digestive system.ppt

The Digestive System :

The Digestive System

Introduction :

Introduction DIGESTION : it is the process under in which food must be broken down into molecules ,that are small enough to enter body cells. This process is known as digestion.

Gastro- Enterology:

Gastro- Enterology The medical specility that deals with the structure ,functions ,diagnosis & treatment of the stomach & intestine is called Gastro- enterology . GASTRO------ STOMACH ENTERO------- INTESTINE LOGY ---------- STUDY

DIGESTIVE SYSTEM:

DIGESTIVE SYSTEM It is the system of the body of the organs concerned with the INGESTION ,DIGESTION & ABSORPTION of food is called digestive system.

DIVISION OF DIGESTIVE SYSTEM:

DIVISION OF DIGESTIVE SYSTEM The digestive system is divided into two groups together compose the digestive system Gastro – intestinal tract Accessory digestive tract

a) Gastro- intestinal tract:

a) Gastro- intestinal tract It is also called alimentary canal It is a continues tube that extend from the mouth to the anus GASTRO- INTESTINAL TRACT INCLUDE MANY ORGANS : A) Pharynx B) Esophagus C) Stomach D) Small intestine E) Large intestine

The accessory digestive tract:

The accessory digestive tract IT INCLUDE THE ORGANS. Teeth Tongue Salivary glands Liver Gall bladder Pancreas Teeth aids helps in the breakdown of food & tongue assist in chewing & swallowing The other accessory digestive organs do not come into direct contact with food, they produce or store secretions & helps in chemical breakdown of food.

Functions of digestive system:

Functions of digestive system The digestive system functions or performs 6 basic process: Ingestion Secretion Mixing & propulsion Digestion Absorption Defecation

FUNCTIONS OF DIGESTIVE SYSTEM:

FUNCTIONS OF DIGESTIVE SYSTEM A) INGESTION : It is the process that involves taking foods & liquid into the mouth. c) MIXING & PROPULSION : in this process there is alternating contractions & relaxation of smooth muscles of the gastro-intestinal tract results into mixing of food with the secretions.

b) SECRETION:

b) SECRETION the cells with in the organs of gastro intestine tract & assessory digestive organs secrete the total amount of 7 liters of water ,buffer ,acids & enzymes

Cont………………d:

Cont………………d This mixture of the food propel them towards the anus is called propulsion. This capability of G.I tract to mix and move material along its length is termed as motility. D) DIGESTION: in this process mechanical & chemical processes break down the ingested food into small molecules. Digestion Mechanical digestion Chemical digestion

a) MECHANICAL DIGESTION:

a) MECHANICAL DIGESTION In this process the teeth cuts & grind food before it is swallowed. Then the smooth muscles of the stomach & small intestine churn the food As a result ,food molecules become dissolved & thoroughly mixed with digestive enzymes.

B) CHEMICAL DIGESTION:

B) CHEMICAL DIGESTION In chemical digestion ,the large carbohydrates ,lipids ,proteins & nucleic acid molecules in food are split into smaller molecules by hydrolysis. Some substances in food can be absorbed without chemical digestion. These include amino acids ,cholesterol ,glucose ,vitamins ,minerals & water.

e) Absorption :

e) Absorption The ingested food ,the mixed secreted fluid & the product of digestion enters into the lining of the lumen of g.i tract is called absorption. The absorbed substances pass into the blood or lymph or circulate to the cells through out the body.

f) Defecation :

f) Defecation In this process ,the waste indigested substances ,bacteria ,sloughed from the lining of G.I tract & digested material. This product not absorbed &leave the body through the anus is called defecation. The material I-e eliminated during defecation is called Feces.

2) Peritoneum:

2) Peritoneum The peritoneum ( peri---around) is the largest serous membrane of the body. The membrane that lines the abdominal cavity and covers most of the abdominal organs. (From the Greek peri- meaning around + tonos meaning a stretching = a stretching around). The peritoneum is divided into two types: Parietal peritoneum Visceral peritoneum.

a) Parietal peritoneum:

a) Parietal peritoneum It is the layer which lines the walls of the abdominopelvic cavity. pertaining to the walls of an organ or cavity.

b) Visceral peritonium:

b) Visceral peritonium It is the layer which cover some of the organs in the cavity is called visceral peritonium. The slim space b/w the parietal & visceral portion of the peritoneum is called peritoneal cavity. The peritoneum contains large folds. these folds helps to bind the organs with each other & to the walls of the abdominal cavity.

Cont……………d:

Cont……………d The peritoneum contains blood vessels ,lymphatic vessels & nerves that supply the abdominal organs. The folds of the peritoneum are given below: The greater omentum The lesser omentum The falciform ligament Mesentery Mesocolon

a) The greater omentum:

a) The greater omentum Omentum is a fat skin. The greater omentum is a large fold of peritoneum that hangs down from the stomach. The greater omentum is the largest peritoneal folds that drapes over the transverse colon & coils of the small intestine. The greater omentum is the largest peritoneal fold. It consists of a double sheet of peritoneum , folded on itself so that it is made up of four layers. The greater omentum contains adipose tissue. The content of the adipose tissues greatly expand with weight gain & giving rise to the bear belly seems in some over weight persons.

