lips

1
lips

• Each lip is divided into
• External aspect----thin Skin with sweat glands,
  hair follicles and sebaceous glands.
• Vermilion region---pink, very thin skin devoid of
  glands and hair follicles.
• Mucous or internal aspect-----str.sq.
  epith.non-kerat. With subepith.irregular
  collagenous C.T having minor mucous salivary
  glands.
• The core of the lips is composed of skeletal
  muscle fibers

2
Lip
3
Oral cavity.

• Oral mucosa
• Gingiva, dorsal surface of the anterior two
  thirds of the tongue, and hard palate are covered
  by keratinized or partially (parakeratinized)
  str.sq.epith. with underlying dense irregular
  collagenous C.T.
• The reminder of oral cavity is covered by
  non-keratinized str. Sq. epith. With underlying
  looser collagenous C.T.

4
Teeth

• Each tooth is suspended in bony socket, the
  alveolus by the periodontal (dense irregular
  collagenous C.T.)
• Each tooth is formed of
• 1-Crownvisible part.
• 2-Root----in the alveolus.
• 3-Cervix---inbetween.
• The inner part of tooth is the pulp that contain
  soft vascular C.T contains bl. and lymph Vessels
  and nerves

5
Mineralized components

• They are
• a.Dentin----surrounds the pulp and is covered
  with
• b.Enamel that cover the crown.
• c.Cementum----that cover the root.

6
Teeth
7
Palate

• It is composed of
• Hard palate (keratinized-st. sq.epith.)
• Soft palate (non-ker.st.sq.epit.)
• Uvula (non-ker.st.sq.epith)
• They separate the nasal cavity from the oral one.

8
Tongue

• It has
• 1-Dorsal surface---its ant. two thirds is covered
  with ker. St. sq.epith. and separated from post
  one third (covered with non-ker. St. sq.epith) by
  a shallow, V-shaped groove, the sulcus
  terminalis.
• 2-Ventral surface---non-ker. St.sq.epith.
• 3-Core of skeletal muscle fibers.
• The dorsal surface of posterior one third has
  lingual tonsils.

9
Tongue
10
Lingual tonsil
11
Lingual papillae

• They are located on the dorsal lateral aspect
  of the tongue.
• There are four types
• 1.Filiform papilla slender structure, covered
  by ker.st. sq. epith.DO NOT have taste buds.
• 2.Fugiform papilla---as mushroom has slender
  stalk connects a broad cap to tongue surface.It
  is covered by non-ker. Str. Epith.It has taste
  buds on dorsal surface of the cap.

12
Filliform Fungi form papillae
13

• 3.Foliate papillae are located along the
  posterior aspect of the tongue. They have taste
  buds in neonate only. They have furrows in which
  glands of Von Ebner (serous) open.
• 4.Circumvallate papillae---8 to 12 just ant. To
  sulcus terminalis. They have Von Ebner serous
  glands. They have taste buds on their sides only.

14
Circumvallate papilla
15
Taste buds

• Are intra-epithelial sensory organs for
  perception of taste.
• Each taste bud is formed of
• 1.Dark cells (type I)
• 2.Light cells (type II)
• 3.Intermediat cells (type III)
• 4.Basal cells (type IV)
• Nerve fibers synapse with types I, II, and III
  (they have long microvilli protruding from taste
  pores)

16
Taste buds
17
Salivary glands

• There two types of salivary glands
• Minor salivary glands (scattered in the mucosa
  of oral cavity-mucous secreting).
• Major salivary glands ( Parotid, sub mandibular
  and sub lingual)

18
Major salivary glands

• There are three pairs of major salivary glands,
  Parotid, submandibular, and sublingual.
• They have C.T capsule. provides septa that divide
  the glands into lobes and lobules (Stroma).
• Their parenchyma consists of secretory portion
  (tubuloalveolar glands) and ducts portion.

19
Secretory portions

• Are formed of serous and/or mucous serous
  secretory cells arranged as acini
  (alveoli-serous) or tubules (mucous) that are
  couched by myoepithelial cells.
• Myoepithelial (basket )cells.
• They share the basal lamina of acinar cells
  (hemidesmosomes).
• They envelope the cells of secretory acinus and
  intercalated ducts (desmosomes)
• They have several long processes.
• They are rich in actin and myosin.
• They press on the acinus to release the product.

