The Digestive System

Kelompok 6Awalia Rizka Maftuha (3415131002)Ranny Apriani Hapsari (3415130996)Halimatus Sadiyah(3415136411)The Digestive System

ENTODERM

(ARKENTERON METENTERON)a. FOREGUT: USUS DEPANb. MIDGUT: USUS TENGAHc. HINDGUT: USUS BELAKANG

SALURAN PENCERNAAN & KELENJAR PENCERNAAN2. SISTEM PERNAFASAN EPITEL PARU-PARUMetenteron (bumbung endoderm) terdiri dari 5 daerah:StomodeumForegutMidgutHindgutProctodeum

IntroductionThe digestive system is used for breaking down food into nutrients which then pass into the circulatory system and are taken to where they are needed in the body.

IntroductionThere are four stages to food processing:Ingestion: taking in foodDigestion: breaking down food into nutrientsAbsorption: taking in nutrients by cellsEgestion: removing any leftover wastes

Pengolahan makanan dalam empat tahapanFigure 21.2

1INGESTI2DIGESTI3ABSORPSI4ELIMINASIFoodPemecahan MekanikPiecesof foodPemecahan Kimia(enzymatic hydrolysis)SmallmoleculesNutrientmoleculesenter bodycellsUndigestedmaterial16I. Digestive system - General considerations

A. Digestive tract - general structure.

1. A hollow tube with lumen of variable diameter.

2. Extends from mouth to anus

3. The wall, starting with the esophagus, shows different specializations along its length that relate to function of various components of digestive tract.

4. Various glands (e.g. salivary glands )and organs (liver, gall bladder, pancreas) are also components of this system.

5. The wall of most of the digestive tract consists of 4 major layers, the a) mucosa, b) submucosa, c) muscularis externa and d) adventitia or serosa. In the oral region, only the mucosa is easily defined.II. ORAL CAVITY

A. The oral cavity is lined with a keratinized or nonkeratinized stratified squamous epithelium depending on what region youre in.

1. This epithelium is often called the mucous epithelium.

2. The transition between the stratified keratinized squamous epithelium of the skin and the stratified non-keratinized squamous epithelium of much of the oral cavity occurs at the lips.

3. The superficial (surface) cells of the non-keratinized epithelium are nucleated (as opposed to those of keratinized epithelium of skin which are not) and have only a few granules of keratin in their cytoplasm.

4. Below the stratified squamous epithelium is a layer of loose connective tissue, the lamina propria.

a. This lamina propria shows some interdigitation with the stratified squamous epithelium of the oral region as the dermis of the skin does with the epidermis.

b. It contains blood and lymph vessels, small glands, nerves and aggregations of lymphocytes.5. Together, the stratified squamous epithelium and the lamina propria form the oral mucosa - No muscularis mucosae

6. Sublingual and submandibular salivary glands lie in tissues below the mucosa (this would be the equivalent of the submucosa or sometimes below it).

7. There is no distinct boundry between the lamina propria and the submucosa and no true muscularis externa in oral region - what muscle there is will be striated. No serosa/adventitia.

B. The roof of the mouth consists of soft and hard palates.

1. The hard palate has an intramembranous bone backing which is covered by a keratinized mucous epithelium.

2. The soft palate has a core of skeletal muscle and is covered by a non-keratinized mucous epithelium.http://mywebpages.comcast.net/wnor/lesson10.htmC. Tongue

1. The tongue consists of a mass of striated muscle covered by a mucosa consisting of a non-keratinized, stratified, squamous epithelium and lamina propria in most places.

a. The mucous epithelium is strongly adherent to the muscle below

b. This is because the C.T.of the lamina propria penetrates into spaces between the muscle bundles.

2. Tongue muscle is striated and composed of bundles that are oriented in 3 planes.

a. This sort of structure increases both the potential stiffness and the mobility of the tongue.http://www.lab.anhb.uwa.edu.au/mb140/

5. Types of papillae found on the dorsal surface of the tongue.

a. Filiform papillae - have an elongated conical shape.

* These papillae have a keratinized surface, are the most numerous and are found over the entire dorsal surface.

* There are no taste buds in the epithelium covering filiform papillae.

b. Fungiform papillae - these are mushroom shaped.

* There are far fewer fungiform than filiform papillae.

* They are found interspersed between the filiform papillae over the entire anterior dorsal surface of the tongue.

* A few taste buds may be found in the epithelium covering these papillae.d. Circumvallate papillae - these are extremely large circular papillae which have a flattened surface that extends above the other tongue papillae. About 12 in number.

* Circumvallate papillae are distributed in the V region of the posterior dorsal surface of the tongue.

