lesson 2 - digestive system organ functions Flashcards
What is the gastrointestinal tract?
Passageway of the digestive system that goes from the mouth to the anus
What do salivary glands do?
Create saliva, which moistens food so that it can move more easily through the esophagus and into the stomach.
Three sets of glands that secrete saliva
- Parotid (in front of ears)
- Sublingual (under and near the sides of the tongue)
- Submaxillary (near the rear of the jaw bone)
The _ has tastebuds to recognise different flavours, and also moves food around when masticating (chewing)
tongue
What happens when salivary glands produce saliva
Because saliva contains salivary amylase, the enzyme begins carbohydrate digestion and is a form of chemical digestion (remember that THE MOUTH is where carb. digestion begins)
Canine teeth are
used for tearing
Molar teeth are
used for crushing
Premolar teeth are
for grinding
Incisor teeth are
for cutting
What is a bolus
A lump mixture of food and saliva that forms during mastication
What is the role of the esophageal sphincter regarding the bolus
It opens up to allow the bolus to enter the stomach
What is the epiglottis?
A flap of tissue that covers the trachea and forces food to go in the esophagus
Why is the esophageal sphincter usually closed?
It prevents stomach acids from regurgitating back into the esophagus
A muscular J-shaped organ in which food is temporarily stored until one of the two forms of digestion take place
The stomach
Where is the stomach placed
Upper left side of the abdominal cavity
A stomach is compared to an accordion, why is this so?
The stomach has folds called rugae, which allows expansion after the consumption of food/liquids. The expansion increases the volume of the stomach and increases surface area, allowing the stomach to absorb nutrients more quickly.
…is an activated form of the enzyme
pepsin
pepsinogen is..
an inactive form of the enzyme
What is chyme?
The action of gastric juice and the churning of food in the stomach converting bolus into a semi-digested food: chyme
The three layers of the stomach wall include
Longitudinal, circular, oblique muscles. They help mix and break the food contents into a suspension of nutrients called chyme and propels it down into the duodenum
What does the pyloric sphincter do, and where is it located?
The pyloric sphincter is located at the end of the stomach, separating it from the small intestine. It regulates the movement of chyme into the small intestine
What protects the stomach from damage?
A layer of mucus secreted by cells lining the stomach
What do chief cells do?
Secrete pepsinogen
What do mucus cells do?
Secrete mucus
What do parietal cells do?
Secrete gastric juice
What is the duodenum?
The first section of the small intestine (located between the stomach and the middle of the small intestine, aka the jejenum)
After foods mix with stomach acid, they move into the duodenum and mix with bile from the gallbladder as well as digestive juices from the pancreas
What is the jejunum?
The jejunum is where chemical digestion ends. It is around 2.5 metres long. Most digestion and nutrient absorption takes place in the jejunum, as it breaks down the remaining proteins and carbohydrates.
What is the ileum?
The ileum is the last and longest stop of the small intestine. It is 3 metres long and contains fewer and smaller villi as compared to the duodenum and jejunum
The __ secretes one litre of __tic fluid and is released into the duodenum everyday to digest the macromolecules/nutrients
Pancrea, pancreatic fluid
Why is the fluid from the pancreas important?
It contains bicarbonates and neutralises the acidic pH of chyme from the stomach
What’s the largest internal organ?
The liver
Importance of the liver
It produces bile, which is stored in the gallbladder. The liver also helps break down old RBC’s (red blood cells)
Billy has hepatic steatosis. Without any research, what can you tell about the naming of this disease?
It has to do with the liver, because hepato/hepatic refers to the liver
What is emulsification and what do bile salts during this process?
Emulsification is the physical breakdown of larger lipids into smaller fat droplets, which is done with the help of bile salts
(a way to remember is soap, as it helps break down grease on a greasy plate. similarily, bile salts break apart the larger lipids into smaller units)
Which hormone plays a part in the flow of bile into the small intestine?
Secretin
What is bile made up of?
Mainly water, but also bile salts, cholestoral, certain fats (ex. ecithin) and bile pigments
What is the most important bile pigment and when is it made?
Bilirubin is made when red blood cells are broken down in the liver. It is also what makes urine yellow and stool brown
Digestion converts starch into
glucose
Digestion converts proteins into
amino acids
Digestion converts lipids into
fatty acids & glycerol
What are villi?
Finger-like projections that are richly supplied with blood vessels. They’re found in the inner lining of the small intestine and absorb nutrients from the food consumed and transfer it into the bloodstream. They also increase the surface area for food absorption
