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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?