Unit 8: Physiology of human body systems
Explore the physiology of the digestive system and the use of the corrective treatments
for nutritional deficiency
The digestive system
The digestive system is made up of the gastrointestinal tract, liver, pancreas and gallbladder. The
gastrointestinal tract is a series of hollow organs that are connected to each other from the mouth to
the anus. The organs that make up the gastrointestinal tract, in the order that they are connected,
include the mouth, esophagus, stomach, small intestine, large intestine and anus.
The mouth
The digestive system begins in your mouth when you chew, the teeth breaks down the food into
smaller parts and mix it with saliva (98% water and has mineral and enzymes) a soft mass or bolus is
,formed and is ready for swallowing, during the mix of the saliva and the food, an enzyme called
salivary amylase which is secreted by the salivary glands breaks down carbohydrates, until the food
is soft and flexible, the tongue and the cheeks push the bolus backwards into the Pharynx (The
pharynx allows the passage of swallowed food that includes solids and liquids into the esophagus).
Saliva is also secreted by the salivary glands. (Anatomy and Physiology in Health and Illness)
Functions:
- Chemical: In digestion of the food as you eat the
salivary glands secretes an important enzyme which is
salivary amylase. These enzymes break down
carbohydrates into disaccharides, such as maltose.
- Physical: The food is chew by the teeth and moved
around the mouth by the tongue and heeks, the cheeks are
muscles which help the food to be mixed with saliva and
form the bolus, the tongue helps with the chewing and
swallowing other functions are taste sensation by the taste
buds.
Esophagus
The esophagus is a flattened muscular tube that connects your
mouth to your stomach, it’s about 25 cm long. The esophagus curves upwards before opening into the
stomach, this sharp angle is believed to be one of the factors that prevents backflow of gastric contents
into the esophagus. Once the esophagus receives food from your mouth when you swallow, the
epiglottis is a small flap which folds over your trachea while eating to prevent choking, as food is
swallowed the process is automatic, the brain sends signals to your muscles in the esophagus so
peristalsis (muscle contractions) begins, which will allow food to move through the digestive system,
the esophagus secretes a large volume of mucus which assist the passage of the bolus during the
peristaltic contraction of the muscular wall. (Anatomy and Physiology in Health and Illness)
Functions:
- Chemical: There’s no chemical changes in the esophagus, but salivary amylase continues
digestion enzymes are not produced in the esophagus.
- Physical: Peristalsis occurs here. This is a muscular contraction, which helps the food to
move along the esophagus into the stomach.
Stomach
The stomach is a hollow organ, or “container”, that holds food while it is being mixed with stomach
enzymes. These enzymes continue the process of breaking down food into a usable form. Cells in the
lining of your stomach secrete a strong acid and powerful enzymes that are responsible for the
breakdown process. When the contents of the stomach are processed enough , they’re released into the
small intestine.
, Functions:
- Chemical: The enzyme pepsin is secreted by the chief cells in the stomach by the
inactive form of pepsinogen. Gastric lipase breaks down triglycerides and the
hydrochloric acid helps to convert pepsinogen into pepsin. The highly acidic
environment kills microorganisms in the food.
- Physical: Contraction and relaxation of smooth muscles mixes the stomach
contents, the pyloric sphincter (ring of smooth muscle) helps to regulate the
movements of chyme into the small intestine. (pubmed.gov)
Small intestine
The small intestine is made up of three segments- the duodenum, jejunum, and ileum the small
intestine is a 22 - foot long muscular tube that breaks down food using enzymes released by the
pancreas and bile from the liver. Peristalsis also works in this organ, moving food through and mixing
with digestive juices from the pancreas and liver.
The duodenum is the first segment of the small intestine. It’s largely responsible for the continues
breaking-down process. The jejunum and ileum lower in the intestine are mainly responsible for the
absorption of nutrients into the bloodstream.
Contents of the small intestine start using semi-solid and end in a liquid form after passing through the
organ. Water, bile, enzymes and mucus contribute to the change in consistency. Once the nutrients
have been absorbed and the leftover-food residue liquid has passed through the small intestine, it then
moves on to the large intestine.
Functions:
- Chemical: Proteins, Lipids and carbohydrates
continue breaking down, the bile salts hold the
triglycerides in the watery environment until the
lipase can break them into the smaller parts that
can enter the intestinal villi for absorption, some
carbohydrates and fibers pass undigested to the
large intestine where they may be broken down by
the intestinal bacteria.
- Physical: Peristalsis also occurs in the small
intestine, the muscle walls contract and is the
force that moves matter through the small
intestine.
Large intestine
The large intestine walls have a simple columnar epithelium, the large intestine has
invaginations (intestinal glands) goblet cells are more abundant in the large intestine.
