LESSONS HOME ECONOMICSsoe20.pomgrammar.ac.pg/PDF/GR10 HECON HECON EJGIREVA...HOME ECONOMICS UNIT 1: FOOD & NUTRITION THE DIGESTIVE SYSTEM. Prepared by Eloi Joy Gireva LESSONS 1 - 4

HOME ECONOMICS

UNIT 1: FOOD & NUTRITION

THE DIGESTIVE SYSTEM.

Prepared by Eloi Joy Gireva

LESSONS 1 - 4

Learning Outcome:

1. Define the topic and terms.

2. Identify the parts and function/s of the digestive system.

3. Discuss the process of digestion and how waste are removed from the body.

4. Identify and discuss some digestive disorders.


Instruction / Timeframe:

• In this lesson you will look at the digestive system again as a revision of what was covered in term 1, from weeks 7 – 9.

• There are 4 learning outcomes to this lesson’s presentation.

• There are 34 slides.

• Slides 4 to 23 covers lessons 1 and 2. This slides are based on the parts of the digestive system.

• Slides 24 and 25 are the activities for lessons 1 and 2.

• Slides 26 to 30 shows additional notes on the process of removing waste and some digestive disorders.

• For slide 31, refer to your assignment. The assignment is labelled as Attachment 1.

• This lesson takes 2 weeks (Week 1 – 2).

• You can complete the activities in your Home Economics book.



Did you know?1. The digestive tract is nine metres in length

from oesophagus to the anus.

2. A person produces 2 litres of saliva in a

day.

3. The mouth cools or warms food to a

suitable temperature.

4. More than 90 per cent of digestion and

absorption takes place in the small intestine.

Lessons 1 - 2

Introduction:

•Have you ever wondered what happens to food inside your body?

•The story of digestion, absorption and metabolism is a fascinating account of how food travels through the body and how the body is able to make use of the nutrients in food and excrete what it does not need.

•First there are some terms you will need to understand.


Terms

• Digestion

• Alimentary Canal

• Metabolism

• Absorption

• Enzymes


Terms and Definitions:• Digestion – the process of breaking down food in the alimentary canal, releasing nutrients in

forms which can be absorbed into the bloodstream the body can use.

• Alimentary canal – a tube through the body along which the food passes from the mouth to the anus.

• Absorption – is the process by which nutrients pass into the cells lining the alimentary canal.

• Metabolism – the sum of the chemical changes that take place as food is changed into simpler compounds for energy, growth, and the maintenance and regulation of the body functions.

• Enzymes – are chemical substances that speed up chemical changes or chemical reactions without getting used up. E.g: digestion


Instruction:

• Before you look at the process of digestion, we will first look at a diagram of the digestive system.

• The diagram in the next slide shows the parts of the digestive system.


Parts of the Digestive System


Duodenum

Ascending colon Descending colon

Transverse colon

Jejunum

Sigmoid colonIleum

Cecum

1. The Mouth

• Teeth

• Saliva

• Salivary glands

• Tongue


1. The mouth:• Digestion begins in the mouth.

• Food is chewed into smaller pieces and mixed with saliva. Saliva is secreted by the salivary glands.

• The name of the enzyme found in saliva is called amylase.

• Amylase is the enzyme in saliva, that breaks down the carbohydrate (sugar and starch) in food.

• The carbohydrates are broken down into glucose so that it can be absorbed into the bloodstream.

• After being chewed, the moistened mixture is pushed by the tongue into the throat where it passes into the oesophagus.

• Teeth: Cut and grinds food into smaller pieces. Saliva is secreted by the salivary glands.

• Salivary Glands: Produce the saliva in your mouth.

• There is no further digestion of carbohydrates until the food passes into the small intestine where it mixes with more substance supplied by the pancreas. Nutrients can now pass into the blood stream.

• Tongue: Helps to push food into your esophagus.


2. The Oesophagus / Esophagus

• Esophagus / Oesophagus

• Epiglottis

• Uvula

• Peristalsis

• Sphincter


Esophagus / Oesophagus

2. The Esophagus/Oesophagus:• A long tube that carries food from the mouth

to the stomach. Food then passes down the oesophagus on its way to the stomach.

• Peristalsis a wave-like muscular action the oesophagus uses to take food from the throat to the stomach.

• Sphincter enables the food to enter the stomach and then squeezes shut to keep the food from flowing back to the oesophagus.

• Epiglottis: The flap of skin that covers the trachea

• Uvula: Covers the nasal passage


3. Stomach

• Stomach: Stores all the food. (warehouse for food)

• Sphincter muscles: The muscles found at each end of the stomach.

• Chyme: Liquid lumpy material that is made by the stomach.


3. The Stomach:

• A major part of protein digestion takes place in the stomach. The stomach muscles churn and mix the food with gastric juices which contain hydrochloric acid and a protein-digesting enzyme called pepsin. Pepsin a substance from the pancreas also helps to break down protein into amino acids.

• A major part of protein digestion takes place in the stomach. Pepsin acts upon the food and breaks down the proteins into amino acids so they are able to be absorbed in the small intestine.

• The food stays in the stomach for two to four hours and the stomach continues to break down the food until it is semi-liquid state, called chyme (pronounced ‘kime’).

• The chyme leaves the stomach and moves into the small intestine.


4. The Small Intestine

• Duodenum

• Jejunum

• Ileum

• Villi


4. Small Intestine

• The small intestine is a coiled and twisted, narrow tube about six metres long that runs from the stomach to the large intestine.

• It is in the small intestine that food is completely broken down and absorption takes place. The small intestine is made up of three parts: the duodenum, the jejunum and the ileum.