20
Salivary secretory unit
21
Serous cells

• Secrete proteins and polysaccharides.
• Are pyramidal with single round, basally located
  nuclei.
• Are rich in rER, Golgi complex, basal
  mitochondria, and epically situated secretory
  granules.
• They have tight junctions, intercellular
  canaliculi and interdigitated baso-lateral
  processes.

22
Mucous cells

• Are short pyramidal cells with basal flattened
  nuclei.
• Have few mitochondria, rER, but rich in Golgi
  complex (to form carbohydrates).
• Have less lateral processes and intercellular
  canaliculi than serous cells.
• Apices of cells are rich in secretory granules.

23
Duct portions

• Are highly branched ducts.
• Begin with the smallest intercalated ducts that
  formed of small cuboidal cells having
  myoepithelial cells.
• Intercalated ducts merge to form striated ducts
  which are cuboidal to columnar cells with
  basolateral folds containing mitochondria. They
  join together to form intralobular ducts that
  unit to form interlobular ducts that join to form
  intralobar and interlobar ducts.
• Terminal ducts open into the oral cavity.

24
Parotid Gland

• The largest salivary gland but produce 30 of
  salivary output.
• It secrets pure serous secretion that rich in
  amylase enzyme, lactoferrins, lysozymes and
  secretory IgA

25
Parotid gland
26
Submandibular Gland

• It produces 60 of salivary output.
• It is mixed but the major portion (90) is serous
  and 10 is mucous.
• It has few serous demilunes that capped the
  mucous tubular secretory unit.

27
Submandibular gland
28
Sublingual Gland

• It is very small and responsible for 5 of
  salivary secretion.
• It is composed of mucous tubules with serous
  demilunes.
• It produces mixed , but mostly mucous saliva.
• Its duct system does not form terminal duct,
  instead several ducts open into the floor of oral
  cavity.

29
Sub lingual gland
30
Alimentary Canal

• Is the tubular portion of digestive system.
• About 9 meters and subdivided into esophagus,
  stomach, small intestine (duodenum, jejunum and
  ileum), and large intestine (cecum, colon,
  rectum, anal canal, and appendix)

31
General structure of Alimentary tract

• It is formed of 4 concentric layers
• I.Mucosa II.Submucosa III.Muscularis
  externa
• IV.Serosa (adventitia)
• I- MUCOSA
• It is formed of
• 1-Epithelium.
• 2-Lamina propria (Vascular C.T) that contains
  lymph vessels, nodules and glands.
• 3-Muscularis mucosa longitudinal smooth muscle.

32
The wall of GIT.(esophagus)
33
II-SUBMUCOSA

• Is formed of dense irregular elastic C.T.
• It has glands ONLY in esophagus and duodenum.
• It is rich in blood and lymph vessels.
• It has enteric nervous plexus (Meissners plexus)
  that houses also post ganglionic parasympathetic
  nerve cell bodies.

34
III-MUSCULRIS EXTERNA

• It is responsible for peristaltic activity.
• It is composed of smooth muscle (EXCEPT in
  esophagus, has both smooth skeletal fibers).
• They are arranged helically.
• Usually organized as inner circular and outer
  longitudinal.
• Between the two layers they have Auerbachs
  myenteric plexus.
• that houses also post ganglionic parasympathetic
  nerve cell bodies

35
Musculsris externa
Auerbachs myenteric plexus
36
IV-SEROSA OR ADVENTITIA

• It covers the muscularis externa.
• It is formed of thin layer of vascular C.T.
• If it is surrounded by simple squamous epith.of
  the visceral layer of peritoneum
  (mesothelium)---It is called serosa.
• If the organ is retropritoneal i.e NO epith.It
  is called adventitia.

