Presentation for Junior College students

2. Eliminated  Egestion
Taken in  Ingestion
Breakdown  Digestion
Utilized  Assimilation
Absorbed  Absorption
STEPS

3. Proteins – building blocks
Carbohydrates – respiratory substrate
Minerals – Ca, Na, K, Fe.
Lipids – stored food
Water – 1.5 litres a day
Vitamins – A, B1, B2, B3, B12, C, D, E, K

4. Vitamins & Diseases due to deficiencies
B12(Cobalamine) – Anaemia, Digestive disorders
A(Retinol) – Night blindness, Scaly skin
D(Calciferol) – Rickets, tooth decay
C (Ascorbic acid) – Scurvy (disease of gums)
B1(Thiamine) – Beriberi, nerve disorders
B2(Riboflavin) – Loss of weight, mental confusion
B3(Niacin) – Pellagra, Skin irritation
E (Tocopherol) – Sterility, muscular disorder
K(Phylloquinone) – Bleeder’s disease

5. Carbohydrates
Found in Honey, Fruits etc.
Chemically composed of C, H & O (2:1) & of 3 types
Composed of two molecules of simple sugars
Disaccharides
Monosaccharides
Made up of simple sugars eg. Glucose, Fructose
Eg. Sucrose, Maltose, Lactose
Sucrose = glucose + fructose, Maltose = glucose +
glucose Lactose = glucose + galactose
Sucrose (sugarcane) Maltose (not in free form)
Lactose (milk)

6. Cellulose is present in green vegetables and is
fibrous indigestible food also acts as roughage
Polysaccharides
Glycogen is stored in liver & muscles
Made up of a number of molecules of simple sugars
Eg. Starch, Glycogen, Cellulose
Starch is seen in rice, Jowar, Maize (staple food)
The monomers are joined by glycosidic linkage

7. Proteins
Animal proteins are called complete proteins as
they contain all the essential amino-acids
Chemically composed of C, H, O, N, S & P.
Units are called as aminoacids
Of the 22, 8 are called essential aminoacids
Essential aminoacids cannot be synthesized
Amino acids are joined by Peptide linkages
Peptide linkage

8. Sources of animal proteins are meat, fish, egg,
milk etc.
Unlike Carbohydrates excess Proteins cannot be
stored.
Proteins are used for repair, wear & tear, they also
form enzymes, antibodies, hormones
Excess Proteins are deaminated in liver
Proteins contd……

9. Lipids
Chemically composed of C, H, O
Butter, cream, nuts, meat, fish, yolk contain lipids.
Units are called as Fatty acids & Glycerols
If in liquid form at room temperature then called oils
Normal person requires 10-25%, (Athletes 40%)
Excess fats cause obesity, High blood pressure,
heart diseases
Deficiency causes dry & rough skin
Protects body from shocks & jerks
Forms cell membrane, acts as solvent for vitamins.
Make food tasty & palatable, richest source of
energy.

10.  Ca & P – Development of bones, teeth
Minerals
 Iron – Haemoglobin
 Na, K & Cl- – Osmotic balance
 Iodine – proper functioning of Thyroid
Inorganic substances required in less quantities
They are obtained from common salt, sea food,
leafy vegetables.
Sources of Ca are milk, egg, fish
Lack of Iron leads to anaemia, source of Iron is fish,
meat, tomatoes, cabbage, leafy vegetables
Lack of Iodine leads to goiter, source of Iodine is salt
& sea food.

11. Water
Human body contains 65% of water
Water acts as solvent, keeps body cool

12. A diet which contains all the nutrients in proper
proportion is called a balanced diet.
Malnutrition is inadequate amount of nutrients taken in
the diet.
Over nutrition : Excess amount of nutrients
Balanced diet contains 60-70% carbohydrates, 20-30%
fats, 10-20% proteins
Older people require 2500 calories per day, whereas
children & young people require 3700 calories per day.
Balanced Diet
Malnutrition

13. Digestive System
Mouth
Buccal chamber
Pharynx
Oesophagus
Stomach
Small Intestine
Large Intestine
Anus
Salivary Glands
Alimentary Canal Associated glands
Gastric glands
Pancreas
Liver

14. Ascending
limb Descending
limb
Appendix
Digestive system of man

17. Mouth
Buccal Cavity
Uppermost transverse slit
Side walls are formed of cheeks, roof by palate,
floor by tongue
Bound by upper lip & a lower lip
Leads to large cavity called buccal cavity
It is used to ingest food
Tongue, teeth, salivary glands are present.
Lined internally by mucous membrane

18. Tongue
Muscular, fleshy, triangular with projections -
papillae
Papillae have sensory receptors called taste buds.
Bound by upper lip & a lower lip
Leads to large cavity called buccal cavity
It is used to mix saliva with food & ingest food
It also helps in swallowing & speech.

