the Digestive System...Identify the organs faction of the digestive system. Describe the structure and functions of the: Salivary glands. Tongue and teeth. The pharynx and esophagus

the Digestive Systemالهضميالجهاز

Identify the organs faction of the

digestive system.

Describe the structure and

functions of the:

Salivary glands.

Tongue and teeth.

The pharynx and esophagus

Describe the location, anatomy

and functions of the:

Stomach, pancreas.

Liver and gallbladder.

Small intestine and large

intestine.

Objectives

Digestive System:

Consists of a group of organs that break down the food we eat into

smaller molecules that can be used by body cells.

Two groups of organs compose the digestive system:

1. The gastrointestinal (GI) tract

2. The accessory digestive organs.

The Digestive System

Or alimentary canal (alimentary = nourishment), is a

continuous tube that extends from the mouth to the anus

through the thoracic and abdominopelvic cavities.

The length of the GI tract is about 5–7 meters (16.5–23 ft ).

1-The gastrointestinal (GI)tract:

1. The mouth الفم

2. Most of the pharynx جزء من البلعوم

3. Esophagusالمرئ

4. Stomachالمعدة

5. Small intestine االمعاء الدقيقة

6. Large intestine.االمعاء الغليظة

Organs of the Gastrointestinal Tract

include:

1.The teeth االسنان

2. Tongue اللسان

3. Salivary glands الغدد اللعابية

4. Liverالكبد

5. Gallbladder (الصفراوية)المرارة

6. Pancreas. البنكرياس

The accessory digestive organs include

1. Ingestion: taking food into mouth.

2. Secretion: release of water, acid, buffers, and enzymes into

lumen of GI tract.

3. Mixing and propulsion: churning and movement of food through

GI tract.

4. Digestion: mechanical and chemical breakdown of food.

Functions of the Digestive System

Cont.

5. Absorption: passage of digested products from GI tract into

blood and lymph.

6. Defecation: elimination of feces.

Organs of the gastrointestinal tract

The accessory digestive organs اعضاء مساعدة

The four layers of the tract, from deep to superficial, are the :

1. Mucosa

2. Submucosa

3. Muscularis

4. Serosa/adventitia

Layers of the GI Tract

The mouth, also referred to as the oral or buccal cavity is formed by:

1. The cheeks

2. Hard and soft palates

3. Tongue

4. The lips or labia

5. Teeth

Mouth الفم

Is a gland that releases a secretion called saliva into the oral cavity The

three major salivary glands:

1. Parotid glands (غدة نكافية) : Are located inferior and anterior to the ears.

2. Sublingual glands( غدة تحت اللسانية) : Are beneath the tongue and superior

to the submandibular glands.

3. Submandibular glands( غدة تحت الفك السفلي) :Are found in the floor of the

mouth.

Salivary Glandsالغدد اللعابية

Chemically, saliva is 99.5% water and 0.5% solutes.

Salivation The secretion of saliva, called salivation.

Amounts of saliva secreted daily vary considerably but average

1000–1500 mL

Composition and Functions of

Saliva

The tongue is an accessory digestive organ composed of skeletal muscle

covered with mucous membrane.

muscles of the tongue:

1-The extrinsic muscles of the tongue move the tongue from side

to side and in and out to maneuver food for chewing

2-The intrinsic muscles of the tongue They alter the shape and size

of the tongue for speech and swallowing.

Tongueلسان

The teeth, or dentes , are accessory digestive organs located in the

mandible and maxillae.

A typical tooth has three major external regions:

1. The crown.

2. Root.

3. Neck.

Children have 20 milk teeth and adults have 32 permanent teeth

Teethاسنان

When food is first swallowed, it passes from the mouth into the

pharynx (= throat) divided into three parts:

1. The nasopharynx: functions only in respiration,

2. The oropharynx: have digestive functions.

3. The laryngopharynx: have digestive functions.

The muscular contractions of these areas help propel food into the

esophagus and then into the stomach.

Pharynxالبلعوم

The esophagus: Is a muscular tube, about 25 cm (10 in.) long,

that lies posterior to the trachea.

From the pharynx to superior portion of the stomach through

the diaphragm an opening called the esophageal hiatus

Functions transport by waves of contraction called

(peristalsis).

Esophagusالمرئ

CONT

Two esophagus sphincters:

1.The upper esophageal sphincter (UES) which consists of

skeletal muscle.

2.The lower esophageal (cardiac) sphincter (LES).

The stomach is a J-shaped enlargement of the GI tract

directly inferior to the diaphragm in the abdomen.