The large intestine is responsible for processing waste so that emptying the bowels is easy and
convenient, the large intestine it’s divided into the cecum, the colon and the rectum, together
Explore the physiology of the digestive system and the use of the corrective treatments
for nutritional deficiency
The digestive system
The digestive system is made up of the gastrointestinal tract, liver, pancreas and gallbladder. The
gastrointestinal tract is a series of hollow organs that are connected to each other from the mouth to
the anus. The organs that make up the gastrointestinal tract, in the order that they are connected,
include the mouth, esophagus, stomach, small intestine, large intestine and anus.
The mouth
The digestive system begins in your mouth when you chew, the teeth breaks down the food into
smaller parts and mix it with saliva (98% water and has mineral and enzymes) a soft mass or bolus is
,formed and is ready for swallowing, during the mix of the saliva and the food, an enzyme called
salivary amylase which is secreted by the salivary glands breaks down carbohydrates, until the food
is soft and flexible, the tongue and the cheeks push the bolus backwards into the Pharynx (The
pharynx allows the passage of swallowed food that includes solids and liquids into the esophagus).
Saliva is also secreted by the salivary glands. (Anatomy and Physiology in Health and Illness)
Functions:
- Chemical: In digestion of the food as you eat the
salivary glands secretes an important enzyme which is
salivary amylase. These enzymes break down
carbohydrates into disaccharides, such as maltose.
- Physical: The food is chew by the teeth and moved
around the mouth by the tongue and heeks, the cheeks are
muscles which help the food to be mixed with saliva and
form the bolus, the tongue helps with the chewing and
swallowing other functions are taste sensation by the taste
buds.
Esophagus
The esophagus is a flattened muscular tube that connects your
mouth to your stomach, it’s about 25 cm long. The esophagus curves upwards before opening into the
stomach, this sharp angle is believed to be one of the factors that prevents backflow of gastric contents
into the esophagus. Once the esophagus receives food from your mouth when you swallow, the
epiglottis is a small flap which folds over your trachea while eating to prevent choking, as food is
swallowed the process is automatic, the brain sends signals to your muscles in the esophagus so
peristalsis (muscle contractions) begins, which will allow food to move through the digestive system,
the esophagus secretes a large volume of mucus which assist the passage of the bolus during the
peristaltic contraction of the muscular wall. (Anatomy and Physiology in Health and Illness)
Functions:
- Chemical: There’s no chemical changes in the esophagus, but salivary amylase continues
digestion enzymes are not produced in the esophagus.
- Physical: Peristalsis occurs here. This is a muscular contraction, which helps the food to
move along the esophagus into the stomach.
Stomach
The stomach is a hollow organ, or “container”, that holds food while it is being mixed with stomach
enzymes. These enzymes continue the process of breaking down food into a usable form. Cells in the
lining of your stomach secrete a strong acid and powerful enzymes that are responsible for the
breakdown process. When the contents of the stomach are processed enough , they’re released into the
small intestine.
, Functions:
- Chemical: The enzyme pepsin is secreted by the chief cells in the stomach by the
inactive form of pepsinogen. Gastric lipase breaks down triglycerides and the
hydrochloric acid helps to convert pepsinogen into pepsin. The highly acidic
environment kills microorganisms in the food.
- Physical: Contraction and relaxation of smooth muscles mixes the stomach
contents, the pyloric sphincter (ring of smooth muscle) helps to regulate the
movements of chyme into the small intestine. (pubmed.gov)
Small intestine
The small intestine is made up of three segments- the duodenum, jejunum, and ileum the small
intestine is a 22 - foot long muscular tube that breaks down food using enzymes released by the
pancreas and bile from the liver. Peristalsis also works in this organ, moving food through and mixing
with digestive juices from the pancreas and liver.
The duodenum is the first segment of the small intestine. It’s largely responsible for the continues
breaking-down process. The jejunum and ileum lower in the intestine are mainly responsible for the
absorption of nutrients into the bloodstream.
Contents of the small intestine start using semi-solid and end in a liquid form after passing through the
organ. Water, bile, enzymes and mucus contribute to the change in consistency. Once the nutrients
have been absorbed and the leftover-food residue liquid has passed through the small intestine, it then
moves on to the large intestine.
Functions:
- Chemical: Proteins, Lipids and carbohydrates
continue breaking down, the bile salts hold the
triglycerides in the watery environment until the
lipase can break them into the smaller parts that
can enter the intestinal villi for absorption, some
carbohydrates and fibers pass undigested to the
large intestine where they may be broken down by
the intestinal bacteria.
- Physical: Peristalsis also occurs in the small
intestine, the muscle walls contract and is the
force that moves matter through the small
intestine.
Large intestine
The large intestine walls have a simple columnar epithelium, the large intestine has
invaginations (intestinal glands) goblet cells are more abundant in the large intestine.
The large intestine is responsible for processing waste so that emptying the bowels is easy and
convenient, the large intestine it’s divided into the cecum, the colon and the rectum, together