19. Teeth
32 teeth in adults, made up of root & crown
Crown is made up of hardest substance enamel
Body of the tooth is made up of dentine (bone like)
Beneath it shows cavity containing blood vessels
& nerves
Study of teeth with respect to the number,
arrangement, development etc is known as dentition.
Dentition in humans is heterodont (4 types)
Dental formula is i 2/2, c1/1, pm 2/2, m 3/3
Each jaw has 16 teeth

20. Pharynx
It is the meeting point of digestive & respiratory
systems.
Epiglottis prevents food from entering the
respiratory tract.
Epiglottis is the flap which guards glottis – opening
of respiratory tract.
Pharynx leads to Oesophagus

22. Stomach
Sac like, ‘J’ shaped
muscular organ 25-30 cm
long
It is divided in to
Cardiac, Fundic & Pyloric
parts.
Cardiac Sphincter &
Pyloric Sphincter are
present at both ends
Cardiac sphincter
prevents regurgitation of
food.

23. Pyloric sphincter
regulates passage of food
into duodenum
Stomach stores food &
churns.
Churning breaks the
food into smaller pieces
& facilitates mixing with
gastric juice.
Stomach contd….

24. Small Intestine
6 mts long & 2.5 cm
wide highly coiled tube.
Coils are kept in
position by mesentries
(connective tissue
membrane)
Mesentries also
support blood vessels,
lymph vessels & nerves.
It is divided into
Duodenum, Jejunum &
Ileum.

25. Duodenum – U shaped,
25 cm long, bile duct &
pancreatic duct opens in
duodenum
Jejunum – 2.5 mt long ,
narrower than duodenum
Ileum – 3.5 mt long,
little broader than
jejunum.
Small Intestine contd….

26. Large Intestine
Broader than small
intestine, 1.5 mt long.
It is divided into Colon,
Rectum & Anus
Colon -- made up of
three parts Ascending,
Transverse, Descending
colon.
Internally lined by
mucosa secreting mucus

27. Mucus helps in easy
passage of undigested
food.
Large Intestine contd….
Rectum – Faecal matter
is stored temporarily
Caecum, a blind pouch
is seen at the junction of
ileum & colon
Elongated worm like
appendix arises from
caecum

28. Large Intestine contd….
Appendix is vestigial in
humans
Digests cellulose in
herbivores,
Anus – opening of
rectum, guarded by anal
sphincter
Removes undigested
food by
defecation/egestion.

29. Ascending
limb Descending
limb
Appendix
Digestive system of man

30. Histology of Stomach
Made up of 4 layers
namely
Serosa Muscularis
Sub mucosa Mucosa
Serosa is outermost
protective layer of
squamous epithelium &
connective tissue
Muscularis layer is
made up of three layers

31. It is the thickest and
responsible for churning.
Histology of Stomach contd…
Submucosa contains
blood vessels, lymph
vessels & nerves
Mucosa is innermost
layer made up of
Muscularis mucosa
Lamina Propria
Epithelium

33. Histology of Stomach contd…..
Muscularis mucosa is
formed from longitudinal &
circular muscles
Lamina propria contains
gastric glands
Epithelium is made up
of columnar cells forming
gastric glands.

34. Gastric Glands
Simple, tubular, branched
/ unbranched
They show 3 types of cells
Chief cells/Peptic cells
Parietal cells/Oxyntic cells
Mucous cells
Chief cells are pyramidal,
secrete pepsinogen
Parietal cells are oval,
secrete dil HCl
Mucous cells secrete
mucous

35. Mucosa is innermost
layer shows finger like
projections called villi
Each villus is lined by
columnar epithelium
Cells show microvilli to
increase area for
absorption
Histology of Intestine
Core of the villus has
loose connective tissue.

36. Histology of Intestine
Connective tissue
encloses central lymph
vessel called lacteal
Core also contains
large number of
capillaries.

