Stomach Definition

The top left side of the abdominal cavity contains the muscular organ known as the stomach. Hydrochloric acid and digesting enzymes are secreted by several stomach cells. These chemicals help the body absorb nutrients by breaking down meals.

Food enters the stomach through the esophagus. When food reaches the esophagus's end, it enters the stomach via a muscle valve known as the lower oesophagal sphincter.

The stomach cells are constantly exposed to digestive juices and stomach contents. Cells produce a mucus coating to defend themselves and regularly regenerate to maintain a healthy stomach lining.

The digestive system (Gastrointestinal) includes the stomach. The gastrointestinal tract (GI tract) is a lengthy tube that starts in your mouth and finishes in your anus which is where stool (poop) departs your body. The GI tract is an essential part of your digestive system.

Function of Stomach

The stomach digests food and transports it to the small intestine. It fulfils three functions:

• Make enzymes and other specialised cells to help with meal digestion.
• Tighten and relax to mix and break down food.
• Store food for later.

How does the Stomach's GI System Compare to that of the Rest of the Body?

Before passing food and drinks through your body, each component of the GI tract disintegrates them. Your body absorbs nutrients and water during digestion. Following that, your large intestine expels the waste products of digestion.

Food Passes through the GI Tract in the Following Ways

• Mouth: The epiglottis is a thin flap of tissue that covers your windpipe and pushes food down your throat when you chew and swallow, guarding against choking.
• Esophagus: The esophagus, which is a hollow tube, is where food passes. To allow food to enter your stomach, the bottom of your esophageal sphincter relaxes. (A sphincter is a muscle with a ring shape that contracts and relaxes.)
• Stomach: Food is broken down and digested in your stomach. Food is held there until it's time for it to be emptied into your small intestine.
• Small intestine: The digestive fluids from your colon, liver, and pancreas combine with food. The walls of your intestines take in water and nutrients from food and send waste to the large intestine.
• Large intestine: Stool is created by your large intestine from waste materials. The stool is pushed into your rectum by it.
• Rectum: Your large intestine's lowest third is known as the rectum. Up until you have a bowel movement, it holds stool.

The stomach is Placed where on the Body?

The stomach is located in the upper abdomen, on your left side. Through this valve, the esophagal sphincter, a muscle at the end of the esophagus, is connected to the top of the stomach. Your small intestine is connected to the bottom of your stomach.

How Large is the Stomach?

Everybody has a different-sized stomach. The stomach contracts when it is empty and expands when it is full. Because of this, the amount and recentness of your meals might affect your stomach size.

What Anatomical Components Make up the Stomach?

The stomach is divided into five separate sections:

1. Cardia: The top of the stomach is known as the cardia. There, the cardiac sphincter prevents food from returning up your oesophagus.
2. Fundus: The circular area close to the cardia is the fundus. It is located beneath your diaphragm, the muscle that helps you breathe.
3. Body (corpus): The body (corpus), or major part of your stomach, is referred to as that. Your stomach contracts inside your body and starts mixing meals.
4. Antrum: Underneath the body is the antrum. It stores food until your stomach is ready to transfer food to your small intestine.
5. Pylorus: stomach's pylorus is located at the bottom. The pyloric sphincter is a part of it. This tissue band controls when and how your stomach's contents enter your small intestine.

Structure of Stomach

The stomach is made up of several layers of muscle and other tissues:

• Mucosa: The mucosa is the inside lining of the stomach. When your stomach is empty, the mucosa exhibits microscopic ridges known as rugae. When the stomach is full, the mucosa in the stomach expands and the ridges flatten.
• Submucosa: The submucosa contains nerve cells, connective tissue, blood vessels, lymph vessels (part of the lymphatic system), and blood vessels. It envelops and shields the mucosa.
• Muscularis Externa: The main muscle in the stomach is called the muscular externa. To break down food, its three layers contract and relax.
• Serosa: The stomach is covered by a membrane layer called serosa.

What Illnesses and Disorders Have an Impact on Your Stomach?

