Essay
Unit 8 Physiology of human body systems assignment C
- Institution
- PEARSON (PEARSON)
Explore the physiology of the digestive system and the use of corrective treatments for dietary related diseases.
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Unit 8 Physiology of human body systemsDigestive system:
The start of digestion begins in the mouth where saliva begins to break down
food using the enzyme amylase. Amylase is the enzyme which breaks down
starch. The teeth chew the food making it easier to go down the oesophagus.
The organs associated
with the digestive
system are the Mouth,
oesophagus, stomach,
small intestine, large
intestine, anus, liver,
pancreas, and
gallbladder.
The oesophagus
transports food from
the mouth to the
stomach. (pharynx)
At the top of the
oesophagus there is a
muscle called upper
oesophageal sphincter
which recognises
when food or liquid is
coming down. The
epiglottis is a small
muscle flap which closes when food travels down to prevent it from entering
the Trachea. Liquid is stopped from entering the nasal cavity by a small flap
called the uvala. When there is no food or liquid detected to come down the
oesophageal sphincter closes. Once the food and liquid has passed these the
muscle contractions known as peristalsis pushes the food and liquid down to
the diaphragm to the lower oesophagus. The lower oesophagus has the same
function as the upper one but instead it allows food and liquid to pass through
to the stomach but closes when there is none. This is to prevent any stomach
acid entering the oesophagus.
, The stomach is the primary organ in the digestive system for breaking down
food containing the enzyme known as pepsin which breaks down protein.
There are several different layers of the stomach the first is Mucosa which is
the stomach’s lining containing ridges (rugae) when empty but flatten when
full. Submucosa’s main function is to protect the mucosa and it has blood and
lymph vessels, connective tissues, and nerve cells. Muscularis externa is a
muscle which has three layers to break down food. The final layer, made from
membrane, is to protect your stomach called serosa. The acid secreted by the
stomach is hydrochloric acid used to break down the food and liquid. It takes
1-3 hours for the food to completely break down. Remaining food is passed
through by the pyloric sphincter to the small intestines.
Function of the liver is to secrete bile (neutralises stomach acid) and purify
nutrient rich blood from the small intestine. The purpose of the bile is to
transport waste to the kidneys and absorb fats and turning them into energy.
The pancreas produces the enzymes for the digestive system. Lipase, amylase,
and protease. Gallbladder where bile is stored and to release into the small
intestine.
The small intestine mixes the food into chyme and moves it along through the
colon using mucus to transport it. Its main function is to absorb water,
vitamins, and nutrients/minerals from the food. Containing the most amount
of digestive enzymes, found in the small intestines are peptidase, maltase,
sucrase, lactase, lipase, and enterokinase. The three different parts of the small
intestine are:
Duodenum, in the shape of a C the duodenum is 10 inches long. It
receives digestive enzymes from the pancreas, gallbladder, and liver
Jejunum is the many parts of middle length of the small intestine
containing many blood vessels.
Ileum is the part of the small intestine which begins to narrow this is
where the most absorption of nutrients occur. (Bile and vitamin B12)
This allows the remaining food to pass into the large intestine but closes
to prevent bacteria entering.
The lining of the small intestines is covered in mucosa into each of these
parts to help absorb the nutrients and water.
Large intestine:
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