The Digestive System

3 functions Digestion – breakdown of food

into nutrients that can be absorbed in the form of molecules

Absorption – passage of nutrients into the bloodstream to be carried to body tissues & cells

Excretion – elimination of waste products

Gastrointestinal Tract Extends from mouth to anus

The gastrointestinal tract consists of the following : Mouth Throat Oesophagus Stomach Duodenum Small bowel Colon Rectum Anus

Other organs of GIT

Liver (hepatobiliary system) Gallbladder Pancreas

These organs lie outside GIT but contribute to the Digestion process

DIGESTIVE SYSTEM

STOMACH

LARGE INTESTINE

LIVER

Mouth Food is moistened and chewed (i.e.

mastication) Contains teeth, tongue, Contains hard & soft palate (roof

of mouth) Contains uvula which stops food

entering the nasal cavity with swallowing

Mouth Cont’d

Salivary glands supply saliva with digestive enzymes for food breakdown

Tonsils – located in oropharynx & produce leucocytes

Oesophagus

Is a tube connecting pharynx to stomach

Moves food into stomach by peristalsis

Oesophagus word component

Word Root

Combining form

Meaning

Oesophag

oesophag/o oesophagus

Stomach Hollow organ Lies below diaphragm in upper

abdominal cavity, LUQ It is divided into three (3) sections i) the fundus ii) the body which is the middle section iii) the pylorus (the lower, small end).

Stomach cont’d Gastric juices break down the food into watery

material to make absorption easier Pepsin (an enzyme) also breaks down food

Has 2 sphincters

1. cardiac sphincter – prevents regurgitation into oesophagus 2. pyloric sphincter – controls passage of food into small intestine

Word Components

Word Root

Combining form

Meaning

gastr gastr/o stomach

pylor pylor/o pylorus

Small Intestine Is 6 metres long

Nutrients from broken down food is absorbed through the intestinal walls

3 sections 1. duodenum –connected to pylorus of stomach 2. jejunum – middle section 3. ileum- lower section and joins onto large intestine

Stoma -stomy Stoma means a surgical opening

-stomy is also referred to an operation to form an opening between two parts e.g. stomach to abdomen

Can be an opening from the intestine onto the outside of the body after surgical removal of part of intestine

-stomy

Is joined onto combining forms to add meaning e.g.

Jejun / o / stomy is creation of a new opening through the

abdominal wall into the jejunum

Ile /o / stomy is creation of a new opening through the

abdominal wall into the ileum

-stomyIt is also used with two combining forms for organs & means an opening between twobody parts or organs that would normally beseparated

Gastr / o / enter / o /stomy is a new surgical opening between stomach and small intestine

NB: when the 2 combining forms gastr/o and enter/o are joined the combining vowel is retained

Suffixes

Gram – refers to a drawing or picture

Graphy – refers to the technique of making a recording

Graph – refers to the instrument that make the recording

Word components

Word root Combining form

Meaning

gastr gastr/o stomach

duoden duoden/o

jejun jenun/o

ile ileo /o

Large Intestine (i.e. large bowel)

1 metre long

Water is absorbed through large intestine back into body

waste becomes solid

Large Intestine cont’d

3 major sections

Caecum hold appendix Colon – ascending colon transverse colon descending colon sigmoid colon rectum

Word components

Word Root Combining Form

Meaning

caec caec/o a blind ended pouch

appendic appendic/o appendage

col col/o large bowel

sigm sigmoid/o sigmoid colon

rect rect/o rectum

peritone peritone/o peritoneum, membrane covering abdominal organs

Liver

Liver –manufactures & releases bile

Lies in RUQWord Root

Combining Form

Meaning

Hepat hepat/o liver

Chol chol/e bile

Gallbladder Lies inferior surface of liver stores bile & releases bile through

common bile duct into duodenum

Word Root Combining Form

Meaning

cyst cyst/o bladder,combined with chole it refers to gallbladder

choledoch choledoch/o common bile duct

lapar lapar/o soft part between ribs & hipsrefers to the abdomen

Pancreas Lies posterior to stomach Produces juices filled with enzymes to

digest food Releases digestive juices into the

duodenum Secretes insulin which is a hormone is

released when blood sugar levels rise

pg 42

Procedures

Cholecystectomy Cholecystography Colonoscopy Enterectomy Hemicolectomy Laparoscopy Uvulopalatopharyngoplasty pg

44

Prefixes

Prefix Meaning

dys difficult

dyspepsia difficulty with digestion

hypo below

hypoglossal below the tongue

sublingual below the tongue

hyper above.or more than normal

hyperemesis

excessive vomiting

Suffixes

Suffix Meaning

pepsia digestion

ostomy surgical opening

colostomy surgical opening into colon

otomy surgical incision

gastrotomy surgical incision into the stomach pg 45

Diseases and disorders Adhesion – fibrous band Ascites – accumulation of fluid in

abdominal cavity Cachexia – abnormally low weight Cirrhosis – scarring of an organ (liver) Divrticulum – abnormal pouch in wall of

a tube (colon ) Cholelithiasis – stones in gallbladder pg

46