The functions of the greater omentum are:

The functions of the greater omentum are Fat deposition: having varying amounts of adipose tissue [1] Immune contribution: having milky spots of macrophage collections [1] Infection and wound isolation: It may also physically limit the spread of intraperitoneal infections.

b) The lesser omentum:

b) The lesser omentum The lesser omentum is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach and the start of the duodenum . It is arise of folds from the stomach & duodenum is called lesser omentum. The lesser omentum is extremely thin, and is continuous with the two layers of peritoneum

c)The falciform ligament:

c)The falciform ligament The falciform ligament attaches the liver to the anterior abdominal wall. It is a broad and thin antero-posterior peritoneal fold. It is composed of two layers of peritoneum closely united together.

d) Mesentery :

d) Mesentery it is fan shaped fold of the peritoneum that bind the small intestine to the posterior abdominal wall. the mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen . The mesentery proper (i.e. the original definition) refers to the peritoneum responsible for connecting the jejunum and ileum (parts of the small intestine ) to the back wall of the abdomen.

d) Mesocolon :

d) Mesocolon It is the fold of the peritoneum that binds the large intestine to the posterior abdominal wall. the peritoneal process attaching the colon to the posterior abdominal wall, and called ascending, descending, etc., according to the portion of colon to which it attaches the peritoneal process attaching the colon to the posterior abdominal wall, and called ascending, descending, etc., according to the portion of colon to which it attaches.mesocol´ic Mesocolon.

Layers of G.I tract:

Layers of G.I tract The entire GI tract can be considered as a hollow tube surrounded by a wall composed of four main layers: Mucosa Submucosa Muscularis Serosa or adventitia

Mucosa :

Mucosa The mucosa or inner lining of the G.I tract is a mucous membrane. It is composed of a layer of epithelium in direct contact with the content of the g.i tract. The mucosa consists of : epithelium (lining the lumen) lamina propria (loose connective tissue ) Muscularis mucosae (thin layer of smooth muscle cells).

a) The epithelium:

a) The epithelium The epithelium is present in the mouth ,pharynx ,esophagus and anal canal is mainly non keratinized stratified sqamous epithelium. All the food products that are digested and absorbed by the body need to pass through the epithelial lining. This epithelial lining may contain goblet cells , that secrete mucus for lubrication The rate of renewal of G,I tract epithelial cells is rapid. Every 5 to 7 days they slough off and are replaced by new cells.

b) lamina propria (loose connective tissue):

b) lamina propria (loose connective tissue ) The lamina propria, situated just below the epithelium, consists of loose connective tissue, with an abundant blood supply. Lymphatic nodules, and plasma cells, and macrophages are common in the lamina propria and form a first line of immunological defense against bacterial and viral invasion . it is also the routes by which nutrients absorbed into the g.i tract & reaches the other tissues of the body.

Cont……………..d:

Cont……………..d These prominent lymphatic nodules contains immune system cell's that protects against disease.

c) Muscularis mucosae (thin layer of smooth muscle cells). :

c) Muscularis mucosae (thin layer of smooth muscle cells). A thin layer of smooth muscles fibers called muscularis mucosae. The muscularis mucosa causes local muscular contractions in the mucosa.

2) SUBMUCOSA:

2) SUBMUCOSA The submucosa consist of aerolar connective tissue that binds the mucosa to the muscularis. It contains many blood & lymphatic vessels that receive absorbed food molecules. submucosa consist of submucosal plexus or plexus of meissner ( network of neurons) The enteric nervous system consist of about 100 ml neurons. ENS is important in controlling secretions by G.I tract.

3) Muscularis :

3) Muscularis The muscularis of the mouth ,pharynx middle parts of the esophagus contains skeletal muscle that produces voluntary swallowing. Involuntary contractions of the smooth helps break down food physically ,mix it with digestive secretions.

c) Serosa :

c) Serosa The serosa is the superficial layer of those portions of g.i tract It is a serous membrane composed of areoler connective tissue.

1) Mouth :

1) Mouth The mouth also referred to as the oral or buccal cavity. It is formed: anteriorly: by lips Posteriorly: oropharynx Laterally: muscles of cheeks Superiorly: hard & soft palate Inferiorly: tongue

a) The Lips or Labia:

a) The Lips or Labia These are fleshly folds surrounding the opening of the mouth. They are covered externally by skin & internally by a mucous membrane. This portion of the lips is non keratinized & the color of the blood in the underlying blood vessels is visible through the transparent surface layer.