Functions of the Stomach:

1. Mixes saliva, food.

2. Temporary storage of food

3. Secretes gastric juice, which contains HCl (kills

bacteria.

4. Secretes gastrin into blood.

Stomachالمعدة

1.The cardia

2.Fundus

3.Body

4.Pyloric part

The stomach has four main

regions:

The pancreas: A retroperitoneal gland

that is about 12–15 cm (5–6 in.) long

and 2.5 cm (1 in.) thick, lies behind

the stomach. consists of:

1. A head

2. A body

3. A tail

Faction :Insulin and glucagon

hormones regulation

Secretion of pancreatic enzymes

Pancreasبنكرياس

The liver is the heaviest gland of the body, weighing about 1.4 kg.

The liver is inferior to the diaphragm right hypochondriac.

The liver is divided into two principal lobes:-

1. A large right lobe

2. A smaller left lobe

Function of the liver :

1. It acts as a mechanical filter by filtering blood.

2. Production of bile that breakdown lipids.

3. Maintaining a normal blood glucose level.

4. Storage site for certain vitamins (A, B12.

Liver and Gallbladder(المرارة)والحويصلة الصفراويةالكبد

Gallbladder (gall- = bile): Is a pear-shaped sac that is

located in a depression of the posterior surface of the liver. It is

7–10 cm (3– 4 in.)

It consists of :

1. A fundus

2. Body

3. Neck

Gallbladder

The main functions of the gall bladder are:

Storage and concentration of bile (Bile is a thick fluid

produced by the liver).

Liver and Gallbladder

Most digestion and absorption of nutrients occur in a long tube called

the small intestine.

Extend from the pyloric sphincter to the large intestine its length is

about 3 m (10 ft ).

It has three divisions:

1.The Duodenum.

2.The jejunum.

3.The ileum (IL-ē-um = twisted).

Small Intestine االمعاء الدقيقة

Duodenum means “12”; width of 12 fingers.

the shortest and starts at the pyloric sphincter of the stomach and is in the form of

a C-shaped tube that extends about 25 cm (10 in.) until it merges with the jejunum.

Is the next portion and is about 1 m (3 ft ) long and extends to the ileum. Jejunum

means “empty,”.

Measures about 2 m (6 ft ) and joins the large intestine at a smooth muscle

sphincter called the ileocecal sphincter (valve).

1.The duodenumاالثنا عشر

2.The jejunumالمعي الصائم:

3.The ileumمعي لفايفي:

1. Mix chyme with digestive juices.

2. Completes digestion of carbohydrates, proteins, and lipids.

3. Absorbs about 90% of nutrients and water that pass through

digestive system.

Functions of the Small

Intestine:

The terminal portion of the GI tract.

The large intestine which is about 1.5 m (5 ft ) long and 6.5 cm (2.5

in.) in diameter, extends from the ileum to the anus.

Functions of the large intestine are the:

1. Completion of absorption.

2. The production of certain vitamins.

3. The formation and expulsion of feces from the body.

Large Intestineاالمعاء الغليظة

CONT.

the four major regions of the large intestine are the:

1. Cecum.المصران االعور

2.Colon.القولون

3. Rectum. لمستقيما

4.Anal canal.القناة الشرجية

A small pouch about 6 cm (2.4 in.) long. Attached to the cecum is a twisted, coiled

tube, measuring about 8 cm (3 in.) in length, called the appendix. The open end of

the cecum merges with a long tube called the colon.

The cecum

The colon

Which is divided into:

1. Ascending colon.الصاعد

2. Transverse colon.المستعرض

3. Descending colon. الناذل

4. Sigmoid colon. C شبيه حرف

Is about 15 cm (6 in.) in length and lies anterior to the sacrum and coccyx.

The terminal )2–3 cm (1 in.) of the large intestine is called the anal canal

The opening of the anal canal to the exterior, called the anus, is guarded by

an Internal anal sphincter of smooth muscle (involuntary) and an External

anal sphincter of skeletal muscle (voluntary).

Normally these sphincters keep the anus closed except during the

elimination of feces.

The rectum

The anal canal

1- The length of the GI tract is .............

A. About 5–7 meters .

B. About 4–6 meters .

C. About 3–8 meters .

D. About 2–9 meters .

2-Gastrointestinal tract include all except-------

A. The mouth

B. Most of the pharynx

C. Esophagus

D. Liver.

3- The stomach include all except- -----

A. The cardia.

B. Fundus.

C. Body.

D. Colon .

4- Small intestine include all except -------

A. The Duodenum.

B. The jejunum.

C. The ileum.

D. the cecum

System ReviewChoose Correct answer?