The Digestive System Flashcards
What are the stages of human digestion
- ingestion
- digestion
- Absorption
- Assimilation
- Egestion
Ingestion
Food enters the digestive system through the mouth
Digestion
Complex food molecules being broken into simpler molecules (mouth & stomach)
Absorption
Products of digestion enter the bloodstream (intestines)
Assimilation
The nutrients that are absorbed are converted into molecules for growth, repair and defence in the cells
Egestion
Waste products of digestion being removed from the body
What are the types of human digestion
- physical/mechanical digestion
- chemical digesiton
Physical/mechanical digestion
The teeth and muscles in the stomach wall prepare food for chemical digestion by breaking down food into smaller pieces
Chemical digestion
Enzymes break food down further into smaller pieces
Name the 4 types of teeth and what they do
- incisors - biting, tearing, cutting
- canines - biting, tearing, gripping
- premolars - chewing, crushing
- molars - chewing, crushing
How many teeth do adults have in total
32
What does physical digestion do
Allows greater surface area for the enzyme to act on, food is easier to swallow
What does amylase do
Breaks down starch into maltose
What does maltase do
Breaks down maltose into glucose
Catalyst
A substance which speeds up a chemical reaction without being used up itself in the reaction. They can be used again and again
Enzyme
A biological catalyst made from proteins
What does the oesophagus do
Connects the mouth to the stomach
Epiglottis
Flap of muscle separating the trachea and oesophagus
Peristalsis
The contractions of which muscles along the oesophagus which pushes food down towards the stomach
What is the stomach
a muscular bag that stores and digests food
What does the physical digestion do in the stomach
Churns food into a liquid
What does chemical digestion do in the stomach
Enzymes and hydrochloric acid kills bacteria and loosens food to make it easier
What is the small intestine, how long is it
90% of digestion occurs in the small intestine. It is roughly 6 metres long
What happens in the small intestine
Minerals and nutrients are absorbed in the small intestine
What is the duodenum
The duodenum attaches the stomach to the small intestine
What does the duodenum do
It carries out chemical digestion by producing digestive enzymes and receiving digestive juices from the pancreas and liver
What is the Villi
The many small fold that the small intestine is covered in
What does the villi do
Absorbs substances such as iron, glucose and amino acids. Into the blood quickly and easily
Name 3 features of Villi
- The walls of villi are only one cell thick
- Each villus has its own capillaries
- capillaries carry out of the digestive system and to the circulatory system where they can travel all over the body
What does the pancreas do
Makes 2 key digestive enzymes called Amylase and lipase
What does the liver do
Produces bile which is stored in the gall bladder and travels to the small intestine, used to break down fats
What is the large intestine, and how long is it
It reabsorbs water from undigested food back into the bloodstream, it is about 1.5 metres long
Faeces, and where it is stored and egested
All the materials our body could not digest. It is stored in the rectum and egested through the anus