Cont…………….d:

Cont…………….d The inner surface of each lip is attached to its corresponding gum by a midline fold of mucous membrane called labial frenulum

Cont…………….d:

Cont…………….d During chewing ,contraction of the buccinators muscles in the cheeks & orbicularis oris muscle in the lips helps keep food between the upper & lower teeth. These muscle Also assist in speech .

c) The Vestibule:

c) The Vestibule The vestibule of mouth (or oral vestibule ) is the anteriormost portion of the oral cavity . It is the space between the cheek / lips and the teeth . [1]

d) Hard palate:

d) Hard palate The anterior portion of the roof of the mouth is called hard palate. It is formed by the maxillae & palatine bones.. It is covered by mucous membrane & forms a bony partition between the oral & nasal cavities.

e) Soft palate:

e) Soft palate The soft palate is the soft tissue constituting the back of the roof of the mouth . The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone

e)Uvula :

e)Uvula It is the pendant fleshy mass hanging from the soft palate. During swallowing the soft palate & uvula drawn inferiorly. It helps in closing off the nasopharynx & prevent swallowed feed & liquid from entering the nasal cavity.

f) Palatopharyngeal arches:

f) Palatopharyngeal arches one of a pair of ridges or folds of mucous membrane that pass downward from the posterior margin of the soft palate to the lateral wall of the pharynx

g) Palatoglossal arch:

g) Palatoglossal arch one of a pair of ridges or folds of mucous membrane passing from the soft palate to the side of the tongue

2) Tongue :

2) Tongue The tongue is a accessory digestive organ & it is movable muscular organ. It forms floor of the oral cavity. It is attached by its base to the hyoid bone & frenulum. The frenulum is also called lingual frenulum. It is the fold of the mucous membrane in the mid line & under surface of the tongue & attached the floor of the mouth.

Cont………………d:

Cont………………d The lingual frenulum helps the tongue to move posteriorly. The upper surface & lateral surface of the tongue is covered with three types of papillae. Papillae are the small, round or cone-shaped protuberances on the top of the tongue that contain taste buds. they are give below : Vallate (circumvallate )papillae Fungi form papillae filiform papillae Foliate papillae

a) Vallate (circumvallate papillae):

a) Vallate (circumvallate papillae) Vallate papillae are also called circumvallate papillae. circumvallate papillae (or vallate papillae ) are dome-shaped structures on the human tongue that vary in number from eight to twelve. Each papilla consists of a projection of mucous membrane from 1 to 2 mm. wide They are arranged in an inverted v shaped on the posterior surface of the tongue. Theses contains taste buds Theses are the largest of papillae & can easily seen on the tongue.

b) Fungi form papillae:

b) Fungi form papillae The fungiform papillae are situated ,mainly at the tip. The fungiform papillae are mushroom shaped papillae (projections) on the tongue . They are more numerous than the vallate papillae. They appear as the red dots on the surface of the tongue. They have taste buds on their superior (upper) surface which can distinguish the four tastes: sweet , sour , bitter , salty ,

c) filiform papillae:

c) filiform papillae The filiform papillae on the smallest of all the papillae. These are small prominences on the surface of the tongue. They are most numerous & present on the surface of the anterior of the two-third of the tongue. Filiform papillae have lack of taste buds. They helps the tongue to move food in the oral cavity.

d) Foliate papillae:

d) Foliate papillae They occur especially in the sides of the vallate papillae . There is a localized area at the side of the base of the tongue , the foliate papillae , in which they are especially abundant The foliate papillae are involved in the sensations of taste and have taste buds embedded in their surfaces.

Functions of tongue:

Functions of tongue The tongue plays an important role : a) MASTICATION : it is the process of chewing of food. Mastication don by the helps of tongue ,teeth & saliva. The tongue mastication helps to move food under the teeth. b) DEGLUTITION : the movement of food from the mouth into the stomach or he act of swallowing is called deglutition. - Tongue helps in deglutition.

Cont…………………d:

Cont…………………d c) SPEECH : tongue helps in speech. d) TASTE : as the taste buds are preset on the tongue .so it helps to produce the sense pf the taste.

3) SALIVARY GLANDS :

3) SALIVARY GLANDS The salivary glands in mammals are exocrine glands , that produce saliva . A salivary gland is the cells that release secretions called saliva into the oral cavity. Mostly saliva is secreted by the major salivary glands: The parotid gland The submandibular gland The sublingual gland

Cont…………….d:

Cont…………….d the percentage contribution to whole saliva; ~25% Parotid, Submandibular Sublingual ~ 67% ~8% minor mucous glands. During stimulated secretion the parotid gland produces majority of the saliva.

a) The parotid gland:

a) The parotid gland The parotid gland is the largest salivary gland It is located inferior & anterior to the ears. Each parotid gland secrete saliva into the oral cavity . it secretes saliva through Stensen's duct into the oral cavity, to facilitate mastication and swallowing

b) The submandibular gland:

b) The submandibular gland The paired submandibular glands are salivary glands located beneath the floor of the mouth. In humans, they account for 70% of the salivary volume and weigh about 15 grams

d) The sublingual gland:

d) The sublingual gland The sublingual glands are salivary glands in the mouth . The sublingual gland are superior to the submandibular gland. They help to produce secretions in the mouth. They are drained by 8-20 excretory ducts called the ducts of Rivinus.

