8 3. digestive system

Digestive System( Also called Gastrointestinal or Alimentary system )

• The food we consume will be broken down into nutrient which later can be absorbed by the body

• There are 6 nutrients that are needed to keep healthy ;1. Carbohydrates2. Fat3. Protein4. Vitamins5. Minerals6. Water

Created By Alfi Msk _ A biology Teacher of GIS JH


1. Carbohydrates

• Are a source of energy

• Excess carbohydrates will be stored in the liver and muscles

• Sources of carbohydrates are rice, corn, sweet potatoes, potatoes, cassavas, etc

• 1 gr of carbohydtares provides 4,1 cal.

• In the digestion process, carbohydrates are brokendown into simple saccharides or monosaccharides

• The body will then absorb these monosaccharides

• If we consume more carbohydrates more than our body needs, the excess will be converted to glycogen or fat

• Glycogen will be stored in the liver or muscles

• Fat will be stored in areas around the waist, around the kidneys, and under the skin

• Lack of carbohydrates will cause the body to be thin and weak, and it will cause a lack of energy, anxiety, and reduced body immunity



There are 3 kinds of carbohydrates, they are ;

1. Monosaccharides carbohydrates that consist of 1 simple sugar they are glucose, fructose, galactose

2. Disaccharides carbohydrates that consist of 2 simple sugars they are ;

a. Maltose = glucose + glucoseb. Sucrose = glucose + fructose c. Lactose = glucose + galactose


3. Polisaccharidescarbohydrates that consist of many simple

sugars for example, rice, bread, potatoes, etc

2. Fat• Its function as a source of energy

• 1 gr of fat provides 9,3 cal

• Fat is acquired from both animals and plants

• Fat that is acquired from animals is called animal fat, for ex. Butter, milk, meat, eggs, etc

• Fat that is acquired from plants is called vegetable oil, coconuts, candlenuts, peanuts, avocado, etc


• In the digestion process, fat is broken down into fatty acids and glycerol with the help of the enzymes

• Fat also has other function ;a. As a food store, that is stored under the skinb. Protect vital organsc. As an insulator and prevents the loss of

body heatd. Helps to dissolve vitamin A, D, E, and K so

that they can be easily absorbed.


3. Protein • The main function of protein is for the formation

of the body’s main structure, cell regeneration, and coordination of biological processes in the body

• 1 gr of protein provides 5,3 cal.

• Proteins are acquired from both animals and plants, that are acquired from animals are called animal proteins (meat, fish, egg, etc) and that are acquired from plants are called vegetable proteins (soybeans, peanuts, green beans, etc)


4. Vitamins• Vitamins are needed only in small amounts, but lack of one of

vitamins can cause avitaminosis.

• Vitamins act as coenzymes (biocatalysts), substances that help accelerate chemical reactions in the body.

• Based on their solubility, vitamins are classified into water-soluble and fat-soluble vitamins.

a. Water-soluble vitamins are vitamin B and C.These vitamins can not be stored in the body, which means that the body will only use as much as it needs and excretes the rest.

b. Fat-soluble vitamins are vitamin A, D, E and KCreated By Alfi Msk _ A biology Teacher of GIS JH

5. Dietary Minerals• Minerals are needed only in small amounts

• Each mineral has certain functions in the body, and lack of a mineral is called mineral deficiency

• Examples of dietary minerals needed by the body are as follows ;1. Calcium (Ca)2. Iron (Fe)3. Iodine (I)4. Phosporus (P)5. Potassium (K)6. Sodium (Na)7. Fluorine (F)


6. Water

• Water is the main component of protoplasm

• The human body contains 60% of water

• In the body, water has the role of ;a. Dissolving nutrients and accelerating chemical

reactionsb. Carrying metabolic wastec. Carrying other bodily substancesd. Forming body fluidse. Regulating body heat



The human body’s “gastrointestinal tract” or “alimentary canal” is up to 10m long

Along this pathway:

Ingestion Digestion Absorption Egestion

About 95% of ingested food is absorbed and made available to our body, the rest is egested

Digestion is the breakdown of substances (other organisms!) into small molecules that can be absorbed by cells

There are two ways of digestion ; Physical/Mechanical Chemical


The 2 ways of digestion

Mechanical Changes the physical form of food

Chew Tear Grind Mash Mix

The breakdown of food into small pieces without chemically changing them into different substances

Helps facilitate chemical digestion by increasing surface area Increased surface area exposes food

pieces to enzymes and other substrate molecules and increases the rate of metabolic reactions

Examples: teeth, stomach (HCl), intestines (bile)

Chemical

Changes the chemical composition of food with the aid of digestive enzymes• Lipids to fatty acids • Proteins to individual amino

acids• Carbohydrates into simple sugars

Digestive enzymes are special proteins that help break up large molecules of food into very tiny molecules that can be absorbed and used by the cells in the form of nutrition.


