THE DIGESTIVE SYTEM
,FUNCTION OF DIGESTIVE ORGANS
Mouth- the digestive process starts in the mouth; it allows food and air to enter the body. It also
contains other organs such as the tongue (taste buds), salivary gland and teeth which help digest food
by motions such as chewing, mixing, and squeezing, this is also known as mechanical digestion. The
tongue helps move food around the mouth while the food is chewed with your teeth the tongue then
rolls the chewed food into a ball and pushes it to the pharynx and into the opening of the oesophagus
Salivary glands- these glands make digestive juice called saliva which is 98% water, and it mixes
with the food and moistures the food so its moves more easily through your oesophagus to your
stomach, furthermore it also enables the movement of swallowing and chewing to help food to be
digested easily, it also contains an enzyme called amylase which breaks down starch in your food to
, maltose sugar. The saliva also contains enzymes such as peroxidase and lysozyme which are
antibacterial and help protect oral infections and gum disease.
Pharynx-The act as swallowing takes place in the pharynx as a reflex, the muscles surrounding the
pharynx work together to transport food and liquid down the oesophagus. The soft part of the roof of
the mouth pushes food into the pharynx and into the oesophagus.
Oesophagus- after the food is swallowed peristalsis pushes the food down the oesophagus to the
stomach through muscle contractions, additionally it also transports saliva and water. Digestion does
not take place in the oesophagus, but the walls secrete mucus to transport food to the stomach easily.
Stomach- The stomach is an important organ in our body as it takes in food from the oesophagus
mixes it and breaks it down and passes it into the small intestine in small portions. However, their man
role is to act as a storage tank for foods that the body has time to digest large meals properly. It
secretes a mixture of acids such as hydrochloric acids which help kill any bacteria in the food, mucus
and digestive enzymes that helps to digest and sanitise our food while it is being stored in the
stomach. chemical digestion begins in the stomach, protein is digestion in the stomach through the
enzyme pepsin which is secreted by the stomach.
Liver- the liver is the second largest organ after the skin, it performs many roles in our body but
specifically for the digestive system, the liver produces bile which is a digestive juice that helps the
body absorb fat into the bloodstream. It also secretes bile to emulsify fats in the small intestine. The
liver converts food into energy, insulin(hormone) turns extra food that contains sugar in our body into
glycogen, glycogen is stored in the liver. The liver also detoxifies chemicals. The liver purifies out blood
to remove large toxins such as alcohol and drugs, it also secretes bile full of fat-soluble toxins and
cholesterol. The liver also stores fast soluble vitamins such as vitamin A, D and B12.lastly the liver
produces hormones that promotes cell growth, and it produces a hormone called Angiotensinogen
which is involved in blood pressure control and regulates sodium and potassium levels in the kidney
Gall bladder- it is a small storage organ located next to the liver; it stores the bile produced by the
liver until its needed for digesting fatty foods in the duodenum in the small intestine. The gall bladder
is very important and the bile it stores help the body break down food and digest fat.
Bile duct- the bile duct is from between the liver and gall bladder and its main function is to carry bile
from the liver and gall bladder through the pancreas and empty it into the duodenum.
Pancreas- the pancreas produces pancreatic enzymes which helps breaks down starch, sugar, and
fats, they are emptied into the upper part of the small intestine (the duodenum). The three enzymes
produced are lipase which breaks down fat, it essential that you have enough lipase in your body
otherwise your body will find it difficult to absorb fats therefore your body will be lacking important
vitamins such as A, D, E and K. The second enzyme is protease which breaks down protein and
protects your small intestine from any bacteria. Lastly amylase which breaks down starch into glucose
that can be used for energy. Lack of this enzyme may cause diarrhoea from undigested carbohydrates.
This the function of the pancreas as an exocrine gland. The other function is the pancreas can act an
endocrine gland therefore the pancreas secretes hormones such as glucagon and insulin which help
control the blood sugar levels.
Duodenum- the duodenum is the first part of the small intestine and is a main organ in the digestive
system, its key role is to complete the earliest stage of digestion. the duodenum receives partially
digested food from the stomach known as chyme. Chemical digestion continues in the duodenum as
the chyme mixes which digestive juices and enzymes to break down food. The duodenum also
neutralises the acidity in the chyme by mixing it will alkaline digestive juices from the pancreas and
liver. It also prepares the chyme for the further digestion that will take place in the ileum and jejunum
by mixing it will bile from the gall bladder to help break down fat.
Jejunum- it is in the middle part of the small intestine and its main role is to absorb the nutrient
present is food such as amino acid, fatty acid and sugar before being passed on to the ileum for further
digestion. The structure of the jejunum allows that to happen as the wall of the jejunum are folded
many times to absorb nutrients and increase surface area. Essentially the jejunum just continues the
digestion of food from the duodenum.
Ileum- the ileum is the last part that makes up the small intestine and its where the remaining
nutrients are absorbed before entering the large intestine. The ileum walls are thinner compared to the
jejunum and duodenum and are highly folded and contains villi which significantly increases the
surface area for absorptions of food. It also absorbs any nutrients that did not get absorbed in the
jejunum or duodenum, for example vitamin B12 and bile acids that will go on to be recycled.
Large intestine- The large intestine has several functions one of their function is converting digested
food into waste products. Cecum is part of the digestive specifically the beginning of the large intestine
and its role is to create space for the mixing of bacteria with chyme (partially digested food) to form
faeces. Another function is absorbing vitamins, the large intestine produces vitamins by its own
bacteria such as vitamin K and B, this is by the remaining polysaccharides and fibre broken down and
converted into short chain fatty acids which are then absorbed by the large intestine through diffusion.
