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1. Anatomy and Histology
Digestive Tract
Source: Medical Histology (laiq Hussain Siddiqui)
Presented to : Dr.Madiha
Presenters:
Iza Batool
Urooj Sajjad
Mahnoor Subhani
Rohma
Aman
Tania
Amna Rasool
Sadaf Fatima
Areeba Mazahar
Muqadas Fatima

2. Alimentary System
A complex network of organs and structures.
A process by which food is broken down into simple substances
that can be absorbed or utilized by the body
Consists of long tube extend from mouth to anus (9m/30 feet in
length) , this tube is called alimentary canal.
Types of organs
a)Primary Digestive Organs : Mouth(oral
Cavity),pharynx,esophagus,stomach, Small Intestine, large
Intestine
b)Accessory Digestive Organs/Glands: Liver,pancreas,salivary
Glands,gall Bladder
Functions
Ingestion
Mechanical and chemical digestion
Absorption
Elimination
Role
Maintain overall health by providing by providing the body with the
necessary nutrients for energy ,growth , and repair

3. Oral CavityOral Cavity
Mouth buccal cavity
It is an irregular space(bounded by lips,cheeks,and palate)
Contains teeth, gums, and tongue
First stage of digestion
Opens anteriorly to the exterior through lips
Posteriorly through fauces into the pharynx
Functions
1.Ingestion 2. Mastication 3.Break Down Of Food.
 Lips (labia)
•External muscular structure
•Surrounds the opening of mouth
•Core is formed by skeletal
muscles embedded in
fibroblastic tissue
Surfaces
1.Cutaneous surface
2.Vermilion zone
3.Oral surface
•Cutaneous surface
(ordinary skin)
Contains hair follicles, sebaceous
glands, and sweat gland
•Vermilion zone (red zone)
Covered by stratified squamous
epithelium thinly keratinized
No sweat or sebaceous glands
•Oral surface
Covered by labial mucosa
Non keratinized squamous
epithelium and lamina propria
Labial salivary glands
FunctionsFunctions
1.Manipulate The Food
2.Initiate The Digestion

4. Cheeks
Muscular fleshy structure
Forms wall of oral cavity
Buccal cavity, formed by skeletal muscles and fibroblastic connective tissue
contains sebaceous or sweat glands
lined by buccal mucosa consist of stratified squamous epithelium
Functions
Facilitate the mastication
Palate
Roof of the mouth
Separating oral cavity from nasal
cavity
Structure
Two parts
1.Hard Palate
2.Soft Palate
Hard Palate:
•Bony part of palate
•Formed by maxilla & palatine
bones
•Provides rigid surface
•Lined by stratified squamous
epithelium
Soft Palate: Muscular part of
Palate
•Oral surface is covered by
squamous non-keratinized
epithelium
•Superior surface is covered by
pseudostratified columnar
epithelium ,supported by lamina
propria
Functions of Palate
• Separation of oral and nasal
cavity
• Formation of oral cavity
• Mixing of food
• Taste and sensory reception

5.  Tongue
Tongue is mobile muscular organ in the
oral cavity
posterior part of tongue forms the anterior
wall of oropharynx
a mass of skeletal muscle covered by
mucus membrane
Surfaces of tongue
1.Superior surface (dorsal)
2.Inferior surface (ventral)
Functions of tongue
•Taste speech chewing and swallowing
•Cleaning
•Breathing
Features
•Root(back part of the tongue that connects
to the floor mouth )
•Tip (very sensitive and perform complex
movements)
•Body (part b/w the root and apex)

6. Parts of tongue
Extrinsic muscles : that moves the tongue around
Changing the position of tongue in the mouth such as:
1.Protrusion 2.retraction 3.lateral movement & elevation
4.Elevation and depression
e.g. Genioglossus , Hyoglossus , Styloglossus , Palatoglossus
Intrinsic muscles : changing the shape of tongue
• shortening & lengthening
• narrowing & widening
• curling and uncurling
e.g. Superior & Inferior Longitudinal Muscles ,Transverse
And vertical muscles
Dorsal surface
Convex on all sides , divided by v-shaped sulcus (sulcus terminalis)
Parts
Oral(anterior two-third) Pharyngeal(posterior one-
third)
Rough due to numerous Appears irregularly nodular (aggre-
small projections called gations of lymphoid nodules) called
Lingual papillae. lingual tonsils.
Lingual papillae
Formed of central core of connective tissue & a covering layer
of stratified squamous epithelium
Types of Papillae
Filiform Fungiform Circumvallate Foliate

Functions of papillae
•Flavor differentiation
•Food manipulation
•Mucus production
•Taste perception
•Antimicrobial defense
•Texture&temperature sensation

7. Filiform papillae:
•Most numerous & the
smallest
•Squamous keratinized
epithelium
•Selender form i.e. thread like
Fungiform papillae:
•Mushroom shaped & contain
taste buds
•Covered by stratified
squamous non-keratinized
epithelium
Circumvallate
papillae:
•Large , flat papillae
form V-shape at the
back of tongue
•Having many taste
bud & Detection of
bitter taste
•Numerous serous glands
( VonEbner
glands/gastatory
glands),lie
embedded in the
base of tongue.
Foliate papillae:
•Relatively small compared to
other
•Life like or foliate shape, with
multiple small projections or
lobes
•Found on lateral margins of
tongue
Glands of the Tongue
a)Von Ebner’s Glands
b)Anterior Lingual Glands
c)Mucous Glands Of The Root

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24. Definition:
OROPHARYNX
The part of the pharynx that conducts food from
the oral cavity into the esophagus.
Location:
Posterior to the mouth, at the level of the
C3–C4 vertebrae.

