lecture on Anatomy of Digestive tract

2. LECTURE BY: DR. SAIQUA LASHARI
M.PHIL PHARMACOLOGY
Reference: Anatomy and Physiology by Kenneth S. Saladin 3rd edition
ANATOMY OF DIGESTIVE TRACT

3. INTRODUCTION
RECEIVES FOOD…ABSORBABLE INTO THE BODY
TWO Sub Divisions
A. Digestive tract
B. Accessory organs

4. DIGESTIVE TRACT
• Tube
• From mouth to Anus
• 9m or 30 feet long
• Tube also called Alimentary Canal
• PARTS
• Oral cavity
• Pharynx
• Esophagus
• Stomach
• Small Intestine
• Large Intestine
Gastrointestinal Tract
Stomach
Small intestine
Large intestine

5. ACCESSORY ORGANS OF DIGESTIVE TRACT
TEETH
TONGUE
SALIVARY GLANDS
LIVER
GALL BLADDER
PANCREAS

7. WALL OF THE DIGESTIVE TRACT
• IT HAS 4 LAYERS
• 01.MUCOSA
• 02.SUBMUCOSA
• 03. MUCULARIS EXTERNA
• 04 SEROSA

9. MUCOSA
• MUCOSA
• Epithelium
• Lamina propria
• Muscularis mucosa
• Epithelium
• 01.Nonkeratinized stratified squamous > from mouth to esophagus and at anal
canal
• 02. Simple columnar Epithelium > Gastrointestinal tract

10. MUCOSA
• Lamina propria
• Loose connective tissue
• Muscularis Mucosa
• Thin layer of smooth muscles

11. SUBMUCOSA
• Thick layer of loose Connective tissue
• Structures present at submucosa
01. Blood vessels
02. Lymphatic vessels
03. Nerve Plexus
04. some mucus secreting glands

12. MUSCULARIS EXTERNA
• TWO LAYERS OF SMOOTH MUSCLES
• 01. Inner circular layer
• 02. outer longitudinal layer

13. SEROSA
• Thin layer of Areolar Connective Tissue
• Topped by simple squamos mesothelium
• Serosa is present from 3-4cm of esophagus upto sigmoid colon
• Adventitia
• Its also a connective tissue layer surronding motuth,pahrynx, esophagus and rectum

14. ENTERIC NERVOUS SYSTEM
• ESOPHAGUS, STOMACH & INTESTINE
• REGULATES > MOTILITY, SECRETIONS, AND BLOOD FLOW
• COMPOSED OF TWO NETWORKS OF NERVES
• 01: Submucosal plexus < Meissners plexus>
• 02: Myenteric Plexus < Auerbach plexus> present at muscularis externa

15. RELATIONSHIP TO THE PERITONEUM
• Peritoneum:
• Serous membrane composed of simple squamous epithelium and it
surrounds internal body organs.
• Mesentery
• It is a continuous set of tissue that attaches the intestine to abdominal wall .
• Stomach and intestine are suspended from the body wall by folding of peritoneum.
• Dorsal Mesentery
• Along the dorsal midline of the abdominal cavity the parietal peritoneum turns inward
and form sheet of tissue that is called dorsal mesentery
• This membrane then folds the GI Tract and forms serosa.
• VENTRAL MESENTERY
• Serous membrane that is present as a sheet of tissue beyond the digestive organ

16. • LESSER OMENTUM
• There is extension of ventral mesentery from right superior margin or lesser
curvature of stomach towards the liver
GREATER OMENTUM
Extension / folds of ventral mesentery that extends from left inferior margin/ greater
curvature and loosely covers the small intestine .