Composition of saliva:

Composition of saliva Saliva is a combined secretions. About 1.5 litres of saliva is produced daily & it consists of : water-------99.5% Solutes------0.5% Sodium Potassium Chloride Bicarbonate Phosphate urea

Cont………,d:

Cont………,d Uric acid Mucus Immunoglobin Enzyme lysozymes

Functions of saliva:

Functions of saliva it helps to keep mucous membrane of the mouth & pharynx moist. It helps to dissolve food It helps to make the sense of taste. Saliva also breaks down food caught in the teeth. Saliva digests carbohydrates, aids in chewing, and helps keep bacteria levels in the mouth down.

4) Esophagus :

4) Esophagus The esophagus is the muscular tube lies posterior to the trachea that carries food, liquids and saliva from mouth to the stomach. It is 25 cm long & about 2 cm in diameter. It lies in the medial of the thorax. The upper & lower of esophagus are closed by sphincter muscles. It is front of the vertebral column & bind the trachea. During swallowing food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach .

Cont……….d:

Cont……….d It connects the mouth to the stomach. It is divided into cervical, thoracic and abdominal parts .

Structure of esophagus:

Structure of esophagus The esophagus is made up of the 4 layers: Mucosa Submucosa Circular muscles Longitudunal muscle .

a) Mucosa :

a) Mucosa The mucosa of the esophagus consist of nonkeratinized stratified squamous epithelium. it is inner lining of g.i tract. It makes the direct contact with the content of G.I tract.

b) Submucosa :

b) Submucosa It is the second layer of esophagus beneath mucosa. It is layer of loose connective tissue containing mucus-secreting gland The submucosa contains areolar connective tissue ,blood vessels and mucous glands. Due to the presence of connective tissues it binds the mucosa with the muscles of the esophagus.

c) Circular muscles:

c) Circular muscles The esophagus consists of muscles in circular. It helps in the contraction of the esophagus & squeeze the bolus towards the stomach. The inner layer of muscle contains circular fibers which form a series of rings around the esophagus.

d)Longitudinal muscle:

d)Longitudinal muscle The esophagus consist of longitudinal muscles. They also help in the contraction to receive the food towards the stomach. The first is an outer muscle layer, whose fibers run longitudinally up and down the length of the esophagus

Functions of esophagus:

Functions of esophagus a) FORMATION OF A BOLUS When a person swallows, the muscular walls of the esophagus contract to push food down into the stomach. Esophagus helps in the formation of a bolus after chewing & swallowing of food. The swallowed food mix with saliva & forms into a soft mass called bolus.

CONT………D:

CONT………D RECEIVE THE SWALLOWED FOOD: The esophagus helps to receive the swallowed food.

5) Stomach :

5) Stomach The stomach is an organ of digestion. It has a saclike shape and is located between the esophagus and the intestines. The stomach is a J shaped dilated portion of the alimentary canal. It is situated inferior to the diaphragm ,superior to umbilical & left hypochondriac region of the abdomen. The stomach connects the esophagus to the duodenum .

Cont…….d:

Cont…….d The stomach serves as a mixing chamber & holding reservoir. The stomach forces a small quantity of material into the first portion of the small intestine. The position & size of the stomach vary continuously.

Anatomy of the stomach:

Anatomy of the stomach The stomach has 4 main parts: The Cardia The Fundus The Body The Pylorus Rugae Pyloric sphincter Lesser curvature Greater curvature

a) Cardia :

a) Cardia The cardia is the anatomical term for the part of the stomach attached to the esophagus . It is the superior opening of the stomach.

b) The fundus :

b) The fundus The fundus of the stomach is the left portion of the stomach's body. The rounded portion i-e superior & left of the cardia is called fundus.

c) The body :

c ) The body The part of the stomach that lies between the fundus and the pyloric antrum. It is inferior to the fundus. The large central portion of the stomach is called the body.

d) The pylorus :

d) The pylorus The region of the stomach that connects to the duodenum is called pylorus. It is divided into two parts: the pyloric antrum , which connects to the body of the stomach. the pyloric canal , which connects to the duodenum. The part of the stomach that lies between the fundus and the pyloric antrum.

e) Rugae :

e) Rugae A fold, crease, or wrinkle, as in the lining of the stomach When stomach is empty ,the mucosa lies in large folds

f) Pyloric sphincter:

f) Pyloric sphincter The pyloric sphincter , or valve , is a strong ring of smooth muscle at the end of the pyloric canal and lets food pass from the stomach to the duodenum . So it communicates with duodenum .

g) Lesser Curvature:

g) Lesser Curvature The boundary of the stomach that in humans forms a relatively short concave curve on the right from the opening for the esophagus to the opening into the duodenum. It is the posterior & concave border of the stomach

h) Greater curvature :

h) Greater curvature The boundary of the stomach that forms a long usually convex curve on the left from the opening for the esophagus to the opening into the duodenum. It is the anterior region of the stomach.

Muscles of the stomach :

Muscles of the stomach The stomach consist of three muscles: a) Oblique muscles b) Longitudinal muscles c) Circular muscles .