25. BOUNDARIES OF THE
OROPHARYNX
•Superior: Soft palate
•Inferior: Hyoid bone
•Anterior: Base of tongue and oral cavity
•Posterior: Pharyngeal wall

26. LINING AND
FUNCTIONS OF THE
OROPHARYNX
Lining and Functions of the Oropharynx
•Non-keratinized stratified squamous
epithelium.
Functions:
•Breathing
•Swallowing
•Speech
•Immunity

27. Digestion, Ingestion, Absorption, and
Excretion.
Tubular Digestive Tract
DEFINATION:
A continuation of the oral cavity that facilitates digestion and absorption.
REGIONS:
Mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
FUNCTIONS:

28. GENERAL WALL STRUCTURE OF THE
TUBULAR DIGESTIVE TRACT
LAYERS:
Mucosa:(Innermost layer)
•Epithilium( absorption/secretion)
•Lamina propria ( connective tissue with vessels/
lymphatics/mucosal glands.
•Muscularis mucosa( separates mucosa and
submucosa)
•Sub-Mucosa: Blood vessels, lymphatics, glands,
•sub-mucosal nerve plexus( meissners plexus)
•Muscularis Externa:
•Inner circular layer( constricts lumen)
•Outer longitudinal layer( facilitates peristalsis)
•Myentric nerve plexus( regulates motility)

29. Serosa/Adventitia:Outermost layer
Serosa( outer visceral layer of the
peritonium covers intraperitoneal
digestive organs.
Adventitia( connective tissue for organs
outside the peritoneal cavity.
Functions:
Lubrication
Protecion
Mobility and attachment.
Cont........

30. ENTERIC SYSTEM :
•Network of nerve cells that control GI tract.
•Largest and most complex part of PNS .
•Known as intrinsic nervous system or second brain.
Location:
Found
throughout the GI tract from the esophagus to anus,
within the walls of gut.
Neural Components:-
•Sensory neurons2- Motor neurons3-
Interneurons

31. Plexuses: Made up of two plexuses called
submucosal and myenteric plexuses.
•ENS communicates with CNS.
•ENS facilitate the function of GI tract.
Function : ENS controls :-
•Digestion
•Absorption
•Motility
•Mucosal transport and secretion

32. •
Blood flow
•Immune response
ESOPHAGUS/Gullet/Food Pipe :
Tube like structure that extends from back of mouth
to lower oesophagal sphinter.
•10-13 Inches Long
•1-2cm Wide

33. Location:
Infront of vertebral column and behind the trachea .
Sphinters:
•UES 2- LES
Layers:The wall of esophagus consists of four
layers :-
•Mucosa
•Submucosa
•Muscularis externa
•Adventia/Serosa
1)Mucosa :
The layer of cell that lines the inside of the
esophagus .It is madeup of three Sublayers:
•Non-keratinized Squamous
Epithelium
•Lemina Propria
•Muscularis mucosae
2)Submucosa:

34. Thin layer of connective tissue located beneath the
esophageal mucosa containing :
•Blood vessels
•Lymphatic vessels
•Nerves( meissner’splexuses )

35. •Specialized mucous glands
3) Muscularis externa:
Also called muscularisproporia consists of Smooth
Muscles.
Layers:
Inner Layer: Inner Layer of Circular smooth muscles.
Outer Layer: Outer layer ofsmooth muscles.
Myentic Layer: Located b/t two layers of muscularis
externa.
i.Key Point:
Upper Third: Skeletal muscle.
Middle Third: Mix of skeletal and smooth muscles.
Lower Third: Smooth muscle.
4)Adventia/Serosa:
i.Some part of esophagus is surrounded by
Serosa .e, Abdominal region
ii.While major part is surrounded by Adventia

36. Adventia is Layer of connective tissue containing blood
vessels , lymphatics , nerves , cervical and region
covered by adventia.
Functions OfEsophagus:-
1)Mucosa:
•Mucus secretion
•protection
2)Submucosa:
•Protection
•Digestion
•Absorption
3)Muscularis:
•Propelling of food towards stomach
4)Adventia:
•Reduce friction
•Provide structural support

38. “Muscular
hollow&digestive
organ, located in
the upper left
region of
abdominal cavity.”
Functions:
•Churning &mixing
•Enzyme action
•Secretion
•Hormones
production
•Absorption
Sphincters
1.Lower Esophageal
Sphincter
2.Pyloric Sphincter
Parts of
stomach
I.Cardia
II.Fundus
III.Body
IV.Pylorus
Walls of stomach
i.Mucosa
ii.Submucosa
iii.Muscularis externa
iv.Serosa
Stomach
(J-shape like sac)
(pH: 1.5-3.5)
(Capacity 1.5liters)
Length 30-38cm
Width 15- 20cm