17. MOUTH
• ORAL / BUCCAL CAVITY
• ORAL ORIFICE
• FAUCES
• LINED BY NONKERATINIZED SQUAMOUS EPITHELIUM
• TEETH…….MASTICATE FOOD
• TONGUE………TASTE, MIX, SWALLOW
• GLANDS ………….MOIST , SOFTEN, MIX

19. • VESTIBULE
• ORAL CAVITY PROPER
• PALATE
LIPS:
Orbicularis oris muscles
• Labial frenulum
• Divion of lips
• Cutaneous area : like skin ,glands and hair
• Red area: tall dermal papillae, no hair no sebacous glands
• CHEEKS
• Buccinator muscles

20. TONGUE
• MUSCULAR AND BULKY
• AGILE
• SENSITIVE ORGAN
• COVERED WITH NONKERATINIZED STRATIFIED
SQUAMOUS EPITHELIUM
• EXHIBITS BUMPS CALLED PAPILLAE
• FILLIFORM, FUNGIFORM, CIRCUVALLATE PAPILLAE

21. TONGUE
• ANTERIOR TWO THIRD BODY
• POSTERIOR ONE THIRD IS ROOT @OROPHARYNX
• BOUNDRY IS V SHAPED
• BEHIND IT IS A GROVE CALLED TERMINAL SULCUS
• LINGUAL GLANDS
• LINGUAL TONSILS @ ROOT

22. • TONGUE
• MUSCULAR STRUCTURE
 Mass of striated muscles covered with the mucous membrane
 Divided into right and left halves by a median septum
 Three parts:
• Oral (anterior ⅔)
• Pharyngeal (posterior ⅓)
• Root (base)
 Two surfaces:
• Dorsal
• VentraL
INTRINSIC MUSCLE…………DELICATE MOVEMENTS
EXTRINSIC MUSCLE………..ATTACHMENT AND MASTICATION
• DORSUM……ARCHED SURFACE ON THE TOP OF TONGUE
MUCOUS MEMBRANE OF TONGUE……….SOFT + PINK
• VELVETY APPEARANCE

23. PALATE
• Separates the Oral cavity from Nasal Cavity
• Helps in breathing while chewing
• Anterior hard (bony) palate
PALATAL RUGAE are the transverse Friction ridges that aid the tongue in holding and manipulating
food
SOFT PALATE
Skeletal muscle and glandular tissue but no bone
It has conical medial projection called Uvula

24. • PALATOGLOSSAL ARCH
• PALATOPHARYNGEAL ARCH< Bigining of Pharynx>
• A pair of muscular arches on each side of the oral cavity
begin dorsally near uvula and follow the wall the cavity to
its floor
• Palatine tonsils are located on the wall of between the
arches
• UVULA………CONICAL STRUCTURE……….MIDDLE OF SOFT
PALATE
PILLARIS OF THE FAUCETS…….DOUBLE FOLDS OF MUSCLE
AND MUCOUS MEMB:…… TONSILS
CHEEKS…….BUCCINATOR MUSCLE
• FLASHY SIDES OF THE FACE
• JOIN LIPS AT NASOLABIAL FOLD

26. SALIVARY GLANDS
Main functions:
• Produces and secretes saliva
• Cleanses the mouth
• Dissolves food chemicals so they can be tasted
• Moistens food, compacting it into a bolus
• Begins the chemical breakdown of food

27. HISTOLOGY OF SALIVARY GLANDS
• Compound tubuloacinar glands
• Tree like arrangemnet
• Bnranching ducts ending in acini
• Some acini have mucus cells that produce mucus
• Some have serous cells that produce thinner fluid rich in amylase and electrolytes
• And some are mixed

29. COMPOSITION OF SALIVA
• : 97-99.5% water
• pH 6.75-7.0
• Electrolytes Sodium, potassium, chloride, phosphate, and bicarbonate
• Mucus
• Salivary amylase
• Lingual lipase
• Lysozyme
• Immunoglobulin-A

31. TYPES OF SALIVARY GLANDS
• Intrinsic Salivary glands: an indefinite number of small glands dispersed in oral cavity
• Lingual glands @ tongue
• Labial glands on inside of lips
• Buccal glands on inside of cheeks
• Small amount of saliva at a constant rate
• Moistens mouth and inhibit bacterial growth
• Salivary amylase and lingual lipase

32. • TYPES OF Extrinsic SALIVARY GLANDS
Submandibular Glands
• Found underneath the mandible
• Sublingual Glands
• Found underneath the tongue
• Parotid Glands
• Found anterior to the ear between masseter and skin
• Saliva travels to oral orifice via ducts from all three glands

33. ‘If there is goodness in
your heart, it will come
to your tongue’.

