Digestive systemDigestive system

Dr. Malik Zohaib AliDr. Malik Zohaib AliDVM, M.Phil. (Anatomy)DVM, M.Phil. (Anatomy)

Digestive systemDigestive system

It consists of muscular tube lined with mucous membrane that is It consists of muscular tube lined with mucous membrane that is continuous with the external skin at the mouth and at the anus. continuous with the external skin at the mouth and at the anus.

FunctionFunction

Ingestion, mastication, digestion and absorption of food and elimination of Ingestion, mastication, digestion and absorption of food and elimination of solid wastes.solid wastes.

Elements of digestive systemElements of digestive system

1. Alimentary Canal1. Alimentary Canal

It is a tube that extends from the lips to the anus. It is a tube that extends from the lips to the anus.

This canal consists of following consecutive segments;This canal consists of following consecutive segments;

Mouth, Pharynx, Esophagus, Stomach, Small intestine, and Large intestineMouth, Pharynx, Esophagus, Stomach, Small intestine, and Large intestine

2. Accessory Organs2. Accessory Organs

Tongue, Teeth, Salivary Glands, Liver, and PancreasTongue, Teeth, Salivary Glands, Liver, and Pancreas

Other relevant structuresOther relevant structures

Abdominal Cavity, Peritoneum and SpleenAbdominal Cavity, Peritoneum and Spleen

Alimentary canalAlimentary canal

MouthMouth

The first part of alimentary canal and is used for holding, grinding, and The first part of alimentary canal and is used for holding, grinding, and mixing food with saliva but may also be used to manipulate the mixing food with saliva but may also be used to manipulate the environment (through grasping of objects) and a defensive and offensive environment (through grasping of objects) and a defensive and offensive weapon. weapon.

PARTS PARTS

The mouth consists of two parts;The mouth consists of two parts;

1. Vestibule1. Vestibule::

It is the small space between the teeth and lips. It is the small space between the teeth and lips.

2. Oral Cavity proper:2. Oral Cavity proper:

Teeth and dental pad enclose this cavity. Teeth and dental pad enclose this cavity.

Lips and cheekLips and cheek

LipsLips

Two musculo-membranous folds which surround the orifice of the Two musculo-membranous folds which surround the orifice of the mouth. The upper lip is deeply grooved with a midline, called philtrum. mouth. The upper lip is deeply grooved with a midline, called philtrum.

The lips are densely innervated by sensory fibers, making them very The lips are densely innervated by sensory fibers, making them very sensitive tactile organs. sensitive tactile organs.

CheeksCheeks

The cheeks form the sides of the mouth. These also present conical papillae.The cheeks form the sides of the mouth. These also present conical papillae.

Hard palateHard palate

It is formed by the incisive, maxilla and palatine bones.It is formed by the incisive, maxilla and palatine bones.

It is bounded in front and on sides by dental arches and is continuous with soft It is bounded in front and on sides by dental arches and is continuous with soft palate behind.palate behind.

Gross featuresGross features

Median Line/Raphe:Median Line/Raphe:

It divides the surface into two equal portions.It divides the surface into two equal portions.

Palatine Ridges:Palatine Ridges:

They cover about two third part of the hard palate.They cover about two third part of the hard palate.

Incisive Papillae:Incisive Papillae:

It is present between the dental pad and first ridge of hard palate.It is present between the dental pad and first ridge of hard palate.

Soft palate and tonsilsSoft palate and tonsils

Soft PalateSoft Palate

It is a musculo-membranous curtain which separates the cavity of the It is a musculo-membranous curtain which separates the cavity of the mouth from that of pharynx.mouth from that of pharynx.

TonsilsTonsils

The tonsils are bean shaped structures which are more or less circumscribed The tonsils are bean shaped structures which are more or less circumscribed aggregation of lymphatic nodules reside in the tonsilar sinus.aggregation of lymphatic nodules reside in the tonsilar sinus.

TongueTongue

TongueTongue

The tongue consists of a mass of muscle covered by mucous membrane. The tongue consists of a mass of muscle covered by mucous membrane.

LocationLocation

The tongue is situated on the floor of the mouth, between the rami of the The tongue is situated on the floor of the mouth, between the rami of the mandible.mandible.

PartsParts

The tongue is divided into three parts.The tongue is divided into three parts.

