DIGESTIVE SYSTEM Flashcards
(39 cards)
also known as the gastrointestinal system, is a collection of organs responsible for breaking down food into nutrients and absorbing them into the body for energy and growth, while also eliminating waste products. It is a long tube that starts in the mouth and ends at the anus, including the esophagus, stomach, and intestines.
DIGESTIVE SYSTEM
Organs of the
digestive system
MAJOR ORGANS
* Mouth
* Esophagus
* Stomach
* Small Intestine
* Large Intestine
ACCESSORY ORGANS
* Liver
* Gall Bladder
* Pancreas
MESSL LGP
- It transport swallowed food and liquids from the throat (pharynx) to the stomach. This is achieved through a series of coordinated muscle contractions called peristalsis, which propel the food bolus along the length of the esophagus.
- also plays a role in preventing
the backflow of stomach acid into the esophagus, a function primarily performed by the lower esophageal sphincter.
ESOPHAGUS
- plays a crucial initial role in digestion by physically breaking down food
through chewing (mechanical digestion) - initiating chemical digestion with a
Saliva, produced by salivary glands, contains enzymes like amylase that begin to break down carbohydrates. - It also prepares the food for swallowing by moistening it with saliva and moving it to the throat.
MOUTH
a series of involuntary, wave-like muscle contractions that propel food and other substances along the digestive tract and other hollow tubes in the body. It’s a key mechanism for digestion, allowing food to move from the esophagus to the stomach, and then through the intestines.
PERISTALSIS
an enzyme that breaks down complex carbohydrates, like starch, into simpler sugars. It’s primarily produced by the pancreas and salivary glands, and plays a key role in digestion.
AMYLASE
is a protective barrier composed of stratified squamous epithelium. This type of tissue is characterized by multiple layers of flat, scale-like cells, and in the esophagus, it’s non-keratinized, meaning it’s not tough or horny like the skin. It also contains connective tissue, nerves, and blood vessels.
Esophageal lining
WHAT IS A DIGESTIVE SYSTEM FOR?
- The digestive system also involves the action of hormones and nerves, which regulate the release of digestive enzymes, control the movement of food, and stimulate the release of digestive juices.
- digestive system works in a coordinated manner to break down food, absorb nutrients, and eliminate waste products, ensuring the body receives the necessary substances for optimal functioning and health.
- Location: At the top of the esophagus, where it joins the pharynx.
- Function: It prevents air from entering the esophagus during breathing and helps prevent reflux of esophageal contents into the pharynx.
- Contraction/Relaxation: Normally contracted to close the opening of the esophagus, but relaxes to allow food and liquids to pass into the esophagus during swallowing.
Upper Esophageal Sphincter (UES)
is a chewed
and moistened food mass formed in the mouth,
BOLUS
The partially digested, semi-liquid food that enters the small intestine after
leaving the stomach.
CHYME
“The bolus, formed in the mouth with saliva, is
swallowed and enters the stomach.
In the stomach, it mixes with gastric
juices, becoming chyme.”
- Location: At the bottom of the esophagus, where it joins the stomach.
- Function: It prevents the backflow of stomach contents (acid and food) into the esophagus, a condition known as gastroesophageal reflux (GERD).
- Contraction/Relaxation: Normally contracted, but relaxes during swallowing to allow food to pass into the stomach.
Lower Esophageal Sphincter (LES)
- primary function is to store food, mix it with digestive juices, and initiate the
breakdown of food into smaller, digestible pieces. This process is crucial for the body’s ability to absorb nutrients. - bolus is now called chyme.
STOMACH
Its main function in the digestive system is to initiate protein digestion in the stomach. It breaks down proteins into smaller peptides (short chains of amino acids). This process prepares the proteins for further breakdown and absorption in the small intestine.
PEPSIN
one of stomach’s gastric juices, creates the highly acidic environment (pH 1.5- 3.5) needed for pepsin to function and for breaking down food. This
juice also kills any microbes that are
found in the bolus. It is also responsible for creating a pH of 2.
Hydrochloric Acid (HCl),
is the enzymes from the saliva glands that stops breaking down carbohydrates.
pH of 2
a ring-shaped muscle located at the lower end of the stomach, acting as a valve to control the passage of partially digested food (chyme) from the stomach into the duodenum (the first part of the small intestine).
pyloric
sphincter
primary function in the digestive system is to complete the breakdown of food and absorb most of the nutrients and water into the bloodstream.
SMALL INTESTINE
The middle section of the small intestine, about 8 feet long. It’s specialized for the absorption of nutrients, especially carbohydrates, proteins, and fats,
which have been broken down in the duodenum.
JEJUNUM
The first and shortest section of the small intestine, a u-shaped organ approximately 10 inches long. It receives semi-digested food (chyme) from the stomach through the pyloric sphincter, and receives digestive juices from the pancreas and liver, along with bile from the gallbladder, which aid in the breakdown of fats and other nutrients.
DUODENUM
PARTS OF SMALL INTESTINE
-
DUODENUM
The first and shortest section of the small intestine, a u-shaped organ approximately 10 inches long. It receives semi-digested food (chyme) from the stomach through the pyloric sphincter, and receives digestive juices from the pancreas and liver, along with bile from the gallbladder, which aid in the breakdown of fats and other nutrients. -
JEJUNUM
The middle section of the small intestine, about 8 feet long. It’s specialized for the absorption of nutrients, especially carbohydrates, proteins, and fats,
which have been broken down in the duodenum. -
ILEUM
The longest section of the small intestine, roughly 12 feet long. It
primarily absorbs vitamin B12 and bile salts, along with any remaining nutrients that were not fully absorbed in the jejunum. It also contains Peyer’s patches, which are lymphatic tissues that help prevent bacteria from entering the bloodstream.
The longest section of the small intestine, roughly 12 feet long. It
primarily absorbs vitamin B12 and bile salts, along with any remaining nutrients that were not fully absorbed in the jejunum. It also contains Peyer’s patches, which are lymphatic tissues that help prevent bacteria from entering the bloodstream.
ILEUM
finger-like projections that significantly increase the surface area, enabling efficient absorption of nutrients from digested food into the bloodstream.
VILLI
- primarily functions as a protective barrier and facilitates absorption and secretion. It lines the inner surface of the digestive tract, acting as a barrier against harmful substances and providing a surface for nutrient uptake.
- lubricates the digestive tract and protects it from digestive enzymes and acids.
MUCOSA
