Part SplanchnologyⅡ

Alimentary system

Respiratory system

Urinary system

Genital system

VisceraMale Genital system

Female Genital system

But the viscera have some general features.

1.Lacations:within or near the important cavities.

2.Tube: each system has a tube with a opening

3.The main functions of the viscera are fulfill the metabolism and maintain the life of the species.

General structures of the viscera

Hollow organs

Solid organs: Hilum

腹股沟中点

anterior median line-

sternal line midclavicular line parasternal line

Ⅰ. The common used reference lines of the thorax

The reference lines of the thorax and abdomen regions

scapular line

paravertebral line

posterior median line

(midvertebral line)

upper right quadrant upper left quadrant

lower right quadrant lower left quadrant

Ⅱ.The abdominal regions

4 regions

9 regions

transtubercular plane

subcostal plane

midclavicular line

epigastric region

umbilical region

pubic region

hypochondrium

flank

groin

digestive canal

digestive glands

Chapter 5 The alimentary system (digestive system)

Composition

Digestive canal• Mouth• Pharynx• Esophagus • Stomach • Small intestine• Large intestine

Duodenum JejunumIleum

Digestive glands

Superior digestive canal

Inferior digestive canal

• Major salivary glands• Liver• Pancreas

Function: ingestion, digestion, absorption, egesting

Mouth Pharynx

Esophagus

Stomach

Duodenum

JejunumIleum

Large intestine

Liver

Pancreas

Major salivary glands

Section 1 The Oral Cavity

Consists of two parts• Oral vestibule : between cheeks and li

p and teeth• Oral cavity proper: within arch of teet

h Oral vestibule leads, by the space behi

nd the molar teeth, into the oral cavity proper

Boundaries• Anterior and lateral: gum and teeth• Posterior: oropharyngeal isthmus• Roof: palate • Floor: tongue, muscles and mucous m

embrane

• PalateTwo parts• Hard palate: anterior 2/3, formed

by the maxilla and palatine bone• Soft palate: posterior 1/3

– Uvula

– Palatoglossal arch

– Palatopharyngeal arch

Oropharyngeal isthmus superiorly formed by the soft palate, both sides of palatoglossal arches, and root of tongue inferiorly.

软腭

soft palate

hard palate

uvula

palatoglossal arch

palatopharyngeal arch

oropharyngeal isthmus※ ※

• Teeth

General features• Two sets:

– Deciduous– Permanent

• Classification: – Incisors– Canine– Premolars– Molars

Deciduous teeth: are 20 in number• Ten teeth in each mandibular and maxillary arch • Central incisor, lateral incisor, canine, first molar and second

molar in each quadrant

Upper jaw Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ total 20

Lower jaw in. in. can. mol. mol.

• Eruption: stars at about 6 mouth of age and continues to beginning of two years

• Shedding: occurs between 6th and 12th years with replacement by permanent teeth

Permanent teeth (adult): are 32 in number • Sixteen in each mandibular and maxillary arch• Two incisors, one canine, two premolars, and thre

e molars in each quadrant

Upper jaw 1 2 3 4 5 6 7 8 total 32

Lower jaw • First permanent molar － appears at about 6 years• Third molars (wisdom teeth) － many erupt at any

time after 12 years of age or not at all (impaction).

General description• Each tooth consists of 3

parts:

– Crown

– Neck

– Root

• Dental cavity － contains connective tissue, blood vessels and nerves, and is continuous with the periodontal tissue through the root canal and apical foramen.

The types of the permanent teeth

incisors canine premolars molars

1 root of tooth 1-2 roots 2( below) or 3(above) roots

crown of tooth

root of tooth

neck of tooth

root canal

Gingivae (gums):oral mucosa that surround the teeth and cover adjacent regions of the alveolar bone.

Calcified tissues• Dentine － is a yellowish white

tissue, that forms the bulk of tooth.

