Get Started. It's Free
or sign up with your email address
digestive system by Mind Map: digestive system

1. 14.2

1.1. Two process in digestion:

1.1.1. Physical digestion

1.1.1.1. Food is broken down into smaller pieces by physical or mechanical means such as crushing, grinding and mixing.

1.1.2. Chemical digestion

1.1.2.1. Food is broken down into small molecules through the action of biological molecules known as enzymes

1.2. enzymes

1.2.1. Carbohydrates : carbohydrases digest carbohydrates into simple sugars

1.2.2. Proteins: proteases digest proteins into amino acids

1.2.3. Fats: lipases digest fats into fatty acids and glycerol

1.3. Parts of the digestive system + how they function:

1.3.1. Mouth:

1.3.1.1. Physical digestion: Strong teeth and jaw muscles in the mouth cut and crush the food into smaller pieces

1.3.1.2. Chemical digestion: Saliva in the mouth contains carbohydrases. Partial digestion of starch, a type of carbohydrate, begins in the mouth.

1.3.1.3. Other functions: Saliva softens and lubricates the food for easier swallowing

1.3.2. Gullet/Oesophagus:

1.3.2.1. Physical digestion: None

1.3.2.2. Chemical digestion: The gullet does not release any digestive juices. However, starch from the mouth continues to be digested by carbohydrases that are mixed with food.

1.3.2.3. Other functions: The muscles of the gullet push the food towards the stomach

1.3.3. Stomach:

1.3.3.1. Physical digestion: The stomach churns food into smaller pieces

1.3.3.2. Chemical digestion: The stomach releases gastric juices that contain proteases to digest proteins.

1.3.3.3. Other functions: The stomach releases gastric juice containing hydrochloric acid, which kills harmful microorganisms and provides the right condition for proteases to act. The stomach has a thick layer of mucus to protect its tissues from damage caused by the hydrochloric acid and proteases from gastric juice. The muscles at both ends of the stomach control the food entering and leaving the stomach.

1.3.4. Small intestine:

1.3.4.1. Physical digestion: None

1.3.4.2. Chemical digestion: The small intestine is the main site for chemical digestion due to the numerous enzymes released. Fats are first digested here due to the presence of lipases in the digestive juices. Carbohydrates, proteins and fats are fully digested here.

1.3.5. Large intestine:

1.3.5.1. Some of the remaining water and mineral salts in the food are absorbed here.

1.3.6. Rectum:

1.3.6.1. Indigestible food and waste from faeces, which is temporarily stored here before it leaves the body.

1.3.7. Anus:

1.3.7.1. Faeces is released through the opening

2. 14.1

2.1. We need the digestive system to break down food into small soluble pieces

2.2. Only then can the digested food be used by body cells to release energy through cellular respiration.

3. 14.3

3.1. Carbohydrates > broken down into glucose and fructose.

3.2. Proteins > broken down into amino acids.

3.3. Fats > broken down into glycerol and fatty acids.

3.4. When there are excessive simple sugars in the body, diabetes happens.

3.4.1. It happens when the level of sugars in blood is too high.

3.4.2. Occurs when the body produces insufficient insulin.

3.4.3. Insulin keeps the blood sugar balanced

3.4.4. Diabetes can also occur when the body does not respond properly to insulin, resulting in a high level of sugar in the blood.

3.4.5. This disease is often linked with obesity and other health issues, such as heart attack, kidney problems, high blood pressure, blindness and stroke.