1. Root: 1. Root: It is attached to the hyoid bone, soft palate and pharynx.It is attached to the hyoid bone, soft palate and pharynx.

2. Body: 2. Body: It constitutes the main mass of the tongue.It constitutes the main mass of the tongue.

3. Apex: 3. Apex: It is free, pointed end of the tongue.It is free, pointed end of the tongue.

Shape and colorShape and color

It is narrower in the middle of the body but width of the apex and root is It is narrower in the middle of the body but width of the apex and root is almost same. The color is variable.almost same. The color is variable.

The entire tongue is mobile through its muscular attachments to the The entire tongue is mobile through its muscular attachments to the hyoid apparatus and mandible.hyoid apparatus and mandible.

TongueTongue

Papillary arrangementPapillary arrangement

The tongue is covered with keratinized stratified squamous epithelium. The tongue is covered with keratinized stratified squamous epithelium. The surface is characterized by a large number of projections called The surface is characterized by a large number of projections called papillae (papilla) that are particularly well-developed on the dorsal surface.papillae (papilla) that are particularly well-developed on the dorsal surface.

Types of Papilla:Types of Papilla: These are of four kinds These are of four kinds

i. Filliform = thread-like i. Filliform = thread-like

They are small thread like; soft to touch.They are small thread like; soft to touch.

ii. Fungiform = mushroom like ii. Fungiform = mushroom like

They are relatively larger and scattered among filliform papillae.They are relatively larger and scattered among filliform papillae.

iii. Lenticulariii. Lenticular

They are rounded papillae on dorsum linguae (dorsal prominence)They are rounded papillae on dorsum linguae (dorsal prominence)

iv. Vallate = cup-shapediv. Vallate = cup-shaped

They are on each side of caudal part of prominence of dorsum. They are on each side of caudal part of prominence of dorsum.

Conti…Conti…

Taste BudsTaste Buds

These are the organs of taste. Following three types of papillae are associated These are the organs of taste. Following three types of papillae are associated with these;with these;

i) Fungiform ii) Vallate iii) Foliatei) Fungiform ii) Vallate iii) Foliate

Gross featuresGross featuresnDorsum Linguae:Dorsum Linguae: It is a dorsal prominence on the dorsal surface of the It is a dorsal prominence on the dorsal surface of the tongue.tongue.nFrenulum Linguae:Frenulum Linguae: A fold of mucous membrane that is attached to the floor A fold of mucous membrane that is attached to the floor of the mouth.of the mouth.nTransverse Groove:Transverse Groove: A furrow present on the dorsal surface of the tongue A furrow present on the dorsal surface of the tongue transversely.transversely.nGlosso-epiglottic FoldGlosso-epiglottic Fold: It passes from the root of the tongue to the base : It passes from the root of the tongue to the base of the Epiglottis. of the Epiglottis.

TeethTeeth

LocationLocation

The teeth are implanted in the alveoli of the bones of the jaws. Teeth The teeth are implanted in the alveoli of the bones of the jaws. Teeth are arranged in two dental arcades, one associated with the mandible and are arranged in two dental arcades, one associated with the mandible and other with the incisive and maxillary bones. other with the incisive and maxillary bones.

PartsParts

A tooth constitutes three parts;A tooth constitutes three parts;

i) Crown: i) Crown: It is visible above the mucous membrane of the gum.It is visible above the mucous membrane of the gum.

ii) Root:ii) Root: anchored part of tooth in a socket of a bone, called an alveolus. anchored part of tooth in a socket of a bone, called an alveolus.

iii) Neck: iii) Neck: junction of crown and root is its neck.junction of crown and root is its neck.

CompositionComposition

Teeth are composed of four types of tissues; (from within to outward)Teeth are composed of four types of tissues; (from within to outward)

i) Pulpi) Pulp: inner part of tooth that contains nerves, vessels and loose CT: inner part of tooth that contains nerves, vessels and loose CT

ii) Dentine:ii) Dentine: connective tissue surrounding the pulp connective tissue surrounding the pulp

iii) Enamel:iii) Enamel: outer surface located in the crown outer surface located in the crown

iv) Cementum:iv) Cementum: outer surface located in the root outer surface located in the root

Conti…Conti…

SurfacesSurfaces

A tooth presents four surfaces;A tooth presents four surfaces;

1. Vestibular: 1. Vestibular: TheThe surface directed towards the lips and cheeks. surface directed towards the lips and cheeks.

