Organisation Flashcards
What are tissues?
Groups of specialised cells with similar structure and function to perform a particular function
What are organs?
Made from a group of different tissues working together to perform a particular function
What are cells?
Basic functional and structural units in a living organism
What are organ systems?
Made from a group of organs with related functions which work together to perform body functions within the organism
What is the role of the stomach?
To start protein digestion
How is pepsin produced?
Pepsin, a protease is produced by the stomach to digest proteins into AMINO ACIDS
What is the role of the digestive system?
To break down large insoluble molecules into smaller soluble food molecules to provide the body with nutrients
What is digestion?
- Process where large, insoluble food molecules (starch and proteins) are broken down into smaller, soluble ones
- Which can now be absorbed into the bloodstream and delivered to cells in the body
How can the small soluble molecules (produced after digestion of food) be used in the body?
- To provide cells with energy (via respiration)
- Building other molecules to grow, repair or function
What is the alimentary canal?
The channel through which food flows through the body and starts at the mouth and ends at the anus. Digestion occurs within this alimentary canal
What are accessory organs?
- Organs which produce substances that are needed for digestion to occur, (enzymes or bile) but food does not directly pass through these organs.
- Examples are the Liver, pancreas, gall bladder or salivary glands
What happens at the mouth?
- Mechanical digestion takes place
- Amylase enzymes in saliva start digesting starch into maltose
- Food shaped to bolus by tongue and lubricated by saliva so it can be swallowed
What happens at the oesophagus?
- A tube connecting the mouth to the stomach
- Contracts after we have swallowed to push bolus down into stomach
What happens at the stomach?
- Food is mechanically digested through churning
- Protease enzymes start to chemically digest proteins
- HCL kills bacteria in food and provides optimum pH for protease enzymes to work
What happens at the small intestine?
- First section is called the duodenum, and is where food coming out of the stomach finishes being digested by enzymes
- pH of small intestine is slightly alkaline (pH 8-9)
- Second section is ileum and is where absorption of digested food molecules takes place
- Second section is long and lined with villi to increase SA where absorption can take place
What happens at the large intestine?
- Water is absorbed from remaining material
What happens at the pancreas?
Produces all 3 types of digestive enzyme -
- amylase
- protease
- lipase
- These enzymes are secreted in an alkaline fluid into the duodenum for digestion
What happens at the liver?
- Produces bile to emulsify fats
- Amino acids which weren’t used to make protein are broken down here producing urea as waste
What happens at the gall bladder?
- Stores bile to release into duodenum as required
Why is bacteria important to digestion?
- The large intestine is home to hundreds of species of bacteria
- They form a microbial ecosystem, playing an essential role in human digestion
- they break down substances we cant digest (cellulose)
- supply essential nutrients
- synthesising vitamin k
- providing competition with any harmful bacteria
What do digestive enzymes do?
- Biological catalysts made of protein
- Digest large, insoluble food molecules into smaller, soluble molecules
- These can be absorbed into the bloodstream
What is metabolism?
The sum of all the reactions happening in a cell or organism in which molecules are broken down
What are substrates?
- Temporarily bind to the active site of an enzyme
- Leads to a chemical reaction and the formation of a product
What is the lock and key model?
- A model where the lock is the enzyme, and the key is the substrate (fits perfectly into the active site of the enzyme)
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