Digestive Tract (Achadiyani)

7/17/2019 Digestive Tract (Achadiyani)

http://slidepdf.com/reader/full/digestive-tract-achadiyani 1/65

By :

Achadiyani, dr.

DIGESTIVE TRACT



I. GENERAL FEATURES OF THE DIGESTIVE TRACT

A. Components : The organs include :

- Oral cavity

- Oral pharynx

- Esophagus

- Small intestine (duodenum, Jejunum, Ileum!- "arge intestine (cecum and appendix, colon!

- #ectum

- $nal %anal

B. General Struture Feature : The &alls organs consist o' layers :

) *ucosa

+ part :

- epithelium - lamina propria - muscularis mucosae



!. Su" muosa :

- Irregular connective tissue

#. $usular%s e&terna : layers o' smooth muscle :- inner circular - outer longitudinal

- outer longitudinal

'. Serosa an( a()ent%t%a



Schematic structure o' a portion o' the digestive tract &ith variouscomponents and their 'unctions

Duct of associatedgland (transport of

secretion)

Lamina propria(support)

Submucosa (support)

Muscularismucosae (mucosal

motility)Submucosal plexus(control of muscle

activity)illus (increase ofucosal surface)

Gland in thelamina propria

(secretion)Inner circularmuscle layer

(motility)Myenteric plexus(controls muscle

contractions)Gland in

submucosal layer(secretions)

Lymph nodule(immunedefense)

uterlongitudinalmuscle layer

(motility)

Serosa(support)

Mesothelium(protective coating!

reduction offriction)





A. L%ps :

There is a transition 'rom non

4eratini5ed mucous mem/rane to the4eratini5ed strati'ied s6uamous epithelium

o' the s4in



"I3 ("ongitudinal Section!

"# $order of thelip% transiton&one'# eurovascular

bundle# rbicularis oris

muscle

*# +pidermis

,-# Dermis

,,# Sebaceousgland

,.# /air follicles(t#s and l#s)

,0# +rectormuscle(arrector pilimuscle)

,1# S2eat gland 3duct andsecretingportions,4# +rector

muscle(arrector pili

,# +pithelium ofthe labial

mucosa.# Lamina propria

of labial mucosa

0# Super5cialartery

1# Labial mucousglands of themucosa 3 alveoliand duct

4# Vein



B. Ton-ue :

There are types o' papillae :

) 9ili 'orm papillae

9ungi 'orm papillae

+ 9oliate papillae

%ircum vallate papillae



8. Nerves (t.s)

9. Arteriole

10. Venule

11. Serousalveoli

12. Interlobularducts

13. Mucousalveoli

14. !cretor"duct

1#. Venule1$. Arterioles

1%. Nerve (l.s)

18. Mucosa &e'iteliu andlaina 'ro'ria

1. Mucosa &e'iteliu andlaina 'ro'ria 2. Muscle (l.s)

3. Muscle (t.s)

4. *un+i,or 'a'illa &e'iteliu andlaina 'ro'ria #. Muscle (o.s)

$. *ili,or 'a'illae

%. *un+i,or 'a'illae

-on+ue & A'e!



1. in+ual e'iteliu

2. aina 'ro'ria

3. Secondar" 'a'illae

4. Venules

#. -aste buds

$. S/eletal uscle,ibers

%. !cretor" ducts

8. Strati,ied suaouse'iteliu

9. ircular ,urro(sulcus)

10. all o, te cicular,urro (sulcus)

11. -aste buds

12. Serous alveoli o,+lands o, te vallate

'a'illae (von bners+lands)

13. !cretor" duct (l.s)

14. -ransversesection o, uscle,ibers

-5N67



-5N67

1. Mucosal rid+es

2. i,,use l"'atictissue

3. Adi'ose cells

4. Mucous alveoli('osterior lin+ual+lands)

#. S/eletal uscle(o.s)

$. 'iteliu andlaina 'ro'ria o,ucosal ,old

%. !cretor" duct

8. Arteriole andvenule

9. Nerve (l.s)

10. S/eletal uscle(l.s)



III. TEETH AND ASSOCIATED STRUCTURE

A. HISTOLOGIC STRUCTURE

. TOOTH STRUCTURE :

a 3ulp %avity

/ entin

c Enamel

d %ementum

!. ASSOCIATED STRUCTURE

a 3eriodontal ligament / $lveolar /one

c ingiva (ums!



