No. 5No. 5

1. Pharynx1. Pharynx 2. Esophagus2. Esophagus 3. Stomach3. Stomach

Section 2 The PharynxSection 2 The Pharynx

The The pharynx pharynx is a musculomembranous tube wis a musculomembranous tube which is used by the digestive system as well as hich is used by the digestive system as well as the respiratory system.the respiratory system.

Location: The pharynx is placed behind the naLocation: The pharynx is placed behind the nasal cavities, the mouth and the larynx. It extensal cavities, the mouth and the larynx. It extends from the base of the skull to the level of the ds from the base of the skull to the level of the sixth cervical vertebra where it becomes the essixth cervical vertebra where it becomes the esophagus. The cricoid cartilage marks this chanophagus. The cricoid cartilage marks this change on the front of the neck.ge on the front of the neck.

CommunicationsCommunications: The pharynx communicates:: The pharynx communicates: a. with the nasal cavity through the nares,a. with the nasal cavity through the nares, b. with the oral cavity through the fauces,b. with the oral cavity through the fauces, c. with the middle-ear cavity through the auditory tubec. with the middle-ear cavity through the auditory tube

s,s, d. with the larynx through the glottis,d. with the larynx through the glottis, e. with the esophagus.e. with the esophagus. DivisionDivision: For descriptive purposes the pharynx is divid: For descriptive purposes the pharynx is divid

ed into three parts:ed into three parts: nasopharynx,nasopharynx, oropharynx,oropharynx, laryngopharynx.laryngopharynx.

ⅠⅠ. . NasopharynxNasopharynx (the Nasal Part o (the Nasal Part of Pharynx)f Pharynx)

LocationLocation:: The nasopharynx is located immediately behind the nThe nasopharynx is located immediately behind the n

asal cavity and is continuous with it through the two lasal cavity and is continuous with it through the two large arge choanaechoanae ((naresnares, posterior nasal apertures)., posterior nasal apertures).

The morphology of the lateral walls of nasopharynx:The morphology of the lateral walls of nasopharynx: On its lateral walls, there are On its lateral walls, there are pharyngeal openings of pharyngeal openings of

auditory tubeauditory tube, through which the nasopharynx receiv, through which the nasopharynx receives the es the auditory tubesauditory tubes that connect the nasopharynx that connect the nasopharynx with the cavity of the middle ear.with the cavity of the middle ear.

The pharyngeal opening of auditory tube lThe pharyngeal opening of auditory tube lies 10ies 10 ～～ 12.5 mm behind and a little bel12.5 mm behind and a little below the posterior end of the inferior nasaow the posterior end of the inferior nasal concha. The posterior lip of this openinl concha. The posterior lip of this opening is prominent, due to the underlying carg is prominent, due to the underlying cartilage of the auditory tube, and is termetilage of the auditory tube, and is termed the d the tubal torustubal torus, behind which lies the , behind which lies the slit-like slit-like pharyngeal recesspharyngeal recess..

Pharyngeal tonsil and tubal tonsil:Pharyngeal tonsil and tubal tonsil: A collection of lymphoid tissue, best developed A collection of lymphoid tissue, best developed

in children, lies in the mucous membrane of thin children, lies in the mucous membrane of the roof and posterior wall of the nasopharynx is e roof and posterior wall of the nasopharynx is known as the known as the pharyngeal tonsilpharyngeal tonsil..

The lateral prolongation of the pharyngeal tonsThe lateral prolongation of the pharyngeal tonsil behind the pharyngeal opening of the auditoil behind the pharyngeal opening of the auditory tube is known as thery tube is known as the tubal tonsiltubal tonsil..

ⅡⅡ. . OropharynxOropharynx (The Oral Part of (The Oral Part of Pharynx)Pharynx)

The The oropharynxoropharynx is a continuation of the is a continuation of the nasopharynx, extending from the soft panasopharynx, extending from the soft palate to the beginning of the laryngopharlate to the beginning of the laryngopharynx.ynx.

It communicates with the oral cavity thrIt communicates with the oral cavity through the ough the faucesfauces..

