Digestive System Flashcards
What is the Digestive system also referred to as?
The gastrointestinal system
What is the Digestive system responsible for?
-changing food and nutrients into waste
What are Digestive Enzymes?
-chemicals that break down food and nutrients into smaller forms so that the body can absorb them
What are the functions of the digestive system?
- Ingestion
- Digestion
- Absorption
- Elimination
Describe the Ingestion function of the digestive system:
- process of taking food in, chewing, and dissolving it in the mouth
- This forms a soft ball (bonus) in preparation for digestion
- this process utilizes the structures of the lips, teeth, face muscles, saliva, tongue, and pharynx
Describe the Digestion function of the digestive system:
-bolus enters the stomach & goes through 2 different digestion processes
—1. Mechanical: 3 layers of smooth muscle within the stomach wall enable the stomach to contract in many directions mashing the food
—2.Chemical: Brain sends messages to the gastric glands in the stomach wall stimulating them to secrete gastric juices such as PEPSIN
Describe the Absorption function of the digestive system:
-Glucose and amino acids are absorbed by active transport after combining with a carrier molecule.
—these nutrient enter the blood through capillaries in the villi and are transported to the liver
-Fatty acids and monoglycerides are absorbed into the epithelial cells of the intestinal lining
—there they are reassembled into triglycerides and packaged as and finally they pass into the villi
Describe the Elimination function of the digestive system:
-The removal of indigestible foods and other wastes materials referred to as FECES from the body
-When feces arrive at the rectum, DEFECATION is stimulated through PERISTALSIS
—This process takes several hours depending on the quality of food and health of the digestive tract
What are the 4 Primary organs of the digestive system?
- Mouth
- Stomach
- Small intestines
- Large intestines
Many stars shine longtime
Describe the Mouth (mastication and deglutition) (chewing and swallowing) step of digestive system
- Food enters the system at the mouth and is chewed by the teeth to break it up into smaller amounts so that it can be swallowed and digested
- the SALIVARY GLANDS produce saliva which contains enzymes that start to break down the food
- The food then is swallowed and moves down into the esophagus (throat)
- the EPIGLOTTIS is a small flap of tissue that covers the trachea (windpipe) to prevent food from entering and going into the lungs
Describe the stomach (gastric digestion) step of the digestive system
- It is a food reservoir and the first MAJOR site of digestion
- digestive glands in the stomach produce pepsin and hydrochloride acid which turn the food into a semi liquid called CHYME
- food leaves the stomach and enters into the small intestine
Where is the stomach located?
-in the upper left quadrant of the abdominal cavity
Describe the small intestines step of the digestive system:
- about 90% of absorption of nutrients occurs here
- Villi, which line the intestines and contain capillaries, absorb the nutrients
- The remaining 10% takes place in the large intestine and in the stomach
- Peristaltic movements are what move food through the small intestine
- the walls of the intestine contract and relax to create segmental waves that push the food through the intestines
What is the small intestine?
A coiled, 20 foot long tube consisting of 3 parts:
- Duodenum
- Jejunum
- ileum
Describe the large intestine of the digestive system (Also known as the bowel)
-extends from the small intestine to the anus.
-it joins the small intestine at the ILEOCECAL VALVE
—This valve closes after food has passed through it to prevent back up of material from the bowel
-the APPENDIX is attached to the caecum
—located in the right lower quadrant of the abdomen
-believed to serve no purpose in the digestive system but problems arise if inflamed or infected
- the large intestine starts at he right lower quadrant, runs superiorly (ASCENDING COLON), crosses the abdominal cavity as the TRANSVERSE COLON and then runs inferiorly down the left side of the abdominal cavity as the DESCENDING COLON
- in the medial lower abdomen it becomes the RECTUM which leads to the external opening called the anus
-Food is stored in the large intestine until it is expelled by DEFECATION
-defecation is controlled by two sphincters
—The internal sphincter is controlled by the autonomic nervous system, as is the rest of the digestive system (this means that a person has no conscious control over their digestive system)
—The EXTERNAL SPHINCTER is controlled by the somatic nervous system and is under voluntary control
What are the accessory organs of digestion?
- Liver
- Gallbladder
- Pancreas
Where is the liver located?
- largest and one of the most complex visceral organs in the body
- lying in the upper right side of the abdomen, just under the diaphragm
- located below the diaphragm in the right upper quadrant of the abdomen, mostly under the ribs
The liver is capable of numerous complex & diverse actions, which include:
- Secretes BILE, which is important in the digestion of fat
- converts excess glucose to glycogen and stores it then releases glucose into the blood when it is needed
- Performs many important functions in the metabolism of proteins, fats & carbohydrates
- manufactures many of the plasma proteins found in the blood (clotting factor)
- detoxifies many drugs and poisons that enter the body
- breaks down bacteria and filters worn-out red blood cells
What does the liver store?
-stores iron and certain vitamins
What does the liver convert?
-converts amino acids to fatty acids and urea