Digestive System Flashcards
What is Digestion
- the breakdown of large food molecules into smaller food
molecules.
What is an Organ
-a group of tissues working together to carry out a specific function.
Organ System
- a group of organs working together to carry out a function.
Catalyst
- a substance which speeds up a vchemical reaction without being
used up itself in the reaction. Catalysts can be used again and again.
• Enzyme
- a biological catalyst made from proteins.
Diffusion
• - the spreading out of a liquid or gas to fill a space.
Peristalsis
– muscular movement that only occurs in the muscles of the
digestive system, pushes food along the system.
Why do we need a digestive system?
• Each cell in our body needs food to carry out its functions.
.food is needed as the nutrients are absorbed into our blood for some cells
It is distributed through our digestive system
1.Ingestion
– food enters the alimentary canal through the mouth
- Digestion
– complex food moleucles being broken into
simpler molecules.
- Absorption
– products of digestion enter the
bloodstream.
- Assimilation
– the nutrients that are absorbed, are converted into molecules for growth, repair and defence in the cells.
5.Egestion
– waste products of digestion being removed from the body
What are the two types of digestion
• Physical/Mechanical Digestion
• Chemical Digestion
What is chemical digestion?
enzymes break food down further into small pieces
What is physical/mechanical
the teeth and muscles prepare food for digestion by breaking down
food into smaller pieces.
The mouth
• Mouth carries out both physical and chemical digestion!
• Physical Digestion 4 types of teeth: Incisors Canines Premolars Molars (32 teeth in adult)
1.Digestion steps in mouth
Mouth
• Chemical Digestion – enzymes in the salivary glands – Amylase
• Amylase enzymes in your saliva break down starch (complex carbohydrate) into a sugar called maltose (simple carbohydrate).
• A second enzyme called maltase breaks down the maltose into glucose
which is small enough to be absorbed into the blood.
• NB- Food is easier to swallow.
2.oesophagus steps in digestive system
The Oesophagus connects the mouth to the stomach.(Food moves through the Oesophagus by Peristalsis.)
• Peristalsis- contractions of the muscles along the oesophagus which pushes food down towards the stomach
3.Stomach steps in the digestive system
• The stomach is a muscular bag that stores and digests food (Physical and Chemical Digestion!)
• Physical – churns food into a liquid
• Chemical – enzymes and Hydrochloric acid kills bacteria and loosens food to make it easier to digest
- Small intestine steps in digestive system
• is where 90% of digestion occurs.
• Minerals and Nutrients are absorbed into the blood here.
• Duodenum attached stomach to the small intestine.
• performs chemical digestion by producing digestive enzymes & getting digestive juices from pancreas and liver.
• When nutrients are broken down small enough in the small intestine – they pass through the walls of the intestine by diffusion
6.villi
• The small intestine is covered in many small folds called Villi
• The Villi are adapted to absorb substances such as iron, glucose and amino acids into the blood quickly and easily.
Features of villi
• Features of Villi:
• The walls of villi are only one cell thick.
• Each villus has its own capillaries.
• Capillaries gets nutrients out of the digestive system to the circulatory system- they can travel all
over the body
The pancreas
• The Pancreas is not part of the digestive system as food does not pass through it.
• However it does make two key digestive enzymes: - Amylase -Lipase
• These enzymes pass to the Duodenum as pancreatic juice.
The liver
• Liver has many important functions for the body.
• Produces Bile which is stored in the Gall Bladder and travels to the small intestine and is used to break down fats
7 the large intestine
.smaller than small intestine
.absorbs water from undigested food back into the blood stream what’s left is food we can’t digest - faeces is egested through the anus
