5th year biology- The digestive system

Canines

Teeth used for ripping and tearing. Carnivores would have a lot of these for ripping meat.

Incisors

Teeth used for cutting. Herbivores would have a lot of these for cutting plants e.g. sheep

Molars and Premolars

Teeth used for crushing and grinding food.

Carnivore

organism that obtains energy by eating only animals. e.g a lion

Herbivore

Organism that obtains energy by eating only plants e.g. sheep or cow

Omnivore

Organism that obtains energy by eating both plants and animals. E.g. humans

Ingestion

Intake of food into the mouth.

Digestion

Breakdown of food substances into smaller forms that it can be absorbed and used.

Absorption

The process by which nutrient molecules pass through the wall of the digestive system into the blood. It happens in the small intestine.

Assimilation

When the bodies cells take in the food molecules from the blood for energy and growth.

Egestion

Removal of undigested food from the body. It happens through the anus.

Stomach

A muscular and elastic sac that stores food. It has an acidic environment (pH 2) as it stores hydrochloric acid (HCl)

Pancreas

An organ that regulates blood sugar levels and also produces enzymes.

liver

Produces bile, Stores Iron/ stores the carbohydrates glycogen/fat soluble vitamins and detoxification

Gall Bladder

An organ that stores bile and releases it into the small intestine when needed.

Bile

A substance produced by the liver that emulsifies up fat particles and neutralises the chyme from the stomach.

Physical digestion

Is the mechanical breaking down of food. e.g. the teeth

Chemical Digestion

Is the breaking down of food using chemicals. e.g. enzymes.

Small intestine

Digestive organ where most chemical digestion and absorption of food takes place. This is where all the nutrients are absorbed into the blood. pH 7-9

Large Intestine

An organ in the body that absorbs water and forms feces.

Villi

Tiny finger-shaped structures that cover the inner surface of the small intestine and provide a large surface area through which digested food is absorbed

Peristalsis

A muscular wave of contractions that causes the movement of food along the alimentary canal.

Oesophagus

Muscular tube which moves ingested food to the stomach by peristalsis

Amylase

An enzyme found in saliva that breaks down starch to maltose. Is also made by the pancreas

Why is digestion necessary?

So molecules can be small enough to diffuse through cell membranes in the digestive system

catabolic reactions

Is when complex molecules are broken down to simpler ones and energy is released.

anabolic reactions

Is the build up large chemicals from smaller ones

An example of a catabolic reaction is ...

Respiration or digestion

An example of a anabolic reaction is ..

Photosynthesis in plants

Lipase

enzyme produced by the pancreas, that breaks down fat, acts in the small intestine.

Symbiotic relationship is defined as...

Relationship between organisms of different species where at least one benefts.

Symbiotic Bacteria is found in the ....

Large intestine, it produces B group vitamins and digests cellulose.