34. TEETH
• Dentition
• 16 in mandible and 16 in maxilla
• On each side of midline there are two incisors, one canine, two
premolars and three molars
• Incisors are chisel like cutting teeth
• Canines are pointed act to puncture and shred
• Premolars and molars crushing and grinding

35. DEVELOPMENT OF TEETH
• DECIDUOUS 20 ( 6- 30 MONTHS)
• PERMANENT 32 ( 6-25 YEARS)
• WISDM 17-25
• TERMS
• Occlusion
• Occlusal surface
• Cusps: rounded bumps
• Bicuspids : premolar

36. DENTITION

37. ANATOMY OF TEETH
• Teeth is embedded socket called alveolus
• Teeth makes joint with alveolus that joint called gomphosis ( between
teeth and bone)
• Periodontal ligament attaches bone and teeth
• Alveolar bone is covered by Gum or also called gingiva
• Gingival Sulcus: space between tooth and gum
• ROOT:
• NECK: point at which crown ,neck and gum meet
• CROWN: Part above the Gum

39. HISTOLOGY OF TEETH
• DENTIN: Living connective tissue(odentocytes), cells embedded
in calcified cell matrix
• Cementum: Living Connective tissue at the root (
cementocytes)
• Enamel : Non cellular secretion released before teeth erupts
Enemal can not be regenerated
Internally teeth has a PULP CAVITY in the crown and a narrow root
canal in the root
PULP : Mass of Loose Connective Tissue, blood and Lymphatic
vessels and nerves
Apical Foramen: Pore at the root of each tooth

40. PHARYNX
• Size: 13 cm ( 5inch)
• Muscular funnel
• Extends from choanae( posterior aperture/ nostrils ) to larynx
• MUSCLES: Skeletal muscles
1: Deeper Layer : longitudinatl
2: Superficical layer : circular
Superior
Middle
Inferior
These muscles force food downwards during swallowing
Inferior layer is always constricted to exclude air from esophagus

41. PAHRYNX

42. REGIONS OF PHARYNX
• NASOPHARYNX
• OROPHARYNX
• LARYNGOPHARYNX
• NASOPHARYNX: Posterior to choanae
• Dorsal to soft palate
• Also has auditory ( Eustachian) tube from Middle ear
• Pharyngeal Tonsils
• Inhaled air turns 90 degrees downwards
• Dust particles larger than 10 um can not make this turn

43. EUSTACHIAN TUBE

44. OROPHARYNX
• Space between soft palate and root of the tongue
• Anterior border is formed by base of the tongue and fauces
• LARYNGOPHARYNX
• Begins with the union of Nasopharynx and oropharynx at the level of Hyoid bone
• ( ia horseshoe-shaped bone situated in the anterior midline of the neck between
the chin and the thyroid cartilage.)

45. HYOID BONE

46. ESOPHAGUS
• Straight muscular tube of 25-30 cm
• Most of the esophagus is at mediastinum
• It begins at cricoid cartilage
• Inferior to pharynx
• Dorsal to trachea
• After passing through the mediastinum esophagus penetrates diaphragm at an
opening called Esophageal Hiatus
• Continuous 3-4 cm and meets stomach at cardiac orifice

47. CRICOID CARTILAGE

48. LOWER ESOPHAGUS SPHINCTER
• It is more constricted
• Its due to muscular tone and constriction of Diaphragm
• Heart Burn /Esophageal reflex

49. WALL OF ESOPHAGUS
• MUCOSAE : Non keratinized squamous epithelium
• Submucosa cotain esophageal glands
• When esophagus is empty its mucosa and submucosa are deeply folded into
longitudinal ridges and lumen looks like star shape in cross section
• Its upper one third is made of skeletal muscles
• Middle one third of mixed smooth and skeletal muscles
• Lower one third of smooth
• VOLUNTARY TO INVOLUNTARY Phase

50. WALL OF ESOPHAGUS

51. ANATOMY OF STOMACH
LECTURE BY: DR. SAIQUA
REFERENCE:ANATOMY AND PHYSIOLOGY 3RD EDITION
BY KENNETH.S SALADIN

52. ANATOMY OF THE STOMACH
• Muscular sac
• Upper left abdominal cavity
• Immediately inferior to diaphragm
• J.Shaped
• Vertical in tall people
• More horizontal in short heighted people
• Capacity of Stomach
50. ML WHEN EMPTY
1.0-1.5. L AFTER TYPICAL MEALS
4. LITERS WHEN EXTREMELY FULL

