Chapter 33 - The Human Digestive System Flashcards
(44 cards)
Define Digestion.
Breaking down of food into its constituent molecules so they can be absorbed into the bloodstream.
Define Egestion.
Removal of undigested food.
Define Excretion.
Removal of waste products of digested food.
What are the two types of digestion?
- Physical (Mechanical)
2. Chemical
- Physical Digestion
Mechanical breakdown of food using teeth and muscle.
Food parts go from large to small.
Through processes such as peristalsis (oesophagus)
- Physical Digestion
Mechanical breakdown of food using teeth and muscle.
Food parts go from large to small.
Through processes such as peristalsis (oesophagus)
- Chemical Digestion.
Involves the chemical breakdown of food using enzymes.
Food is broken down into its simplest unit.
E.g Starch to Glucose.
What are the 5 stages of digestion?
- Ingestion
- Digestion
- Absorption
- Assimilation
- Elimination
Ingestion
- Taking in Food (consumption)
- Occurs in the mouth
Ingestion
- Taking in Food (consumption)
- Occurs in the mouth
Absorption
Simplest substance being taken into the bloodstream through the lining of the alimentary canal.
Absorption
Simplest substance being taken into the bloodstream through the lining of the alimentary canal.
Absorption
Simplest substance being taken into the bloodstream through the lining of the alimentary canal.
Assimilation
Putting food to use in the body.
Elimination
Egestion- Removal of undigested waste
Excretion - Removal of waste after digestion.
Polymer and Monomer
- Starch ——- Glucose
- Fat ——– Triglyceride
- Protein ——- Amino Acids
Alimentary Canal
This is a long muscular tube that runs through the body from the mouth to the anus.
Mouth
- Release saliva.
- Saliva is made of a combination of water, mucus and amylase.
- Water and mucus moisten and lubricates the food making it easier to swallow.
amylase
-Starch —————– Maltose
-Works best in a slightly alkaline environment (pH 7.5)
-Food is chewed and lubricated until a bolus is formed (Ball of food). This bolus moves back the throat into and down the oesophagus.
Teeth
- There are four types of teeth.
- Incisors, Canines, Pre-molars and Molars.
- Breakdown of food into smaller pieces so it is easier to move down the oesophagus/ swallow. And is also a greater surface area for enzymes to work on.
- Total No. of teeth in adults is 32
- Total No. of teeth in children is 20.
Incisors
Function - Cut and bite
No. in adults - 8
No. in children - 8
Canines
Function - Cut and tear
No. in adults - 4
No. in children - 4
Pre-Molars
Function - Crush and grind
No. in adults - 8
No. in children - 8
Molars
Function- Crush and grind
No. in adults - 12
No. in children - 0
Dental Formula
Tells us the number of each tooth on the upper and lower jaw of one side of the mouth.
- I = 2/2
- C = 1/1
- Pm = 2/2
- M= 3/3