The oropharynx therefore receives food The oropharynx therefore receives food from the oral cavity and air from the nasfrom the oral cavity and air from the nasopharynx.opharynx.

Palatine tonsils and lingual tonsilsPalatine tonsils and lingual tonsils:: On the side walls are two On the side walls are two palatine tonsilspalatine tonsils.. Embedded in the base of the tongue is an aggregate oEmbedded in the base of the tongue is an aggregate o

f f lingual tonsilslingual tonsils.. Tonsilar ringTonsilar ring: the palatine tonsil together with the pha: the palatine tonsil together with the pha

ryngeal tonsil of the nasopharynx and the lymphoid tiryngeal tonsil of the nasopharynx and the lymphoid tissue on the back of the tongue (lingual tonsil) completssue on the back of the tongue (lingual tonsil) complete a e a tonsilar ringtonsilar ring, but it does not form a strong defense , but it does not form a strong defense system against the spread of infection from the oral asystem against the spread of infection from the oral and nasal cavities to the lower respiratory organs.nd nasal cavities to the lower respiratory organs.

ⅢⅢ. . LaryngopharynxLaryngopharynx (The Larynge (The Laryngeal Part of Pharynx)al Part of Pharynx)

The laryngopharynx extends from the oropharThe laryngopharynx extends from the oropharynx above to the esophagus below. Anteriorly iynx above to the esophagus below. Anteriorly it communicates with the cavity of the larynx tt communicates with the cavity of the larynx through the inlet of the larynx.hrough the inlet of the larynx.

Piriform recessPiriform recess:: A small recess, termed the A small recess, termed the piriform recesspiriform recess, lies , lies

on each side of the laryngeal orifice. Foreign bon each side of the laryngeal orifice. Foreign bodies may become lodged in this recess.odies may become lodged in this recess.

Section 3 The EsophagusSection 3 The Esophagus The esophagus is a muscular tube, about 25 cThe esophagus is a muscular tube, about 25 c

m long, that connects the pharynx with the stom long, that connects the pharynx with the stomach.mach.

LocationLocation: it is located behind the trachea. It pa: it is located behind the trachea. It passes down through the lower part of the neck sses down through the lower part of the neck and the superior and posterior parts of the meand the superior and posterior parts of the mediastinum, pierces the diaphragm at the level diastinum, pierces the diaphragm at the level of the tenth thoracic vertebra, and ends at the of the tenth thoracic vertebra, and ends at the cardiac orifice of the stomach. It is a narrowest cardiac orifice of the stomach. It is a narrowest portion of the alimentary canal except for the portion of the alimentary canal except for the vermiform appendix.vermiform appendix.

ConstrictionsConstrictions: The esophagus is constricted at:: The esophagus is constricted at: ① ① its commencement, 15 cm from the incisor tits commencement, 15 cm from the incisor t

eeth,eeth, ② ② where is crossed by the left bronchus, 25 cm where is crossed by the left bronchus, 25 cm

from the incisor teeth,from the incisor teeth, ③ ③ where it passes through the diaphragm, 40 cwhere it passes through the diaphragm, 40 c

m from the incisor teeth.m from the incisor teeth.

Section 4 The StomachSection 4 The Stomach

The stomach (or gaster) is the most dilated poThe stomach (or gaster) is the most dilated portion of the alimentary canal.rtion of the alimentary canal.

Shortly after passing through the diaphragm, tShortly after passing through the diaphragm, the esophagus empties into the stomach. he esophagus empties into the stomach.

FunctionsFunctions: Its function of stomach is to prepar: Its function of stomach is to prepare ingested food by mechanical and chemical e ingested food by mechanical and chemical means for digestion.means for digestion.

Its shape and position are varied Its shape and position are varied from person to person and modified from person to person and modified by changes within itself and the by changes within itself and the surrounding viscera. surrounding viscera.

CapacityCapacity: Its mean capacity varies : Its mean capacity varies with age, being about 30 ml at birth, with age, being about 30 ml at birth, increasing gradually to about 800 ml increasing gradually to about 800 ml at puberty, and commonly reaching at puberty, and commonly reaching to about 1500 ml in the adult.to about 1500 ml in the adult.