Functions of stomach :

Functions of stomach It helps to mix the food with gastric juices & saliva. It helps to hold the food or makes the temporary storage before entering into the small intestine. It helps to secrete gastric juices which contains HCL & pepsin.

Cont…………………d:

Cont…………………d HCL kills bacteria & pepsin helps In the digestion of protein. It releasing numerous chemicals such as digestive hormones , enzymes and gastric juices which help to break down food molecules in the chyme & into small particles for absorption into the bloodstream. An empty stomach has a volume of approximately 50 mL. But typically after a meal, its capacity expands to about 1 liter of food, and may expand to hold as much as 4 liters

6) Teeth :

6) Teeth The teeth are accessory digestive organs located in the sockets of the mandible & maxillae. Teeth (singular tooth) are small, calcified , whitish structures found in the jaws (or mouths) of many vertebrates that are used to break down food .

Structure of teeth:

Structure of teeth The teeth contains three parts: a) THE CROWN : the crown is the visible portion above the level of the gums. b) THE ROOT : the roots is the part which is embedded in the gums. c) THE NECK : it is the junction & meeting point of the crown & root.

Cont…………..d:

Cont…………..d d) PULP CAVITY : The enlarged part of the cavity is called pulp cavity lies within the crown. e) ENAMEL: The dentine of the crown is covered by enamel that consist of calcium phosphate & calcium carbonate. - Enamel is the hardest substances in the body.

Cont……………d:

Cont……………d There are 16 teeth on both the top and bottom jaw Each jaw consists of specific teeth, which are incisors (cutting teeth), canines (tearing teeth) and molars (grinding teeth).

Sets of teeth:

Sets of teeth Humans have two sets of teeth. Deciduous teeth or primary dentition. Permanent teeth or secondary dentition .

a) Deciduous teeth:

a) Deciduous teeth It is also called primary teeth or milky teeth. It begins to erupt at about 6 months of age. 1 pair of teeth appears at about each month until 20 teeth are present. The 20 teeth is complete deciduous teeth & their time or eruption is given below:

Dentition Time of Eruption:

Dentition Time of Eruption Central incisor --------------- 8 -12 months Lateral incisor ----------------- 12-24 months Cuspid or canine -------------- 16-24 months First molar --------------- 12-16 months Second molar --------------------- 24-32 months

b) Permanent teeth:

b) Permanent teeth Permanent teeth is also called secondary dentition. All the deciduous teeth are lost generally b/w the ages of 6 -12 years ,they are replaced by permanent teeth. The permanent dentition contains 32 teeth that erupt b/w the age of 3 up to adulthood. There are 32 teeth in a complete permanent set & there time of eruption is given below:

Dentition time of eruption:

Dentition time of eruption Central incisor----------- 6-8years Lateral incisor------------ 8-9 years Canine ------------ 11-12 years First premolars----------- 9-10 years Second premolars--------10-12 years First molars ----------------- 6-7 years Second molars -------------- 12-13 years Third molar or wisdom tooth: 17-25years.

Functions of teeth:

Functions of teeth The incisor & canine teeth are the cutting teeth. They are used for biting off pieces of food. Premolars & molars are broad flat & they are used for grinding & chewing food. To breakdown food into smaller pieces to aid in the process of digestion Helps with speech

Cont……………d:

Cont……………d Personal appearance : Teeth can keep our facial profile. Without teeth, our face will look collapsed. If teeth are kept healthy, our appearance will even be better.

7) Pancreas :

7) Pancreas The pancreas is the pale gray gland weight about 60 gms. It is 12 to 15 cm long & 2.5 cm thick. It lies posterior to the greater curvature of the stomach.

Parts of pancreas:

Parts of pancreas THE HEAD : it is the expended portion of the organ near the curve of duodenum. THE BODY : the part that is superior & left of the head is called the body. THE TAIL : the tail lies in the front of the left kidney.

Cont……………..d:

Cont……………..d The pancreas both an exocrine gland & endocrine gland. Exocrine gland : this consist of a large numbers of lobules & secreting cells. The functions of the exocrine pancreas is to produce pancreatic juices that digest carbohydrates ,proteins & fats. b) Endocrine gland : The endocrine pancreas secrete the hormone INSULIN & GLUCAGON which are concerned of blood glucose level

Functions of pancreas:

Functions of pancreas FORMATION OF PANCREATIC JUICE : Each day pancreas produces 1200-1500 ml of pancreatic juices which helps in the digestion of carbohydrates ,fats & proteins. It is clear ,colorless liquid consist of water ,salt ,sodium bicarbonate & several enzymes. b) SECRETIONS OF HORMONE : The cells of the pancreas secrete the hormone like glucagon ,insulin which helps to control blood glucose level.