39. Mucosa
•Inner most layers
•Comes in contact
with food
•Having Gastric pits
or foveolae in which
at the several
glands openings
present
Functions
•Protects the
stomach lining from
digestive acids and
enzymes attacks
Layers
Surface Epithelium
(columnar epithelium cells
or surface mucus cells)
Secretemucin mucus(alkaline)
Lamina propria ( highly
vascularized connective tissue)
Most of the space occupied by the
glands
Muscularis mucosae (thin
layer)
Smooth muscle fibers into inner circular & outer longitudinal
Submucosa
•Beneath the mucosa
•Contains blood vessels and submucosal plexus nerves
•Consists of dense connective tissue & adipose tissue
•No glands present

40. Muscularis Externa
•Composed of three smooth muscles
layers
•Contracts and relaxes to mix food
Serosa
•Outer visceral layer of peritoneum
•Consists of connective tissue covered by mesothelium
•Provides friction free environment for churning
GLANDS OF STOMACH
a.Gastric(in the fundus and body)
b.Cardial(narrow region around the inlet)
c.Pyloric(in the pyloric antrum & canal)
Gastric glands(fundic)
•Gastric juice, production of acid & enzymes
•Regions a. Isthmus b. Neck c. Base
•Contains five types of cells
Types of cells
1.Mucous neck cells 3. Chief cells
2.Parietal cells 4. Enterioendocrine
5. Stem cells
Mucous neck cells
•In the neck region of gastric glands, columnar/pyramidal shape
•Soluble mucus with chyme and function to lubricate gastric content
Parietal cells
•Oxyntic cells, present in isthmus and neck regions
•Secrete Hcl, large, round to pyramidal shape
•Due to their peripheral location, close to the wall of gland(in Latin parietis means wall)

41. •Intracellular canaliculus(communicates with the
lumen of the gland, increase the surface area
for HCl secretion
•Inactive parietal cells
•Active parietal cells
•Hcl secretion stimulated by gastrin hormone
•Also secrete intrinsic factor
Chief cells(zymogenic cells)
•Secrete pepsin
•Columnar/pyramidal , protein secreting cells
•Gastric lipase
Enteroendocrine cells
•Located in the neck and bases of the glands
•DNES and EC cells
•Secrete serotonin
Stem cells
•Columnar cells found in the neck region
•Undifferentiated cells ( form linings of gastric glands
•Constant turnover of cells ensured
Cardial glands
•Found in cardia
•Lined by mucus secreting cells
•Enteroendocrine and parietal cells , no chief
cells
•Lysozymes , gastric juice secretion &
protection against esophageal epithelium
Pyloric Glands
•Located in the lamina propria of pyloric
antrum&canal
•Tubular branched glands
•Gastric pits are deeper in these regions
•Lined mainly by mucous secreting cells
•Few parietal and many enteroendocrine
cells
•G cells that secretes gastrin

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44. Large Intestine
(Colon)
Presented By: Syeda Muqaddas Fatima

45. Sample Footer Text
2
Colon
1-Mucosa
2-Submucosa
i.Epithelium
ii.Lemina Propria
iii.MALT
Iv. Muscular Mucosae
Dense C.T
3-Muscularis
4-Serosa/
Adventia
SMOOTH MUSCLES
Teniae Coli
Haustra Coli
Appendices Epiploica
Sigmoid+Transverse Colon by Serosa
Assending+ Descending Colon by Adventia

46. 3
Vermiform Appendix
At Birth
Absent IncreasesRegresses
Crypts Formed Are Poor
Star Shaped Lumen
Serosa Contains Lympholic Nodules
20 years10-12 years
Rectum
Crypts of Liberkuhn are few+Deeper
Uniform Thickness of Outer longitudinal layer
No Teniae Coli
iii. Most part cove d by Adve
Sn
amt
pli
e Fa
oo,
terS
Texo
t me Part by Serosa

47. T way to get started
is to quit talking and
begin doing.
Walt Disney
Sample Footer Text
4
Anal Canal
"Extended from Rectum Ampulla to Anus"
Outer = Stripped+ Voluntary
Inner =Smooth+Involuntary
Folds
Pathological Dilation
Anal Glands
Longitudinal
Semilunar
Anal ColumnsAnal Valves
2 Anal Sphincters
Veins
ii.SubMusocai.Musoca
Piles

48. 5
20XX
Sample Footer Text
Caecum
Functions
contains bacteria that •
•ferment food
Detoxify food
•Digest plant fibers i.e, Cellulose
Moistens the solid waste
Colon
Rectum
Anus
Absorption of Water and Electrolytes
Production of•Vitamin K
•Vitamin B
•Vitamin B7( BIOTIN)
Storage of Fecal Material
(water,cholesterol,bile,mucus,bacteria,plant fibers,
sloughed off mucosal cells)
Discharge of SolidWaste
Malfunctions
Diarrhea
Constipation