37
Esophagus

• Mucosa---stratified sq.epith non-ker,fibroelasic
  lamina propria and longitudinal muscularis
  mucosa (smooth muscle).
• L.P has cardiac glands (mucous) near the pharynx
  (upper region) and stomach (lower region).
• Submucosa has mucous esophageal glands proper.
• Muscularis externa of upper third is skeletal
  muscle, middle third is both smoothskeletal and
  the lowest third is smooth muscle.
• Adventitia until pierces diaphragm---serosa

38
Mucosa and submucosa of esophagus
submucosa
39
Gastro-oesophageal junction
esophagus
stomach
40
Parts of the stomach
41
Fundic mucosa
Fundic glands have Short pitsone forth of
mucosa. Simple or branched tubular glands. Are
rich in parietal chief cells.
42
Fundic gland
43
Surface columnar gastric cell
They secrete thick mucous
44
Mucus neck cell
45
Parietal cell
Acidophilic cells, apical invaginations that have
canaliculi lined by microvilli. Secrete HCl and
gastric intrinsic factor (absorption of Vit.B12
in the ileum).
46
Chief cell
Basophilic cytoplasm. Secrete pepsinogen,
rennin and gastric lipase
47
DNES cells
48
Pyloric glands
49
Fundic glands

• Their pits are short about one quarter of length
  of mucosa.
• Are simple or branched tubular glands.
• Are numerous and crowded.
• Pyloric glands
• Their pits are deep---about half the length of
  mucosa.
• They are branched and convoluted---many cross
  sections.
• The predominant cells are mucous neck cells
  that secrete both mucous and lysozyme.

50
Small intestine

• It has 3 regions duodenum, jejunum and ileum.
• It has
• Plicae circulares---transverse folds of
  mucosa and submucosa.
• VilliFinger like protrusions of lamina
  propria that is covered with epithelium.They
  contain Bl. lymphatic vessels (lacteal), smooth
  muscle fibers, loose CT and lymphoid cells.
• Micrvillimodifications of the apical region
  of plasmalemma of epithelial cells of villi and
  surface epithelium.
• Crypts of Lieberkuhn-invaginations of epithelium
  into the L.P between the villi form glands

51
Cells of the villi and crypts of small intestine
52
Cells covering the Villi

• Surface absorptive cells that has brush
  (microvilli) border and covered wih thick
  glycocalx that has dipeptidase and disaccharidase
  enzymes.They have Junction complex.
• Goblet cellsIncrease toward the ileum.
• DNES cells.
• M cells (microfold cells)-phagocytose and
  transport Ag present in the intestinal lumen.

53
Absorbtive columnar cells
54
M-cell
55
Crypts of Lieberkuhn

• They are simple tubular glands that open between
  villi.
• They are composed of surface absorptive cells,
  goblet cells, regenerative cells, DNES cells and
  Paneth cells.
• Paneth cells occupy the bottom of crypts.They
  have acidophilic (eosinophilic) secretory
  granules. They secrete lysozyme (antibacterial
  agent)

56
Paneth cell
57
Submucosa of the duodenum

• Is formed of dense irregular fibroelasic CT.
• Rich in bl. lymphatic vessles.
• Contains Meissners plexus (parasympathetic).
• Contains Brunners glands that producea mucous
  and bicarbonate-rich fluid as well as urogastron
  that inhibits HCl production.

58
Duodenum
59
Wall of the duodenum
60
Duodenum
61
Gastrodeodenal junction
62
Regional differences of small intestine

• Duodenum is the shortest part (25cm). Its villi
  are broader, taller and more numerous. Its
  submucosa has Brunners glands.
• Jejunum-its villi are narrower, shorter. And
  sparser than in duodenum. Goblet cells are more.
• Ileum-its villi are shortest, sparest, and
  narrowest. Its lamina propria has lymphoid
  nodules (peyers patches) opposite the attachment
  of the mesentery.

63
Large intesine

• It is divided into-cecum, colon, rectum, and anus
  (appendix is blind outpouching of the cecum).
• It has NO villi.
• It is rich in crypts that are composed of same
  cells as small intestine but NO Paneth cells.
• Goblet cells increase from cecum to the sigmoid.
• The outer layer of muscularis externa is not
  continuous (3 fascicles-taeniae coli).
• Serosa has fat called appendices epiploicae.

64
Colon
65
(No Transcript)
66
Vermiform Appendix

• It is long diverticulum of cecum.
• It has shallow crypts of Lieberkuhn.Its mucosa is
  composed of surface absorptive cells, goblet
  cells, DNES cells, M-cells, infrequent Paneth
  cells and lymphoid nodules around the wall.
• It is invested by serosa.

