LSC: Digestive System

What is the aim of the digestive system?

To digest food.

Why do we need food?

To produce energy.

What is ingestion?

Eating.

What is mastication?

Chewing.

What is digestion?

Breaking down food.

What is absorption?

Taking nutrients into the body.

What is assimilation?

Using nutrients in the body.

What is transportation?

Moving substances in the body.

What is egestion?

Removal of waste.

What is the correct order of digestion steps?

Ingestion → Mastication → Digestion → Absorption → Transportation → Assimilation → Egestion

What is mechanical digestion?

Physical process that breaks down food.

What happens in mechanical digestion?

• Tearing

• Pushing

• Mixing

• Grinding / crushing

What is the result of mechanical digestion?

Food is broken into smaller pieces.

What is chemical digestion?

Chemical process that crushes food.

What substances are involved in chemical digestion?

• Gastric juices

• Hydrochloric acid

What is the result of chemical digestion?

Food is broken into simplest form.

Name the main organs of the digestive system.

• Mouth

• Oesophagus

• Stomach

• Liver

• Pancreas

• Small intestine

• Colon

• Rectum

• Anus

What do teeth do?

Chew food into smaller pieces.

What does the tongue do?

Mixes food with saliva to form a bolus.

What do salivary glands do?

Release saliva to help swallowing.

What does the oesophagus do?

Uses peristalsis to move food down.

What does the stomach do?

Digests food.

What does the liver do?

Produces bile and glycogen.

What does the gall bladder do?

Stores bile.

What does the pancreas do?

Secretes hormones and pancreatic juice.

What does the small intestine do?

• Digestion

• Absorption

• Contains villi

What does the colon do?

Absorbs water to form faeces.

What does the rectum do?

Temporary storage of faeces.

What does the anus do?

Releases faeces from the body.

What happens in the mouth?

• Teeth and tongue work

• Bolus forms

What do salivary glands do in movement of food?

Help with swallowing food.

What is a bolus?

A ball of food formed in the mouth.

What happens in the oesophagus?

Food moves down using peristalsis.

What is peristalsis?

Movement of food down the oesophagus.

What happens in the stomach?

Food is moved and broken down.

What happens in the small intestine?

Food continues moving and digestion occurs.

What happens in the colon?

Food waste moves and water is absorbed.

What happens in the rectum?

Waste is stored.

What happens at the anus?

Waste leaves the body.

What is peristalsis?

Movement of the bolus down the oesophagus by involuntary muscle contractions.

What happens during peristalsis?

• Circular muscles contract behind the bolus

• Circular muscles relax in front of the bolus

• This pushes food forward

What are villi?

Hair-like outgrowths in the small intestine.

What is the function of villi?

Increase surface area for absorption.

Where are villi found?

In the small intestine lining.

Why do we need food for energy?

To survive and perform the 7 life processes.

Why do we need food for growth?

To generate new cells.

Why do we need food for health?

It provides nutrients to keep us healthy.

Why do we need food for recovery?

To replace dead cells and repair wounds.

What is nutrition?

The process whereby organisms obtain energy by taking in food to allow life processes to take place.

What is the function of carbohydrates?

Source of energy.

What can a shortage of carbohydrates lead to?

An unhealthy decrease in body weight.

What is the function of fats?

Reserve source of energy.

What can a shortage of fats lead to?

Kidney failure and stunted growth.

What is the function of proteins?

Building material to produce and repair cells.

What can a shortage of proteins lead to?

• Kwashiorkor

• Marasmus

• Muscle weakness

What is the function of vitamins?

Promote chemical reactions in the body.

What can a shortage of vitamins lead to?

• Night blindness

• Rickets

• Scurvy

What is the function of minerals?

Ensure normal growth and development.

What can a shortage of minerals lead to?

• Anaemia

• Muscle cramps

• Osteoporosis

What is the function of fibre?

Promotes movement in the digestive system.

What can a shortage of fibre lead to?

• Constipation

• Cancer

What is a balanced diet?

A diet where sufficient food is ingested in the correct proportions.

What is an unbalanced diet?

A diet where sufficient food is ingested, but in incorrect proportions.

What is the difference between a balanced and an unbalanced diet?

• Balanced diet → Correct proportions of food.

• Unbalanced diet → Incorrect proportions of food.

What is malnutrition?

A shortage of one nutrient, but an excess of another nutrient.

What is undernutrition?

Too few nutrients are ingested.

Give two examples of undernutrition.

• Kwashiorkor

• Marasmus

What is overnutrition?

Too many nutrients are ingested.

Give an example of overnutrition.

Obesity.