Gastrointestinal disorders may affect the stomach. Digestive issues may only occur in specific circumstances, such as if you feel heartburn when pregnant. A chronic (permanent) sickness is another option.

The following are typical conditions that affect the stomach:

• (GERD) Gastroesophageal reflux disease: When your oesophagus is invaded by stomach contents, resulting in coughing or heartburn.
• Indigestion (dyspepsia): A burning, aching, or uncomfortable feeling in your upper stomach.
• Gastric ulcers: Stomach lining erosion that may cause pain and bleeding.
• Peptic ulcer disease: stomach ulcers or duodenal ulcers, lesions in the small intestine's initial part
• Stomach cancer: When the stomach's malignant cells start to expand out of control.
• Gastritis: Discomfort in the stomach.
• Gastroparesis: muscular contractions in your stomach are impacted by damaged nerves.

How to Maintain a Healthy Stomach?

You can modify your lifestyle to keep your stomach and digestive system healthy. You could:

• Depending on your size and degree of exercise, you should drink at least 50 ounces of water each day.
• Depending on your age and gender, consume 25 to 35 grammes of fibre each day.
• Use healthy coping mechanisms to reduce stress, like meditation.
• Give up using tobacco products or smoking.
• Limit your alcohol consumption.
• Get regular exercise
• Limit the number of processed meals you eat.

Histology

The four layers of the stomach's wall are identical to those of the bulk of the alimentary canal, but the mucosa and muscle have been altered to better carry out the functions of this particular organ. Along with the typical circular and longitudinal smooth muscle layers, the muscular also features an inner oblique smooth muscle layer. As a result, food can be mechanically broken down into smaller pieces and forced through the canal by the stomach's powerful churning action. Only surface mucus cells, which release an alkaline mucus layer as protection, make up the stomach mucosa's epithelial lining. Each gastric gland, which secretes a complex digesting fluid known as gastric juice, has an entrance marked by a large number of gastric pits that give the epithelium the look of a well-used pincushion.

The stomach glands are made up of several cell types, even though mucus cells predominantly make up the walls of the gastric pits. The cardia and pylorus glands are primarily composed of mucus-secreting cells. The cells that make up the pyloric antrum release mucus and many hormones, including the majority of the stimulatory hormone gastrin. The fundus and body of the stomach, where the majority of chemical digestion takes place, have much larger glands that produce the majority of gastric secretions. These glands are made up of a variety of secretory cell types. These include enteroendocrine cells, mucous neck cells, chief cells, and parietal cells.

Parietal Cells

The core region of the stomach glands contains the majority of parietal cells, which are among the body's most highly differentiated epithelial cells. These rather big cells generate both intrinsic factors and hydrochloric acid (HCl). The high acidity of the stomach contents (pH 1.5 to 3.5) is caused by HCl, which is also required to activate the pepsin protein-digesting enzyme. Additionally, acidity helps to denature proteins, increasing their availability for enzymatic digestion while also killing a large portion of the germs you eat with food. The small intestine requires the glycoprotein known as an intrinsic factor for the absorption of vitamin B12.

Chief Cells

Primarily located in the basal regions of the glands, pepsinogen, the inactive proenzyme form of pepsin, is released by the primordial cells of the gastric glands. Pepsinogen must be converted to pepsin by the presence of HCl.

Mucous Neck Cells

The mucus produced by the goblet cells of the surface epithelium is considerably different from the mucus produced by the mucous neck cells in the top region of the stomach's gastric glands. This mucus' function is yet unknown.

Enteroendocrine Cells

The interstitial fluid of the lamina propria is secreted with a variety of hormones by enteroendocrine cells situated in the stomach glands. One of these is gastrin, mostly secreted by enteroendocrine G cells.

Summary

All digestive processes involving the stomach, excluding eating and urinating, take place in the stomach. It stirs meals ferociously. Gastric juices are released by the stomach, which help food to be digested and absorb some alcohol and aspirin. The stomach begins the digestion of proteins in addition to continuing the breakdown of carbohydrates and fats. The pyloric sphincter allows it to gently release food into the small intestine after storing it as an acidic liquid called chyme.