The digestive tract Flashcards
(36 cards)
What are the accessory organs involved in digestion?
Salivary glands, biliary glands, liver, gallbladder, exocrine pancreas
These organs assist in the digestion process but are not part of the digestive tract itself.
What is the main purpose of digestion?
To make nutrients absorbable
This involves breaking down large foodstuffs into smaller molecules.
What are the four basic digestive processes?
- Motility
- Secretion
- Digestion
- Absorption
Each of these processes plays a critical role in the digestion and absorption of nutrients.
What is motility in the digestive system?
Movement of the stomach and intestines due to muscle contractions
This includes voluntary actions like chewing and involuntary actions like peristalsis.
What is peristalsis?
Radial contractions that propel food through the digestive tract
It is a key component of motility.
What role do acinar cells play in the pancreas?
They secrete hormones into the pancreatic duct
Acinar cells are crucial for the secretion of digestive enzymes.
Where does digestion and absorption primarily occur?
In the small intestine
This is where digestion is completed and most nutrients are absorbed.
What is the pH level of the stomach due to?
HCl secretions
The acidic environment is necessary for digestion but can also damage tissues.
What is the structure of the digestive tract?
It is essentially a tube that is continuous from mouth to anus
Contents are technically outside the body until absorbed.
What are the layers of the digestive tract?
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
Each layer has specific functions and structures that facilitate digestion.
What is the function of the mucosa layer?
Protective surface modified for secretion and absorption
It contains both exocrine and endocrine gland cells.
What is the role of saliva in digestion?
Begins digestion of carbohydrates and lipids, facilitates swallowing, provides lubrication
Saliva contains enzymes like amylase and lipase.
What are the main components of saliva?
- Water
- Electrolytes
- Proteins
Saliva also contains antibacterial agents like lysozyme and lactoferrin.
What triggers sweet tastes?
Glucose or artificial sweeteners
Sweet tastes are mediated by T1R family receptors.
What is the function of taste buds?
Chemoreceptors that detect taste stimuli
They send signals to the brain for taste perception.
What is deglutition?
The process of swallowing
It includes several stages: oral, oropharyngeal, and esophageal.
What happens during the esophageal stage of swallowing?
A primary peristaltic wave moves the bolus through the esophagus
This stage takes about 5-9 seconds.
What is the role of the gastroesophageal sphincter?
Maintains a barrier between the stomach and esophagus
It prevents reflux of gastric contents.
What are the primary tastes recognized by taste receptors?
- Sweet
- Bitter
- Umami
- Salt
- Sour
These categories encompass a wide range of taste sensations.
What is the role of the mesentery?
Suspends digestive organs from the inner wall of the abdominal cavity
It is a double fold of peritoneum that supports the digestive tract.
What is the primary function of the submucosa layer?
Provides elasticity and contains larger blood and lymph vessels
It supports the mucosa and muscularis layers.
What is the general structure of the layers of the digestive tract?
The digestive tract has the same general structure throughout but can vary slightly with some local characteristics of each region.
What is the mucosa?
The mucosa is the inner epithelial layer, a protective surface modified in particular areas for secretion and absorption.
What are exocrine gland cells?
Exocrine gland cells are responsible for secretion into the digestive tract lumen.