* Many taste buds can be found in the epithelium covering their lateral surfaces.http://www.lab.anhb.uwa.edu.au/mb140/7. Taste budsa. Oval multicellular structuresb. Cells surround a cavity that communicates with the oral cavity via a small pore between the apexes of the cells.c. Dissolved substances enter the cavity through this pore and come into contact with the microvilli of gustatory cells (neuroepithelial sensory cells) of the taste bud.d. These chemical stimuli are transduced to an electrical impulse that is transmitted through afferent axons of cranial nerves 7, 9, and 10 that synapse on the basal portions of the neuro-epithelial cells.e. Action potentials travel along these axons to the portions of the brain responsible for our sense of taste.

http://www.lab.anhb.uwa.edu.au/mb140/The Human Digestive SystemThe bolus passes down the esophagus by peristalsis.Peristalsis is a wave of muscular contractions that push the bolus down towards the stomach.

The Human Digestive SystemTo enter the stomach, the bolus must pass through the lower esophageal sphincter, a tight muscle that keeps stomach acid out of the esophagus.

The Human Digestive SystemThe stomach has folds called rugae and is a big muscular pouch which churns the bolus (Physical Digestion) and mixes it with gastric juice, a mixture of stomach acid, mucus and enzymes.

The Human Digestive SystemThe acid kills off any invading bacteria or viruses.The enzymes help break down proteins and lipids. Chemical Digestion.The mucus protects the lining of the stomach from being eaten away by the acid.

The Human Digestive SystemThe stomach does do some absorption too.Some medicines (i.e. aspirin), water and alcohol are all absorbed through the stomach.The digested bolus is now called chyme and it leaves the stomach by passing through the pyloric sphincter.

32StomachFunctionsMix foodReservoirStart digestion ofProteinNucleic acidsFatsActivates some enzymesDestroy some bacteriaMakes intrinsic factor B 12 absorptionDestroys some bacteria

AbsorbsAlcoholWaterLipophilic acidB 12

The Human Digestive SystemChyme is now in the small intestine.The majority of absorption occurs here.The liver and pancreas help the small intestine to maximize absorption.The small intestine is broken down into three parts:

The Human Digestive SystemDuodenumBile, produced in the liver but stored in the gall bladder, enters through the bile duct. It breaks down fats.The pancreas secretes pancreatic juice to reduce the acidity of the chyme.

The Human Digestive SystemJejunumThe jejunum is where the majority of absorption takes place.It has tiny fingerlike projections called villi lining it, which increase the surface area for absorbing nutrients.

37Small IntestineSecretes digestive enzymesPeptidasesAmino-Di-Tri-SucrasesMaltaseLactaseSaccharidasesDi-Tri-LipaseNucleases

The Human Digestive SystemEach villi itself has tiny fingerlike projections called microvilli, which further increase the surface area for absorption.

The Human Digestive SystemIleumThe last portion of the small intestine is the ileum, which has fewer villi and basically compacts the leftovers to pass through the caecum into the large intestine.

The Human Digestive SystemThe large intestine (or colon) is used to absorb water from the waste material leftover and to produce vitamin K and some B vitamins using the helpful bacteria that live here.

43Large IntestineHistologyNo villiNo permanent circular foldsSmooth muscleTaeniae coliHaustraEpiploic appendagesOtherwise like rest of Gl tract44Large IntestineFunctionsMechanical digestionHaustral churningPeristalsisReflexes GastroilealGastrocolicChemical digestion Bacterial digestionFerment carbohydratesProtein/amino acid breakdown AbsorbsMore waterVitamins B K Concentrate/eliminate wastesThe Human Digestive SystemAll leftover waste is compacted and stored at the end of the large intestine called the rectum.When full, the anal sphincter loosens and the waste, called feces, passes out of the body through the anus.

47LiverFunctionsMakes bileDetergent emulsifies fatsRelease promoted by:Vagus n.CCKSecretinContainsWaterBile saltsBile pigmentsElectrolytesCholesterolLecithin

48LiverDetoxifies/removesDrugsAlcoholStoresGycolgenVitamins (A, D, E, K)Fe and other mineralsCholesterolActivates vitamin DFetal RBC productionPhagocytosisMetabolizes absorbed food moleculesCarbohydratesProteinsLipids

49LiverDual blood supplyHepatic portal veinDirect input from small intestineHepatic artery/veinDirect links to heart

50Feces Formation and DefecationChyme dehydrated to form fecesFeces compositionWaterInorganic saltsEpithelial cellsBacteriaByproducts of digestionDefecationPeristalsis pushes feces into rectumRectal walls stretchControlParasympatheticVoluntary

RuminansiaGrazer: makan rumput (sapi, kerbau, biri-biri)Browser: makan ranting & semak (rusa & kerabatnya )Keduanya (kambing)

Hewan pemamah biak (ruminansia) adalah sekumpulan hewan pemakan tumbuhan (herbivora) yang mencerna makanannya dalam beberapa langkah:menelan bahan mentah mengeluarkan makanan yang sudah setengah dicerna dari perutnya mengunyahnya lagi. Lambung hewan-hewan ini tidak hanya memiliki satu ruang (monogastrik) tetapi lebih dari satu ruang (poligastrik, harafiah: berperut banyak).Pencernaan Ruminansia Alat pencernaannya terdiri: Mulutfaringesophaguslambung(rumen, retikulum, omasum,abomasum)usus halus (duodenum, ileum, jejenum)usus besaranus.

