healthy
reproductive system
- necessary for the clotting of
blood.
•Vitamins are classified into two groups
1.vitamins soluble in water – vitamin B and C ,
2.vitamins soluble in fat- vitamin A, D, E and K.
Effect of deficiency
night blindness
dry and scaly skin
-
-
beri-beri (injury
to the nervous
system and
paralysis)
pellagra
anaemia
scurvy (gusi
merah)
anaemia
low resistance to
infections
(especially the flu)
- rickets (weak and
curved bones)
- tooth decay
- sterility
- infertility
- blood slow to clot
PMR 2011
dieases
pellagra
anemia
ricket
Beri beri
scurvy
Minerals
•minerals are simple chemicals usually found in the body.
•our bodies need more calcium and phosphorus than the minerals.
•(because they help to form strong bones and teeth)
•minerals are needed for good health.
Sources and functions of minerals as well as the effects of mineral deficiencies
effects of
deficiency
* rickets
* brittle bones
and teeth
* poor blood
clotting
Minerals
sources of food
Functions
Calcium
milk, eggs, vegetables,
cheese
* forms strong bones and
teeth
* helps blood to colt
iron
liver,, meat, eggs,
vegetables
iodine
seafood, vegetables,
iodinised salt
* forms haemoglobin in
red the thyroid blood
cells
* produces hormones in
the thyroid gland
sodium
common salt,
* balances body fluid
phosphorus
meat, milk, eggs, beans
* forms strong bones and
teeth
* muscle
cramps
* rickets
* dental decay
fluorine
drinking water, fish,
vegetables
* protect teeth
* Dental decay
potassium
meat, fish, cereals
* maintains a healthy
nervous system
* muscle
cramps
* anaemia
* Goitre
Fibre
•Fibre is made up of cellulose which cannot be digested by the body.
•A shortage of fibre in our daily diet can cause constipation and sometimes
even bowel cancer.
•Vegetables, fruit, beans, lentils and brown bread are examples of food rich
in fibre.
Water
Water is needed by the body for:
1. helping in the digestion of food
2. transporting
digested
food
substances
3. transporting excretory products
such as urea.
4. maintaining the concentration of
blood.
5. maintaining the body temperature
6. all metabolic processes
The importance of a balanced diet
• A balanced diet is one which contains carbohydrates, proteins, fats,
minerals, vitamins, water and fibre in the correct quantities and
proportions.
• A balanced diet is necessary for:
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supplying the required energy
balanced body growth
maintaining the health of the body
preventing deficiency diseases such as scurvy and rickets.
• A balanced diet varies according to one’s
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Age
size
sex
job
climate
state of health
Factors that influence a person’s
needs for a balanced diet
Factors
sex
age
body size
physical
activity
weather
the group requiring more energy
men required more energy compared
to women of the same age and body
size.
babies, children and teenagers require
more energy compared to adults or the
elderly. Example: the heartbeat of
baby is 100 beats a minute compared
to an adult who has 75 beats per
minute.
big-size
individuals
require
more
energy size compared to small-sized
individuals.
Reason
men are more active
this group is more active and
the life processes are faster.
big-sized individuals require
more energy for their life
processes.
an individual who does heavy work uses heavy work requires more
more energy compared to another who energy to perform.
does light work.
more energy is required to
individuals living in places with cold
maintain the body temperature
weather require more energy compared
in a cold place.
to individuals living in places with warm
weather.
The calorific value of food
PMR 06, 07, 11
• The calorific value of food is the amount of
heat energy released when one gram of food
is completely burnt in the air.
• The calorific value of food is measured in
kilojoules per gram (kJ/g) or kilocalories per
gram (kcal/g)
• The calorific value differs for different types of
food. Table below shows the calorific value of
some of the food that we eat daily.
The calorific value of food PMR 06, 07, 11
Kedah 12
FOOD TEST (experiment) PMR 03
Classes of
food
Tester
observation
Glucose
Benedict solution
Fehling Solution
Brick-red precipitate
Heat
Protein
Millon reagent
Brick-red precipitate
Heat
Starch
Iodine solution
Dark blue
No need to heat
Fat
- Filter paper
- Alcohol/ethanol
-Translucent spot
- white-emulsion (cloudy)
- Heat
- No need to heat
Food test
PMR 2011
Kedah 2012
HUMAN DIGESTIVE SYSTEM
• Digestion is the process of breaking down large and complex
food substances into smaller, simpler molecules. These
molecules are soluble and can be absorbed by body cells.
