DIGESTION – is the process of reducing food into smaller particles or molecules

that will be absorb by the body.

FUNCTIONS:1. To break up big pieces of food into tiny particles.2. To break the tiny particles of food molecules that

will dissolve in the body fluidsand pass through the cell walls to be used by the cells.

3 PHASES OF DIGESTION3 PHASES OF DIGESTION

1. INGESTION – process of getting food 1. INGESTION – process of getting food 2. DIGESTION PROCESS 2. DIGESTION PROCESS

2 STAGES2 STAGESA. MECHANICAL PHASE – process by which food is A. MECHANICAL PHASE – process by which food is

acted upon physically.acted upon physically.B. CHEMICAL PHASE - process of converting food B. CHEMICAL PHASE - process of converting food

from complex molecules into its simplest form.from complex molecules into its simplest form.3. EGESTION / DEFECATION – process of 3. EGESTION / DEFECATION – process of

eliminating the undigested food from the in the eliminating the undigested food from the in the form of feces.form of feces.

ALIMENTARY TRACT / FOOD ALIMENTARY TRACT / FOOD TUBETUBE

MOUTHMOUTH ESOPHAGUSESOPHAGUS STOMACHSTOMACH SMALL INTESTINESMALL INTESTINE LARGE INTESTINELARGE INTESTINE RECTUMRECTUM ANUSANUS

ALIMENTARY TRACTALIMENTARY TRACT

ACCESSORY ORGANSACCESSORY ORGANS

GLANDSGLANDS LIVERLIVER GALL BLADDERGALL BLADDER PANCREASPANCREAS

ACCESORY GLANDSACCESORY GLANDS

DIGESTION IN THE MOUTHDIGESTION IN THE MOUTH

-Upon entering the mouth the food will be physically broken down into pieces by the Teeth with the help of the tongue and the buccinator muscle.

MUCUS – comes from the lining of the mouth which moisten the food facilitates swallowing

SALIVA - another secretion from the glands located at the different areas of the mouth which lubricates the food

3 KINDS OF SALIVARY GLANDS3 KINDS OF SALIVARY GLANDS

PAROTID GLANDS - the largest among the 3 PAROTID GLANDS - the largest among the 3 glands which are located on each side of the glands which are located on each side of the face , in front of the ears.face , in front of the ears.

SUBMAXILLARY GLANDS – lies with in SUBMAXILLARY GLANDS – lies with in the angle of the lower jaw.the angle of the lower jaw.

SUBLINGUAL GLANDS – found under the SUBLINGUAL GLANDS – found under the tongue tongue

TONGUE – acts as the organ of taste using taste buds

- it pushes the food towards the teeth- helps in swallowing the food

•SWEET TASTE – sensed at the tip of the tongue.•SOUR TASTE - sensed at the lateral part of the tongue•BITTER TASTE – sensed at the back part of the tongue

TONGUETONGUE

DIGESTION IN THE ESOPHAGUSDIGESTION IN THE ESOPHAGUS

ESOPHAGUS- a long tube which carries the ESOPHAGUS- a long tube which carries the food from the mouth to the stomachfood from the mouth to the stomach

PHARYNX- serves as the passage way for PHARYNX- serves as the passage way for both air and foodboth air and food

EPIGLOTTIS – covers the glottis to prevent EPIGLOTTIS – covers the glottis to prevent the food from entering the respiratory tractthe food from entering the respiratory tract

* PERISTALSIS- a rhythmic wave like mascular * PERISTALSIS- a rhythmic wave like mascular action that pushes the food further down the action that pushes the food further down the alimentary canalalimentary canal

DIGESTION IN THE STOMACHDIGESTION IN THE STOMACH

CARDIAC SPHINCTER – closes and opens CARDIAC SPHINCTER – closes and opens to allow the flow of food from the esophagus to allow the flow of food from the esophagus to the stomachto the stomach

STOMACH – large, J – shaped bag like STOMACH – large, J – shaped bag like structure which is located at the end of the structure which is located at the end of the esophagusesophagus- the lining is thick wrinkled membrane ith - the lining is thick wrinkled membrane ith gastric glands, the walls of each gland are gastric glands, the walls of each gland are lined with secretory cells.lined with secretory cells.

SECRETORY CELLSSECRETORY CELLS

SECRETES:SECRETES:1.1. ENZYMES –ENZYMES –- Proteases which break down proteinsProteases which break down proteins- Pepsin breaks down protein into peptonePepsin breaks down protein into peptone- Rennin acts on milk protein allowing the milk to Rennin acts on milk protein allowing the milk to

clotclot2. HYDROCHLORIC ACID- helps break up connective 2. HYDROCHLORIC ACID- helps break up connective

tissues and cell membranes in food, it also helps in tissues and cell membranes in food, it also helps in destroying the bacteria in the systemdestroying the bacteria in the system

3. MUCUS 3. MUCUS

PERISTALTIC MOVEMENT- the squeezing action of the stomach which churn and mix the food together with the gastric juices

PYROLIC VALVE- the valve that opens and closes several times letting the food from the stomach enter the small intestine

PANCREASPANCREAS

Secretes hormones that regulate the balance of Secretes hormones that regulate the balance of the blood glucosethe blood glucose

Secretes pancreatic juices which is emptied Secretes pancreatic juices which is emptied into the duodenuminto the duodenum

EMULSIFICATION- is the process of EMULSIFICATION- is the process of breaking down fats into tiny droplets.breaking down fats into tiny droplets.