Diagram of a sagittal section from an incisor toothin position in the mandibular bone

ron

5dontoblasts

oot

nael

entin

uticleNec/:ul'

Alveolar bone

:eriodontal li+aent

6in+iva

oot canal

eentuA'ical ,oraen



B. TOOTH DEVELO/$ENT

Sur'ace o' tongue on the region close to its ; < shaped /oundary

/et&een the anterior and posterior portions O/serve the lymphoidnodules, lingual tonsils, glands and papillae



IV. /HAR*N0

The pharynx is shared /y the respiratory and digestive tracts

. T+e Resp%rator1 p+ar1n&

- Its superior portion

- "ined /y respiratory epithelium

!. T+e Oral p+ar1n& 2orop+ar1n&3

- Its in'erior portion

- "ined /y non 4eratini5ed strati'ied



V. ESOPHAGUS

- Mucosa : - Non keratinized stratified squamous epithelium

- Lamina propria : esophageal cardiac glands

- Muscularis mucosae

- Sub Mucosa : - esophageal glands

- Muscularis Extera :

- he upper third : skeletal muscle

- he middle third : skeletal and smooth muscle- he lo!er third : smooth muscle



833E# ESO3=$8S (T#$>S;E#SE SE%TIO>!

1. Strati,ied suaouse'iteliu

2. aina 'ro'ria

3. Muscularis ucosae(soot uscle)

4. Subucosa

#. ircular uscle la"er(s/eletal)

$. onnective tissuebeteen uscle la"ers

%. on+itudinal uscle

la"er (s/eletal)

8. Adventitia

9. "'atic nodule

10. uct 'assin+ trou+uscularis ucosae

11. Mucos alveoli(eso'a+eal +lands)

12. ucts13. Arteriole and venule

14. Adi'ose cells

1#. Venule

1$. Adi'ose tissue

1%. Arter"

18. Vein

19. Nerves



VI. STO$ACH

The stomach has major regions :

- %ardia

- 9undus

- %orpus (1ody!

- 3ylorus

Gastr% muosa

- lining o' simple columnar epithelium

- They secrete a neutral mucus



4 Lam%na propr%a :

a. Car(%a : - %ardiac glands (/ranched tu/ular!

- 3roduce mucus and lyso5yme

". Fun(us an( Corpus 2"o(13

- 9undic glands :

) 3arietal cells : =%l, intrinsic 'actor

%hie' cells : pepsinogen, lipase

+ Serotonin secreting cells



. /1lorus

4 /1lor% -lan(s :

- $ll glandular cell types may /e present

- 3arietal cells : rare - %hie' cells

- astrin-secrening cells (-cells!

4 $usular%s muosae : - inner : circular

- outer : longitudinal

4 Su"muosae

4 $usular%s e&terna %s arran-e( %n # la1ers :

- inner : o/li6ue

- middle : circular

- outer : longitudinal



#egions o' the stomach and their histologic structure

:it

;unction o, +landand base o, 'itaina 'ro'ria6lands

Muscularis ucosaeardia

:it

ardia

so'a+us

:it

uodenu:"lorics'incter

Nec/

Nec/

<ase

<od"

6land

6land

aina 'ro'ria

"' noduleMuscularisucosae

Subucosa:"lorus



%$#I$ ("O>IT8I>$" SE%TIO>!

1. a'illar" (t.s)

2. a'illar" (l.s)

3. Venules

4. Arteriole#. Venule it

eol"=ed

blood$. Muscularis e!terna &inner la"er (sootuscle)

%. Subucosa8. Muscularis ucosae &

inner circular and outerlon+itudinal la"ers

9. Arter" iter"troc"tes

10. Strati,ied suaouse'iteliu o, eso'a+us

11. so'a+eal +lands12. so'a+eal cardiac +lands

(t.s)13. ucts o, eso'a+eal +lands

(t.s)14. aina 'ro'ria o,

eso'a+us

1#. uct o, eso'a+ueal +lands(l.s)1$. aina 'ro'ria o, stoac

1%. ardiac +lands

18. 6astric e'iteliu (ucouscolunar)

19. *oveolae (+astric 'its)

20. 6astric +lands

21. ie, cells

22. Mucous nec/ cells23. :arietal cells



STO*$%= : 98>%8S O# 1O?