2. Lingual:2. Lingual: The surface directed towards the tongue. The surface directed towards the tongue.

3. Contact: 3. Contact: The surface in contact with adjacent tooth in the same dental The surface in contact with adjacent tooth in the same dental pad.pad.

4. Masticating: 4. Masticating: The surface which comes in contact with opposite tooth in jaw.The surface which comes in contact with opposite tooth in jaw.

Sets of TeethSets of Teeth

All the domestic animals are diphyodont. This means they develop a set of All the domestic animals are diphyodont. This means they develop a set of deciduous teeth (also called baby teeth or milk teeth) that fall out and are deciduous teeth (also called baby teeth or milk teeth) that fall out and are replaced with permanent teeth.replaced with permanent teeth.

Thus, there are two sets of teeth based on animals’ growth period.Thus, there are two sets of teeth based on animals’ growth period.Deciduous Teeth Deciduous Teeth Permanent TeethPermanent Teeth

Conti…Conti…

Types of teethTypes of teeth

The teeth are of four types named as follows; The teeth are of four types named as follows;

IncisorIncisor = front, cutting tooth. = front, cutting tooth.

CanineCanine = long, pointed bonelike tooth for grasping and tearing. = long, pointed bonelike tooth for grasping and tearing.

PremolarPremolar = cheek tooth that grinds food. = cheek tooth that grinds food.

Molar Molar = caudal cheek tooth that grinds food.= caudal cheek tooth that grinds food.

Dental formulaDental formula

Dental formula represents the type and number of each tooth type found in Dental formula represents the type and number of each tooth type found in that species.that species.

i) Deciduous Teeth {I 3/3, C 1/1, PM 3/3}i) Deciduous Teeth {I 3/3, C 1/1, PM 3/3}

ii) Permanent Teeth {I 3/3, C 1/1, PM 4/4, M 2/3}ii) Permanent Teeth {I 3/3, C 1/1, PM 4/4, M 2/3}

Salivary GlandsSalivary GlandsSalivaSaliva

The secretion of all the salivary glands is called the saliva. It is the first secretion The secretion of all the salivary glands is called the saliva. It is the first secretion encountered with food in its progress through the alimentary tract.encountered with food in its progress through the alimentary tract.

Salivary glands empty their secretions through ducts that open in mouth at the Salivary glands empty their secretions through ducts that open in mouth at the gums. Saliva contains starch-splitting amylase enzyme, ptylalin. gums. Saliva contains starch-splitting amylase enzyme, ptylalin.

Type of glands on the basis of structureType of glands on the basis of structure

The salivary glands are basically, classified into two categories;The salivary glands are basically, classified into two categories;

1. Chief Salivary Glands1. Chief Salivary Glands

i) Parotid glandi) Parotid gland

ii) Mandibular gland ii) Mandibular gland

iii) Sublingual glandiii) Sublingual gland

2. Minor Salivary Gland2. Minor Salivary Gland

i) Labial gland i) Labial gland

ii) Buccal glandii) Buccal gland

iii) Lingual glandiii) Lingual gland

iv) Palatine glandiv) Palatine gland

Conti…Conti…

Location of glandsLocation of glands

Parotid Gland Parotid Gland located ventral to the ear in relation to the caudal border of the located ventral to the ear in relation to the caudal border of the mandible. mandible.

Mandibular Gland Mandibular Gland usually located ventral to the parotid gland.usually located ventral to the parotid gland.

Sublingual Gland Sublingual Gland located deep to the mucous membrane along the ventral side located deep to the mucous membrane along the ventral side of the lateral surface of the tongue, near the floor of the mouth. of the lateral surface of the tongue, near the floor of the mouth.

Type of glands on the basis of nature of secretionsType of glands on the basis of nature of secretions

The salivary glands are classified as serous, mucous or mixed glands.The salivary glands are classified as serous, mucous or mixed glands.nSerous glandsSerous glands secrete a watery fluid. secrete a watery fluid.nMucous glands Mucous glands secrete mucus, a viscous material that acts as a protective secrete mucus, a viscous material that acts as a protective covering for the surface of mucous membrane.covering for the surface of mucous membrane.nMixed gland Mixed gland produces both mucous and serous fluids.produces both mucous and serous fluids.

The parotid salivary gland secretes primarily a serous saliva. The parotid salivary gland secretes primarily a serous saliva.

