Class notes
fdgzuio tzuio b
- Course
- Institution
dfghzujiopu+ fdghujiopü frtgzuiopü
[Show more]
Seller
Followfrankeicki
Content preview
The stomach is a vital organ in the digestive system, playing a crucial role in the process ofbreaking down food and facilitating nutrient absorption. Located in the upper abdomen, just
below the diaphragm, the stomach is a muscular, hollow organ shaped like a sac.
One of the primary functions of the stomach is to store the food we consume and gradually
release it into the small intestine for further digestion. Upon swallowing, the food enters the
stomach through the esophagus, where it is mixed with gastric juices. These juices, including
hydrochloric acid and enzymes such as pepsin, help break down the food into smaller
particles.
The stomach's muscular walls contract and relax in a coordinated manner, churning and
mixing the food with the gastric juices. This process, known as mechanical digestion, helps to
break down large food particles into a semi-liquid mass called chyme.
The stomach also plays a vital role in chemical digestion. The gastric juices secreted by the
stomach lining contain enzymes that start the breakdown of proteins into smaller molecules,
aiding in their digestion. Additionally, the acidic environment created by hydrochloric acid
helps kill harmful bacteria that may be present in the food.
Apart from digestion, the stomach is involved in the absorption of certain substances. While
the majority of nutrient absorption occurs in the small intestine, some substances, such as
alcohol and certain medications, can be absorbed directly through the stomach lining and
enter the bloodstream.
The stomach also acts as a barrier, preventing the contents of the intestine from flowing back
into the esophagus. The lower esophageal sphincter, a muscular ring located between the
esophagus and the stomach, helps in this regard by closing tightly after food enters the
stomach.
The entire process in the stomach typically takes a few hours, depending on the composition
of the meal. Once the food is adequately digested and transformed into chyme, it gradually
passes through the pyloric sphincter, a valve at the lower end of the stomach, and enters the
small intestine for further digestion and absorption of nutrients.
In summary, the stomach serves as a storage and mixing chamber for food, where mechanical
and chemical digestion begin. It aids in the breakdown of proteins, kills bacteria, and absorbs
certain substances. Without the stomach's crucial functions, the digestion and absorption of
nutrients would be severely impaired, leading to potential health issues.
Furthermore, the stomach also plays a role in the regulation of appetite and satiety.
Specialized cells in the stomach lining release hormones such as ghrelin, which stimulate
hunger and increase food intake, and peptides that signal feelings of fullness and suppress
appetite. These hormonal signals help maintain a balance between food intake and energy
expenditure, contributing to overall energy homeostasis.
Another important function of the stomach is its role as a protective barrier. The strong acidic
environment in the stomach helps to kill ingested bacteria and other pathogens, preventing
them from causing infections or reaching the intestines. The stomach lining itself is coated
with a layer of mucus that acts as a protective barrier against the acid, preventing damage to
the stomach tissues.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller frankeicki. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.02. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
56326 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now