1. Sur,ace e'iteliu(ucous secretin+colunar)

2. <aseent ebrane

3. aina 'ro'ria

4. *oveolae (+astric'its)

#. 6astric +lands>nec/ re+ion

$. Mucous nec/ cells

%. :arietal cells

8. *oveola

9. 6astric +land o'enin+into ,oveola

10. 6astric +land(nec/)

11. aina 'ro'ria

12. 6astric +land>transverse section

13. ie, cells



STO*$%= : 98>%8S O# 1O?

1. 6astric +lands (l.S)

2. aina 'ro'ria

3. :arietal cells

4. ie, or ="o+eniccells

#. Sub+landular

re+ion o, telaina 'ro'ria

$. Venule

%. Subucosa

8. :arietal cells

9. ie, or ="o+eniccells

10. 6astric +lands(t.s)

11. :arietal cell

12. ie, or="o+enic cells

13. Muscularisucosae (circularla"er)

14. Muscularisucosae(lon+itudinal la"er)



VII. S$ALL INTESTINE

The small intestine, &hich include :- duodenum : retroperitoneal

- jejunum : intraperitoneal

- ileum : intraperitoneal

To increase the a/sorptive sur'ace :

) 3licae circulares (@erc4ringAs value! :

consisting mucosa and su/mucosa

Intestinal villi : epithelium B lamina propria

+ *icro villi



Electron micrograph o' epithelium o' the small intestine Chen vie&ed &ith

the light microscope, a/undant microvilli at the apex can /e seen to 'or, the

striated /order $t le't are lymphocytes migrating in the epithelium In the

center is an enteroendocrine cell (E! &ith its /asal secretory granules



A

<

Muscularis ucosaeaina

'ro'ria

6lands (cr"'ts)

ells slou+in+ o,,

Soot uscle

a'illar"

6oblet cells

"'atic ca'illar"

Striated border

Soot uscle

"'oc"tes

Soot uscle

nteroendocrinecells

"'oc"tes

6oblet cells

Mitosis

:anet cells



Schematic diagram illustrating the structure o' the small intestine

$ The small intestine under lo& magni'ication In the villus to the le't,

o/serve the des6uamation o' the epithelial cells 1ecause o' constant

mitotic activity o' the cells 'rom the /lind end the glands and the

up&ard migration o' these cells (dashed arro&s!, the intestinal

epithelium is continuously rene&ed O/serve the intestinal glands (o'

"ie/er4uhn!

1 The intestinal glands have a lining o' intestinal epithelium and go/let

cells (upper portion! $t a lo&er level, the immature epithelial cellsare 're6uently seen in mitosisD note also the presence o' 3aneth and

enteroendocrine cells $s the immature cells progress up&ard, they

di''erentiate and develop microvilli, seen as a striated /order in the

light microscope %ells proli'eration and cell di''erentiation occur

simultaneously in the /lind end o' these glands% $ villus tip sho&ing the columnar covering epithelium &ith its

striated /order and a moderate num/er o' go/let cells %apillaries, a

lymphatic capillary, smooth muscle cells and leu4ocytes can /e seen

in the connective tissue core o' the villlus "ymphocytes are in the

epithelial layer in great num/ers %ells are sloughing o'' at the apex

o' the villus



$uosa o, t+e small %ntest%ne :

) ;illi

Intestinal glands (crypts o' "ie/er4uhn!

- These simple tu/ular glands

- They are lined /y :

7 a/sorptive cells

7 go/let cells7 panethAs cells

7 entero endocrine cells

7 undi''erentiated cells



S*$"" I>TESTI>E : 8OE>8*("O>IT8I>$" SE%TIO>!