The mandibular and sublingual glands are classified as mixed glands. The mandibular and sublingual glands are classified as mixed glands.

Most of the minor salivary glands have a mucous secretion. Most of the minor salivary glands have a mucous secretion.

PharynxPharynxIt is a musculo-membranous sac which forms common passage for both the It is a musculo-membranous sac which forms common passage for both the

respiratory and digestive systems.respiratory and digestive systems.

Division Division

The pharynx is divided into three parts;The pharynx is divided into three parts;

1. Oropharynx: 1. Oropharynx: Its dorsal and ventral boundaries are the soft palate and root of Its dorsal and ventral boundaries are the soft palate and root of the tongue respectively.the tongue respectively.

2. Nasopharynx: 2. Nasopharynx: extends from the posterior nares to the junction of palatopharyngeal extends from the posterior nares to the junction of palatopharyngeal arches.arches.

3. Laryngopharynx: 3. Laryngopharynx: It is situated dorsal to the larynx.It is situated dorsal to the larynx.

OpeningsOpenings

The cavity of the pharynx presents seven openings as following:The cavity of the pharynx presents seven openings as following:

i) One opening of ----------------------------Oral cavity i) One opening of ----------------------------Oral cavity (Oropharynx)(Oropharynx)

ii) Two openings of --------------------------Nasal cavity ii) Two openings of --------------------------Nasal cavity (Nasopharynx)(Nasopharynx)

iii) Two openings of --------------------------Eustachian tubesiii) Two openings of --------------------------Eustachian tubes (Auditus larynges) (Auditus larynges)

iv) One opening of ----------------------------Larynx iv) One opening of ----------------------------Larynx (Laryngopharynx)(Laryngopharynx)

v) One opening of ………………………-Esophagus v) One opening of ………………………-Esophagus (Aditus oesophagi)(Aditus oesophagi)

EsophagusEsophagus

It is a collapsible, musculo-membranous tube extends from the pharynx to the It is a collapsible, musculo-membranous tube extends from the pharynx to the stomach. stomach.

Course Course

From the pharynx the esophagus passes dorsal to the trachea, enters into From the pharynx the esophagus passes dorsal to the trachea, enters into thoracic cavity via thoracic inlet and then passes through the diaphragm at the thoracic cavity via thoracic inlet and then passes through the diaphragm at the esophageal hiatus. Within the abdominal cavity, the esophagus joins the esophageal hiatus. Within the abdominal cavity, the esophagus joins the stomach.stomach.

Division Division

The esophagus consists of two parts; The esophagus consists of two parts;

i) Cervical Parti) Cervical Part

ii) Thoracic partii) Thoracic part

Blood and nerve supplyBlood and nerve supply

The esophageal artery from the thoracic aorta provides the blood to The esophageal artery from the thoracic aorta provides the blood to esophagus.esophagus.

Esophageal muscles, both striated and smooth, are innervated by the vagus Esophageal muscles, both striated and smooth, are innervated by the vagus nerve.nerve.

StomachStomach

It is the large dilatation of the alimentary canal just behind the diaphragm.It is the large dilatation of the alimentary canal just behind the diaphragm.

It is a muscular bag forming the widest and most distensible part of the It is a muscular bag forming the widest and most distensible part of the digestive tube. digestive tube.

It intervenes between the esophagus and the small intestine.It intervenes between the esophagus and the small intestine.

Small intestineSmall intestine

The small intestine is the tube which connects the stomach with the large The small intestine is the tube which connects the stomach with the large intestine.intestine.

Division Division

The small intestine is clearly divisible into two parts;The small intestine is clearly divisible into two parts;

i) Fixed part:i) Fixed part: It is termed as the duodenum. It is termed as the duodenum.

ii) Mesenteric Part: ii) Mesenteric Part: It consists of the jejunum and ileum. It consists of the jejunum and ileum.

1.1.DuodenumDuodenum

The duodenum is the shortest, widest and most fixed part of the small intestine. The duodenum is the shortest, widest and most fixed part of the small intestine. It is the first part of the small intestine, begins at the pylorus. It forms It is the first part of the small intestine, begins at the pylorus. It forms S-shaped curve distinctly.S-shaped curve distinctly.

AttachmentAttachment

It is closely attached to the right side of the dorsal body wall by a short It is closely attached to the right side of the dorsal body wall by a short mesentery, the meso-duodenum. mesentery, the meso-duodenum.