1. Ingestion: occurs when materials enter digestive tract via the mouth

2. Mechanical processing: crushing and shearingmakes materials easier to propel along digestive tract

3. Digestion: is the chemical breakdown of foodinto small organic fragmentsfor absorption by digestive epithelium

6 Functions of the Digestive System


4. Secretionis the release of water, acids, enzymes, buffers, and

salts by epithelium of digestive tractby glandular organs

5. Absorption movement of organic substrates, electrolytes,

vitamins, and water across digestive epithelium into interstitial fluid of digestive tract

6. Excretion removal of waste products from body fluids


Components of the Digestive System

Digestive Tract

Gastrointestinal (GI) tract divided into: Alimentary canal. Accessory digestive

organs.

Is a muscular tube

Extends from oral cavity to anus


• Your digestive tracts or food tube consist of the following: (1) mouth (2) esophagus (3) stomach (4) small intestine (5) large intestine (6) Anus

• The accessory organs are :(1) salivary glands (2) pancreas (3) liver (4) gallbladder


The Organs of Digestive System movie


Digestion from the Mouth

• Saliva – lubricates the food and secretes an enzyme, ptyalin or salivary amylase, that convert starch to maltose

• 3 Salivary Glands• Parotid glands• Submaxillary glands• Sublingual glands


• Tongue – pushes the food to the back of your mouth

• Bolus – a soft, mass of rounded ball of food that is being chewed


• Pharynx – an alimentary canal where food goes down after the digestion in the mouth

• Epiglottis- a flap of tissue that closes over the trachea to prevent the food from entering

• Esophagus – carries the food down the stomach

Digestion from the Esophagus


Stomach a large J-shape organ found at the end of the

esophagus contraction of the muscles of the stomach causes the

churning, squeezing and twisting effect it where partial digestion of food happens

Cardiac spincter – closes and opens to allow the flow of food from the esophagus to the stomach

Pepsin – enzymes secreted in the stomach that breaks down the protein

Digestion from the Stomach


• Pyloric valve or spincter – opens and closes to allow the food getting in the small intestine

• Chyme – partial product retained in the stomach before transferring into the small intestine


• 3 Major Parts1. duodenum – upper 20 cm2. jejunum – 2.5 meters long3. ileum – longest half coiled into the abdominal cavity

• It is where the final digestion and absorption of food take place

• Villi – small finger-like projection in the lining of the small intestine that is used in absorption

• Maltase – enzymes that break down maltose into glucose

Digestion from the Small Intestine


• Pancreas – a digestive gland that serves 2 functions:1. secrete hormones

that regulate blood glucose

2. secretes pancreatic juice that netralizes the acid in the stomach

PANCREAS


LIVER• The liver is the

largest gland in our body that carries the gall bladder


GALL BLADDER

• Gall bladder – Produces a blue green fluid called bile

The Gallbladder Movie



LARGE INTESTINE

• Undigested food goes down into the large intestine

• It is where the absorption of water is happen

• It is also called as colon

FECES – remaining food material


RECTUM AND ANUSRectum• 20 to 30 cm • a muscular cavity

where feces is temporarily stored

Anus – end of the alimentary canal

The Digestive System movie



The Digestive System Diseases

Appendicitisthe inflammation of the appendixmay cause inflammation of the diaphragm membranethe basic treatment of appendicitis is surgical removal of the appendix appendectomy

Constipationthe delayed passage of wastecontinuous constipation may be a symptom of other diseaseswill cause irregular defecation and headache

Parotitis or Mumpsis a feverish cold caused by virus, soon followed by swelling and stiffening in the region of the parotid salivary glands in front of the earif you suffer mumps, take a vitamin C supplement and consult a doctor

Xerostomiais a disease that infects the oral cavityIt may cause dry mouth due to the distrubed production of saliva, which will later affect the food processing in the mouth


8 3. digestive system

Education

alfi msk

biology teacher of gis

biology teacher ofgis

vitamins vitamins

body tobe

body fluidse

small carbohydrates

monosaccharides carbohydrates