• The process of digestion in the alimentary canal:
a.
physical digestion /mechanical digestion
– involves the mechanical process of breaking down large pieces of food
into smaller particles using the teeth and the churning movements of the
alimentary canal.
• b.
-
chemical digestion
involves the action of various enzymes in breaking down
complex food molecules. These complex molecules are
insoluble but the end products of chemicals digestion are
simpler molecules which are soluble.
Human Digestive
system
mouth
anus
The liver also plays a vital role in excretion. It
removes toxic chemicals from the blood
through a series of chemical reactions.
trakea
perut
pancreas
Usus kecil
Usus besar
Human digestive system….
Try to answer ….
G
A
B
H
I
J
K
L
C
D
E
F
Mouth
• i.
Digestion begins in the mouth.
• ii.
The teeth chew and grind food into
smaller particles.
• the salivary glands secrete glands secrete saliva which
contains an enzyme called amylase.
• Amylase digests starch and converts it to maltose, a
type of sugar.
• The wave-like contractions of the oesophagus muscles
are known as peristalsis.
stomach
• in the stomach, food is mixed with gastric juices.
Gastric
• glands in the stomach wall.
– Gastric juices contains hydrochloric acid and
enzymes (rennin and pepsin) .
– rennin – coagulate milk.
– Pepsin – digest protein into peptone (amino acid)
– The functions of hydrochloric acid include:
• Hydrochloric acid stops the action of the enzymes in saliva.
• It also kills bacteria in food.
– Enzymes in the gastric juices start the digestion of
protein. Example:
•
– Partially digested food is then released into the
duodenum.
small intestine
• The duodenum is the first parts of the small intestine.
bile and pancreatic juice. (bile is
– The duodenum receives
stored in the gall bladder)
– The function of bile:
• Emulsifications of fat i.e. breaking up large fatty globules into small droplets
for enzymic action.
• Preparation of an alkaline medium for enzymic action.
starch into glucose
– The protease digests protein/peptones into amino acids.
– The pancreatic amylase digests
fat
– The lipase digests
into fatty acid and glycerol.
– The small intestine (ileum) produces enzymes which digest maltose
into glucose (simple sugar)
– Digestion is completed in the small intestine.
– The digested food is then ready to be absorbed through the thin walls
of the small intestine into the bloodstream.
PMR 2004
PMR 2005
Selangor 2011
PMR 2011
Absorption of digested food
• The efficiency of absorption of digested food at the
small intestine can be increased by:
• more villus to increase surface area
• villus with very thin walls
• Each villus has a network of a blood capillaries and a
lacteal.
• Glucose, amino acids, minerals and water-solube
vitamins are absorbed into the blood capillaries.
• Fatty acids, glycerol and fat-soluble vitamins (vitamin A,
D, E and K) are absorbed into the lacteal.
Lacteal and blood capillary in villus
•
The efficiency of absorption of digested food at the small intestine can be increased by:
– more villus to increase surface area
•
•
•
•
villus with very thin walls
•
•
•
•
Large of surface area (more villi)
Thin wall (one cell thick)
Moist surface (enable gas to dissolve)
Surrounded by a network of blood capillaries.
Each villus has a network of a blood capillaries and a lacteal.
Glucose, amino acids, minerals and water-solube vitamins are absorbed into the blood
capillaries.
Fatty acids, glycerol and fat-soluble vitamins (vitamin A, D, E and K) are absorbed into the
lacteal.
• Fatty acids, glycerol and fat-soluble vitamins
(vitamin A, D, E and K) are absorbed into the
lacteal.
• Glucose, amino acids, minerals and watersolube vitamins are absorbed into the blood
capillaries.
Resap - difuse
End product of digestion
Class of food
Carbohydrate
s/starch
Protein
Fat
enzyme
Amylase
End product
Glucose
Protease
lipase
Amino acid
Fatty acid &
glycerol
Parts of the digestive tract
parts of the
digestive tract
Mouth
Oesophagus
Stomach PMR
03
Duodenum
small intestine
large intestine
Rectum
Anus
Functions
 chew and grinds food using the teeth
 digests cooked starch. The amylase enzymes in the saliva change
cooked starch to maltose.