OpeningOpening

The bile duct and pancreatic duct joins together and opens at the same The bile duct and pancreatic duct joins together and opens at the same point in the duodenum.point in the duodenum.

Conti…Conti…

2.2. JejunumJejunum

It is the longest part of the small intestine. The jejunum is defined by the It is the longest part of the small intestine. The jejunum is defined by the marked increase in the length of the supporting mesentery. It forms marked increase in the length of the supporting mesentery. It forms numerous coils arranged in festoon manner around the mesentery.numerous coils arranged in festoon manner around the mesentery.

Attachment Attachment

The mesentery which attaches the jejunum named the mesojejunum. The mesentery which attaches the jejunum named the mesojejunum.

3.3. IleumIleum

The ileum is the short and last part of the small intestine that joins the great The ileum is the short and last part of the small intestine that joins the great intestine. It is distinguished from the jejunum by a fold of mesentery intestine. It is distinguished from the jejunum by a fold of mesentery between it and the cecum. between it and the cecum.

AttachmentAttachment

The portion of mesentery that is responsible for attachment of this small The portion of mesentery that is responsible for attachment of this small terminal part is called the mesoilium terminal part is called the mesoilium

Large intestineLarge intestine

The large intestine extends from the termination of the ileum to the anus.The large intestine extends from the termination of the ileum to the anus.

PARTS PARTS

The large intestine, just like small intestine, is also divided into three The large intestine, just like small intestine, is also divided into three parts;parts;

1.1.CaecumCaecum

The caecum is a blind sac between the small intestine and colon.The caecum is a blind sac between the small intestine and colon.

It presents three parts;It presents three parts;

i) Basei) Base

ii) Bodyii) Body

iii) Apexiii) Apex

Conti…Conti…

2.2. ColonColon

The colon can be said to have;The colon can be said to have;

Ascending colon and Descending colonAscending colon and Descending colon

AttachmentAttachment

This part of large intestine is attached with the lateral body wall by This part of large intestine is attached with the lateral body wall by mean of a fold peritoneum, called the Mesocolon.mean of a fold peritoneum, called the Mesocolon.

3.3. RectumRectum

Terminal part of the alimentary canal, extends from the pelvic inlet to the Terminal part of the alimentary canal, extends from the pelvic inlet to the anus.anus.

AttachmentAttachment

The attachment of rectum is by mean of Mesorectum, a fold of peritoneum The attachment of rectum is by mean of Mesorectum, a fold of peritoneum around rectum.around rectum.

Accessary organs Accessary organs

LiverLiver

It is the largest gland of the body, constituting about 1-2 % of total adult body It is the largest gland of the body, constituting about 1-2 % of total adult body weight. It secretes bile and performs various other metabolic functions. weight. It secretes bile and performs various other metabolic functions.

LocationLocation

The liver is always located immediately caudal to the diaphragm (in contact The liver is always located immediately caudal to the diaphragm (in contact with it) and tends to be located on the right side.with it) and tends to be located on the right side.

DescriptionDescription

The liver presents two surfaces; The liver presents two surfaces;

(i) Parietal (diaphragmatic) Surface(i) Parietal (diaphragmatic) Surface

It is convex and attached with the diaphragm and with last 2-3 rib.It is convex and attached with the diaphragm and with last 2-3 rib.

(ii) Visceral Surface(ii) Visceral Surface

It is related to the stomach, pancrease and esophagus. It is related to the stomach, pancrease and esophagus.

Gall BladderGall Bladder

It is pear-shaped sac that lies partially in contact with the visceral surface of It is pear-shaped sac that lies partially in contact with the visceral surface of the liver.the liver.

It is regarded as the diverticulum of the bile duct; or reservoir for the bile.It is regarded as the diverticulum of the bile duct; or reservoir for the bile.

Conti…Conti…

Ligaments of liverLigaments of liver

The attachment of the liver is governed by six chief ligaments;The attachment of the liver is governed by six chief ligaments;

1. Coronary Ligament1. Coronary Ligament

2. Falciform Ligament2. Falciform Ligament

3. Hepatorenal Ligament3. Hepatorenal Ligament

4. Round Ligament4. Round Ligament

5. Right Lateral Ligament5. Right Lateral Ligament

6. Left Lateral Ligament6. Left Lateral Ligament

Blood SupplyBlood Supply

The liver receives two blood supplies. The liver receives two blood supplies.