LIVERLIVER

Is the largest gland in the body; it has Is the largest gland in the body; it has a gallbladder which produce a bilea gallbladder which produce a bile

Bile- serves as the emulsifier of fatsBile- serves as the emulsifier of fats

DIGESTION IN THE SMALL DIGESTION IN THE SMALL INTESTINEINTESTINE

- IT IS WHERE THE FINAL DIGESTION - IT IS WHERE THE FINAL DIGESTION AND ABSORPTION TAKES PLACEAND ABSORPTION TAKES PLACE

SMALL INTESTINESMALL INTESTINE

3 MAJOR PARTS3 MAJOR PARTS

1.1. DUODENUM- the upper 20cm long tube DUODENUM- the upper 20cm long tube connected to the stomachconnected to the stomach

2.2. JEJUNUM-2.5cm longJEJUNUM-2.5cm long

3.3. ILEUM-longest half coiled through the ILEUM-longest half coiled through the abdominal cavityabdominal cavity

SMALL INTESTINESMALL INTESTINE

duodenum

jejunum

ileum

GLANDS IN THE SMALL GLANDS IN THE SMALL INTESTINEINTESTINE

1.1. Erepsin- change peptone to amino acidsErepsin- change peptone to amino acids

2.2. Maltose- acts on dextrin and maltoseMaltose- acts on dextrin and maltose

3.3. Sucrase- acts on sucroseSucrase- acts on sucrose

4.4. Lactose acts on LactoseLactose acts on Lactose

Villi-are tiny fingerlike projections coming out Villi-are tiny fingerlike projections coming out of the folds of the mucosa or membranous of the folds of the mucosa or membranous lininglining

-it increases the area for absorption-it increases the area for absorption

THE LARGE NTESTINE/COLONTHE LARGE NTESTINE/COLON

Shorter than the small intestine but larger in Shorter than the small intestine but larger in diameter(7cm)diameter(7cm)

It absorb water from the undigested food It absorb water from the undigested food materials materials

LARGE INSTESTINELARGE INSTESTINE

LARGE INTESTINELARGE INTESTINE

RectumRectum- last 20-30cm of the colon- last 20-30cm of the colonAnusAnus- forms the end of the digestive tract- forms the end of the digestive tractFecesFeces-remaining food that is being -remaining food that is being eliminated through the anuseliminated through the anusAppendixAppendix-fingerlike structure found -fingerlike structure found between the large & small intestinebetween the large & small intestine

AILMENTS OF THE DIGESTIVE AILMENTS OF THE DIGESTIVE SYSTEMSYSTEM

Appendicitis, Appendicitis, - acute inflammation of the - acute inflammation of the vermiformvermiform (wormlike) appendix, a blind tube projecting (wormlike) appendix, a blind tube projecting from the from the cecum,cecum,—the beginning of the large —the beginning of the large intestine. The appendix, located in the lower intestine. The appendix, located in the lower right side of the abdomen, is an organ with no right side of the abdomen, is an organ with no known function in humans. If the appendix known function in humans. If the appendix wall ruptures, infection may spread to the wall ruptures, infection may spread to the abdominal cavity, causing peritonitis. abdominal cavity, causing peritonitis.

Symptoms of appendicitis include pain and Symptoms of appendicitis include pain and cramps in the area between the right hip bone cramps in the area between the right hip bone and the navel, fever, nausea and vomiting, and the navel, fever, nausea and vomiting, constipation, and diarrhea. The treatment is constipation, and diarrhea. The treatment is surgical removal of the appendix surgical removal of the appendix (appendectomy). Although the frequency of (appendectomy). Although the frequency of appendicitis is highest among young adults, appendicitis is highest among young adults, the ailment can affect persons of any age.the ailment can affect persons of any age.

Peptic ulcers are ulcers of the stomach Peptic ulcers are ulcers of the stomach (gastric) or small intestine (duodenal). In (gastric) or small intestine (duodenal). In addition to the pain caused by the ulcer itself, addition to the pain caused by the ulcer itself, peptic ulcers give rise to such complications as peptic ulcers give rise to such complications as hemorrhage from the erosion of a major blood hemorrhage from the erosion of a major blood vesselvessel

ConstipationConstipation

- occurs when the large intestine absorbs too - occurs when the large intestine absorbs too much water because food residues are moving much water because food residues are moving slowly. As a result, the feces become hard and slowly. As a result, the feces become hard and dry, which may make elimination difficult.dry, which may make elimination difficult.

Anorexia NervosaAnorexia Nervosa- mental illness in which a person has an - mental illness in which a person has an intense fear of gaining weight and a distorted intense fear of gaining weight and a distorted perception of their weight and body shape. perception of their weight and body shape. People with this illness believe themselves to People with this illness believe themselves to be fat even when their weight is so low that be fat even when their weight is so low that their health is in danger. A person with their health is in danger. A person with anorexia nervosa severely restricts food intake anorexia nervosa severely restricts food intake and usually becomes extremely thin. and usually becomes extremely thin.

Bulimia, an eating disorder in which persistent Bulimia, an eating disorder in which persistent overconcern with body weight and shape leads overconcern with body weight and shape leads to repeated episodes of binging (consuming to repeated episodes of binging (consuming large amounts of food in a short time) large amounts of food in a short time) associated with induced vomiting, use of associated with induced vomiting, use of laxatives, fasting, and/or excessive exercise to laxatives, fasting, and/or excessive exercise to control weight. Bulimia was classified as a control weight. Bulimia was classified as a distinct disorder by the American Psychiatric distinct disorder by the American Psychiatric Association in 1980; the name was changed to Association in 1980; the name was changed to bulimia nervosa in 1987.bulimia nervosa in 1987.