Digestion Flashcards
What is the gastrointestinal tract?
How long is it in a living and a dead person?
- pathways that food moves through from ingestion to defacation
- purpose is to move the food
- mouth - pharynx - esophagus - stomach - small intestine - large intestine - rectum - anus
- 16-23 feet in living person
- 23-30 feet in dead person
What are accessory organs?
- They help break down food but food doesn’t enter through these organs
- includes teeth, tongue, salivary glands, liver, gallbladder, pancreas
What are the processes of digestion?
- ingestion:eating, mouth only
- secretion: accessory organs and GI tract create 7 litres of digestive fluid daily
- propulsion: swallowing and peristalsis (smooth muscles contract to push down the food through the GI tract - involuntary)
- digestion: two types - chemical: uses enzymes (saliva or stomach acids) - mechanical: uses force (chewing)
- absorption: nutrients and other molecules pass into the blood stream
Defamation: unabsorbed materials (feces) are eliminated
What does the mouth include and what is it also know as?
- Includes the tongue, teeth, lips, cheeks, palates, and salivary glands.
- aka the oral cavity
What are the functions of the palates in the mouth?
- Forms the roof of the mouth
- splits into two parts the hard (formed by bone and forms a rigid surface that the tongue can push against while chewing) and the soft palate (made up of skeletal muscle and elevates when we swallow)
What are the functions of the tongue?
- moves food between teeth during chewing
- mixed food with saliva forming a bolus which is pushed down the pharynx and esophagus
- helps with speech
What is the tongue made of?
- covered in peg-like protection called papillae that contain taste buds
- made of skeletal muscle
What are the functions and what is the lips and checks made of?
- keep the food between our teeth when we chew
- both made of skeletal muscle covered by skin
What are some facts about teeth?
- There are 32 permanent teeth
- made of dentin covered in enamel
- each tooth has two main parts: the crown and the root
- teeth are embedded based on shape and function
What are the functions of salivary glands/saliva?
-saliva dissolves food chemicals to allow taste. Moisten food to create a bolus. Digests starchy foods with the enzyme salivary amylase
- the major salivary glands are found outside of the mouth and are activated by food (produce over 1.5 litres of saliva per day)
- minor glands inside the mouth continually secrete saliva to keep the mouth moist
what are some facts about the stomach
It’s on the left side of the abdomen bellow the liver
Ranges from 6 and 10 inches long but volume varies based on how much food is in it
Has 3 layers of muscles that contract and relax allowing the stomach to digest and push food
The stomach lining contains mucus and gastric pits which lead to gastric glands
What are functions of the stomach
Temporary food storage
Digests food chemically and mechanically which produces chyme
Absorption of alcohol and aspirin
What are the parts of the stomach
- cardia
- pyloric
- body
- oblique layer
- circular layer
- longitudinal layer
- fundus
What do gastric glands do?
Make the stomach contents acidic (pH 1.5 to 3.5)
Activates pepsin which digest protein
Chemical digestion of food
Kills bacteria in our food
What are some facts about the pharynx?
Also known as the throat
Broken into three parts: nasopharyn, oropharynx, and laryngopharynx
Food, fluids, and air travel from the mouth and down the the oropharynx
The pharynx is lined with stratified squamous epithelium which protects it from abrasions
The wall of the pharynx includes three layers of muscle which contracts to propel food down the pharynx and to the esophagus
What are some facts about the esophagus?
Approximately 10 inches long
The top is made of voluntary skeletal muscle
The bottom is made of invulentary smooth muscle
The muscles push food from the pharynx to the esophagus to the stomach using peristalsis (coordinated muscle movement.
Collapsed when food isn’t going through
Has an upper esophageal sphincter at the top
- opens when food goes down it to let it pass in the stomach but closes when food isn’t going through it to keep air out of the GI tract
Has a lower esophageal sphincter
- closed when food isn’t going through it to prevent regurgitation of food and stomach acid into the esophagus
Why does heart burn happen
It happens because stomach acid gets into your esophagus because the lower esophageal sphincter did not close fast enough of properly
What is the order of the intestines
- duodenum
- Jejunum
- Ileum
- Appendix
- Cecum
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon
- Rectum
- Anal cavity
What are some facts about the small intestines
It’s the longest part of the GI tracts - 7-13 feet in living
Extends from the pyloric sphincter to the ileacecal valve
The pyloric sphincter controls how much Chyme is put in the stomach
The site of most chemical digestion and where most absorption happens
Jejunum 8 feet and the ileum is 12 feet
Chemical digestion secrets 1-2 litres of intestinal juice a day (bile and pancreatic juice which put together digests proteins carbohydrates and fats
Absorption: nutrients are passed into the blood stream the small intestine has a large surface area to allow absorption easier
What are some facts of the large intestine
Only 5 feet long
Wraps around the small intestine extending from the ileacecal to the anus
Contains over a thousand types of bacteria
What is the function of the large intestine
It absorbs remaining water from food remains
