the digestive system it is responsible for ensuring the absorption of nutrients necessary for our survival. It is in this area that the digestion of what we eat takes place, a process that is characterized by the breakdown of food into smaller and simpler molecules that our bodies can take advantage of. The digestive system of human beings It is formed by different organs and some attached glands, which help producing substances fundamental to the digestion process.
Know more: Healthy eating - essential for the individual's physical and mental well-being
Organs of the digestive system
The organs of the digestive system are:
- Mouth
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Anus
Next, we'll talk a little more about these organs and their roles in the digestive process.
Mouth
Digestion starts in the mouth and in it the food suffers the action of teeth and saliva. teeth act on mechanical digestion, breaking the food into particles. The first set of teeth is called the deciduous or milk set and is made up of 20 teeth. In an adult person, the permanent dentition is made up of 32 teeth. In each arch (upper and lower) 16 teeth are found.
four incisors, two canines, four premolars and six molars.Saliva acts on chemical digestion, being present in it the enzyme ptialin, which starts the digestion of carbohydrates. In addition, saliva moistens the food, which makes it easier to swallow. The tongue plays an important role in this process, as it helps to mix food with saliva and push the bolus toward the pharynx.
Read too: Is the tooth a type of bone?
Pharynx
The pharynx is an organ common to the digestive system and the respiratory system. The bolus passes through this organ and goes towards the esophagus.
Esophagus
The esophagus is a kind of tube that is about 25 cm long. He connects the pharynx to the stomach. The food cake passes through this tube thanks to the peristaltic contractions, which are made by the muscles that make up the organ and ensure the movement of the bolus towards the stomach. See the following figure illustrating this process.
Stomach
The stomach is an organ that resembles a pouch, being a dilated portion of the digestive system. This organ receives the bolus and mixes it with a secretion produced by cells from its walls: the gastric juice. Among the substances that make up the gastric juice are pepsin, which acts in the digestion of proteins, and hydrochloric acid, which works by ensuring that the stomach environment is favorable for the performance of pepsin. After suffering the action of gastric juice, the bolus moves towards the small intestine and is called chyme.
Small intestine
The small intestine is the longest portion of the digestive system, being over six meters long. It is divided into three parts: duodenum, jejunum and ileum. The duodenum is about 25 centimeters and, despite its short length, it plays a big role in the digestive process.
This is where the chyme receives secretions from the pancreas (pancreatic juice), the liver (bile) and the small intestine itself (enteric and intestinal juice). All these secretions are responsible for the most of the digestion of food. After undergoing all the changes in the small intestine, the chyme is called a chyle.
In addition to digestion, the small intestine, especially the jejunum and ileum, acts on the absorption of nutrients. Absorption is efficient at this location, as the intestinal wall has a series of folds called the villi. In addition, the cells also have folds called microvilli. The villi and microvilli ensure an increase in the contact surface and promote greater absorption.
Read too: Why does the stomach “rump”?
Large intestine
The large intestine is smaller than the small intestine, measuring about 1.5 m. The following regions in the organ can be distinguished: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. O chyme travels through the large intestine, and, during the process, the excess water is absorbed and fecal cake (stool) is formed. Feces are passed through the anus.
the adnexal glands
Attached to the digestive system are some glands that directly participate in the digestion process by releasing important secretions. Are they: salivary glands, liver and pancreas. At salivary glands are responsible for the production of saliva, which, as said, helps moisten the food and starts the digestion of carbohydrates.
O liver it acts in the production of bile, a substance that acts in the emulsification of fats, that is, it facilitates the action of enzymes on fats. Bile is produced by the liver but remains stored in the gallbladder. Finally, we have the pancreas, which produces the pancreatic juice that acts on the digestion of proteins, lipids and carbohydrates.
It is noteworthy that the pancreas and liver have functions that go beyond digestion. The liver, for example, plays a role in neutralizing toxic substances, synthesizing clotting factors and storing substances such as glycogen. The pancreas, in turn, acts in the production of two hormones: a insulin and glucagon, which act to control glucose levels in the body.
Exercise on the digestive system
Now that you've learned a little more about the digestive system and the digestion process, let's test your knowledge of the subject. Based on the knowledge gained from this text, list the following columns:
|
I- Teeth II- Saliva III- Pharynx IV- Esophagus V- Stomach VI- Small intestine VII- Large Intestine VIII- Liver IX - Pancreas |
( ) Promote the mechanical digestion of food. ( ) Largest organ of the digestive system. ( ) Organ common to the respiratory and digestive system. ( ) Secrets the bile. ( ) It has the enzyme ptyalin, which acts in the digestion of carbohydrates. ( ) Produces gastric juice. ( ) Performs peristaltic movements. ( ) Where water absorption and stool formation occur. ( ) Produces insulin and glucagon. |
ANSWER:
(I) Promote the mechanical digestion of food.
(VI) Largest organ of the digestive system.
(III) Organ common to the respiratory and digestive system.
(VIII) Secrets the bile.
(II) It has the enzyme ptyalin, which acts in the digestion of carbohydrates.
(V) Produces gastric juice.
(IV) Perform peristaltic movements.
(VII) Where water absorption and stool formation occur.
(IX) Produces insulin and glucagon.