53. FOUR REGIONS
• 1: Cardiac Region
• 2: Fundic Region(Fundus)
• 3: Body(corpus)
• 4: Pyloric Region
• Lesser curvature
• Greater curvature

54. REGIONS OF STOMACH
• 1: Cardiac Region : Small area immediately inside cardiac orifice
• 2: Fundic Region ( Fundus): Dome shaped portion superior to the
esophageal attachment
• 3: Body ( corpus): Makes up greatest part of the stomach inferior
to cardiac orifice
• 4: Pyloric Region: Slightly narrower pouch at the inferior end :
ANTRUM & PYLORIC CANAL

55. REGIONS OF THE STOMACH

56. STOMACH WALL
• MUCOSA
• SUBMUCOSA
• MUSCULARIS EXTERNA
• SEROSA

57. STOMACH WALL
Mucosa is formed by
Simple Columnar Glandular Epithelium
Apical surface of cells is filled with mucin
Mucosa and submucosa are flat when Stomach is full
But when its empty mucosa and submucosa form wrinkles called
RUGAE
Lamina propria is almost entirely occupied by tubular glands

58. GASTRIC PITS
• Depressions in Gastric Mucosa are called Gastric Pits
• Cells near the Bottom divide continuously
• Tubular Glands open into the bottom of the gastric pit
• Gastric Glands
• Cardiac Glands
• Pyloric Glands

59. CELLS AT GASTRIC PITS
01: Goblet cells / MUCOS cells(
cardiac and pyloric region)
02: PARIETAL CELLS( gastric glands)
03: CHIEF CELLS(chymosin and
lipase in infancy and pepsinogen
throughout the life)
Lower half of gastric glands and
absent from cardiac and pyloric
region
4&5: ENTEROENDOCRINE CELLS(D
&G cells) throughout the stomach
mucosa

61. ANATOMY OF THE SMALL INTESTINE
LARGEST PART OF THE DIGESTIVE TRACT
Coiled mass
Beneath the stomach and liver
6-7 m long in a cadavar
2m long in a living person
Diameter is 2.5 cm( 1 inch )
Mucosa is highly folded and has circular folds
Mucosa has visible projections called Villi
And villus cells possess microscopic microvilli

62. GROSS ANATOMY OF SMALL INTESTINE
THREE REGIONS
01: DUODENUM
02: JEJUNUM
03: ILEUM

63. DUODENUM, JEJUNUM , ILEUM
• DUODENUM
• 25 cm (10inches)
• Begins at Pyloric valve
• Arcs around the head of the pancreas
• Passes to the left
• Ends at a sharp bend called Duodenojejunal flexure
• JEJUNUM
2.5M( 8FEET)
Present at upper left coil
• ILEUM
• 3.5 M ( 12 FEET)
• Present at lower right
• Ends at ileoceccal junction

64. MICROSCOPIC ANATOMY
• Circular Folds ( plicae circulare)
• 10mm high
• Folds are externally invisible
• Present only in mucosa and submucosa
• Present at duodenum to ileum
• Functions of Circular Folds

65. VILLI OF THE SMALL INTESTINE
• 0.5 – 1mm high
• Shape is tongue to finger like
• Villi are largest at Duodenum
• And become progressivle smaller in distal region of small intestine
• Villus
• Possess two types of epithelial cells
• Columnar absorptive cells
• Goblet mucos secreting cells

66. VILLUS
• Core of the villus is filled with areolar connective tissue of lamina propria
• ARTERIOLES
• CAPILLARY NETWOR
• LACTEAL
Nutrients are absorbed by blood capillaries and fat is
absorbed by Lacteal Lymphatic vessel
Core of the Villus is also has a smooth muscles that
contract periodically

67. CELLS OF VILLUS
• Villus cells possess brush border microvilli that are about 1um
• CONTACT DIGESTION
• Brush border enzymes help in digestion of the food
• CRYPTS OF LEIBERKUHN
• These are pores at the base of the Villi
• They open at tubular glands
• Their upper half posses absorptive cells and Goblet cells
• Their lower half posses dividing stem cells