1. The Hepatic artery, a branch of ceoliac artery (first branch of abdominal 1. The Hepatic artery, a branch of ceoliac artery (first branch of abdominal aorta) supplies the liver. It is the nutrient blood artery of liver. aorta) supplies the liver. It is the nutrient blood artery of liver.

2. The Portal vein carries blood from the stomach, intestines and spleen to the 2. The Portal vein carries blood from the stomach, intestines and spleen to the liver, while all the venous blood is pour down into the posterior vena cava via liver, while all the venous blood is pour down into the posterior vena cava via hepatic veins.hepatic veins.

Conti…Conti…

Functions of liver Functions of liver

1. Metabolism 1. Metabolism of carbohydrates, fats and proteins. of carbohydrates, fats and proteins.

2. Synthesis 2. Synthesis of bile and prothrombin. of bile and prothrombin.

3. Excretion 3. Excretion of drugs, toxins, poisons, cholesterol, bile pigments and heavy of drugs, toxins, poisons, cholesterol, bile pigments and heavy metals metals

4. Protection 4. Protection by conjugation, phagocytosis, antibody formation and excretion.by conjugation, phagocytosis, antibody formation and excretion.

5. Storage 5. Storage of glycogen, iron, fat, vitamin A and D.of glycogen, iron, fat, vitamin A and D.

SpleenSpleen

It is normally called the graveyard of RBCs.It is normally called the graveyard of RBCs.

It is a lymphatic organ which acts as a filter for blood and plays an important It is a lymphatic organ which acts as a filter for blood and plays an important role in the immune responses of the body.role in the immune responses of the body.

LocationLocation

It lies on the stomach just behind the diaphragm.It lies on the stomach just behind the diaphragm.

DescriptionDescription

The spleen may be described as having The spleen may be described as having two endstwo ends;;

i) Dorsal end or basei) Dorsal end or base

ii) Ventral endii) Ventral end

Two SurfacesTwo Surfaces

i) Parietal surface (convex and related to diaphragm) i) Parietal surface (convex and related to diaphragm)

ii) Visceral surface (concave and attached to the stomach)ii) Visceral surface (concave and attached to the stomach)

Two BordersTwo Borders

i) Anterior borderi) Anterior border

ii) Posterior borderii) Posterior border

Conti…Conti…

LigamentsLigaments

There are two ligaments that attach the spleen with other viscera.There are two ligaments that attach the spleen with other viscera.

1. Gastro-splenic ligament1. Gastro-splenic ligament

2. Suspensory Ligament 2. Suspensory Ligament

Blood supplyBlood supply

The splenic artery; a branch of the celiac artery enters the hilus of the spleen. The splenic artery; a branch of the celiac artery enters the hilus of the spleen.

The splenic vein carries blood to the portal vein.The splenic vein carries blood to the portal vein.

Functions of spleenFunctions of spleen

1. Phagocytosis:1. Phagocytosis:

2. Haemopoiesis:2. Haemopoiesis: It is an important haemopoietic organ during foetal life but It is an important haemopoietic organ during foetal life but lymphopoiesis continues throughout life. lymphopoiesis continues throughout life.

3. Immune Responses: 3. Immune Responses: Under antigenic stimulation, there occurs increased Under antigenic stimulation, there occurs increased lymphopoiesis for cellu-lar responses and increased formation of plasma cells for lymphopoiesis for cellu-lar responses and increased formation of plasma cells for the humoral responses.the humoral responses.

4. Storage of RBCs: 4. Storage of RBCs: Red blood cells can be stored in the spleen and Red blood cells can be stored in the spleen and released into the circulation when needed.released into the circulation when needed.

PancreasPancreas

The pancreas (pan = all; kreas = flesh) is a gland that is partly exocrine and The pancreas (pan = all; kreas = flesh) is a gland that is partly exocrine and partly endocrine.partly endocrine.

It is soft, reddish brown, loosely lobulated and elongated organ. The exocrine It is soft, reddish brown, loosely lobulated and elongated organ. The exocrine part secretes the digestive pancreatic juice and the endocrine part secretes part secretes the digestive pancreatic juice and the endocrine part secretes hormones, e.g. insulin.hormones, e.g. insulin.

LocationLocation

It lies entirely to the right of the median plane with the visceral surface of the It lies entirely to the right of the median plane with the visceral surface of the liver and attached with the duodenum.liver and attached with the duodenum.