• Enamel － is a head, brittle white tissue that covers the crown of the tooth

• Cement － is an unusual form of bone that covers the root of the tooth

Periodontal tissue• Periodontal membrane

• Alveolar bone

• Gum

• Tongue － muscular organ

Two parts: divided two parts by v-shaped terminal sulcus

• Body of tongue － ant 2/3 ， apex of tongue － free rounded tip

• Root of tongue － post 1/3

At the apex of terminal sulcus is a small median pit, the foramen cecum of tongue

Lingual mucous membrane • Papillae of tongue

– filiform papillae

– fungiform papillae

– foliate papillae contain taste buds

– vallate papillae

• Lingual tonsil

－ masses of submucosal lymphoid tissue on the root of tongue

lingual tonsil

vallate papillae

terminal sulcus

foliate papillae

fungiform papillae

filiform papillae

Inferior surface of tongue

• Frenulum of tongue － a midline fold of mucous membrane connecting tongue to floor of mouth

• Sublingual caruncle － small elevation

• Sublingual fold

frenulum of tongue

sublingual caruncle

sublingual fold

sublingual gland

Muscles of tongue• Intrinsic muscles of tongue

– Involved in changing shape of tongue

– Include longitudinal, transverse and vertical muscles of tongue

• Extrinsic muscles of tongue – Genioglossus Arises from mental spine of mand

ible and inserts into either side of midline of tongue

Action: acting together draw tongue forward and downward (depresses and protrudes tongue ); acting along making apex of tongue to opposite side

Intrinsic muscles

superior longitudinal muscle

inferior longitudinal muscle

transverse muscle

vertical muscle

Extrinsic muscles

※ genioglossus

• Major salivary glandsParotid gland• superficial part and deep part• triangular in shape, lies below

and in front of the external acoustic meatus, and partially covers the masseter.

• Parotid duct: arises front anterior border of gland, runs over the masseter a finger’s breadth below the zygomatic arch to pierce the buccinator and opens into the mouth cavity, opposite the upper second molar tooth

Submandibular gland • Position: lies in submandibular tri

angle, between anterior and posterior bellies of digastric

• Duct opens on to sublingual caruncle

Sublingual gland• Position: situated beneath the mu

cous membrane of the floor of mouth

• Ducts – Major sublingual duct － open

s onto the sublingual caruncle– Minor sublingual ducts － ope

n onto the sublingual fold

Section 2 The Pharynx

General features• A –fibromuscular tube, part

of digestive and respiratory systems

• Extends from base of skull to the inferior border of cricoid cartilage (lower border of C6 level)

• Three segments

soft palate

Inferior border of the vertebra C6

upper margin of the epiglottis

nasopharynx

oropharynx

laryngopharynx

torus tubariuspharyngeal recess

opening of the pharyngotympanic tube

pharyngeal tonsil

Nasopharynx － posterior to nasal cavities

• Extends from the base of skull to level of soft palate

• Structures– Opening of the pharyngoty

mpanic tube – Torus tubarius– Pharyngeal recess– Pharyngeal tonsil

Oropharynx － posterior to oral cavity

•Lies below soft palate, extends to upper border of epiglottis

•Palate tonsils

palate tonsil

Laryngopharynx

• Structures– Piriform fossae － lies

on each side of the inlet of larynx. piriform fo

ssa

Section 3 The Esophagus

• General features － a muscular tuber about 25cm long, connecting the pharynx at level of C6 vertebra, passes through the diaphragm at level of T10 vertebra and after 1~2 cm enters the stomach

• Division: Cervical part Thoracic part Abdominal part

Four constrictions • At its beginning, 15cm from in

cisors, lies at level of C6, is the narrowest part of the esophagus

• Where it is crossed by the arch of aorta

• Where it is crossed by left main bronchus, 25cm from incisors, lies at level of intervertebral disc between T4 and T5.

• Where it passes through the esophageal hiatus of diaphragm, 40cm from incisors, at level of T10

arch of aorta

left main bronchus

esophageal hiatus

junction

Section 4 The Stomach

• Position: in the epigastric,umbilical, and left hypochondrium regions.

• Shape-J-like shape• Two surface: anterior and posterior• Two openings

– Cardia– Pyloric orifice: Pyloric sphincter

• Four regions

• Cardia

• Fundus of stomach

• Body of stomach

• Pyloric part: Pyloric antrum and Pyloric canal

Cardia

Fundus of stomach

Body of stomach

Pyloric antrumPyloric canal

Pyloric part

• Two curvatures

• Lesser curvature : short, concave and directed to the right and upward, near its lower part is angular incisure

• Greater curvature : long, convex and directed to the left and downward, at the junction of left margin of esophagus and greater curvature is cardiac notch

pyloric orifice

lesser curvature

greater curvature

angular incisure

cardiac notch

cardiac orifice

pyloric sphincterpyloric valve

Section 5 The Small Intestine

• About 6-7m long, • Divided into

– Duodenum

– Jejunum

– Ilium

Duodenum

Jejunum Ilium

• Duodenum

Four parts • Superior part

– Duodenal cap – Superior duodenal flexure

• Descending part– Longitudinal fold of duo

denum– Major duodenal papilla– Minor duodenal papilla– Inferior duodenal flexure

• Inferior part• Ascending part

– duodenojejunal flexure

superior part

ampulla (duodenal cap )

pylorus

superior duodenal flexure

circular mucosal folds

descending part

major duodenal papilla

minor duodenal papilla

inferior duodenal flexure

• Suspensory muscle of duodenum (ligament of Treitz), a surgical landmark, descends from the right crus of diaphragm to duodenal termination.