68. PANETH CELLS
• Clustered at the base of each crypt
• They possess lysozymes
• Phospholipase
• Defensins
• ALL OF THESE CELLS PROTECT AGAINST BACTERIAL INFECTIONS

69. BRUNERS GLANDS
• Present specifically at DUODENUM Submucosa
• They secrete bicarbonate rich mucus
•
• Throughout the small intestine Lamine propria and submucosa have large
population of lymphocytes
• PEYERS PATCHES
• Lymphatic Nodules present at ileum

70. MUSCULARIS EXTERNA
• Two layers
• Inner circular layer is quite thick layer
• Outer longitudinal layer is a thin layer

71. ANATOMY OF THE SMALL INTESTINE

72. GROSS ANATOMY OF THE
LARGE INTESTINE
• Diameter is 6.5cm ( 2.5inch) and is larger than that of the
small intestine
• Length is 1.5 m( 5 feet) long
• TENIAE COLI: bands of smooth muscle that create pocket-
like sacs (haustra)
Begins at Cecum
• CECUM is a blind pouch in lower right abdominal quadrant
inferior to ileocecal valve
• APPENDIX is attached to lower end of cecum it is 2-7 cm
long

73. COLON
• Region of large intestine between the ileocecal junction
and anal canal
• Divided into 4—segments
• Ascending colon
• Transverse colon
• Descending colon
• Sigmoid colon

74. REGIONS OF LARGE INTESTINE
• ASCENDING COLON begins at the ileocecal valve and
passes up the right side of the abdominal cavity
• It makes a 90° turn at the right colic ( hepatic) flexure and
becomes a transverse colon
• TRANSVERSE COLON passes horizontally across the upper
abdominal cavity and turns 90° downward at the left colic(
splenic) flexure near the spleen
Here it becomes descending colon which passes down the
left side of the abdominal cavity

75. • The pelvic cavity is narrower than the abdominal cavity so at the
pelvic inlet the colon turns medially and downward forming a
roughly S-shaped portion called SIGMOID COLON
• In pelvic cavity the sigmoid colon straightens and forms rectum
• The RECTUM has three transverse folds called rectal valves
• The final 3cm of large intestine is ANAL CANAL
EPIPLOIC appendages are small pouches of peritoneum filled with
fat present along the colon but absent at rectum

76. ANATOMY OF THE COLON

77. MICROSCOPIC ANATOMY OF
THE LARGE INTESTINE
• Simple columnar epithelium for absorption
except in the anal canal where there is
stratified squamous
• No villi, no digestive-secreting cells
• Goblet cells produce mucus for lubrication of
feces
• Bacterial flora synthesize vitamin B and most of
the vitamin K needed for blood clotting

78. MICROSCOPIC ANATOMY OF
THE LARGE INTESTINE

79. ANATOMY OF THE LIVER
• Reddish brown gland
• Located immediately inferior to the diaphragm
• It fills most of the hypochondriac and epigastria of abdomen
• Bodys largest gland that weights 1.4kg (3lb)
• 4-LOBES
• Right lobe, Left lobe, quadrate lobe and caudate lobe
• Right and left lobes are separated fom each other by the falciform ligament
• Falciform ligament is the sheet of mesentery that suspends liver from diaphragm
and anterior abdominal wall
• Round ligament is the remnent of umblical vein that carries blood from the
umblical coord to liver of the fetus

80. • Square shape quadrate lobe next to gall bladder
• Tail like caudate lobe posterior to it .
• Porta hepatis: is an irregular opening between caudate and quardate lobes
• Its also entry point of the hepatic portal vein, proper hepatic artery and exit for then
bile passages
• Gall bladder is attached to a depression between quadrate lobe and right lobe
• Posterior region has a deep groove from where inferior vena cava passes up to the
heart
• Superior surface of the liver is bare and attached to diaphragm and other areas are
covered by serosa.