1. Rongga Mulutdibentuk oleh tiga atap:palatum durum (langit-langit keras)palatum mole (langit-langit lunak)velum palastini (bagian tepi)Dasar rongga mulut bersifat lunakDi dalam rongga mulut: gigi, lidah, kelenjar ludah.rahang dapat bergerak menyamping untuk menggiling makanan.lidah : untuk mengambil makanan & menempatkan pada gigiludah : mengandung enzim yang ada hubungannya dengan selulosa (makan rumput)gigi tidak punya taring

Susunan gigi hewan ruminansia

I= insisivus = gigi seriC= kaninus = gigi taringP= premolar = geraham depanM= molar = geraham belakang

33000000Rahang atasMPCIICPMJenis gigi33044033Rahang bawahFungsi gigi seri dan gerahamGigi geraham molar: menggiling & menggilas dinding sel tumbuhan yang mengandung selulosa (gerakan gigi ke kiri & ke kanan gerakan menggiling & menggilas)Pada diastema:lidah dijulurkan untuk merenggut rumput & memasukkannya ke dalam mulutgigi seri : memotong & menjepit makanan

2. FaringFaring merupakan persimpangan saluran nafas dengan saluran cerna. jalan makan harus cepat. Pada faring, bolus tidak akan berubah.3. EshopagusKerongkongan berfungsi sebagai penyalur bolus ke rumen.Pada kerongkongan terdapat kelenjar sekretoris: makanan tidak berubah.59LambungLambung terdiri dari : kardia, fundus, badan (sekresi pepsin dan HCl) dan pylorus (sekresi mucus : gastrin). Lambung berfungsi sebagai tempat menyimpan bahan makanan sementara, lambung mengalami proses mekanis dan kimiawi, adanya gerakan lambung dan cairan lambung bersifat asam. Lambung terbagi menjadi 4 ruang, yaitu rumen, retikulum, omasum, abomasum

RumenDi rumen terdapat simbiosis anatara hewan pemamah biak dengan bakteri dan flagelata yang dapat menghasilkan enzim selulose. Bakteri yang mampu menghancurkan selulose contohnya adalah Cytophaga dan Cypromonas subtilis. Akibat perombakan oleh flagelata ini, feses dapat digunakan untuk pupuk dan dapat pula digunakan sebagai bahan dalam pembuatan biogas melalui proses peragian.Di dalam rumen terjadi pencernaan protein dan polisakarida, serta fermentasi selulosa oleh enzim selulase. Bakteri di dalam perut besar juga akan membentuk vitamin B-kompleks. Dari rumen, makanan masuk ke retikulum.

RetikulumDi retikulum, makanan dibentuk menjadi gumpalan-gumpalan kasar yang disebut bolus. Pada saat sapi beristirahat, bolus yang disimpan sedikit demi sedikit dikeluarkan dari retikulum untuk dikunyah lagi. Sesudah itu ditelan lagi masuk ke retikulum, lalu ke omasum, di omasum terjadi penyerapan air dari pengunyahan, dan selanjutnya ke abomasum.AbomasumAbomasum merupakan tempat terjadinya sekresi asam dan enzim pencernaan untuk mencerna makanan. Hasil pencernaan di abomasum menghasilkan bentuk bubur yang disebut kim.Kim kemudian menuju usus dua belas jari dan masuk ke bagian usus halus lainnya. Di usus halus ini terjadi penyerapan hasil pencernaan, sedangkan makanan yang tidak tercerna menuju usus besar dan mengalami penyerapan air menjadi feses. Kemudian, feses menuju rektum dan keluar melalui anus.Usus HalusPada usus kecil / halus sangat penting dalam pemecahan dan absorpsi. Terjadi pemecahan bahan makanan secara sempurna dan penyerapan sari makanan secara besar-besaran di duodenum, jejenum, dan ileum. Usus KasarUsus kasar (intestinum crasum = colon) mempuyai ciri-ciri sbb:Ukuran lebih besar daripada usus halus dan terdapat sakulasi (kantong-kantong)Pada usus kasar terjadi fermentasi dan absorpsi air dan elektrolit secara intensifUsus kasar hanya sedikit menggunakan gerakan peristaltik.KesimpulanPerjalanan makanan pada pencernaan hewan ruminansia:1. Rumput di mulut dikunyah 2. Esofagus 3. Rumen, pencernaan polisakarida,protein, dan fermentasi selulosa oleh enzim selulase 4. Retikulum, membentuk bolus 5. Mulut, dikunyah lagi 6. Retikulum 7. Omasum 8. Abomasum, pencernaan oleh enzim pencernaan.