Lobes of pancreasLobes of pancreas

There are two lobes of the pancreas;There are two lobes of the pancreas;

i) A large Right Lobei) A large Right Lobe

ii) A small Left Lobe.ii) A small Left Lobe.

Blood supplyBlood supply

The arteries of the pancreas, pancreatic arteries, come from the branches of The arteries of the pancreas, pancreatic arteries, come from the branches of the celiac & anterior mesenteric arteries. The pancreatic veins carry blood to the celiac & anterior mesenteric arteries. The pancreatic veins carry blood to the portal vein.the portal vein.

Conti…Conti…

Functions of pancreas Functions of pancreas

1. Digestion: 1. Digestion: Pancreatic juice contains many digestive enzymes e.g Trypsin, Pancreatic juice contains many digestive enzymes e.g Trypsin, Amylase, Lipase.Amylase, Lipase.

2. Endocrine function: 2. Endocrine function: Insulin helps in utilizations of sugar in the cells. Insulin helps in utilizations of sugar in the cells. Deficiency of insulin results in hyper-glycemia. The disease is called diabetes Deficiency of insulin results in hyper-glycemia. The disease is called diabetes mellitus.mellitus.

3. Pancreatic Juice: 3. Pancreatic Juice: It provides appropriate alkaline medium (pH – 8) for the It provides appropriate alkaline medium (pH – 8) for the activity of the pancreatic enzymes.activity of the pancreatic enzymes.

Abdominal cavityAbdominal cavity

The abdominal cavity is the largest of the body cavities. The abdominal cavity is the largest of the body cavities.

It encloses the peritoneal cavity between its parietal and visceral layers. It encloses the peritoneal cavity between its parietal and visceral layers.

It is separated from the thoracic cavity by……. Diaphragm.It is separated from the thoracic cavity by……. Diaphragm.

It is continuous behind with ……………………… Pelvic cavity.It is continuous behind with ……………………… Pelvic cavity.

FlankFlank

It is the part of the lateral wall of the abdominal cavity which is formed of soft It is the part of the lateral wall of the abdominal cavity which is formed of soft organs.organs.

Paralumber fossaParalumber fossa

It is the triangular depression on the upper part of the flank.It is the triangular depression on the upper part of the flank.

PeritoneumPeritoneum

It is a large thin serous membrane which lines the abdominal cavity and pelvic It is a large thin serous membrane which lines the abdominal cavity and pelvic cavity. It is in the form of a closed sac which is in-vaginated by a number of cavity. It is in the form of a closed sac which is in-vaginated by a number of viscera.viscera.

Peritoneal cavityPeritoneal cavity

It is formed by the lining of the peritoneum. It is formed by the lining of the peritoneum.

CompositionComposition

The peritoneum is composed of an outer layer of fibrous tissue, which gives The peritoneum is composed of an outer layer of fibrous tissue, which gives strength to the membrane and an inner layer of mesothelial cells which strength to the membrane and an inner layer of mesothelial cells which secrete a serous fluid which lubricates the surface, thus allowing free secrete a serous fluid which lubricates the surface, thus allowing free movements of viscera.movements of viscera.

Layers of peritoneum Layers of peritoneum

As a result, the peritoneum is divided into:As a result, the peritoneum is divided into:

(i) An outer or parietal layer(i) An outer or parietal layer

(ii) An inner or visceral layer(ii) An inner or visceral layer

(iii) Folds of peritoneum by which the viscera are suspended.(iii) Folds of peritoneum by which the viscera are suspended.

Conti…Conti…

1.1. Parietal Peritoneum Parietal Peritoneum

It lines the inner surface of the abdominal and pelvic walls and the It lines the inner surface of the abdominal and pelvic walls and the lower surface of the diaphragm. lower surface of the diaphragm.

It is loosely attached to the walls by extra-peritoneal connective tissue and It is loosely attached to the walls by extra-peritoneal connective tissue and can, therefore, be easily stripped.can, therefore, be easily stripped.

2.2. Visceral peritoneum Visceral peritoneum

It lines the outer surface of the viscera, to which it is firmly adherent.It lines the outer surface of the viscera, to which it is firmly adherent.

In fact, it forms a part and parcel of the viscera. In fact, it forms a part and parcel of the viscera.

