THE DIGESTIVE SYSTEM

Mouth

Pharynx

Esophagus

Stomach

Small intestine

Large Intestine

The digestive tract, tube or alimentary tract (6)

Pancreas

Liver

Gall Bladder and Bile ducts

Abdominal Accessory Organs of Digestion (3)

mouth

Breaks up food particles assists in producing spoken language

Salivary glands

Saliva moistens and lubricates food Amylase digests polysaccharides

Pharynx

swallows

esophagus

Transports food

Liver

Breaks down and builds up many biological molecules. Stores vitamins and iron. Destroys old blood cells. Destroys poisons Bile aids in digestion.

stomach

stores and chums food. Pepsin digest protein. HCI activates enzymes. breaks up food. kills germs. Mucus protects stomach wall/ Limited absorption

Gall bladder

stores and concentrates bile

Pancreas

Hormones regulate blood glucose levels. Bicarbonates neutralize stomach acid. Trypsin and chymotrypsin digest proteins. Amylase digest polysaccharides, Lipase digest lipids

Small intestine

Completes digestion. Mucus protects gut wall. Absorbs nutrients, most water Peptidase digests proteins. Sucrases digest sugars. Amylase digest polysaccharides

large intestine

Reabsorbs some water and ions. Forms and stores feces

Anus

Opening for elimination of feces

Rectum

stores and expels feces

Digestive system

has been developed to provide a means by which food is taken into the body and broken down into simple molecules that can be absorbed by the body

Carbohydrates

Fats or lipids

Proteins

Mineral salts

Vitamins

Water

6 TYPES OF SUBSTANCES REQUIRED TO MEET BODILY REQUIREMENTS

Ingestion

Is the taking into the mouth of food

mastication

chewing

deglutition

swallowing

Digestion

Is the breaking up of complex food molecules into small simple molecules that can pass through living membranes

Proteins to amino acids

Fat(lipids) to fatty acids and glycerine

Carbohydrates to glucose, fructose and galactose

Enzymes break up the three foods

Absorption

The passage of digested food products into blood or lymph capillaries.

Uptake of products from the intestine.

Passing of dissolved substances from blood capillaries into intercellular spaces and from these to any body cells

Habitus or body build

Weight

Position

Phase of respiration

State of fullness

FACTORS DETERMINING POSITION OF ABDOMINAL ORGANS

Right upper quadrant

Right lower quadrant

Left upper quadrant

Left lower quadrant

Division into 4 Quadrants

Upper ➢ Right hypochondriac region

Epigastric region

Left hypochondriac region

Middle ➢ Right lumbar region

Umbilical region

Left lumbar region

Lower ➢ Right iliac region

Hypogastric region

Left iliac region

DIVISION ONTO 9 REGIONS

Lumen

Is the cavity within any hollow organ

Peritoneum

The membrane that lines the abdominal and pelvic cavities

Parietal peritoneum

The lining of the abdominal and pelvic cavities. It also forms the mesentery of the intestine

Visceral peritoneum

Forms the outer covering membrane of most abdominal and pelvic organ

Peritoneal cavity

The potential space between the visceral peritoneum covering the organs and the parietal peritoneum

Mesentery

Is a double layer of peritoneum that extends from the parietal peritoneum on the posterior abdominal wall to the small intestine

Mesocolon

Is a similar double layer of the parietal peritoneum between some parts of the large intestine and the posterior abdominal wall

Omentum

Is a double layer of peritoneum that extends between two organs

Greater omentum

Is a fold of peritoneum that extends from the lower margin of the stomach to the transverse colon

Lesser omentum

Is a fold of peritoneum between the stomach and the liver

Sphincter

Is a thickened ring of the circular layer of visceral muscle that surrounds the opening of a hollow organ

Peristalsis

Is a contraction wave that passes along the dilatation

Segmentation

Is a contraction of a small segment of bowel that divides the contents into two parts

Stenosis

The narrowing of the lumen of a hollow organ

Atresia

Absence of lumen or canal in a hollow organ that normally has one

Serous layer

Muscular layer

Submuscular layer

Mucous coat

The structures of Walls of Digestive Tract

Serous layer

visceral layer of peritoneum that covers most abdominal and pelvic organ

Muscular layer

located under the serous covering consists in most parts of two layers of visceral muscle, an outer longitudinal muscle and an inner circular layer

Submuscular layer

a layer of loose connective tissue

Mucous coat

or lining membrane of an organ is a layer of epithelium adjacent to the lumen or cavity

➢ Vestibule

➢ Teeth

➢ Tongue

➢ Salivary glands

 Parotid

 Submandibular

 Sublingual

PARTS OF mouth

➢ Nasal pharynx

➢ Oral pharynx

➢ Laryngeal pharynx

Parts of Pharynx

Fundus

Body

Pyloric part

Pylorus

Parts of Stomach

Vestibule

is the space between the cheeks and the lips on its outer side and the teeth and gums on the inner side