1. inin+ e'iteliu &colunar cells itstriated borders and+oblet cells

2. Intervillous s'ace

3. Intertinal villus (l.s)

4. Muscle ,ibers in a villus

#. Intestinal +lands o'enin+into intervillous s'aces

$. Intestinal +lands (l.s)

%. Intestinal +lands (t.s)

8. uodenal +lands

9. is'laced ,ibers o, teuscularis ucosae

10. Arteriole11. Venule

12. :aras"'atetic

+an+lion o, te "enteric'le!us

13. Villi it core o, laina'ro'ria and uscle ,ibers

14. aina 'ro'ria 'ro'er

1#. Muscularis ucosae

1$. uodenal +landse!tendin+ into te ucosa

1%. Subucosa itduodenal +lands

18. Muscularis e!terna &inner circular and outerlon+itudinal la"ers

19. Serosa (visceral'eritoneu)

S*$"" I>TESTI>E JEJ8>8* I"E8*



S*$"" I>TESTI>E : JEJ8>8* < I"E8*

1. Villi (l.s)

2. Intervillous s'aces

3. Intestinal +lands(cr"'ts o, ieber/un)

4. 'iteliu#. aina 'ro'ria

$. Muscularis ucosae

%. Subucosa

8. ircular uscle

la"er

9. on+itudinaluscle la"er

10. Serosa

19. Adi'ose tissue

20. Neurovascularbundle

21. "'atic nodule

11. Sur,ace e'iteliu & striated? ordered and +oblet cells

12. Villus (t.s)

13. Villus (o.s)

14. ontracted villus

1#. Soot uscle,ibers in villi

1$. Villi (t.s)

1%. Intestinal +lands(t.s)

18. :aras"'atetic

+an+lia o, te"entric 'le!us



1. 6oblet cells inintestinal +lands

2. ells it striatedborders

3. :anet cells (cells it acido'ilic+ranules)

4. Muscularis

ucosae (l.s)

1. Ar+"ro'ilic,ibers in telaina 'ro'ria

2. Ar+enta,,in cellsin intestinal+lands

:AN-@ S A6N-A**IN S



VIII. LARGE INTESTINE5 t+%s %nlu(es

- caecum

- ascending (colon!

- transverse (colon!

- descending (colon!

- sigmoid (colon!

- rectum



A. $uosa :

- #ectum : vertical 'olds called the rectal columns (o'

*orgagni!

B. Su"muosa :

- lo&er rectum : hemorrhoidal plexus

C. $usular%s e&terna :

- %olon : smooth muscle at the outer longitudinal layer is

gathered into + thic4 longitudinal /ands called taenia coli

D. a()ent%t%a an( Serosa

( !



"$#E I>TESTI>E %O"O> (C$"", T#$>S;E#SE SE%TIO>!

1. Seresa (visceral'eritoneu)

2. :aras"'atetic +an+lia o, te"enteric 'le!us

3. Arterioles

4. Venules

#. Muscularis e!terna &inner circular la"er(l.s)

$. Muscularis e!terna & outerlon+itudinal la"er (l.s)%. a'illaries

8. Arteries and vein

9. Subucosa

10. Muscularis ucosae

11. :aras"'atetic+an+lion

12. Arteriole13. Nerves

1#. 6landulare'iteliu & +obletcells

14. Sur,ace e'iteliu &colunar it striatedborders

1$. Intestinal +lands (t+.s)1%. "'atic nodule

18. 6erinal center

19. aina 'ro'ria

20. Intestinal +lands (l.s)

21. Intestinal +lands (t.s)

22. 6oblet cells

23. "'atic nodule

24. Serosa 2#. Muscularis e!terna

2$. Subucosa

2%. Mucosa



3hotomicrograph o' a sectiono' large intestine O/serve theintestinal glands &ith a/undant

go/let cells

Mesocolon

Mucosa

Subucosa

ircular uscle

-enia coli (lon+itudinaluscle)

A''endi!e'i'loica

%ross section o' colon



I0. A//ENDI0 2VER$IFOR$ A//ENDI03

- evagination o' the in'erior end o' the cecum

- many lymphoid nodules

- smaller - 'e&er and shorter crypts than colon

$ppendix (3anoramic vie& transverse section!



$ppendix (3anoramic vie&, transverse section!



0. ANAL CANAL

6 T+e muosa :

7 cm has typical colonic epithelium7 #eplaced /y strati'ied s6uamous epithelium continues

to the anal opening

6 Lam%na propr%a : =emorrhoidal plexus

6 Su"muosa : 6se/aceous glands

- circum anal apocrine s&eat glands

6 $usular%s

7 Inner : thic4 circular layer o' smooth muscle involuntary internal anal sphincter

4 D%stal : composed o' s4eletal muscle voluntary external

anal sphincter



$>$" %$>$" ("O>IT8I>$" SE%TIO>!