37. Salivary Glands
Multicellular, three pairs namely
Sub lingual Sub mandibular Parotid
They contain two types of cells namely
Serous cells & Mucous cells
Serous cells produce watery enzyme called Ptyalin
/ Salivary Amylase
Mucous cells produce mucous which binds the food
& makes it slippery to be swallowed easily

38. Liver
Covered by thin
membrane of connective
tissue called Glisson’s
capsule
Made up of hexagonal
units called hepatic
lobules
Between the lobules i.e portal area lie hepatic blood
vessels & bile ducts
Reddish brown below diaphragm, largest gland, 1.2
to 1.5 Kg.

39. Each lobule has central
vein surrounded by
hepatic cells / hepatocytes
in the form of hepatic
cords
Liver contd…
Spaces between the
cords are called sinusoids.
They contain large, amoeboid, phagocytic Kupffer
cells
They ingest toxins, & remove worn out RBC’s
Hepatic cells are polygonal, with distinct nuclei &
granular cytoplasm.

40. Liver contd…..
Cytoplasm stores glycogen & fat droplets , cells
secrete bile.
Bile capillaries carry Bile to Bile ducts which further
carry it to hepatic duct which finally deposits it in gall
bladder

42. Functions
Secrete bile which emulsifies fats
Stores excess of glucose
Excess of proteins are deaminated & urea is formed
Synthesizes vitamins A, D, K, B12
Forms proteins Prothrombin & Fibrinigen
Produces RBC’s (haemopoiesis) in early developmental
stages
Digests worn out RBC’s

43. Pancreas
Leaf shaped, lies
between gap of duodenum
& stomach
Some part is endocrine
& some is exocrine hence
mixed gland.
Exocrine part is made
up of flask shaped lobules
called acini
Acini are made up of
single layered pyramidal
cells.

44. Pancreas contd…..
Acini secrete alkaline pancreatic juice
Common Bile duct joins with pancreatic duct to form
hepato-pancreatic duct & opens in duodenum.
It is guarded by sphincter of Oddi

45. Delta cells secrete
somatostatin hormone
which decreases the
secretion of Glucagon &
Insulin.
These hormones control
the blood sugar level
Pancreas contd…..
Endocrine part is made up of groups of cells called
as islets of Langerhans
They are made up of A or Alpha and B or Beta cells
A cells secrete Glucagon, B cells secrete Insulin

46. Physiology of Digestion
Carried out by Mechanical and Biochemical Methods
Mastication/chewing, peristalsis, churning brings about
mechanical digestion
Series of catabolic reactions which hydrolyze the food
is called biochemical digestion.
Then food ball called bolus is pushed in Oesophagus
Digestion in Buccal Cavity
Mastication, chewing, mixing with saliva takes place
Tongue mixes food with saliva, moistens and binds.
Due to this food gets paste like consistency
This process is called as deglutition/swallowing

47. Starch Maltose
Salivary Amylase
pH 6.8
 Saliva contains 98% water & 2% other constituents.
 Other constituents are Na, K, Ca, Chloride,
bicarbonates.
 30% starch is converted into maltose in mouth.
 Lysozyme in saliva is antibacterial agent, prevents
infection.
Digestion in Buccal Cavity
Peristalsis, churning, mixing with Gastric juice.
Digestion in Stomach

48. Gastric Juice contains
HCl– stops activity of amylase
HCl, Mucous, Pepsinogen (inactive ), intrinsic factor
Provides acidic medium
kills germs, Softens food
Pepsinogen Pepsin
Acidic medium
Proteins Proteoses + Peptones
Pepsin
Acidic medium
 Stomach stores food for 4 to 5 hours.

49. Mucous forms protective layer, prevents action of
HCl on the stomach wall
Secretion of gastric juice is controlled by sight, smell
& taste of food.
Food is converted into semi solid mass called chyme
Acidic chyme travels to Duodenum through Pyloric
sphincter.
Digestion in Stomach contd…
Acidic chyme is a semisolid mass
Renin in infants digests caesin from milk.