Conti…Conti…

3.3. Folds of Peritoneum Folds of Peritoneum

Many organs within the abdomen are suspended by folds of peritoneum. Many organs within the abdomen are suspended by folds of peritoneum. Such organs are mobile. The degree and direction of mobility are Such organs are mobile. The degree and direction of mobility are governed by the size and direction of the peritoneal fold. governed by the size and direction of the peritoneal fold.

Other organs are fixed and immobile. They rest directly on the dorsal Other organs are fixed and immobile. They rest directly on the dorsal

abdominal wall. These organs are said to be retroperitoneal. abdominal wall. These organs are said to be retroperitoneal.

Peritoneal folds are given various names; Peritoneal folds are given various names;

(i) Omentum:(i) Omentum: Large peritoneal folds attached to the stomach are called Large peritoneal folds attached to the stomach are called omenta omenta (omentum) (omentum) which means “cover”. which means “cover”.

Types of omentaTypes of omenta Greater Omentum:Greater Omentum: It extends from greater curvature of stomach like It extends from greater curvature of stomach like

an apron.an apron. ii) lesser omentum: ii) lesser omentum: It extends from lesser curvature of the stomach.It extends from lesser curvature of the stomach. iii) Gastro-splenic Omentum:iii) Gastro-splenic Omentum: It extends from the greater curvature to the It extends from the greater curvature to the

spleen.spleen.

Conti…Conti…

(ii) Mesentary(ii) Mesentary

It is a fold of peritoneum which attaches the intestines to the dorsal wall of the It is a fold of peritoneum which attaches the intestines to the dorsal wall of the abdomen. abdomen.

In general, the name of the fold is made up of the prefix “mes” or “meso” In general, the name of the fold is made up of the prefix “mes” or “meso” followed by the name of the organ. For example, the fold suspending the small followed by the name of the organ. For example, the fold suspending the small intestine is called the mesentery; and a fold suspending part of the colon is intestine is called the mesentery; and a fold suspending part of the colon is called mesocolon.called mesocolon.

Types of mesentaryTypes of mesentary

1.1.Mesentary of small intestestine:Mesentary of small intestestine:

Mesoduodnum, Mesojejunum and Mesoilium………. Attach the small Mesoduodnum, Mesojejunum and Mesoilium………. Attach the small intestine.intestine.

2.2.Mesentary of large intestestine:Mesentary of large intestestine:

Mesocolon & Mesorectum …………… Attach the large intestine.Mesocolon & Mesorectum …………… Attach the large intestine.

(iii) Ligaments:(iii) Ligaments: In many situations, double-layered folds of peritoneum In many situations, double-layered folds of peritoneum connect organs to the abdominal wall or each other. Such folds are called connect organs to the abdominal wall or each other. Such folds are called Ligaments.Ligaments.

Conti…Conti…

Functions of peritoneum Functions of peritoneum

1. Movements of Viscera: 1. Movements of Viscera: The chief function of the peritoneum is to The chief function of the peritoneum is to provide a slippery surface for free movements of abdominal viscera. They provide a slippery surface for free movements of abdominal viscera. They permits peristaltic movements of the stomach and intestines. permits peristaltic movements of the stomach and intestines.

2. Protection of Viscera: 2. Protection of Viscera: The peritoneum contains various phagocytic The peritoneum contains various phagocytic cells which guard against infection. Lymphocytes present in normal cells which guard against infection. Lymphocytes present in normal peritoneal fluid provide both cellular and humoral immunological defense peritoneal fluid provide both cellular and humoral immunological defense mechanisms. mechanisms.

3. Absorption: 3. Absorption: The mesothelium acts as a semipermeable membrane across The mesothelium acts as a semipermeable membrane across which fluids and small molecules of various solutes can pass. Thus, the which fluids and small molecules of various solutes can pass. Thus, the peritoneum can absorb fluid effusions from the peritoneal cavity. peritoneum can absorb fluid effusions from the peritoneal cavity.

4. Healing Power And Adhesion: 4. Healing Power And Adhesion: The mesothelial cells of the peritoneum The mesothelial cells of the peritoneum can transfer into fibroblasts which promote healing of the wounds.can transfer into fibroblasts which promote healing of the wounds.

5. Storage of Fat: 5. Storage of Fat: Peritoneal folds are capable of storing large amounts of Peritoneal folds are capable of storing large amounts of fats; particularly in obese individuals.fats; particularly in obese individuals.