67
Vermiform appendix (Human)
68
Vermiform appendix (Rabbit)
69
(No Transcript)
70
Rectum and Anal canal

• Rectum has fewer but deeper crypts than colon.
• Epithelium of anal mucosa is simple cuboidal from
  rectum to pectinate line, then st.sq.non-ker.
  Epith to the anus, then st.sq.ker. Epith. At
  anus.
• Lamina propria of anal canal has anal glands.
• Submucosa of anal canal has internal and external
  hemorroidal plexuses.
• It has internal and external anal sphincters.

71
Pancreas

• It is both an exocrine (digestive juices) an
  endocrine (hormones) gland.
• The excretory part is formed of acini ducts.
• Acinar cells are pyramidal cells with basal round
  nuclei that surrounded by basophilic cytoplasm
  (rER, polysomes).
• Apex of acinar cells have zymogen
  granules-acidophilic.
• Acinar cells secrete many digestive enzymes in
  the duodenum.

72
Duct portion of Pancreas

• Ducts begins within the center of acini with the
  terminus of intercalated duct forming
  centroacinar cells (pale simple cuboidal cells)
  but not form wall of acini.
• Acini have not myoepithelial cells.
• Centroacinar cells intercalated cells secrete a
  bicarbonate-rich buffer solution.
• Intercalated ducts merge to form intralobular
  ducts that merge to form interlobular ducts, that
  give main pancreatic duct.

73
Pancreas
74
Pancreas
75
Endocrine portion (Islets of Langerhans)

• Islet is pale, spherical vascularized collection
  of cells.
• It is surrounded by reticular cells.
• It is formed of 5 types of cells
• ß cells70 more in centersecrete insulin
  (decreses blood sugar level).
• a cells---20 more in peripherysecrete
  glucagonincrease blood glucose level.
• d cells---5--secrete somatostatinparacrine
  and endocrine (reduce smooth muscle contraction).
• G cells---1---secrete gastrin---increas HCl.
• PP cells1---secrete pancreatic
  polypeptideinhibit exocrine pancreatic secretion.

76
Islet of Langerhans
77
Liver ( its unit is the classic liver lobule)
78
(No Transcript)
79
Portal triad (area)
It houses 1-branches of hepatic
artery. 2-tributaries of portal
vein. 3-interlobular bile ducts. 4-Lymph
vessels.
It is isolated from liver parenchyma by limiting
plate of modified hepatocytes
80
Three concepts of liver lobules
1-Classic liver lobule---Bl. Flows from periphery
toward central vein. 2-portal lobule---bile flows
to a particular interlobular duct. 3-Hepatic
(portal) acinusin which three concentric regions
of hepatocytes surrounding a distributing artery
in the center.
81
Classic liver lobule
It is formed of anastomosing plates of
hepatocytes of tow cells thick. There are blood
sinusoids between plates that separated from
hepatocytes by perisinusoidal Space of
Disse. Space of Disse contains A- Plasma.
B-Reticular fibers. C-fat storing cells (Ito
cells). D-nonmyelinated nerve fibers. .E-
Microvilli of hepatocytes. F-Pit cells (natural
killer cells).
82
Hepatic sinusoids

• They have gap junctions.
• They have fenestrae.
• They show Kupffer cells, that originate from
  monocytes (phagocytic) and rich in lysosomes and
  have filopodia-like projections.
• They receive blood from inlet arterioles and
  inlet venules.
• Their blood flows into the central vein that give
  sublobular ,then collecting veins to form hepatic
  veins.

83
(No Transcript)
84
Hepatocytes
Lateral domain
Sinusoidal domain
85
Hepatic ducts

• Bile canaliculi that formed by hepatocytes cell
  membranes.
• Bile canaliculi merge with cholangiole (short
  tubules formed of a combination of hepatocytes,
  low cuboidal cells and oval cells).
• Bile from cholangioles enters canals of Hering
  (branches of interlobular ducts).
• Interlobular ducts are lined with simple cuboidal
  epithelium.
• Interlobular ducts merge to form hepatic bile
  ducts.

86
Gall bladder

• It is composed of 4 layers.
• 1-Simple columnar epithelium.
• 2-vascularized loose CT lamina propria that
  contains small mucous glands.
• Smooth muscle arranged as inner oblique and outer
  longtudinal layers.
• Serosal adventitia.

87
Gall bladder