81. MICROSCOPIC ANATOMY OF LIVER
• Hepatic Lobules : Interior of the liver is filled with cylinder like tiny
lobes
• They are 2mm long and 1mm in diameter.
• Its has a central vein that is surrounded by hepatocytes
• Hepatocytes are the epithelial cells and cuboidal in shape.
• Hepatocytes form plates of cells that are one to two cell thick
• Hepatic sinusoid is the blood filled space between the plates of
hepatocytes
• Hepatic sinusoids are lines by fenestrated endothelium
• Sinusoid also posses hepatic macrophages known as Kupffer cells

82. • Lobes of the liver are separated by a connective tissue sheet
• In liver hepatic lobes meet there is also a hepatic triad formed by two blood
vessels and one bile ductule
• Proper hepatic artery and hepatic portal vein
• Bile canaliculi: liver secretes bile into narrow channels present between sheets
of hepatocytes
• From bile canaliculi bile passes into bile ductules of bile triades
• From ductules goes into right and left hepatic ducts
• They converge on the inferior side of liver and form common hepatic duct .
• Cystic duct that drains from gall bladder also joins common hepatic duct
• union of cystic and c.heptic duct forms bile duct decends through lesser
omentum

83. • Hepatopancreatic ampulla is an expanded chamber formed
after the joining of hepatic duct with the pancreatic duct.
• Major duodenal papilla is the tissue fold at duodenum
where the ampulla terminates
• At the Papilla there is opening of the hepatopancreatic
ampulla called hepatopancreatic sphincter or sphincter of
oddi

84. HEPATOCYTES
• Polyhedral cells 20-30µm
• Eosinophilic
• Large nucleus /binucleate
• Bile canaliculi
• Gap junctions between
hepatocytes
• Hepatocyte surfaces related to:
• Perisinosoidal space
• Adjacent hepatocyte
• Bile canaliculi

85. HEPATOCYTES
• Nucleus
• Prominent nucleolus
• Disperse chromatin
• Polyploidy
• Cytoplasm
• Glycogen-lacey
appearance
• Fat-spherical vacoules
• Ribosomes & RER-
basophilia
• SER
• Mitochondria-
eosinophilic
• Lysosomes

86. FINE STRUCTURE OF HEPATOCYTES
• Rough endoplasmic reticulum – protein synthesis
• Smooth endoplasmic reticulum – oxidation, methylation
• Conjugation of bilirubin to gluronate – bilirubin glucoronide
• Synthesis of bile acids
• Golgi apparatus – near nucleus
• Formation of lysomes
• Secretion of proteins, glycoproteins, lipoproteins into plasma
• Lysosomes –turnover & degradation of organelles
• Mitochondria
• Peroxisomes –
• Important for oxidation of excess fatty acid
• Breakdown of hydrogen peroxide
• Breakdown of purines to uric acid

87. • Bile canaliculi 1-2µm diameter
• Limited by plasma membrane
of hepatocytes
• Tight junctions
• Canaliculi empty into bile
ductules lined by cuboidal cells
called cholangiocytes
• Hering’s canals
• Bile ducts –portal spaces
• Right & left hepatic ducts
• Direction of bile flow –
opposite to that of blood

88. LOBULATION
• CLASSIC HEPATIC LOBULE
• Central vein at center
• Portal triads at periphery
• Area near portal triad well
supplied by oxygen & nutrients
• Area near central vein not well
supplied

90. LOBULATION (CONTINUED)
• PORTAL LOBULE
• Triangular area
• Three central veins
• Portal triad at center
• Consists of tissues
draining bile into bile duct

91. LOBULATION (CONTINUED)
• LIVER ACINUS
• Diamond shaped area
• Two portal triads
• Two closest central veins
• Based on nature of blood supply & O2
gradient
• ZONE 1- nearest arteriole- most O2 &
nutrients, oxidative metabolism
• ZONE III –near central vein – least O2
& nutrients, glycolysis, lipid
formation,ischemic necrosis
• ZONE II – intermediate range

93. COMPARISON

95. LIVER REGENERATION
• Has strong capacity for regeration
• Compensatory hyperplasia
• Original mass of tissue restored
• Surgical removal produces similar response
• Important in liver transplant
• LIVER STEM CELLS (oval cells)
• Present in initial epitetlium of bile ductules near portal areas
• Can give rise to hepatocytes & cholangiocytes

96. EXTRAHEPATIC BILIARY PASSAGES
• Simple columnar epithelium
• Subepithelial CT:
• Elastic fiber
• Lymphoid tissue
• Mucous glands-tubuloalveolar
• BV, nerves
• COMMON BILE DUCT
• Smooth muscle fibers-isolated
• Oblique & transverse fibers-
near duodenum