• Villi: Tiny projections on the inner walls of the small intestine where absorption takes place.

• Duodenum: the tube that connects the stomach and the small intestine.

• Jejunum: middle part of the small intestine.

• Ileum: the tube that connects to the large intestine.


Duodenum

• In the duodenum, the chyme is further digested by

pancreatic juice (pepsin) from the pancreas, bile juice

from the liver and intestinal juices.

• These substances reduce (break down) carbohydrates to

glucose, protein to amino acids and fats to fatty acids

and glycerol for absorption.

• Trypsin is another enzyme that helps to break proteins

down into smaller parts.

• Lipase is the enzyme that breaks down fats or lipids into

fatty acids and glycerol.

• The nutrients are now in a state where they can be absorbed.


Jejunum:

• Reaching the jejunum or middle part of the small intestine, the digested products of carbohydrate, protein and fats and most of the vitamins and minerals are absorbed.

• The walls of the intestine are lined with millions of tiny, finger-like projections called villi that absorb the nutrients, which are then carried to where they are needed in the body.

Ileum:

• In the ileum absorption of Vitamin B12 and bile salts take place.

• The waste foodstuff, assisted by the indigestible fibre in food, then passes to the large intestine.

• From this last section of the small intestine, the leftover foodstuff, passes into the large intestine.

• The journey through the small intestine has taken three to four hours and the absorption process is almost completed.

5. The Large Intestine / Colon

• Large Intestine:

Three Parts:

1. Ascending Colon

2. Traverse Colon

3. Descending Colon

• Appendix: Attached to the beginning of the ascending colon


5. The Large Intestine / Colon:

• Large intestine or colon is a thick, large, U-shaped tube.

• Its function is to remove water from the undigested matter and form solid waste or faeces that can be excreted through the anus. The indigestible fibre in food helps the process as it gives bulks to waste matter. Foodstuff can take more than a day to pass through the colon.

• The indigestible fibre in food helps this process as it gives bulk to the waste matter.

1. Ascending colon: is the beginning part of the colon that is located on the right side of the body.

2. Transverse colon: is the longest and most moveable part of the colon that crosses the abdomen.

3. Descending colon: is the part of the intestine located on the left side of the body. It stores the remains of digested food that will be emptied into the rectum.

4. Appendix: is attached to the beginning of the ascending colon.

• Foodstuff can take more than a day to pass through the colon.

• Water can be absorbed at any point from the stomach through the large intestine.


6. The Rectum

• Rectum

• Anus


• From the large intestine, the waste passes to the rectum, which is a tube about 15 centimetres long, leading from the large intestine to the anus.

• As the faeces is pushed into the rectum, it stimulates a desire to defecate.

• The function of the rectum is to store the faeces until it is a convenient time for it to be excreted.

Other Parts of the Digestive System

• Liver: Makes bile and sends it to the gall bladder.

• Bile: A substance produced by the liver and stored in the gall bladder.

• Gall Bladder: Receives bile from the liver and stores the bile

• Pancreas: Breaks down sugars and starches.



Activity


a.

b.

d..

c.

e.

1. Study the diagram of the digestive

on the right and identify the parts of

the digestive system.

a.

b.

c.

d.

e.

2. Differentiate between absorption and

digestion.

3. There are three parts of a small

intestine.

a. What are they?

b. Choose one from 1.a. and explain

briefly what happens takes place

there.

Extra Activity:

1. Find out what an enzyme is.

2. What are the functions of enzymes in the human digestive system?

3. Name these enzymes and find out their specific functions.

4. In your workbook or exercise book, draw up a table headed Enzyme and Specific Function and enter your findings.


The Process of Removing Waste

• Kidneys: Filter the water and dissolved wastes in the body.

• Ureters: Narrow tubes that carry urine from your kidneys to the bladder.

• Bladder: Urine is stored in the bladder

• Urethra: A narrow tube that carries urine from the body


Lessons 3-4

Problems of the Digestive System

• Indigestion

• Diarrhoea

• Stomach ulcers

• Cirrhosis

• Kidney stones

• Colon cancer

• Appendicitis


Problems or disorders of the digestive system:

These are some of the problems or disorders of the digestive system:

• Indigestion: Stomach too acidic, may be caused by eating too fast or too much or by spicy or acidic foods.

• Diarrhoea: Watery feces; caused by bacteria, virus, food poisoning, nutritional deficiencies.

• Ulcers: Sores on the inner walls of the stomach or small Intestines.

• Cirrhosis: Destruction on liver tissue; caused by drinking too much alcohol.

• Kidney Stones: Crystals in the kidney; may block passage of urine to the bladder.

• Colon Cancer: Uncontrolled growth of abnormal cells in large intestine.

• Appendicitis: Inflammation of the appendixPrepared by Eloi Joy Gireva

Problems of the Digestive System


Colon Cancer Appendicitis

Stomach Cancer

Gall Stones

Care of the Digestive System

• The best way to take care of the digestive is to practice healthful eating habits• Eat a variety of food from different food groups, low in fat high in fiber.• Do not hurry through your meals. Enjoy your food.• Eat enough food to satisfy your hunger.

• Drink plenty of water.• Have regular dental checkups.


Activity

Work on your assignment which is labelled as Attachment 1.



END OF LESSONS 1 - 4

Documents

LESSONS HOME ECONOMICSsoe20.pomgrammar.ac.pg/PDF/GR10 HECON HECON EJGIREVA...HOME ECONOMICS UNIT 1: FOOD & NUTRITION THE DIGESTIVE SYSTEM. Prepared by Eloi Joy Gireva LESSONS 1 - 4