Cavity

is the hollow space, the receiving chamber of the digestive tract

Hard palate

consist of palatine bones. Floor of the nasal cavities

Soft palate

contains no bone but is a fold epithelium at the posterior margin of hard palate

Fauces

space between the mouth and the oral pharynx

Palatoglossal arch

extends from the soft palate to the base of the tongue on either side

Palatopharyngeal arch

reaches from the soft palate to the side wall of the pharynx on either side

The teeth

bite, chew it to produce smaller particles more accessible to the digestive enzymes

The tongue

muscular organ covered by epithelium with small projections on the upper surface

Salivary glands

3 pairs; they are alveolar glands and secrete saliva, a watery mucous fluid containing the enzyme ptyalin. (digest carbohydrates)

Parotid gland

lies on the side of the face in front of and below the opening of the ear

Parotid duct

Stensen’s duct

Submandibular gland

lies under the floor of the mouth on each side

Submandibular duct

Wharton’s duct

Sublingual gland

lies in the floor of the mouth, anterior to the submandibular

Sublingual duct

Duct of Rivinus

12\.5 cm (5 inches) long

The Pharynx is how long?

Esophagus (gullet)

is a tube about 25 cm (10 inches) in length and extends from the laryngeal part of the pharynx to the stomach

stomach

a collapsible reservoir of food

2 openings Cardiac and pyloric

2 sphincters Cardiac and pyloric

An angular notch

2 curvatures Greater and lesser

3 parts Fundus, body, pyloric

The STOMACH has

Cardiac orifice

an opening between the lower end of the esophagus and the upper stomach

Pyloric orifice

is an opening in the lower end of the stomach, between it and the duodenal part of the small intestine

Cardiac sphincter

is located at the cardiac end of the stomach. It prevents regurgitation of the stomach contents into the esophagus

Pyloric sphincter

located at the pyloric end of the stomach in the pylorus. It keeps the opening closed except for relaxation to allow the stomach contents to enter the duodenum

The lesser curvature

short right curved border that extends from the cardiac to the pyloric openings of the stomach

The greater curvature

is much longer left curved border of the stomach

Angular notch

is a notch on the lower part of the lesser curvature of the stomach where it bends sharply to the right

Fundus

part that lies above the cardiac opening

Body

part between the cardiac opening and the angular notch

Pyloric part

part between the angular notch and the pyloric opening

Pylorus

is a constricted area between the pyloric part of the stomach and the first or superior part of the duodenum

Rugae

are folds lining membrane that usually run longitudinally

Gastric glands

simple tubular glands in the mucosal layer of the stomach

➢ Duodenum

 Superior part (cap)

 Descending part

 Horizontal part

 Ascending part

➢ Jejunum

➢ Ileum

parts of small intestine

➢ Cecum and appendix

➢ Ascending colon

➢ Right colic flexure (hepatic)

➢ Transverse colon

➢ Left colic flexure (splenic)

➢ Descending colon

➢ Sigmoid colon (pelvic)

➢ Rectum

➢ Anal canal

➢ Anus

parts of Large Intestine

small intestine

Has smaller lumen than the large intestine

➢ Single continuous tube but in order to accommodate to the abdomen it is coiled upon itself repeatedly

\

7m (23ft) in length

how long in length is the small intestine?

Duodenum

25 cm (10 in) of the small intestine form a loop in the upper right abdomen

Superior duodenum

the first part, passes up and to right from the pyloric opening of the stomach. It includes the duodenal cap or bulb

Descending duodenum

passes downwards from the superior part, and ends by joining the horizontal part. The common bile duct opens into it from the back

Horizontal duodenum

extends to the left from the descending part

Ascending duodenum

passes up from the horizontal part, and joins the jejunum posterior to the stomach, close to the angular notch

Jejunum

second part of the small intestine, forms about two-fifths of the remaining part. About 2.7 m (9 ft) in length. It is quite mobile

Ileum

the 3rd part of the small intestine forms the remaining three-fifths of the small intestine and is about 3.9 m (13 ft) long

Ileocecal opening

is the opening between the terminal part of the ileum and cecum

Ileocecal sphincter of valve

is a thickened layer of circular muscle at the ileocecal opening

Circular folds

are folds in the lining membrane of the small intestine that encircle its lumen

Villi

are very minute microscopic fingerlike projections of the mucosal lining of the small intestine that cover the circular folds and the hollows among them

Aggregated lymph follicles

are collections of lymphatic tissue in the mucosa of the small intestine

Solitary lymph follicles

are single follicles of lymphatic tissue, and are also found in the lining of the small intestine

Intestinal glands

lie in the mucosa in the intervals between the bases of the villi. They are tubular glands

large intestine

is the final division of the digestive tube. About 1.5 m (5 ft) in length