Figure 21.12ACARNIVOREHERBIVORESmallintestineStomachCecumColon(largeintestine)Small intestine69Beberapa mamalia mengolah selulosa dengan bantuan mikroba pada usus besar atau cecumCecum adalah kantung tempat pertemuan usus halus dan usus besarContoh : pada kuda dan gajahMamalia lain mengolah ulang kotoran mereka untuk diambil nutrients-nyaContoh : Kelinci dan beberapa rodentia70

BIRDMouthEsophagusStomachGizzardCropIntestineAnus71PERKEMBANGAN SISTEM PENCERNAANMetenteron (bumbung endoderm) terdiri dari 5 daerah:StomodeumForegutMidgutHindgutProctodeum

SALURAN PENCERNAAN

Bentuk memanjangLanjutan pharynxDilapisi epitel stratified rambut silia mesentriumOesophagusBag.dorsal tumbuh lebih cepat drpd ventral (kurvatura mayor dan minor)Jendolan di bag.kranial menjadi bag.fundusMengalami rotasi 90o, kurvatura mayor di kiri minor di kananAda hepar, ventriculus terdorong ke sebelah kiri rongga abdomen

VentriculusModerm splangnik membentuk :1. tunika sub-mukosa2. tunika muskularis3. tunika serosaUjung distal ventriculus : pilorusPembatas dgn duodenum : sfinkter pilorusVentriculusAves memiliki proventriculusRumiantia memiliki rumen, reticulum, psalteriumMamalia memiliki cardia, fundus, corpus, pylorus Perbandingan Ventriculus

Posterior ventriculus cloacaBag.pertengahan masih berhubungan dgn yolk sac, di sebelah ventral embryoDilihat dr yolk sac, intestine bagian :Kranial akan menjadi duodenum, jejenum, sebagaian ileumCaudal akan menjadi ileum posterior, colon, rectumIntestineDitunjang oleh mesentrium dorsal dan ventralMengalami torsion (pelekukan), rotation (pemutaran), herniasi, dan coiling (penggulungan)Pemutaran anti clock wise, porosnya arteri mesenterika superior, bag.kranial ke kanan dan caudal ke kiri.Intestine

Rongga abdominal tidak membesar, intestine terus memanjang herniasi di daerah tali pusat (hernia umbilikus)Coiling di bagian ileumUjung distal ileum colon asenden, menjendol ke arah caudal. Penjuluran pada saekum : appendix (usus buntu)IntestineLanjutan usus halusTerdiri dari colon dan rectum (paling ujung saluran pencernaan)berdasar letak anatominya, colon asenden, c.transversal, c.desenden, dan c.sigmoid Paling distal rectum, lapisan endoderm berdempet dgn ektoderm : membran anusMembran anus pecah : lubang anus

Usus Besar

Dari satu lapisan menjadi vili, berlekuk-lekukTerbentuk glandula Lieberkuhn (penjuluran epitel yg berlipat ke dlm mukosa) di daerah ususglandula Brunner di daerah duodenumkelompok limfonodulus : glandula limfa dan bercak Peyer di sub mukosa (masa fetus)

Perubahan pada Epitel di Usus

Kotoran fetus (mekoneum) tertelan fetus sampai ke dalam usus halus. Mekoneum steril, berwarna hijau.Mekoneum terdiri dari campuran mukus, empedu, sel yg terlepas, rambut nalugo, sekresi kelenjar kulit.For Your Infohttp://www.rvc.ac.uk/review/abdomen/HTML/intestinal3.htmhttp://www.rvc.ac.uk/review/abdomen/HTML/intestinal.htmhttp://embryology.med.unsw.edu.au/Notes/images/git/greater-omentum.jpg&imgrefurl=http://embryology.med.unsw.edu.au/Science/ANAT2341lab05_3.htm&usg=__ihRXMc7PLkmiIZVLx2VmZxtU0Ys=&h=419&w=537&sz=48&hl=id&start=1&zoom=1&tbnid=OBipB03dNaroaM:&tbnh=103&tbnw=132&ei=ZB-FT66vFcumrAerndm3Bg&prev=/search%3Fq%3Dperkembangan%2Blambung%26hl%3Did%26client%3Dfirefox-a%26sa%3DX%26rls%3Dorg.mozilla:en-US:official%26biw%3D1126%26bih%3D397%26tbm%3Disch%26prmd%3Dimvnsb&itbs=1

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