8) Liver :

8) Liver The liver is the heaviest gland of the body. It weights about 1.4 kg in an average adult. It is situated in the upper & right part of the abdomen ( hypochondriac region )

ORGANS ASSOCIATED WITH THE LIVER:

ORGANS ASSOCIATED WITH THE LIVER Superior --- diaphragm Anterior --- abdominal wall Inferior --- stomach ,duodenum ,inferior vena cava Posterior ---esophagus ,gall bladder 5) Laterally --- lower ribs

Anatomy of the liver:

Anatomy of the liver The liver has four lobes: Right lobe Left lobe Caudate lobe Quadrate lobe

a) Right Lobe:

a) Right Lobe The right lobe is larger than the left lobe. It is the principal lobe of the liver The right lobe & the left lobe is attached with each other with the falciform ligament. It is the fold of the peritoneum that helps to attach he liver to anterior wall. The right lobe is situated in the anterior part of the liver.

B) The left lobe:

B) The left lobe The left lobe is smaller and more flattened than the right. It is situated in the epigastric and left hypochondriac regions. Its upper surface is slightly convex and is moulded on to the diaphragm

c) Caudate lobe :

c) Caudate lobe The caudate lobe is situated upon the postero-superior surface of the liver on the right lobe of the liver , opposite the tenth and eleventh thoracic vertebrae .

d) quadrate lobe:

d) quadrate lobe The quadrate lobe is an area of the liver situated on the under surface of the right lobe. The caudate lobe ( posterior hepatic segment ) , is situated upon the postero-superior surface of the liver on the right lobe of the liver , It is opposite the tenth and eleventh thoracic vertebrae .

Functions of liver :

Functions of liver Carbohydrates Metabolism : the liver is important organs which helps to maintain blood glucose level. When blood glucose gets lower , the liver breakdown glycogen to glucose & release glucose into the blood. GLYCOGEN BREAKDOWN GLUCOSE When blood glucose level is high. The liver converts the sugar like fructose ,galactose & glucose to glycogen for storage in the body.

2) Fat metabolism:

2) Fat metabolism The cells of the liver (hepatocytes) helps to store fatty acids like lipoprotein ,cholesterol which can be used further to provide energy to the body.

c) Protein metabolism:

c) Protein metabolism It helps to deactivate the proteins by removing the nitrogenous portion from amino acids when not required for formation new proteins. The nitrogenous portion helps to form urea & excreted through urine. So it helps in protein metabolism.

d) Detoxification of drugs & hormones:

d) Detoxification of drugs & hormones The liver helps to detoxified substances such as alcohol & same drugs like penicillin ,erythromycin & sulfonamide. e) Excretion of bilirubin : - liver helps to excrete out the bilirubin from the blood & secreted it into the bile & eliminates it by feces from the body.

f) Secretion & synthesis of bile:

f) Secretion & synthesis of bile The cells of the liver helps in the formation of bile. It include bile salt ,bile pigment & cholesterol. Bile bitter-tasting, dark green to yellowish brown fluid, produced by the liver that aids the process of digestion of lipids in the small intestine . Bile is a composition of the following materials: Water (85%), bile salts (10%), mucus and pigments (3%), fats (1%), inorganic salts (0.7%) and cholesterol (0.3%).

g) Storage:

g) Storage the liver helps in primary storage. - vitamins: A,D,E & K Minerals: Iron & copper Water soluble Vitamin: B12 ,riboflavin & Niacin . Liver helps to release these substances when needed else where in the body.

h) Production of heat:

h) Production of heat The liver helps to produce higher amount of heat. It is the main heat producing organ of the body.

9) Small intestine:

9) Small intestine The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine . The major event of digestion & absorption occurs in a lone tube called small intestine. It is a 3 meter long & 2.5cm in diameter.

Cont…….d:

Cont…….d The small intestine is divided into three structural parts: .. Duodenum 26 cm (9.8 in) in length Jejunum 2.5 m (3-6 ft) Ileum 3.5 m (6-12 ft)

A) Duodenum:

A) Duodenum It is the shortest region of the small intestine. The duodenum is the first section of the small intestine . the duodenum is a hollow jointed tube about 10–12 inch long connecting the stomach to the jejunum

b) Jejunum :

b) Jejunum The jejunum is the middle section of the small intestine The jejunum lies between the duodenum and the ileum It is 1 meter long It extends to the ileum.

c) ileum:

c) ileum The ileum is the final section of the small intestine . The ileum follows the duodenum and jejunum and is separated from the cecum by the ileocecal valve . It is also called the first part of large intestine. It is about 2 meter long.

Functions of small intestine:

Functions of small intestine It helps in the movement of the content of food. It helps in completion of chemical digestion. It helps to gave protection against infection due to the presence of HCL. It helps in the absorption of nutrients.

Large intestine :

Large intestine The large intestine is the terminal portion of the G.I tract. It helps in the completion of absorption & helps in the formation & expulsion of feces from the body.

