Unit 8 - Physiology of Human Body Systems (UNIT8C)
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Chiamaka Udoye
What is the digestive system
The digestive system is a group of organs, such as pancreas, gastrointestinal tract and gallbladder, that works
together with the purpose of helping the body to absorbs nutrients by breaking down food
What does the digestive system do
the digestive system convert food into energy and nutrient for it to be absorbed by the body to maintain proper
bodily function. Any excess food particle will be excreted out of the of the through bowel movement
why is digestion important
the digestive system disintegrates and absorbs nutrient such as minerals, protein, fats, carbohydrates and vitamins
to use to maintain vital bodily function namely energy production, growth of cells, repairing of cell, etc
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Chiamaka Udoye
what organ make up the digestive system
Mouth
the mouth also called the oral cavity is the first part of the digestive system. Inside the mouth there are numerous
auxiliary organs such as the tongue, teeth and salivary glands. The mouth has many functions such as breathing
chewing, drinking, talking, swallowing, chewing, etc. it experiences both chemical and mechanical digestion
how its plays a role in the digestive system
the food is chopping and grinding the food into little bits called bolus by the teeth which is then moisten by the
saliva, which contain an enzyme called amylase, that disintegrate the starch into smaller sugars like dextrin and
maltose. The tongue mixes the food with saliva then pushes it to the pharynx,
Pharynx
the pharynx also referred to as the throat is located in the middle of the neck and is part of both the respiration and
digestive system. It takes air from the nasal cavity to send to the lung and takes food from the oral cavity to send to
the oesophagus. It experiences mechanical digestion the pharynx has many functions such as;
Creates a pathway for air to enter the respiratory system
Food bolos and drinks are transferred to the digestive system
Prevents food bits to enter the lungs
It equalises pressure and drain fluid from the ear
It plays a role in digestion by having a special structure which direct food to the oesophagus while also plays a role in
the respiratory system, directing air into the lungs.
Oesophagus
The oesophagus also referred to as the gullet is an empty muscular tube that runs from the trot near the windpipe to
the stomach.it main function is to carry food bolus from the mouth to the stomach. It is a mechanical digestive organ
In digestion, a muscular valve at the top of the oesophagus called the upper oesophageal sphincter senses the food
coming and relaxes to let the food pass though then shuts it tight to prevent it from flowing back. When this happen
a series of periodic contraction called which pushes down the food until it reaches another muscular valve at the
lower oesophagus called the lower oesophageal sphincter. It relaxes when sensing foo and allow it to pass into the
stomach then shut it tightly to prevent digestive acid from entering the oesophagus
Stomach
Stomach is a hallow J shaped organ found in the left side of the upper abdomen that produces enzymes and
digestive acids used to break down food so that it can proceed to the small intestine. The upper part of the stomach
is attached to the lower oesophageal sphincter while the lower end of the stomach is connected to the small
intestine. This is a chemical type of digestion. The stomach has many functions such as;
To break down food with the use of contraction and relaxation
To generate special enzymes a cell to digest food
To hold food temporarily
in digestion, the stomach produces digestive acid to disintegrate the food and stores it until its ready to be emptied
into the small intestine
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Chiamaka Udoye
small intestine
the small intestine also referred to as the small bowel is a long empty tube that runs from the stomach to the large
intestine. The intestine is in charge of breaking down the food into liquid, absorbing nutrient and harden of waste. it
is a chemical digestive system. The small intestine has many functions such as;
Absorption of nutrient
Removal of water
Breaking down of food
The small intestine is divided into 3 main parts;
Duodenum
This is the first and smallest part of the small intestine. It is a brief sloping chute that forms a “C” shape around the
pancreases before joining the jejunum. In digestion, digestive organs such as the pancreas, liver and gall bladder
empty their digestive enzymes and acids into the duodenum to disintegrate food.
Jejunum
This is the second part of the small intestine and is found in the abdominal cavity in between the duodenum and
ileum. It is held up by a organ called mesentery and appears red because of to numerous blood vessel suppling it. In
digestion, the food is moved from the duodenum to the jejunum though a series of systematic contraction and
relaxation called peristalsis where the water and nutrients such as sugars, protein, amino acid atty acid, etc from the
food are absorbed into the body
Ileum
It is the longest and last segment in the small intestine and the place where the digested food stays the most time. It
is help up by the mesentery and is rich in lymphatic fluids. The walls in the ileum are very narrow and blood supply
are reduced.in digestion, most of the food are absorbed and any excess waste are emptied into the large intestine
Large intestine
The large intestine, also referred to as the large bowel or the colon, is a long empty tube that extend from the small
intestine to the anus and is found in the lower abdominal cavity. This is a chemical digestive organ.
colon
it is charge of hardening food waste into poop, storing it and finally excreting it out the body. In digestion, after
receiving the liquefied food from the small intestine is dehydrated. This is done by absorbing the water and
electrolytes in the liquidised food. Furthermore, the bacteria inside the colon further breakdown or feed on the
food. It is a chemical digestive organ.
Rectum
The rectum is a empty compartment found between the colon and the anus. It is a mechanical type of organ. There
are many functions in the rectum such as;
It collects Stool from the colon
Hold the stool until excretion happen
Let you know when to excrete
In digestion, when the colon is filled up it passes to the rectum which in turn gives the urge to defecate.
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