Digestive System Flashcards
What is digestion?
Digestion is the breakdown of large food molecules into smaller molecules
What is an organ?
An organ is a group of tissues working together to carry out a specific function
What is an organ system?
An organ system is a group of organs working together to carry out a function
What is a catalyst?
A substance which speeds up a chemical reaction without being used up itself in the reaction. Catalysts can be used agin and again
What is an enzyme?
A biological catalyst made from proteins
What is diffusion?
The spreading out of liquid or gas to fill a space
What is a 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
- Nutrients are broken down from food into small pieces to be absorbed into our blood and carried out to the cells all around our body
What are the 5 stages of human digestion
- Ingestion
- Digestion
- Absorption
- Assimilation
- Egestion
Stages: What is ingestion
Food enters the alimentary canal (digestive system) through the mouth
Stages: What is digestion
Complex food molecules being broken into simpler food molecules
Stages: What is absorption
Products of the digestion enter the blood stream
Stages: What is assimilation
The nutrients that are absorbed, are converted into molecules for growth repair and defence in the cells
Stages: what is egestion
Waste products of digestion being removed from the body
What are the types of human digestion
- Physical/Mechanical digestion - The teeth & muscles in the stomach wall prepare food for chemical digestion by breaking down the food into smaller pieces
- Chemical digestion - Enzymes (amylase and saliva) break food down further into smaller pieces
Explain the mouth
- Mouth carries out both physical and chemical digestion
- Physical digestion - 4 types of teeth
- Incisors —> biting, tearing & cutting
- Canines —> biting tearing and gripping
- Premolars —> Chewing & crushing
- Molars —> Chewing & crushing
- Total of 32 teeth in adults
Explain the oesophagus
- The oesophagus connects the mouth to the stomach
- Food moves through the oesophagus by peristalsis
What is Epiglottis
Flap of muscle separating trachea and oesophagus
What is peristalsis
The contractions of the muscles along the oesophagus which pushes food down towards the stomach
Explain the stomach
- The stomach is a muscular bag that stores and digests food
- Physical and chemical digestion
- Physical - churns food into liquid
- Chemical - enzymes and hydrochloric acid kills bacteria and loosens food to make it easier to digest
Explain the small intestine
- Roughly 6 meters long and is where 90% of digestion occurs
- Minerals and nutrients are absorbed into the blood here
- Duodenum attached stomach to the small intestine
- When nutrients are broken down small enough in the small intestine - they pass through the walls of the intestine by diffusion
What does duodenum do
Duodenum carries out chemical digestion by producing digestive enzymes and receiving digestive juices from pancreas and liver
Explain Villi from the small intestine
- The small intestine is covered in many small folds called Villi
- The Villi are adapted to absorb substances such as iron, glucose & amino acids into the blood quickly and easily
What are the features of Villi
- The walls of Villi are only one cell thick
- Each villus has its own capillaries
- Capillaries carry nutrients out of the digestive system and to the circulatory system where they can travel all over the body
