2. • We need food for energy.
Our body uses energy to function.
3. • When we exercise additional energy is needed.
– This energy initially comes from
carbohydrates.
– When our carbohydrates run out the body
uses fats.
4. • We also need food for
growht and repair.
And to be healthy.
5.
6. Why do we need vitamins and
minerals?
• Why do we need
minerals?
• We need Calcium for bones
• We need Iron in order that red
blood cells will be able to
transport oxygen and CO2
• We need Fluorine for healthy
teeth
• We need common salt
(sodium chloride) for
physiological processes in
cells
• We need Potassium for
kidney functions
• Why do we need
vitamins?
• If you don’t have enough
vitamins, you can suffer from :
• Vit. A : unhealthy skin, poor
night vision
• Vit. B: Retardeed growth,
and a deficience disease
called beri-beri
• Vit. C: scurvy (escorbuto)
• Vit. D: rickets (raquitismo)
8. Why do we need water?Why do we need water?
• In our cells, chemical reactions take place
in water
• Waste chemicals are diluted in water in
our body in order to be passed out of our
bodies
• Blood transport substances are dissolved
in water
9. The main function of fibre is to keep the digestive system healthy
and functioning properly. Fibre aids and speeds up the excretion
of waste and toxins from the body, preventing constipation.
No.
To digest fibre, the enzyme cellulase must be present to break down cellulose,
which compose the cell wall. In our digestive system, we can't synthesis this
enzyme. Thus, we can't digest fibre.
http://www.helpwithcooking.com/nutrition-information/dietary-fibre.htm
http://answers.yahoo.com/question/index?qid=20070827021030AA78Smu
l
b)b)
a)a)
Guess the questionsGuess the questions
10. The main function of fibre is to keep the digestive system healthy
and functioning properly. Fibre aids and speeds up the excretion
of waste and toxins from the body, preventing constipation.
Can we digest fibre?
No.
To digest fibre, the enzyme cellulase must be present to break down cellulose,
which compose the cell wall. In our digestive system, we can't synthesis this
enzyme. Thus, we can't digest fibre.
http://www.helpwithcooking.com/nutrition-information/dietary-fibre.htm
http://answers.yahoo.com/question/index?qid=20070827021030AA78Smu
l
b)b)
a)a)
Guess the questionsGuess the questions
11. What is the function of fibre?
The main function of fibre is to keep the digestive system healthy
and functioning properly. Fibre aids and speeds up the excretion
of waste and toxins from the body, preventing constipation.
Can we digest fibre?
No.
To digest fibre, the enzyme cellulase must be present to break down cellulose,
which compose the cell wall. In our digestive system, we can't synthesis this
enzyme. Thus, we can't digest fibre.
http://www.helpwithcooking.com/nutrition-information/dietary-fibre.htm
http://answers.yahoo.com/question/index?qid=20070827021030AA78Smu
l
b)b)
a)a)
Guess the questionsGuess the questions
20. Excess of fat in adiposeExcess of fat in adipose
tissuestissues
Levels have been rising sinceLevels have been rising since
the 1980sthe 1980s
1 in 4 Americans is now obese1 in 4 Americans is now obese
Possible reasons for the risePossible reasons for the rise
-Increased portion sizes-Increased portion sizes
-Increased intake of refined-Increased intake of refined
carbohydrates (may alsocarbohydrates (may also
be implicated in rising ratesbe implicated in rising rates
of diabetes)of diabetes)
Obesity
21.
22. Digestion
• Digestion is the breakdown of large food
molecules into small food mollecules in
the digestive system, so that they can be
absorbed into the bloodstream and
carried to every cell of the body.
23. Digestive system
• Digestive truct
• Glands
Esophagus
Stomach
Small intestines
Large intestines
Rectum and anus
Salivary glands
Liver
Gallbladder
Pancreas
24. Path of FoodMouth--chewing
Pharynx--conscious swallowing
Esophagus--transport to stomach
Stomach--mechanical
and chemical breakdown
Small Intestines--
chemical digestion and absorption
Large Intestines--
resorb water, form feces
Rectum---collect and expel feces
25.
26.
27. MOUTHMOUTH
MechanicalMechanical and
chemical digestionchemical digestion
start in the mouth.mouth.
http://www.passmyexams.co.uk/GCSE/biology/digestive_system.html
Saliva contains the enzyme amylase ( it breaks down starch into sugar).
Saliva also contains mucus which lubricates the food and helps it pass down the oesophagus.
28. PeristalsisPeristalsis
The oesophagus has circular muscles in the wall.
These muscles contract behind the bolus to push it
along and the muscles in front of the food relax.
This way food passes along the oesophagus to
thestomach. This movement is known as
peristalsisperistalsis.
http://www.passmyexams.co.uk/GCSE/biology/digestive_system.html
30. STOMACH FUNCTION
– Protein breakdown--
pepsin secreted by
epithelial lining
– Acidic conditions--for
pepsin to work and to
kill bacteria
–Mechanical and chemical
breakdown of food
gastric juices
gastric juices
The gastric juices contain protease enzymes and hydrochloric acid
33. INTESTINES
• Small Intestine
• Large Intestines Resorption of water
Absorption of
nutrientsDuodenum / Jejunum / Ileum
CecumCecum,, coloncolon,, rectumrectum andand anal canalanal canal..
thethe ascending colonascending colon, the, the transverse colontransverse colon, the, the descending colondescending colon, and the, and the sigmoid colonsigmoid colon..
34. Small Intestine:
Modifications for absorption
Transverse ridges of mucosa
Increase surface area
Microvilli:
Increase surface a
Modifications
decrease distally
Villi
Move chyme, increase contact
Length
Increase surface area
36. Interesting Facts about the
Digestive System…•We eat about 500kg of food per year.