4. 'iteliu o, te rectal

#. Muscularis ucosae

$. "'atic nodule

%. Intestinal +land

8. aina 'ro'ria

9. Sub ucosa

10. ectuanus Bunction

11. Anal Valve

12. -erinal uscularis ucosa

13. 'iteliu and laina'ro'ria o, teanal ucosa

14. Internal anal s'incter

1#. Internal eorroidal'le!us

1$. !ternal anal s'incter>

subcultaneous

division (s/eletal uscle)

1. Muscularis e!ternao, te rectu &tic/ened circularla"er (internal anals'incter

2. Muscularis e!ternaouter lon+itudinalla"er

3. evator ani uscle(s/eletal uscle)

A .

7 ' ' e r ' a r t o , a n

a l c a n a l

< .

o 2 e r '

a r t o , a n a l c a n a l



istinguishing 'eatures o' the &alls o' the digestive tract



%ontd distinguishing 'eatures o' the &alls o' the digestive tract



GLANDS ASSOCIATED 7ITH THE DIGESTIVE TRACT

A. Components o, t+e s1stem :

. Sal%)ar1 -lan(s :

- parotid glands- su/mandi/ular glands

- su/lingual glands

!. /anreas

#. L%)er '. Gall "la((er

B. Glan(ular Su" un%t

. Lo"es

!. Lo"ules

#. A%n% 2or Al)eol%3

C. E&or%ne Duts :

. Intra lo"ular (uts : a. Inter alate( (uts

". Str%ate( (uts

!. Inter lo"ular (uts





T+e struture o, t+e su"man(%"ular 2su"ma&%llar13

-lan(. A%n% %n t+e seretor1 port%on are ompose( o,

p1ram%(al serous 2l%-+ter olor3 an( muous 2st%pple(3

ell an( t+e tu"ules o, muous ells. T+e nule% o, serousells are eu+romat% an( roun(e( an( an aumulat%on

o, rou-+ en(oplasm% ret%ulum %s e)%(ent %n t+e "asal

t+%r( o, t+e ell. T+e ape& o, t+e ell %s ,%lle( 8%t+

prote%n 9 r%+ seretor1 -ranules. T+e nule% o, muous

ells5 ,lattene( 8%t+ on(ense( +romat%n5 are loate(

near t+e "ases o, t+e ells. $uous ell +a)e l%ttle rou-+

en(oplasm% ret%ulum an( onta%n (%st%nt seretor1

-ranules. T+e s+ort %nteralate( (uts are l%ne( 8%t+

u"o%(al ep%t+el%um. T+e str%ate( (uts are ompose( o,olumnar ells 8%t+ su+ +arater%st%s o, %on

transport%n- ells as "asal mem"rane %n)a-%nat%ons an(

m%to+on(r%al aumulat%on. $1oep%t+el%al ells are

s+o8n %n (arer olor.



I. SALIVAR* GLANDS : . /AROTID GLANDS :

4 Serous seretor1 ells

4 /arot%( seret%ons : 6 !; < total sal%)ar1

)olume

S$"I;$#? "$> : 3$#OTI



S$"I;$#? "$> : 3$#OTI



!. SUB $ANDIBULAR 2 SUB$A0ILLAR*3 GLANDS

6 3roduced 2F G o' the salivary volume

- %ontain serous and mucous mostly serous :



/+otom%ro-rap+ o, a set%on o, +uman su"man(%"ular -lan(.O"ser)e t+e presene o, (ense o, t+%s tu"uloa%nar -lan(. In t+elo8er r%-+t re-%on %s a str%ate( (ut 2SD3. T+e arro8 %n(%ates a(em%lune 8+ere serous ells are eentr%all1 (%splae(5 assum%n-

t+e ,orm o, a resent.

# SUB LINGUAL GLANDS:



#. SUB LINGUAL GLANDS:

- 3roduced . G o' the salivary volume

- %ontain mucous and serous mostly mucous

3hotomicrograph o' a humansu/lingual gland sho&ing the

predominance o' mucous cells

Examples o' an intralo/ular (I!

and connective < tissue

ensheathed interlo/ular (E!duct are also present



II. /ANCREAS

6 The pancreas is serous

- %ontain islets o' langerhans

- %ells types : 3ancreatic acinar cells,

centro acinar cells

I l d



:otoicro+ra' soin+ te

a''earance o, te acinar 'ortion o,

te 'ancreas it its secretor" cells.