50. In Duodenum Bile juice & Pancreatic juice are added.
Digestion in Small Intestine
Bile neutralizes acidic chyme
Bile is yellowish green, made up of water, bile
pigments, cholesterol & bile salts
Bile salts like Sodium glycocholate & Sodium
taurochlorate emulsify fats
Pigments are bilirubin, biliverdin produced due to
breakdown of Haemoglobin.
Pancreatic juice has many enzymes, water & Na salts

51. Starch
Digestion in Small Intestine contd…
Lipids
Trypsinogen
Chymotrypsinogen
Maltose
Fatty acids + Glycerols
Trypsin
Chymotrypsin
Intestinal juice contains Enterokinase which brings
about following conversions
Trypsin
Inactive Active
Pancreatic amylase
Alkaline medium
Pancreatic lipase
Alkaline medium
Enterokinase
Alkaline medium

52. Proteins +
Proteoses +
Peptones
Polypeptides
Polypeptides Dipeptides
Digestion in Small Intestine contd…
Trypsin
Chymotrypsin
Maltose
Sucrose
Lactose
Glucose + Fructose
Glucose
Glucose + Galactose
Dipeptides Aminoacids
Emulsified Fats Fatty acids + Glycerols
Maltase
Sucrase
Lactase
Dipeptidases
Lipase
Thus chyme is converted to liquid chyle

53. Diffusion of food in the inner lining of digestive tract is
called absorption
Absorption & Assimilation
Water, salts & glucose is absorbed by stomach wall
Remaining nutrients are absorbed by intestine.
Amino acids are absorbed by blood vessels, fatty
acids & glycerol get absorbed by lymph vessels &
lacteals, lacteals finally open into blood vessels.
Glucose & Fructose is absorbed by blood vessels by
osmosis, diffusion & active absorption.
Absorbed food becomes a part of protoplasm and is
called assimilation.

54. Undigested, unwanted residue is sent to large intestine
Egestion
Water is reabsorbed & semisolid waste faeces is
thrown out.
Nutritional Imbalance
It effects the structure & function of body parts & leads
to diseases called Dietary Deficiency Diseases
Deficiency of nutrient appears as some disorder.
Thus excessive nutrients cause adverse effect on the
body.
Excess animal fats promote cardiovascular diseases
Excessive animal proteins may cause cancer of large
intestine
Excessive vitamins cause adverse effect on the body.

55. PEM – Protein energy malnutrition is caused by
inadequate proteins, vitamins & minerals, reported in
children of growing age.
NUTRITIONAL DISORDERS
KWASHIORKER
Affects infants & children (1 to 3 years)
Loss of apetite
Symptoms
Underweight, Stunted growth
Poor brain development
Anaemia
Protruding belly
Slender legs Bulging eyeballs
Oedema (swelling) of lower legs & face.

56. 1 gm/kg in adults, 2 gm/kg in children
Sources – cereals, fish, meat, milk, groundnuts, peas,
beans, leafy vegetables
It is due to ignorance, poverty & infectious disease
like Diarrhoea, measles, respiratory infections,
intestinal worms.
KWASHIORKER contd…

57. MARASMUS
Prolonged PEM, affects infants under one year
Deficiency of all the nutrients, due to replacement of
mothers milk too early by low protein food
Stored fats & tissue proteins are used for energy.
Results in impaired growth, retards mental
development.
Subcutaneous fat disappears hence ribs become
prominent, limbs become thin & skin becomes dry &
wrinkled.
Extreme leanness (emaciation), loss of weight results
Atrophy (less growth) of digestive & intestinal glands
leads to diarrhoea

58. INDIGESTION
Non specific term including variety of upper abdominal
complaints like
Heart burn, regurgitation, dyspepsia
Acid reflux into Oesophagus due to large meal or
hyper-secretion of acid.
Other factors include physical position like lying down,
bending over, increased pressure on stomach, loss of
sphincter tone.
Avoidance of large meals, smoking, alcohol, fatty food,
weight reduction, taking antacids.

59. CONSTIPATION
Decrease in frequency of stools to less than one per
week or difficulty in defeacation which results in
abdominal pain, distortion & rarely perforation
Inactivity, low fiber diet are contributory factors.
Affected Colonic mobility due to neurological
dysfunction
Jaundice
Abnormal bilirubin metabolism & excretion.
Excess haemolysis of RBC’s, producing more Bilirubin
It obstructs flow of bile from liver to duodenum
Unconjugated Biliribin is fat soluble and has toxic
effect on brain cells
Bilirubin level may rise to 40 to 50 micromol/l (3 to 13)

60. Effects of raised Bilirubin includes pruritis (itching)
caused by irritating effects of bile salts on skin, pale
face, dark urine and whitish stool
No specific drug but supportive care, bed rest &
treatment of cause