It contains the complete overview of the human digestive system.

2. DIGESTIVE SYSTEM AND BMR
PRESENTATION BY:
USMANKHALID
AND
MUHAMMADWASEEM

3. TODAY YOU WILL HERE ABOUT

4. THE SYSTEM OF ORGANS
RESPONSIBLE FOR
GETTING FOOD INTO AND
OUT OF THE BODY AND
FOR MAKING USE OF FOOD
TO KEEP THE BODY
HEALTHY.
The Digestive System

5. Phases of Digestion

6. Digestion
Mechanical
Changes the physical form of food
 Chew
 Tear
 Grind
 Mash
 Mix
We eat about 500kg of food per
year

7. Digestion
Chemical
 Changes the chemical composition of food with the aid of
digestive enzymes
 Lipids to fatty acids
 Proteins to individual amino acids
 Carbohydrates into simple sugars
 Digestive enzymes are proteins that act as catalysts within
living cells.
 Catalysts increase the rate at which chemical reactions occur
without being consumed.

8. The Digestive Tract
a.k.a GI Track
A long muscular tube
with many sections and
areas.
Begins with the mouth
and ends with the anus.
GI tract is about 9
meters (30 feet) long
It takes the GI tract 1-3
days to eliminate the
ingested food

9. The Digestive Tract

10. Mouth
Functions:
 Food enters in the mouth or oral cavity
 Tasting
 Mechanical breakdown of food (mastication)
 Mastication takes 20 seconds
 Secretion of salivary glands (salivary amylase)
 Amylase begins the breakdown of starches
 Salivary glands produce about 1.5 L per day of saliva
 Saliva contains 99.5% water and 0.5% solute
 In the mouth, food is either cooled or warmed to a more
suitable temperature

11. Mouth
 Tongue
 Mixes and rolls food into tiny
mashed up bits (Bolus)
 Pushes the bolus toward the
pharynx and into the esophagus
when swallowing.

12. Anatomy of the Mouth and Throat

13. Esophagus
A straight muscular tube that is about 10 inches
(25 cm) long which connects the mouth with the
stomach
Food takes about 4 to 8 seconds as it passes
through to the stomach.
Its walls contain smooth muscles that contracts
in wavy motion (Peristalsis) that pushes the
food towards stomach
food would get to a person's stomach, even if
they were standing on their head
 Acid from stomach gets in here that’s heartburn

14. Peristalsis

15. Stomach
J-shaped muscular sac which is 25 cm long
Churns and grinds together the bolus into smaller
pieces.
Food is mixed with gastric juices (hydrochloric
acid and enzymes) secreted by the stomach walls.
The stomach’s volume can range from 0.5 liters
when empty to up to 6 liters
It takes between 1-4 hours to empty

16. Stomach

17. Stomach
HCL -helps break down food, kills
bacteria and helps pepsin work properly
Pepsin – major enzyme; converts proteins
into peptides in the presence of HCL.
Mucus – lubricates food and protects the
stomach from strong acids.
Converts the bolus into a liquid called
(chyme) after 4 hrs of mechanical and
chemical digestion
Chyme passes into the small intestine.

18. Movements in Stomach

19. Small Intestine
Site of greatest amount of digestion and absorption
6 meters Long (20 ft), coiled tube beneath the stomach
Takes about 4 – 8 hrs to complete its journey
Where the pancreatic enzymes and bile (from liver) are added
Digested nutrients are absorbed through intestinal
walls
Has folded inner walls covered with fingerlike projections (villi;
sing. – villus) that absorbs digested food
Peristalsis moves the undigested food to the large intestine
An adult female’s small intestine is longer than the average adult
male’s
Surface area almost 2,700 square feet — the size of a tennis court

20. Large Intestine
a.k.a. Colon
Larger diameter, but shorter (5 ft)
Water and minerals are absorbed
from the undigested food
Waste stays for 10 – 12 hours.
400 different species of bacteria in
colon

21. Large Intestine

22. Large Intestine
Rectum
 Waste is pushed into the expanded portion (15 cm) of
the large intestine.
 Solid waste stays in the rectum until it is excreted
through the anus as feces.
Anus
 Is muscular ring that controls ejection
 Every day 12 liters of digested food flow through the
digestive system, but only 100 mls is lost in feces
Appendix
 Hangs on the right side of the large intestine.

23. Accessory Organs
Produce or store enzymes that helps in digestion
LIVER
 Largest gland of the body 1.5 kg
 500 different functions
 Stores vitamins A,D,E,K
 Produces bile
watery, greenish substance that emulsify
(separate)FATS
 Secretes bile to the gall bladder
 Processes nutrients in blood
 Filters out toxin waste
 Called body’s energy factory
 Contains 10% of body blood
 Pumps 1.4 liters of blood per minute

24. Accessory Organs
Gall bladder
 Stores bile in between meals
 Secretes bile to the SI through the bile
duct during mealtime.
 Bile is an emulsifier NOT an enzyme.
 Emulsification is the first preparation
of fat for chemical digestion
 fatty diet can cause gallstones

25. Accessory Organs
Pancreas
 Produces a juice that contains
enzymes (amylase) to break down
carbohydrates, fats and protein and
regulates blood sugar (insulin)
 Secretes the juice into the SI
through the pancreatic duct.

