digestive system

7/17/2019 Digestive System

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The Digestive System

Dr. M. Azhari


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Digestion

Processing of food Types

Mechanical (physical) he!

Tear "rind

Mash

Mi#

hemical

ata$olic reactions %nzymatic hydrolysis

ar$ohydrate

Protein

&ipid


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Digestion

Phases

ngestion

Movement

Digestion

A$sorption

*rther digestion


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Digestive System ,rganization

"astrointestinal ("l) tract (Alimentary canal) T*$e !ithin a t*$e

Direct lin-path $et!een organs

Str*ct*res Mo*th ,ral avity

Pharyn#

%sophag*s

Stomach

D*eden*m /e0en*m

lle*m

aec*m

Ascending colon

Transverse colon


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GASTROINTESTINAL

SMOOTH MUSCLE

Resting potential is -40 to -80 mV !s!all" nea#t$e lo%e# en& o' t$is #ange

Ele(t#ogeni( Na)*-AT+ase ma" (onti,!te mo#eto #esting potential

Slow waves to ./ pe# min!te a#e os(illationso' #esting mem,#ane potential

A(tion potentials a#e slo% %it$ little o1e#s$ootL-t"pe Ca/2($annels in1ol1e&


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Digestive System ,rganization

Descending colon

Sigmoid colon

ect*m

An*s

Accessory str*ct*res 3ot in t*$e path

,rgans Teeth

Tong*e

Salivary glands

&iver

"all $ladder

Pancreas


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Anatomy of the Mo*th and

Throat


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6*man Decid*o*s and

Permanent Teeth


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Dorsal S*rface of the Tong*e


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The Ma0or Salivary "lands


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Degl*tition (s!allo!ing)

Se9*ence :ol*ntary stage

P*sh food to $ac- ofmo*th

Pharyngeal stage aise

Soft palate

&aryn# ; hyoid

Tong*e to soft palate

%sophageal stage

ontract pharyngealm*scles

,pen esophag*s

Start peristalsis


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Degl*tition (s!allo!ing)

ontrol 3erves

"lossopharyngeal

:ag*s

Accessory


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1'

%sophag*s

=s*ally collapsed (closed)

' constrictions Aortic arch

&eft primary $ronch*s Diaphragm

S*rro*nded $y S3S ple#*s (sympathetic nervous system)


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Peristalsis and Segmentation


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%sophag*s

Sphincters

=pper

&o!er

A$normalities

Achalasia

Atresia

6ernia


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Stomach

=s*ally @/ shaped

&eft sideB anterior to the spleen

M*co*s mem$rane

" cells C ma-e gastrin

"o$let cells C ma-e m*co*s

"astric pit C ,#yntic gland C Parietal cells C Ma-e6l

hief cells C ymogenic cells Pepsin

"astric lipase


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Anatomy of the Stomach


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Stomach

' m*scle layers ,$li9*e

irc*lar

&ongit*dinal

egions ardiac sphincter

*nd*s

Antr*m (pylor*s)

Pyloric sphincter

:asc*lar

nner s*rface thro!n intofolds C *gae

ontains enzymes that !or-

$est at p6 1E2


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Stomach

(gastric motility) *nctions

Mi# food

eservoir

Start digestion of

Protein 3*cleic acids

ats

Activates some enzymes

Destroy some $acteria

Ma-es intrinsic factor C

Small ntestine

Secretes digestiveenzymes Peptidases

AminoE

DiE TriE

S*crases

Maltase

&actase

Saccharidases DiE

TriE

&ipase

3*cleases


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Small ntestine

ontrol

e9*ires pancreatic

enzymes H $ile to

complete digestion


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&arge ntestine

%#tends from ileocecal valve to an*s

egions

ec*m C Appendi#

olon Ascending

Transverse

Descending

ect*m Anal canal


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Anatomy of the &arge ntestine


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&arge ntestine

6istology

3o villi

3o permanent circ*lar folds

Smooth m*scle

Taeniae coli

6a*stra

%piploic appendages

,ther!ise li-e rest of "l tract


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&arge ntestine

*nctions

Mechanical digestion 6a*stral ch*rning

Peristalsis

efle#es

"astroileal

"astrocolic

hemical digestion C


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Ho% $o#mones #eg!late

gast#i( empt"ing

CCK, gastrin, GIP(gastric inhibitory peptide),and secretin all promote constriction of pyloricsphincter

Secretin and GIP decrease force of antralcontractions

Gastrin and CCK increase force of antralcontractions. Under most circumstances the

effect on the pyloric sphincter predominatesll of these tend to slo! gastric emptying


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UOENAL CONTROL O5

GASTRIC EM+T3ING

A(i& (a!ses #elease o' se(#etin) 1aso1agal

#e'le6es) an& ente#i( ne!#al #e'le6es 5ats #elease CC* an& GI+

Amino a(i&s an& pepti&es #elease gast#in

H"pe#toni(it" #eleases !n($a#a(te#i7e&

ente#ogast#one9 an& eli(its a ne!#al #e'le6


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&iver

&ocation . 6ypochondri*m

%pigastric region

+ &o$es &eft

J*adrate

a*date

ight %ach lo$e has lo$*les C ontains hepatocytes C

S*rro*nd sin*soids C eed into central vein


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'>

&iver

*nctions Ma-es $ile

Detergent C em*lsifiesfats

elease promoted $yK :ag*s n.

I

Secretin

ontains Fater


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&iver

Deto#ifiesremoves Dr*gs

Alcohol

Stores "ycolgen

:itamins (AB DB %B I) e and other minerals

holesterol

Activates vitamin D

etal


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&iver

D*al $lood s*pply

6epatic portal vein Direct inp*t from small

intestine 6epatic arteryvein

Direct lin-s to heart


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The D*oden*m and elated

,rgans


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The ,rgans and Positions in the

A$dominal avity


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Str*ct*res of the Alimentary

anal

digestive system

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