ⅠⅠ. The Morphology of Stomach. The Morphology of Stomach

The stomach presents:The stomach presents: two openingstwo openings, i.e. cardiac and pyloric op, i.e. cardiac and pyloric op

enings.enings. two curvaturestwo curvatures, i.e. greater and lesser cu, i.e. greater and lesser cu

rvatures.rvatures. two surfacestwo surfaces, i.e. anterior and posterior , i.e. anterior and posterior

surfaces.surfaces. four partsfour parts, i.e. a cardiac part, a fundus, a , i.e. a cardiac part, a fundus, a

body, and a pyloric part.body, and a pyloric part.

ⅠⅠ) Two openings) Two openings

Cardiac orificeCardiac orifice: The opening by which the eso: The opening by which the esophagus communicates with the stomach is the phagus communicates with the stomach is the cardiac orifice (cardia).cardiac orifice (cardia).

It is situated to the left of the median plane, beIt is situated to the left of the median plane, behind the seventh costal cartilage, 2.5 cm from ihind the seventh costal cartilage, 2.5 cm from its junction with the sternum, and at the level ots junction with the sternum, and at the level of the eleventh thoracic vertebra. It is placed abf the eleventh thoracic vertebra. It is placed about 10 cm from the anterior abdominal wall anout 10 cm from the anterior abdominal wall and 40 cm from the incisor teeth.d 40 cm from the incisor teeth.

Pyloric orificePyloric orifice: The opening into the duodenu: The opening into the duodenum is the pyloric orifice (pylorus).m is the pyloric orifice (pylorus).

Its position is usually indicated by a circular groIts position is usually indicated by a circular groove on the surface of the organ, which indicateove on the surface of the organ, which indicates the position of the s the position of the pyloric sphincterpyloric sphincter. In the l. In the living subject, at operation, it can be identified iving subject, at operation, it can be identified by the by the prepyloric veinprepyloric vein, which runs vertically a, which runs vertically across its anterior surface.cross its anterior surface.

ⅡⅡ) Two curvatures) Two curvatures

1. 1. lesser curvaturelesser curvature: The right border of the sto: The right border of the stomach, which is concave, is called the lesser curmach, which is concave, is called the lesser curvature. It extends between the cardiac and pylvature. It extends between the cardiac and pyloric orifices, and forms the right (or posterosuoric orifices, and forms the right (or posterosuperior) border of the stomach.perior) border of the stomach.

The most dependent part of the curve may forThe most dependent part of the curve may form a notch, named the m a notch, named the angular incisureangular incisure, which , which separates the stomach into right and left parts.separates the stomach into right and left parts.

2. 2. greater curvaturegreater curvature: The convex left border is : The convex left border is called the greater curvature.called the greater curvature.

It starts from the cardiac orifice at the cardiac iIt starts from the cardiac orifice at the cardiac incisure to the pyloric orifice.ncisure to the pyloric orifice.

Directly opposite the angular incisure of the lesDirectly opposite the angular incisure of the lesser curvature the greater curvature presents a ser curvature the greater curvature presents a bulge, which is the left extremity of the pyloric bulge, which is the left extremity of the pyloric part of the stomach; this is limited on the right part of the stomach; this is limited on the right by a slight groove, which indicates the subdiviby a slight groove, which indicates the subdivision of the pyloric part into a sion of the pyloric part into a pyloric antrumpyloric antrum a and a nd a pyloric canalpyloric canal. .

ⅢⅢ) Two surfaces ) Two surfaces

1. anterior surface1. anterior surface 2. posterior surface2. posterior surface

ⅣⅣ) Four parts) Four parts

Including:Including: the cardiac part,the cardiac part, the fundus,the fundus, the body,the body, the pyloric part.the pyloric part.

1. 1. fundusfundus: The part of the stomach to the left of and ab: The part of the stomach to the left of and above the cardiac orifice is called the fundus of the stomove the cardiac orifice is called the fundus of the stomach.ach.

2. 2. cardiac partcardiac part: The parts of the stomach near the card: The parts of the stomach near the cardiac orifice.iac orifice.