Cont……………d:

Cont……………d The large intestine is 1.5 meters long & 6.5 cm in diameter. It extends from the ileum to the anus. It is attached to the posterior abdominal wall by mesocolon

Parts of large intestine :

Parts of large intestine Cecum Colon Rectum Anal canal

a) Cecum :

a) Cecum It is pouch about 6cm long hanging inferior to the ileocecal valve. Ileocecal valve is the opening from the ileum into the intestine .it allow passes of material from the small intestine into large intestine.

b)Colon :

b)Colon The open end of the cecum merge with a long tube called the colon. it is divided into four portions. Ascending colon Transverse colon Descending colon Sigmoid colon

a) Ascending colon:

a) Ascending colon The ascending colon is one part of four sections of the large intestine . This first section of the large intestine is connected to the small intestine by a section of bowel called the cecum . The ascending colon runs through the abdominal cavity, upwards toward the transverse colon for approximately eight inches (20 cm). It is on the right side of the abdomen.

Function of ascending colon:

Function of ascending colon One of the main functions of the colon is to remove the water and other key nutrients from waste material and recycle it back into the body. As the waste material exits the small intestine it will move into the cecum and then the ascending colon . The waste material is moved upwards toward the transverse section of the colon by a process called peristalsis .

b) Transverse colon:

b) Transverse colon The transverse colon is the large part of the colon that attaches the ascending colon to the descending colon by crossing the abdominal cavity. The transverse colon the longest and most movable part of the colon , This part of the colon is curved and has the appearance of forming an arch.

Function of transverse colon:

Function of transverse colon it extracts water and salt from solid wastes before they are eliminated from the body

c) Descending colon:

c) Descending colon The descending colon is part of the large intestine. The large intestine is responsible for the absorption of water and other substances, such as salts. It passes down to the left side of the abdominal cavity.

4) Sigmoid colon :

4) Sigmoid colon The sigmoid colon is the part of the large intestine after the descending colon and before the rectum. The name sigmoid means S-shaped (see sigmoid ). The walls of the sigmoid colon are muscular, and contract to increase the pressure inside the colon, causing the stool to move into the rectum. It forms a loop that averages about 40 cm. in length, and normally lies within the pelvis ,

c) Rectum :

c) Rectum The rectum is the final straight portion of the large intestine . The human rectum is about 12 cm long. The rectum stores solid waste until it leaves the body through the anus. It is slightly dilated section of the colon. It lies anterior to the sacrum & coccyx.

Anal canal :

Anal canal The terminal of the rectum is called anal canal. It is 2-3cm long. The opening of the anal canal is exterior is called anus. It consist of internal & eternal sphincter muscles. Theses muscles helps to close the anus except the elimination of feces.

Function of large intestine :

Function of large intestine Absorption: then large intestine helps to complete the absorption of nutrients like water ,mineral salts & vitamins from the digestive products. Microbial activity : the large intestine consist of feces so it is colono9sed by many bacteria's like E.coli ,enterobacter & streptococcus. In the colon ,these bacteria's are harmless but if they transferred to another parts of the body it can produce toxicity & infection. So colon in the large intestine helps to maintain microbial activity.

c) Defecation :

c) Defecation The large intestine helps in the defecation by forcing the content of feces into sigmoid colon then it passes into rectum & helps to empty the large intestine.

Gall bladder:

Gall bladder The gall bladder is a pear shaped sac located in the depression of the posterior surface of the liver. The gallbladder it stores and concentrates bile. The gallbladder is connected to the liver by the hepatic duct. It is approximately 3 to 4 inches (7.6 to 10.2 cm) long and about 1 inch (2.5 cm) wide.

Parts of gall bladder:

Parts of gall bladder It has three parts: The fundus: The fundus of gallbladder is the portion of the gallbladder which lies the farthest from the cystic duct . It is the broad portion. b) The body: it is the main central portion. c) The neck: it is portion continuous with cystic duct.

Functions of gall bladder:

Functions of gall bladder Storage of bile : the gall bladder helps to store bile until it is needed in small intestine. Release of stored bile : the gall bladder release the bile by muscular contraction of gall bladder. - Contraction of gall bladder is stimulated by the hormones CCK ( cholecystokinin) secreted by duodenum.

Bile & its composition :

Bile & its composition A yellowish brownish green liquid secreted by the hepatocytes is called bile. Hepatocytes secrete 800-1000ml of bile daily It is excretory & digestion secretions. It plays an important role in EMULSIFICATION: it is the breakdown of large lipids into droplet & helps to absorbs lipids during digestion.

Composition of bile:

Composition of bile Water Bile acids Bile salts Mineral salts Mucus Bile pigment---bilirubin Cholesterol.

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Process of digestion & Absorption

Process of digestion & absorption :

Process of digestion & absorption Digestion is the process of mechanical & chemical breakdown of foods to convert it into simple & small molecules that can be absorbed &used by body cells is called digestion. It is two types: DIGESTION Mechanical digestion chemical digestion

Cont…………..d:

Cont…………..d In the whole process of digestion there is group of organs of G.I tract that are involved: Mechanical &chemicals digestion in the mouth Mechanical & chemical digestion in the stomach Mechanical & chemical digestion in the small intestine Mechanical & chemical digestion in the large intestine

Slide 145:

Organs of digestion Mechanical digestion Chemical digestion a) Mouth Mechanical digestion in mouth result's from chewing. Food is chewed with help of tongue ,teeth & saliva. The chewed food changes into soft ,easily swallowed mass called BOLUS . 1.Two enzymes helps in chemical digestion in the mouth. SALIVARY AMYLASE LINGUAL LIPASE 1.SALIVARY AMYLASE : it helps in the breakdown of starch & carbohydrates ,disaccharides & starch is breakdown into monosaccharide's. 2.LINGUAL LIPASE:- it helps in the breakdown of triglycerides into fatty acids.

