Digestive System

Question 1

What is the alimentary canal?

Answer 1

The route food travels through the body and waste products are expelled.
Where digestion and absorption takes place.

Question 2

Functions of alimentary canal

Answer 2

1. Ingestion
2. Propulsion - swallowing, peristalsis
3. Mechanical breakdown
4. Chemical digestion
5. Absorption
6. Excretion

Question 3

Structures of digestive system

Answer 3

1. Mouth
2. Salivary glands (water, mineral salts, ptyalin)
3. Pharynx
4. Oesophagus
5. Liver
6. Gallbladder
7. Pancreas
8. Stomach
9. Small intestine
10. Large intestine
11. Rectum
12. Anal canal

Question 4

Which is the fastest macronutrients to be absorbed?

When does absorption begin?

Where does absorption take place / nutrients taken?

Answer 4

Carbs are the quickest to be absorbed, then protein, then fats.

Absorption begins 3-6 hours after eating.

Most nutrients absorbed by small intestine and taken to blood.

Question 5

What are complex carb and the types?

Answer 5

Long complex chains of glucose molecules, broken into glucose.

Refined - manufactured or processed carbs.
Unrefined - natural carbs.

Question 6

What are the 3 forms of carbohydrates?

Answer 6

Sugar - found naturally in certain food e.g. honey, milk, veg.

Starch - sugar units bonded together to release energy gradually e.g. bread, rice, pasta, potatoes.

Fibre - only in plant food e.g. wholegrain, veg, beans, pulses.

Question 7

Are types of fats different at room temperature?

What are fats made of?

Answer 7

Liquids are called oils.
Solids are called fats e.g. lard.

Glycerol and 3 fatty acids (triglyceride).

Question 8

What are the 2 healthy fats and what do they do?

Answer 8

Monounsaturated fats - help lower bad cholesterol and blood triglyceride levels.

Polyunsaturated fats - controls BP, reduces inflammation, enhances transport of oxygen by red blood cells.

Question 9

What is cholesterol?

Answer 9

A fat produced by the liver and released into the blood.

Doesn’t mix well with blood so encased with lipoproteins.
- VDL (very low density lipoproteins)
- LDL (low density lipoproteins)
- HDL (high density lipoproteins)

Question 10

What do proteins do and types of amino acids?

Answer 10

Play role in growth, maintenance and repair.

Essential amino acids - 9 out of 20 are essential to daily diet (meat/soy).

Non-essential amino acids - 11 out of 20, not needed in daily diet as body produces them.

Question 11

Types of proteins

Answer 11

Complete proteins - contain all 9 essential amino acids.

Incomplete proteins - lacking 1 or more essential amino acid.

Complementary proteins - combining plant based foods together to get the 9 essential amino acids (rice/beans, veg/nuts).

Question 12

Insoluble and soluble fibre

Answer 12

Insoluble - not dissolvable in water, aids elimination of food.

Soluble - dissolves in water, partly digested, helps lower cholesterol.

Question 13

What are the 3 accessory organs in digestion and their function?

Answer 13

Liver - produces bile which helps digest fats.

Gallbladder - stores bile + releases it into small intestine.

Pancreas - secretes digestive enzymes to break carb, proteins + fats entering the duodenum from the stomach.

Question 14

What is the timescale for digestion overall and in the stomach, small intestine, large intestine?

Answer 14

24-72 hours.

Stomach - 2-6 hours
Small intestine - 3-6 hours
Large intestine - 4-72 hours as stool is stored in sigmoid colon.

Question 15

How much fluid is needed a day?

What are the 3 functions of fluid in digestion?

Answer 15

1.5 - 2 litres.

1) Helps transport nutrients around the body.
2) Prevents dehydration.
3) Optimises metabolic rate and energy levels.