•We produce 1.7 litres of saliva each day.
•In the mouth, food is either cooled or warmed to a more suitable temperature.
•The oesophagus is approximately 25cm long.
•Muscles contract in waves to move the food down the esophageus. This means that food would get to a
person's stomach, even if they were standing on their head.
•An adults stomach can hold approximately 1.5 litres of material and produces about 2.5 litres of gastric juice
everyday.
•In an average person, it takes 8 seconds for food to travel down the food pipe, 3-5 hours in small intestine and
3-4 days in the large intestine.
•The human body takes 6 hours to digest a high fat meal and takes 2 hours for a carbohydrate meal.
•Every day 11.5 litres of digested food, liquids and digestive juices flow through the digestive system, but only
100mls is lost in faeces.
•Most of us pass somewhere between 200 and 2,000 ml of gas per day. These emissions are composed of five
gasses: nitrogen (N2), oxygen (O2), carbon dioxide (CO2), hydrogen (H2), and methane (CH4).
37. Overview of the Digestive System 1
- the first part of the digestive system, where food enters the body. Chewing and salivary enzymes
in the mouth are the beginning of the digestive process (breaking down the food).
- glands located in the mouth that produce saliva. Saliva contains enzymes that break down
carbohydrates (starch) into smaller molecules.
- the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called
peristalsis) to force food from the throat into the stomach.
- rhythmic muscle movements that force food in the esophagus from the throat into the stomach.
Peristalsis is involuntary - you cannot control it. It is also what allows you to eat and drink while
upside-down.
- a large organ located above and in front of the stomach. It filters toxins from the blood, and makes
bile (which breaks down fats) and some blood proteins.
- a sack-like, muscular organ that is attached to the esophagus. Both chemical and mechanical
digestion takes place in the stomach. When food enters the stomach, it is churned in a bath of
acids and enzymes.
Salivary glands / Stomach / Mouth / Esophageus / Peristalsis / Liver
12 3 4 56
38. Overview of the Digestive System 1
- the first part of the digestive system, where food enters the body. Chewing and salivary enzymes
in the mouth are the beginning of the digestive process (breaking down the food).
- glands located in the mouth that produce saliva. Saliva contains enzymes that break down
carbohydrates (starch) into smaller molecules.
- the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called
peristalsis) to force food from the throat into the stomach.
- rhythmic muscle movements that force food in the esophagus from the throat into the stomach.
Peristalsis is involuntary - you cannot control it. It is also what allows you to eat and drink while
upside-down.
- a large organ located above and in front of the stomach. It filters toxins from the blood, and makes
bile (which breaks down fats) and some blood proteins.
- a sack-like, muscular organ that is attached to the esophagus. Both chemical and mechanical
digestion takes place in the stomach. When food enters the stomach, it is churned in a bath of
acids and enzymes.
Salivary glands / Stomach / Mouth / Esophageus / Peristalsis / Liver
1
3
2
4
5
6
12 3 4 56
39. Overview of the Digestive System 2
- food in the stomach that is partly digested and mixed with stomach acids. It goes on to the small
intestine for further digestion.
- a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical
which is produced in the liver) into the small intestine.
- a digestive chemical that is produced in the liver, stored in the gall bladder, and secreted into the
small intestine.
- an enzyme-producing gland located below the stomach and above the intestines. Enzymes from
the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine.
- the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum.
1 2 34 5Pancreas / Duodenum / Chyme / Gall bladder / Bile
40. Overview of the Digestive System 2
- food in the stomach that is partly digested and mixed with stomach acids. It goes on to the small
intestine for further digestion.
- a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical
which is produced in the liver) into the small intestine.
- a digestive chemical that is produced in the liver, stored in the gall bladder, and secreted into the
small intestine.
- an enzyme-producing gland located below the stomach and above the intestines. Enzymes from
the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine.
- the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum.
1 2 34 5Pancreas / Duodenum / Chyme / Gall bladder / Bile
1
3
2
4
5
43. Overview of the Digestive
System
Ileum - the last part of the small intestine before the large intestine begins.
Cecum - the first part of the large intestine; the appendix is connected to the cecum.
Appendix - a small sac located on the cecum.
Ascending colon - the part of the large intestine that run upwards; it is located after the cecum.
Transverse colon - the part of the large intestine that runs horizontally across the abdomen.
Descending colon - the part of the large intestine that run downwards after the transverse colon and
before the sigmoid colon.
Sigmoid colon - the part of the large intestine between the descending colon and the rectum.
Rectum - the lower part of the large intestine, where faeces are stored before they are excreted.
Anus - the opening at the end of the digestive system from which faeces (waste) exits the body
44.
45.
46. • We eat about 500kg of food per year.
• We produce 1.7 litres of saliva each day.
• In the mouth, food is either cooled or warmed to a more suitable temperature.
• The oesophagus is approximately 25cm long.
– Muscles contract in waves to move the food down the esophageus. This means that food would get to a person's stomach, even if
they were standing on their head.
• An adults stomach can hold approximately 1.5 litres of material and produces about 2.5 litres of gastric juice
everyday.
• In an average person, it takes 8 seconds for food to travel down the food pipe, 3-5 hours in small intestine and 3-
4 days in the large intestine.
• The human body takes 6 hours to digest a high fat meal and takes 2 hours for a carbohydrate meal.
• Every day 11.5 litres of digested food, liquids and digestive juices flow through the digestive system, but only
100mls is lost in faeces.
• Most of us pass somewhere between 200 and 2,000 ml of gas per day. These emissions are composed of five
gasses: nitrogen (N2), oxygen (O2), carbon dioxide (CO2), hydrogen (H2), and methane (CH4).