 The salivary glands secrete saliva which contains an enzyme
called amylase.
 Amylase digests starch and convert it to maltose (a type of
sugar)
 bolus-shaped food is moved from the mouth to the stomach along
the oesophagus by wave-like muscular contractions called
peristalsis.
 holds food, secretes gastric juices which begin the digestion of
protein
 secretes acids contains hydrochloric acid which kill the bacteria
in food.
 receives bile from the liver and pancreatic juice from the
pancreas.
 Digestion and absorption of food.
 secretes intestinal juice which completes the digestion of
protein, carbohydrates and fat.
 Absorbs end products of digestion into the blood.
 absorption of most of the remaining water and minerals.
 stores faeces
 removes faeces through defecation.
Chemical digestion in human digestive
Part
Mouth
Secretes
Source of secretes
End product
Saliva
Salivary gland
Starch  maltose/glucose
Hydrochloric
acid
Wall of the stomach
Destroy bacteria in food.
Prepare acid medium for
digestion in stomach.
Stomach
Gasteric
juice/jus
gaster
Duodenum
Bile
Liver
Emulsify of fat.
Prepare alkali medium for
digestion in small intestine.
Pancreatic
juice
Pancreas
Starch  maltose/glucose
Protein  peptone/amino acid
Fat  fatty acid & glycerol
Wall of the small
intestine
Maltose  glucose
Peptone  amino acid
Small intestine
Protein  peptone
R&R
PART OF
ALLIMANTARY
CANAL
SECRETED BY
Characteristic of
secretion
MOUTH
SALIVA
Alkaline
STOMACH
GASTER JUICE
Acidic
BILE
Alkaline
PANCREAS
JUICE
DUODENUM
CARBOHYDRATE
Alkaline
PROTEIN
SMALL
INTESTINE
INTESTINE
JUICE
CLASS OF FOOD
INVOLVE
REACTION AND DIGESTION PRODUCT
CARBOHYDRATE
STARCH
MALTOSE
PROTEIN
PEPTONE
PROTEIN
FAT
FAT
DROPS OF FAT
FAT
DROPS OF FAT
FATTY ACID + GLYCEROL
STARCH
STARCH
MALTOSE
PEPTONE
PEPTONE
AMINO ACID
PROTEIN
PEPTONE
AMINO ACID
CARBOHYDRATE
COMPLEX SUGAR
alkaline
SIMPLE SUGAR
Digestion, absorption and use of food in
human beings
nutrients
carbohydrates
proteins
fats
Digestion
Amylase
(mouth, small
intestine)
Protease
(stomach,
small
intestine)
Lipase (small
intestine)
End products
glucose
Amino acids
Fatty acids
and glycerol
diffuse in small
intestine
HEALTHY EATING HABITS
The food pyramid PMR 05, 08
Food Pyramid
Absorption of the products of
digestion
• The inner
surface of the
small intestine (6
metres long)
covered with
millions of small
projections
about 1mm long.
These
projections are
called villi @
villus.
villi
•
The efficiency of
absorption of digested
food at the small
intestine can be
increased by:
• more villus
to increase
surface
area
• villus with
very thin
walls
Visking tube (experiment)
• Visking tube
• Water
temperature
• water
REABSORPTION OF WATER AND
DEFACATION
• Reabsorption of water
• The main function of
big intestine is to
reabsorb water.
• Defecation
• Undigested food in the
big intestine is
expelled as faeces
through the process of
defecation.
Healthy eating habits
• Healthy eating habits will help maintain a
healthy body.
• Unhealthy eating habits cause various health
problems.
1. excessive nutrient
Sugar
Salt
fat/oil
2. lack of nutrient
Protein
Roughage/fiber
Vitamins
health problems
tooth decay, obesity, diabetes
high blood pressure, heart problems, kidney damage
heart problems, high blood pressure
health problems
kwashiorkor in children
Constipation
lower immunity to diseases
Penutup
1. Baca Surah Al-`Ashr
2. Tasbih Kifarah.