97. GALL BLADDER
• Parts
• Three layers
• MUCOSA
• Epithelium- simple columnar
• Striated border
• Lamina propria has collagen fibers,
muscle fibers, BV,
tubuloacinar glands

98. GALL BLADDER
• Epithelium –absorptive
cells
• Microvilli
• Intercellular spaces
• Mitochondria
• Apical mucous
granules

99. GALL BLADDER
• MUSCULAR LAYER
• Interlacing smooth muscle
fibers
• Elastic & reticular fibers
between muscles
• Perimuscular layer
• Adventitia / serosa

101. PANCREAS ANATOMY
stomach
esophagus
ductus choledocus
duodenum
duct of
Santorini
duct of
Wirsung
pancreas

103. PANCREATIC SECRETIONS
1. PROTEASES (70%)
Endopeptidases (trypsin, chymotrypsin, elastases)
Exopeptidases (carboxypeptidases)
trypsinogen trypsin activates all other precursors
enterokinase
(duct walls)
2. NUCLEASES (DNAase, RNAase)
3. PANCREATIC AMYLASE (hydrolyse starch and glycogen)
4. PANCREATIC LIPASE (triglycerides fatty acids and glycerol)

104. PANCREAS (PANORAMIC)
pancreatic acini
islet of
Langerhans
islet of
Langerhans
BV
pancreatic lobe

105. PANCREATIC SECRETORY DUCTS
LARGE SECRETORY DUCT INTERLOBULAR DUCT
acinus
simple
cuboidal
epithelium
simple
columnar
epithelium

106. EXOCRINE PANCREAS
interlobular
duct
intercalated
duct
nerve
acinus
pyramidal
secretory
cellbasal basophilia
(rough ER)
zymogen
granules
centro-
cells blood
vessel
rough
endoplasmic
reticulum
golgi
apparatus
golgi
vesicles
conden
vacuole
zymoge
granules
merocrine secretion
(exocytosis)

107. INTERCALARY DUCTS AND CENTROACINAR CELLS
intercalary duct
intercalary
duct
centroacinar
cell

108. PANCREATIC EXOCRINE SECRETORY CELL
zymogen
granules
centroacinar
cell

109. CELL BIOLOGY OF PANCREATIC SECRETION
1. SYNTHESIS
14
C -leucine + tRNA
14
C-amino-acyl tRNA
mRNA for
chymotrysinogen
ribosomes
chymotrysinogen
2. SEGREGATION
mRNA
ribosomes
polypeptide
RER cisterna
3. INTRACELLULAR TRANSPORT
RER
transitional
elements
golgi
apparatus
golgi vesicles
4. CONCENTRATION
H2O
H2O
condensing vacuoles
5. INTRACELLULAR
STORAGE
zymogen
granules
6. DISCHARGE
exocytosis

110. EXPERIMENTAL METHODS IN CELL SECRETION
1. SUBCELLULAR FRACTIONATION
(grind and find)
density
gradient
centrifugation
zymogen
granules
condensing
vacuoles
golgi
microsomes
(RER)
vesicles
cpm
14
C
leucine
cpm
14
C
leucine
cpm
14
C
leucine
RER golgi cond zymogen RER golgi cond zymogen RER golgi cond zymogen
(3 mins) (7 mins) (80 mins)
pulse chase
2. RADIOAUTOGRAPHY
(cook and look)
developed silver grains
photographic
emulsion
ultrathin
section
pancreatic
acinar cell

111. ISLET OF LANGERHANS
alpha cell
beta
cell
blood
capillary
acinus
beta cell
alpha
cellfenestrated
capillary
(insulin)
(glucagon) vascular pole
(secretion by exocytosis)
INSULIN- increases membrane
permeability to glucose
promotes glycogenesis decrease blood glucose levels
GLUCAGON - promotes glycogenolysis increases blood glucose levels
“ ANTAGONISTIC HORMONES”

112. ISLET OF LANGERHANS

113. ISLET OF LANGERHANS - TEM

114. STAINED ALPHAAND BETA CELLS
ALPHA CELLS BETA CELLS