Slide 146:

Organs of digestion Mechanical digestion Chemical digestion b) Stomach Mechanical digestion in stomach starts after swallowing. After swallowing the food enters into the stomach with peristalsis movement As the digestion process the chyme reach the pylorus Five enzymes helps in the chemical digestion in the stomach. Salivary amylase Lingual lipase Pepsin Gastric lipase Hydrochloric acid (HCL) Salivary amylase: it is secreted by salivary glands. It helps in the breakdown of starch & carbohydrates. b) Lingual lipase: it is secreted by glands in the tongue. - It helps in the breakdown of fatty acids & lipids.

Slide 147:

Organs of digestion Mechanical digestion Chemical digestion b) Stomach As it reaches the pylorus ,the mixing of the food with secretions is continuous . The waves pushes the chyme forward & forced into the duodenum. c) Pepsin : it is secreted by chief cells of the stomach It helps in the breakdown of proteins. d) Gastric lipase: it is secreted by chief cells of stomach. It helps in the breakdown of fatty acids. e) Hydrochloric acid (HCL): it is secreted by parietal cells & kills microbes into the food.

Slide 148:

Organs of digestion Mechanical digestion Chemical digestion c) Small intestine The mechanical digestion in small intestine occurred by segmentation & peristalsis. Segmentation helps to mix chyme with digestive juices. The chemical digestion helps small intestine in the digestion of carbohydrates ,proteins & lipids with the help of enzymes in small intestine. Salivary amylase Pepsin Lipase (gastric & lingual) a)Salivary amylase: the salivary amylase helps in the digestion of carbohydrates & starch. b) Pepsin :the pepsin is a pancreatic juices like trypsin & chemotrypsin helps in the breakdown & digestion of proteins.

Slide 149:

Organs of digestion Mechanical digestion Chemical digestion c) Small intestine 3.In small intestine segmentation occurs rapidly in the duodenum. i -e 12 times/min. c) Lipase (gastric & lingual): the lipase enzyme helps in digestion of lipids.

Slide 150:

Organs of digestion Mechanical digestion Chemical digestion d) Large intestine The mechanical digestion in large intestine occurs when the chyme passes from the ileum to cecum. Then the content of colon moves to transverse colon & then passes to the rectum. The chemical digestion of large intestine occurs with the help of mucus secreted by glands not by enzymes. The bacteria also helps to convert the remaining protein to amino acids.

Absorption :

Absorption The passage of digested nutrients from the G.I tract in the blood or lymph is called absorption. About 90% of absorption of all the nutrients occurs in small intestine & 10% in stomach &large intestine occurs.

Cont………….d:

Cont………….d Absorption in small intestine Absorption in large intestine .

a) Absorption in small intestine:

a) Absorption in small intestine The small intestine plays an important role in the absorption of nutrients. About 90% of absorption of nutrients occurs in small intestine Some of the absorption of nutrients in small intestine is given below: ABSORPTION OF CARBOHYDRATES: all carbohydrates are absorbed as monosaccharide's in small intestine. The capacity of small intestine to absorb monosaccharide is large i -e: 120gms/hour.

b) Absorption of amino acids :

b) Absorption of amino acids Normally 95-98% of the proteins is digested & absorbed in small intestine. Absorption of amino acids mainly occurs in the duodenum & jejunum.

c) Absorption of lipids :

c) Absorption of lipids Small intestine helps in the absorption of about 95% of lipids in adult. d)ABSORPTION OF VITAMINS: - The small intestine helps in the absorption of fat soluble vitamin 1-e: A,D,E & k.

Cont……………..d:

Cont……………..d It also helps in the absorption of water soluble vitamin. i-e vitamin B & C. e) ABSORPTION OF WATER: The total volume of fluid that enters the small intestine daily is 9.3 L The small intestine absorbs about 8.3 L of the fluids of the fluids & remaining passes into large intestine. 1.0 L of water is Excreted in the feces each day.

f) Absorption of electrolytes:

f) Absorption of electrolytes Many of the electrolytes absorbed by the small intestine come from gastrointestinal secretions & some are part of ingested foods & liquids. Sodium ion gets absorbed are not lost in the feces. Small intestine helps in the electrolytes such as iron ,potassium ,magnesium& phosphate ions.

Absorption on large intestine:

Absorption on large intestine

a) Absorption in large intestine :

a) Absorption in large intestine When the digested content remains in large intestine for 3-10 hours. It becomes solid or semisolid because of water absorption is called feces. About 90% of water absorption occurs in small intestine & 10% large intestine. It absorbs enough water to maintain the body’s eater balance.