26. Sites of nutrition absorption

28. Websites and reference
Professor Steven Dion, Teresa Ward & Kelly Baker
Salem State College - Sport, Fitness and Leisure Studies
Dept
http://www.medtropolis.com/VBody.asp
http://www.innerbody.com/htm/body.html
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digest
ion/smallgut/anatomy.html
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages
/F/FramesVersion.html
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digest
ion/basics/index.html
http://www.bartelby.com/107/241.html

29. Basal Metabolic Rate
MetabolismMetabolism is the sum of all the chemical and physicalis the sum of all the chemical and physical
processes that occurs in organisms in order to maintain lifeprocesses that occurs in organisms in order to maintain life
 Breathing, blood circulation and nerve functionBreathing, blood circulation and nerve function
 CatabolismCatabolism -- The metabolic breakdown of complex molecules
into simpler ones, often resulting in a release of energy.
 Ex: glucose for energy, burning fat, breaking down tissue (aging)
 AnabolismAnabolism- the phase of metabolism in which simple- the phase of metabolism in which simple
substances are synthesized or built up into the more complexsubstances are synthesized or built up into the more complex
materials of living tissuematerials of living tissue
 Ex:Ex: formation of protein from amino acids, storing energy,formation of protein from amino acids, storing energy,
building muscle or tissuebuilding muscle or tissue

31. Calories
The energy obtained from carbohydrates, proteins
and fats are measured in units called calories
The amount of energy released when nutrients are
broken down is measured in units called calories
The energy needed to raise the temperature of 1
gram of water through 1 °C (now usually defined as
4.1868 joules)
The energy needed to raise the temperature of 1 Kg
of water through 1 °C is called kilocalories
 Fats = 9 calories/gm
 protein= 4 calories/gm
 carbohydrates = 4 calories/gm

32. Basal Metabolic Rate
BMR is a measure of the rate at which a person's
body "burns" energy, in the form of calories, while at
rest
The energy required by an individual during
physical, emotional and digestive rest
It the minimum energy required to sustain vital
functions like working of heart, brain, circulation,
respiration etc

33. Factors affecting BMR
Age: BMR decreases with aging. Its higher in children
Sex: Females have less BMR than men due to more body
fats and less lean mass
Climate: In colder regions BMR is higher and in tropical
regions BMR is lower.
Race: higher in Eskimos, lower in Asians
Body Temperature: With a rise in body temperature by
each degree F, BMR increases by 7%.
Diet: Vegetarians have 11% less BMR than meat eaters.
BMR falls after prolonged starvation.

34. Factors affecting BMR
Sleep: The greater relaxation of muscles during sleep than
during walking time decreases BMR by about 10%.
Pregnancy: BMR is increased in pregnancy during the
third trimester.
Exercise : Individual who habitually indulge in muscular
exercise e.g. athletes and laborers have higher BMR than
sedentary workers.
Drugs: caffeine, nicotine and Benzedrine increase the
BMR.
Health: Fever, illness, or injury may increase resting
metabolic rate
Body surface area: Body composition

35. Factors affecting BMR

36. BMR Harris-Benedict equation
The Harris–Benedict equation was produced by
James Harris and Francis Benedict, which was
published in 1919 by the Carnegie Institution of
Washington
BMR for men
 66+( 13.7×weight in kg )+(5×height in cm)–(6.8×age in years )
BMR for women
 655+(9.6×weight in kg)+(1.8×height in cm)–(4.7×age in years )
Example: You are a 30 year old female. You are 5'6" tall
(167.6 cm) and weigh 120 pounds (54.5 kg). Your BMR =
655 + 523 + 302 - 141 = 1339 calories/day.

37. Activity Multiplier
Sedentary = BMR x 1.2 (little or no exercise, desk job)
Lightly active = BMR x 1.375 (light exercise/ sports 1-3
days/week)
Moderately active = BMR x 1.55 (moderate exercise/
sports 6-7 days/week)
Very active = BMR x 1.725 (hard exercise every day, or
exercising 2 xs/day)
Extra active = BMR x 1.9 (hard exercise 2 or more times
per day, or training for marathon, or triathlon, etc.

38. Total Daily Energy Expenditure
[TDEE]
Example:
Your BMR is 1339 calories per day activity level is
moderately active (work out 3-4 times per
week). Your activity factor is 1.55 and your TDEE
is 1.55 x 1339 = 2075 calories per day. This is
the total calories you could eat everyday if you
wanted to maintain your weight.
TDEE is the total number of calories that your
body expends in 24 hours, including all activities