Mechanical & Chemical Digestion + Absorption

What is mechanical digestion?

What is mechanical digestion?

Aka Physical digestion is break down of goods using physical processes to increase the surface area and the efficiency of chemical digestion.

examples of physical break down processes

• Chewing

• slicing

• grinding

• squeezing

• Etc

First place where Mechanical digestion happens

Mouth

• Teeth cut, slice, grind up food into smaller pieces

• Tongue pushes/ food against hard palate

Second place where Mechanical digestion happens

Esophagus

• 2 muscle layers squeeze food/bolus as it moves to the stomach (peristalsis). Longitudinal compress, rings move down

3rd place where Mechanical Digestion happens

Stomach

• 3 muscle layers contract very tightly to break food down

4th place where mechanical digestion happens

Small intestine

• Squeezing, mixing with bile + enzymes

Where does Mechanical digestion happen?

Mouth Esophagus Stomach Small intestine

What is your Esophagus lined with, and why?

Its lined with mucus & saliva to reduce the friction between the esophagus & bolus Mucus prevents hydrochloric acid from eating the stomach

What does Emulsification do

increases the efficiencies and creates more surface area

What is chemical digestion

the break down of food by acid & enzymes into macronutrients that can be absorbed by the body

Where does Chemical digestion happen?

Mouth Stomach Small intestine

First place food is chemically digested

Mouth Salivary glands makes & secrete salivary amylase to break down starch into complex carbohydrates which are called polysaccharides (Many, sugars) Starch is where the sugar in the plants is

2nd place food is chemically digested

Stomach

• Its going to make & release hydrochloric acid until the pH level drops to 2.4

• Next pepsin & pepsinogen breaks down protein into polypeptides

3rd place food is chemically digested #1

Small Intestine Pancreas makes & releases Lipase breaks down lipids (fats) into fatty acids and glycerol, which can be absorbed in the blood stream

3rd place food is chemically digested #2

Small Intestine Pancreas makes & releases Protease which breaks down polypeptides into amino acids, which can be absorbed

3rd place food is chemically digested #3

Small Intestine Pancreas makes & releases Pancreatic amylase to break polysaccharides into monosaccharides, which can be absorbed.

What happens when absorption goes wrong?

• Diarrhea

• Constipation

What is Diarrhea?

Not enough water is absorbed through the large intestine because the feces moves to quickly

Why does Diarrhea happen?

When lining of Large intestine irritated by:

• foods that are spicy, greasy, or too acidic

• Food intolerances

• too much fiber

• Illness (usually bacteria)

Causes watery, loose stool

What is constipation?

Too much water is absorbed through the large intestine because either move too slow or sits too long

Why does constipation happen?

• Dehydration

  • low water intake

  • Diarrhea

• not eough fiber

• holding in you poo

Causes hard dry stool