,FUNCTION OF DIGESTIVE ORGANS
Mouth- the digestive process starts in the mouth; it allows food and air to enter the body. It also
contains other organs such as the tongue (taste buds), salivary gland and teeth which help digest food
by motions such as chewing, mixing, and squeezing, this is also known as mechanical digestion. The
tongue helps move food around the mouth while the food is chewed with your teeth the tongue then
rolls the chewed food into a ball and pushes it to the pharynx and into the opening of the oesophagus
Salivary glands- these glands make digestive juice called saliva which is 98% water, and it mixes
with the food and moistures the food so its moves more easily through your oesophagus to your
stomach, furthermore it also enables the movement of swallowing and chewing to help food to be
digested easily, it also contains an enzyme called amylase which breaks down starch in your food to
, maltose sugar. The saliva also contains enzymes such as peroxidase and lysozyme which are
antibacterial and help protect oral infections and gum disease.
Pharynx-The act as swallowing takes place in the pharynx as a reflex, the muscles surrounding the
pharynx work together to transport food and liquid down the oesophagus. The soft part of the roof of
the mouth pushes food into the pharynx and into the oesophagus.
Oesophagus- after the food is swallowed peristalsis pushes the food down the oesophagus to the
stomach through muscle contractions, additionally it also transports saliva and water. Digestion does
not take place in the oesophagus, but the walls secrete mucus to transport food to the stomach easily.
Stomach- The stomach is an important organ in our body as it takes in food from the oesophagus
mixes it and breaks it down and passes it into the small intestine in small portions. However, their man
role is to act as a storage tank for foods that the body has time to digest large meals properly. It
secretes a mixture of acids such as hydrochloric acids which help kill any bacteria in the food, mucus
and digestive enzymes that helps to digest and sanitise our food while it is being stored in the
stomach. chemical digestion begins in the stomach, protein is digestion in the stomach through the
enzyme pepsin which is secreted by the stomach.
Liver- the liver is the second largest organ after the skin, it performs many roles in our body but
specifically for the digestive system, the liver produces bile which is a digestive juice that helps the
body absorb fat into the bloodstream. It also secretes bile to emulsify fats in the small intestine. The
liver converts food into energy, insulin(hormone) turns extra food that contains sugar in our body into
glycogen, glycogen is stored in the liver. The liver also detoxifies chemicals. The liver purifies out blood
to remove large toxins such as alcohol and drugs, it also secretes bile full of fat-soluble toxins and
cholesterol. The liver also stores fast soluble vitamins such as vitamin A, D and B12.lastly the liver
produces hormones that promotes cell growth, and it produces a hormone called Angiotensinogen
which is involved in blood pressure control and regulates sodium and potassium levels in the kidney
Gall bladder- it is a small storage organ located next to the liver; it stores the bile produced by the
liver until its needed for digesting fatty foods in the duodenum in the small intestine. The gall bladder
is very important and the bile it stores help the body break down food and digest fat.
Bile duct- the bile duct is from between the liver and gall bladder and its main function is to carry bile
from the liver and gall bladder through the pancreas and empty it into the duodenum.
Pancreas- the pancreas produces pancreatic enzymes which helps breaks down starch, sugar, and
fats, they are emptied into the upper part of the small intestine (the duodenum). The three enzymes
produced are lipase which breaks down fat, it essential that you have enough lipase in your body
otherwise your body will find it difficult to absorb fats therefore your body will be lacking important
vitamins such as A, D, E and K. The second enzyme is protease which breaks down protein and
protects your small intestine from any bacteria. Lastly amylase which breaks down starch into glucose
that can be used for energy. Lack of this enzyme may cause diarrhoea from undigested carbohydrates.
This the function of the pancreas as an exocrine gland. The other function is the pancreas can act an
endocrine gland therefore the pancreas secretes hormones such as glucagon and insulin which help
control the blood sugar levels.
Duodenum- the duodenum is the first part of the small intestine and is a main organ in the digestive
system, its key role is to complete the earliest stage of digestion. the duodenum receives partially
digested food from the stomach known as chyme. Chemical digestion continues in the duodenum as
the chyme mixes which digestive juices and enzymes to break down food. The duodenum also
neutralises the acidity in the chyme by mixing it will alkaline digestive juices from the pancreas and
liver. It also prepares the chyme for the further digestion that will take place in the ileum and jejunum
by mixing it will bile from the gall bladder to help break down fat.
Jejunum- it is in the middle part of the small intestine and its main role is to absorb the nutrient
present is food such as amino acid, fatty acid and sugar before being passed on to the ileum for further
digestion. The structure of the jejunum allows that to happen as the wall of the jejunum are folded
many times to absorb nutrients and increase surface area. Essentially the jejunum just continues the
digestion of food from the duodenum.
Ileum- the ileum is the last part that makes up the small intestine and its where the remaining
nutrients are absorbed before entering the large intestine. The ileum walls are thinner compared to the
jejunum and duodenum and are highly folded and contains villi which significantly increases the
surface area for absorptions of food. It also absorbs any nutrients that did not get absorbed in the
jejunum or duodenum, for example vitamin B12 and bile acids that will go on to be recycled.
Large intestine- The large intestine has several functions one of their function is converting digested
food into waste products. Cecum is part of the digestive specifically the beginning of the large intestine
and its role is to create space for the mixing of bacteria with chyme (partially digested food) to form
faeces. Another function is absorbing vitamins, the large intestine produces vitamins by its own
bacteria such as vitamin K and B, this is by the remaining polysaccharides and fibre broken down and
converted into short chain fatty acids which are then absorbed by the large intestine through diffusion.