<asal laina Intercalatedduct C"o+en

+ranules

Acinar cells

entroacinar cells

Sceatic drain+ o, te structure o, 'ancreatic acini.

Acinar cells (dar/er color) are '"raidal> it +ranules at

teir a'e! and rou+ endo'lasic reticulu at te cell

base. -e intercalated duct 'artl" 'enetrates te acini.

-ese duct cells are /non as centroacinar cells (li+ter

color). Note te absence o, "oe'itelial cells.

3$>%#E$S (SE%TIO>$" ;IEC!



3$>%#E$S (SE%TIO>$" ;IEC!



3$>%#E$TI% $%I>I

(S3E%I$" 3#E3$#$TIO>!

3$>%#E$TI% IS"ETS

(S3E%I$" 3#E3$#$TIO>!

1. C"o+en

+ranules

2. <aso'ilic

(croo'ilic)

1. Al'a cells

2. <eta cells

3. a'illaries

4. onnectivetissue

#. :ancreaticacinus

III LIVER



III. LIVER

a. General Struture

6 partly covered /y lissonAs capsule

- %ells are arranged in one-or -cell-thic4 plates that

are separated /y the hepatic sinusoids

- The liver has a dual /lood supply :

7 3ortal vein

7 =epatic artery

$lso has + drainage systems :

7 =epatic vein

7 "ymphatic vessels

7 1ile duct



-ree diensional as'ect o, te noral liver. In te u''er center veinD in te loer center>

te 'ortal vein. 5bserve te bile canaliculus (dar/er color)> liver 'lates (li+ter color)>

@erin+s canal> Eu',,er cells sinusoid> ,atstorin+ cell> and sinusoidal endotelial cell.



B.General Funt%ons :

) 3rotein Synthesis 1ile productions

+ *eta/olit storage

etoxi'ication H Inactivation

C. Bloo( Suppl1

) =epatic portal vein

=epatic artery

+ =epatic sinusoid %entral vein

. =epatic vein



Schematic diagram of a

classic liver lobule. Branches

of the hepatic artery (HA) and

hepatic portal vein (PV) empty

blood into hepatic sinusoids

(S) through !hich it flo!

to!ard the central vein. "he

endothelial lining of the

sinusoids is discontinuous

and is separated from theradial plates of hepatocytes

by the space of Disse. Bile

canaliculi receive bile from

the hepatocytes that border

them and convey it to!ard thebile ducts in the portal triads.

"he arro!s sho! that blood

and ile flo! in opposite

directions.



D. CELL T*/ES :

) =epatocytes @up''erAs cells

+ 9at-storing cells

E. LIVER LOBULES :

) %lassic liver lo/ule

3ortal lo/ule

+ =epatic acinus (o' #appaport!



Schematic dra!ing illustrating the

territories of the classic liver

lobules hepatic acini and portal

lobules. "he classic lobule has acentral vein (#V) and is outlined by

the solid lines that connect the

portal spaces (PS). "he portal

lobules (lighter color) have their

centers in the portal spaces$ they

are outlined by lines that connectthe central veins (upper triangle).

"he portal lobules constitute the

portion of the liver from !hich bile

flo!s to a portal space. "he hepatic

acinus (dar%er color) is the regionirrigated by a single distributing

vein (diamond shaped figure).

&ones of the hepatic acinus are

indicated by ' '' and '''.

"I;E# "O18"E"I;E# "O18"E



"I;E# "O18"E"I;E# "O18"E



"I;E#"I;E#

eticuloendoteliu



"I;E#"I;E#

<ile canaliculi



F. B%l%ar1 trat :

1ile canaliculus /ile ductules (also called cholangioles

or =eringAs canals! /ile ducts hepatic duct

common /ile duct (ductus choledochus!

IV. GALL BLADDER :

A. $uosa :

- Simple columnar epithelium

- "amina propria

B. $usular%s :

- Smooth muscle 'i/ers

C. A()ent%t%a = Serosa

GALL BLADDER



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Digestive Tract (Achadiyani)