• Jejunum and ileum

circular fold

aggregated lymphatic

follicles

solitary lymphatic

follicles

jejunum

ileum

Jejunum and ileum

Characteristics Jejunum Ileum

Position Upper 2/5 Lower 3/5

Diameter Greater Less

Wall Thicker Thin

Circular folds Larger, numerous and large villi

Fewer ， smaller and less abundant villi

Vascularity Greater Less

Colour Deeper red Paler pink

Lymphatic follicles Solitary Aggregated

Fat in mesentery Less More

Section 6 Large Intestine

• Approximately 1.5m long, • Five parts:

– Cecum

– Vermiform appendix

– Colon

– Rectum

– Canal

Large Intestine Features• Larger• Taeniae coli• Haustra of colon• Omental appendice

taeniae coli

haustra of colon

omental appendices

• Cecum Blind sac, first part of larg

e intestine, with largest diameter and thinnest wall

• Lies in right iliac fossa• The ilium enters the cecu

m obliquely, and partially invaginates into it, forming the ileocecal valve － consists of two folds, probably delays flow of ileal contents into large intestine

ileum

ileocecal fold

ileocecal orifice

• Vermiform appendix

• Blind worm-like tube, 6 － 8cm long, about 0.5cm in diameter

• Opens into posteromedial aspect of cecum ，about 2 cm below ileoceal orifice

• The base at the appendix lies at the point of convergence of three colic bands (used as a guide to find the appendix during operation)

mesoappendix appendicular vessels

taeniae coli

• Surface marking of the base is at the so-called McBurney’s point which is at junction of lateral and middle thirds of line joining right anterior superior iliac spine and umbilicus

Mesentery of vermiform appendix• Triangular mesentery － extends fr

om terminal part of ileum to appendix

• Appendicular a. runs in free margin of the meseoappendix then along wall of appendix

Tip variable in position

• Preileal

• Pelvic

• Retrocecal

• Retroileal

• Subcecal

• Colon

• Ascending colon– right colic flexure

• Transverse colon– left colic flexure

• Descending colon descends almost vertically from left colic flexure to sigmoid colon at left iliac crest.

• Sigmoid colon － extends from descending colon to rectum at level of S3.

• Rectum

Position: within pelvic cavity, extends from S3 to pelvic diaphragm.

Curves• Sagittal plane

– Sacral flexure convex backward– Perineal flexure convex forward.

• Coronal plane– Upper and lower part － convex

to the right.– Middle part － convex to the left.

Lower part of rectum dilated, to form ampulla of rectum,three transverse folds of rectum

sacral flexure

perineal flexure

anal canal

ampulla

of rectum

• Anal canal• Anal columns － 6-11 in number, • Anal valves• Anal sinuses • Anorectal line• Pectinate line

– Above line, of endodermal origin– Below line, of ectodermal origin

• Anal pecten• White line (anocutaneous line) • Anus• Anal sphincters

– Sphincter ani internus– Sphincter ani externus

anal columns

anal valves

anal sinus

anal pecten

pectinate line white line

sphincter ani internus

sphincter ani externus

Comparison between the sites above and below the pectinate line

  the site above the pectinate line the site below the pectinate line

  epithelium simple cuboidal epithelium stratified squamous epithelium

 

aterial supply superior and inferior rectal artery anal artery

 

venous return hepatic portal vein internal iliac vein

 

lymph drainage lumbar lymph nodes superficial inguinal lymph nodes

innervation visceral nerves somatic nerves

 

• Position Most of liver lies in the right hyp

ochondrum and epigastric region, less part extending into the left hypochondrum.

Section 7 The Liver

• Shape• Two surfaces

– Diaphragmatic surface Convex and smooth

• Divided into right and left areas by falciform lig.