3. 3. pyloric partpyloric part: The part near the pyloric orifice. It inclu: The part near the pyloric orifice. It includes pyloric antrum and pyloric canal.des pyloric antrum and pyloric canal.

4. 4. bodybody: The main portion of the stomach is called the : The main portion of the stomach is called the body of stomach. The body of stomach is continuous body of stomach. The body of stomach is continuous above with the cardiac part and below with the pyloriabove with the cardiac part and below with the pyloric part.c part.

ⅡⅡ. Location and Relations . Location and Relations

Ⅰ Ⅰ) Location) LocationThe greater part of the stomach lies in the The greater part of the stomach lies in the

left hypochondriac, the smaller part of it left hypochondriac, the smaller part of it lies in the epigastric of the abdomen.lies in the epigastric of the abdomen.

Ⅱ Ⅱ)Relations)RelationsThe stomach has many important relationThe stomach has many important relation

s.s.

1. The anterior surface1. The anterior surface

The left part of the anterior surface is posterior tThe left part of the anterior surface is posterior to the left costal margin. It is contact with the do the left costal margin. It is contact with the diaphragm.iaphragm.

The upper and left part of this surface becomes The upper and left part of this surface becomes posterolateral and is in contact with the gastriposterolateral and is in contact with the gastric surface of the spleen. c surface of the spleen.

The right half is in relation with the left and quadThe right half is in relation with the left and quadrate lobes of the liver and with the anterior abrate lobes of the liver and with the anterior abdominal wall.dominal wall.

When the stomach is empty, the transverse coloWhen the stomach is empty, the transverse colon may lie on the front of this surface.n may lie on the front of this surface.

2. The posterior surface2. The posterior surface

The posterior surface is related to the diaphraThe posterior surface is related to the diaphragm, the left suprarenal gland, the upper part ogm, the left suprarenal gland, the upper part of the front of the left kidney, the splenic artery, f the front of the left kidney, the splenic artery, the anterior surface of the pancreas, the left cothe anterior surface of the pancreas, the left colic flexure, and the upper layer of the transverslic flexure, and the upper layer of the transverse mesocolon. These structures form the shalloe mesocolon. These structures form the shallow w stomach bedstomach bed, but the stomach is separable f, but the stomach is separable from them, and can slide over them, due to the rom them, and can slide over them, due to the intervening omental bursa.intervening omental bursa.

ⅢⅢ. Musculature and Inner Surface . Musculature and Inner Surface

Ⅰ Ⅰ) The musculature of the stomach) The musculature of the stomachThere are three layers of smooth muscle.There are three layers of smooth muscle.The outer longitudinal layer of muscle is best developed The outer longitudinal layer of muscle is best developed

along the curvatures and is continuous with the longitalong the curvatures and is continuous with the longitudinal muscle of the esophagus and duodenum.udinal muscle of the esophagus and duodenum.

The inner circular layer is uniform over the stomach but fThe inner circular layer is uniform over the stomach but forms a thickened muscular ring at the pylorus; this is torms a thickened muscular ring at the pylorus; this is the he pyloric sphincterpyloric sphincter..

The stomach also possesses, between the longitudinal aThe stomach also possesses, between the longitudinal and circular layer, an incomplete layer of oblique musclnd circular layer, an incomplete layer of oblique muscle.e.

Ⅱ Ⅱ) The inner surface of the stomach) The inner surface of the stomachThe mucosa of the stomach is rather thick and vThe mucosa of the stomach is rather thick and v

elvety. When the stomach is empty it is thrown elvety. When the stomach is empty it is thrown into characteristic ridges or rugae. These rugainto characteristic ridges or rugae. These rugae are most prominent in the body and fundus e are most prominent in the body and fundus of the stomach.of the stomach.

The mucosa of the pyloric antrum and the canal The mucosa of the pyloric antrum and the canal is smooth. Gastric ulcers and neoplasms distoris smooth. Gastric ulcers and neoplasms distort the mucous pattern and can be detected radit the mucous pattern and can be detected radiologically.ologically.