Chapter 36 Flashcards
What are functions of digestive system (Gastrointestinal system ?
-Breaks down food into smaller components so it can be absorbed and used by the body
-Responsible for collecting and eliminating waste making sure waste gets out the body so it does not poison us
-Synthesizing vitamins and storage them
-Entry of nutrients, vitamins, minerals, electrolytes and water.
-producing enzymes and has specialized cells that secrete hormones
-Part of endocrine system,
What does the GI tract need in order to be able to digest and absorb nutrients?
Needs to be healthy and intact
-Intact without any ulcerations, tears,torchions and resistant to own secretions
-Must be resistant to own secretions
Why must the GI tract be resistant to its own secretions ?
To prevent self digestion!
-protect tissues
-prevent infections
Many secretions, secreted by the GI tract are meant to breakdown proteins, and other foods. So it has to resist the acidic enzymes it makes because it would destroy the GI tract or the digestive tract is digested itself.
Why does the GI tract require the presence of enzymes for the digestion and absorption of nutrients?
Enzymes break down food into is constituent parts (nutrients)and eliminate waste
What makes up the upper DIgestive system?
Mouth, esophagus and stomach
-Acts intake source and receptacle
-food passes and intial digestion starts
What makes up the middle portion of the GI tract?
Small intestine, duodenum, jejunum and ileum
-Absorptive processess occur
What makes up the lower segment of the digestive system?
Cecum, colon, and rectum
-Storage channel for waste elimination
What makes up the fourth part of the digestive system ?
Accessory organs; salivary glands, liver and pancreas
-Produce secretions to dismantle foods and regulate use and storage of nutrients
**Gastrointestinal wall structure
What is the mucosal layer responsible for?
-Mucus LUBRICATEs
-protects the inner surface of the alimentary canal
**Gastrointestinal wall structure
Describe the submucosal layer
- connective tissues
-contains blood vessels, nerves, and structures that are responsible for secreting digestive enzymes
**Gastrointestinal wall structure
What is the muscle layers responsible for?
-smooth muscle
-Facilitates movements needed for transport
**Gastrointestinal wall structure
what is the peritoneum responsible for?
-Tissue located outside the intestine
-Without it the Intestinal tract would be loosely hanging in the abdomen
What are two types of movements i the gastrointestinal tract?
-Tonic movement
-Rhythmic movements
**Movements of gastrointestinal tract
What are tonic movements ?
-Constant and occur at junction points (sphincter)
-Last minutes to hours
**Movements of gastrointestinal tract
What are Rhythmic movements?
-Intermittent
-Churn food and move forward the food along digestive tract
-Moves food through contracting movements
-Defined rest periods
What are the phases of swallowing?
-oral phase
-pharyngeal phase
-Esophageal stage
What is the oral phase of swallowing?
-Food enters mouth and collects at the back of the mouth
-Pushed upwards and backward by the tongue and goes into the upper pharynx and starts to move down the pharynx
What is the pharyngeal phase of swallowing
Once food is located in the pharynx
-Softpalate pulled forward, The palatopharyngneal folds must close so that food doesn’t come back up to the mouth
-Vocal cords close and epiglottis covers larynx so that food goes down
-Respiration is suspended
-Bolus is moved backward into esophagus through constrictuve movements of the pharynx
What is the esophageal stage
Food travels down pharynx’s into esophagus
Food triggers the esophageal walls to stretch, and the stretchings triggers CNS reflexes and initiate peristalsis
What is gastric motility
Action of the stomach
what is the process of gastric motility ?
Stomach converts food into chyme
1.Churning begins and food is converted into chyme (peristaltic mixing)
2.Once ready the pyloric sphincter opens up and chyme passes through
3.Chyme empties into the duodenum
4. Peristaltic begins in the small intestine
5.Chyme is moved through the small intestine into the illeocecal junction
6. Once in the illeocecal junction another sphincter will open and food will enter the cecum
7.Churning and and propulsive continues as the food moves though the large intestine, through rectum
and anus which then signals…
8. Defecation initiation ( removing wast through pooping
What does defecation mean?
Process where body gets rid of waste materials from the digestive system in simpler terms poop
What helps control the process of defecation?
Internal sphincter and external sphincter
**Control of defectation
What does the Internal sphincter do?
-Autonomic process (we have nor control over it
-Under reflexive control
-
**Control of defectation
What does the external sphincter do?
-Must be engaged through voluntary control
-Person must have control both neurological and physically of the external sphincter so it can open up waste products and so that defections can occur
How much ML of fluid is secreted into the GI tract daily?
about 7,000 mL of fluid
What does it mean that the secretions are mainly water and have some sodium and potassium?
-It means GI tract releases Water, sodium and potassium which means a person should have a balanced amount of sodium, water and potassium in their diet so the the GI can function properly
What is the function of saliva?
-Keep mouth intact and avoid destruction or ulcerations of the mouth through the enzymes it secrete
-Lubricate food and allows it to moves through the esophagus
-Salivary glands produces saliva to make it easier for swallowing
- Saliva contains digestive enzymes that begins the breakdown process of turning food into to chyme in the mouth
-Contains enzyme, lysozyme, antibacterial agent
-cleans mouth
-Contains ptyalin and amylase for digestions starches
-Rich in mucus
What does the stomach produce on its own?
Gastric acid and pepsin which produce hydrochloric acid
What does hydrochloric acid do?
Acidic acid thats aids in breaking down food and converting it into chyme
What secretes pepsinogen?
chief cells
What is pepsinogen converted into?
Converted into pepsin when it is exposed to low pH(acidic) gastric juices
Why is the Gastric mucosal barrier important ?
-Protects the stomach from pepsin
-Resistant to secretions high in acid that is produced
-If not intact, the stomach will be destroyed by the hydrochloric acid process
-hydrochloric is not selective so it will get rid of anything it needs to
Describe the small intestine
-Has large surface are
-Contains Villi
WHat is the vili?
finger like protrusions that line the small intestine
-Vili are micro system that aid in digestion and absorptions
-They have goblet cells that provide lubrication through the production of mucus
-Have about 25,000 in the small intestine
-Covered with cells called enterocytes that aid with digestions
What do brush border enzymes do?
Release specialized enzymes digest carbohydrates, fats and proteins
What would happen if the vili was destroyed or inflamed
Process of absorption and digestion is interrupted
what do brush border enzymes convert polysaccharides into?
Monosaccharides so they can be absorbed
What does the pancreatic lipase break fat down into?
simple fatty acids and bile salts which provide emulsification to allow for absorption
what do protease enzymes do?
reduce peptides into amino acids for easy absorption
What is digestion?
Digestion is the chemical breakdown of the ingested food into absorbable molecules.
Taking big parts of food into smaller parts of food
(breaking down)
Movement of materials through the GI tract at a rate that facilitates absorptions
What is absorption?
Absorption refers to the movement of nutrients, water and electrolytes from the lumen of the small intestine into the cell, then into the blood
Process of moving nutrients and other materials from the external environment if the GI tract into the internal environment
What are the fucntions of the large intestine
-Responsible for reabsorbing water
-Moving waste along the colon so it can exit the body
What kind of bacteria does the gut have?
Gut microflora
What is the gut?
Natural habitat of large and diverse bacterial community
What is the functions of Gut flora?
-Has bacteria that provides protection help with metabolism
required for GI health and overall health