– Visceral surface

falciform ligment

ligamentum teres hepatis

right triangular ligament left triangular

ligament

Visceral surface － has a H-shaped fissures and grooves

• Left limb of H – Anteriorly: fissure for

ligamentum teres hepatis

– Posteriorly: fissure for ligamentum venosum

• Right limb of H – Anteriorly: fossa for g

allbladder– Posteriorly: sulcus for

vena cava

• Cross-bar of H is the porta hepatis: traversed by right and left hepatic ducts, left and right branches of proper hepatic artery and hepatic portal vein, nerves and lymphatic vessels. These structures which are surrounded by connective tissue called hepatic pedicle

• Four lobes: left, right, quadrate and caudate lobes

Inferior vena cava

fissure for

ligamentum teres

gallbladder

fissure for ligamentum venosum

Right lobe

Caudate lobe

Quadrate lobe

ligamentum teres hepatis

Left lobe

porta hepatis ※※

hepatic artery proper

portal

vein

common

hepatic

duct

Inferior border –thin and sharp

• Notch for ligamentum teres hepatis

• Notch for gallbladder

The segments of the liver• The segmentation of the liver, bases upon the principal divis

ions of the proper hepatic artery and accompanying hepatic ducts and hepatic portal vein － Glisson system.

• The hepatic veins, however do not follow the same pattern and vary: their main tributaries tend to run rather intersegmental.

Section 7 Extrahepatic Biliary Apparatus

Composition • Gallbladder

• Cystic duct

• Left and right hepatic ducts

• Common hepatic duct

• Bile duct

• GallbladderPosition :lies in fossa for gallbladd

er on visceral surface of liverFour parts• Fundus of gallbladder Surface projection: at the junctio

n of right midclavicular line and right costal arch

• Body of gallbladder• Neck of gallbladderFunction: receives,stores and con

centrates bile

fundus of gallbladder

body of gallbladder

neck of gallbladder

cystic duct

• Biliary duct system

• Right and left hepatic ducts unite outside of liver to form the common hepatic duct

• Cystic duct joins common hepatic duct to form bile duct

• Bile duct and pancreatic duct run obliquely through the wall of the descending part of duodenum where the two ducts usually unite to form the hepatopancreatic ampulla (ampulla of Vater), which rounded by sphincter of hepatopancreatic ampulla (sphincter of Oddi), each has an independent sphincteric mechanism for regulating flow, and opens at the major duodenal papilla

Bile is secreted by the liver cells

Common hepatic duct

when the fat enters the small intestine, the gallbladder contracts, the sphincter of hepatopancreatic ampulla relax

Bile duct

Major duodenal papilla

Biliary ductuli Right and left hepatic ducts

Cystic duct Gallbladder (store, concentrate)

left hepatic duct

common hepatic duct

cystic duct

bile duct

hepatopancreatic ampulla

(ampulla of Vater)

pancreatic duct

right hepatic duct

major duodenal papilla

Triangle of Calot• Boundaries: the common hepatic duct on the left, the cysti

c duct on the right, the liver, superiorily• Content: cystic artery

Sect ion 8 The Pancreas

• Shape and Position• A soft yellowish lobulat

ed gland• Lies behind the peritone

um on the posterior abdominal wall, roughly at the level of of L1~L2

• Five parts• Head - Flattened and locate

d in C-shaped curvatune of duodenum

• Uncinate process• Neck － constricted part• Body• Tail － runs in base of spleno

renal ligament to reach hilum of spleen

• Pancreatic duct• Main Pancreatic duct

– Begins at tail and throughout gland

– Joins common bile duct before entering descending part of duodenum at major duodenal papilla

• Accessory pancreatic duct– Opens 2cm above main

duct at minor duodenal papilla

• Pancreas Function

The pancreas is both an exocrine and an endocrine gland.

The exocrine portion of the gland produces a secretion that contains enzymes that are capable of hydrolyzing proteins, fats, and carbohydrates.

The endocrine portion of the gland-the pancreatic islet produces the hormones insulin that play a key role in carbohydrate metabolism.

Definition of superior and inferior alimentary canal. Structures of the soft palate. Definition of oropharyngeal isthmus. Structures of mucous membrane of tongue. Action of genioglossus. Names, position and openings of salivary glands. Classification of pharynx and structures of the nasopharynx. Constrictions of esophagus. Shape and structures of stomach and duodenum.

Highlights

Structures of descending part of duodenum.Position of caecum and vermiform appendix. Characteristic of cecum and colon. Position of ileocecal valve. Shape of rectum. Structures of anal canal. Shape and position of liver. Position and structure of porta hepatis. Boundaries and content of Triangle Calot. Formation of biliary ducts. Position and shape of pancreas.

Highlights