Digestive System 2 Flashcards
What is the length of the digestive tract?
It extends from the mouth to the anus.
What does the wall of the digestive tract consist of?
- outer serosa (or an adventitia)
- muscularis externa
- submucosa
- inner mucosa
What does the “mucosa” layer constist of?
- inner epithelium
- middle lamina propria
- outer muscularis mucosae
Where is the muscularis mucosae absent?
- mouth
- pharynx
- portions of the esophagus
- rumen
What does the mouth lack? (which parts of the wall?)
- submucosa
- muscularis externa
What does the digestive tract consist of?
only TUBULAR organs!
What is the outermost layer of all tubular organs?
2 options:
- tunica serosa
- tunica adventitia
Is it possible to find both tunica serosa and tunica adventitia in one place in tubular organs?
NO!
Is it possible to find both tunica serosa and tunica adventitia in the same tubular organ?
yes, just at different locations!
What is the difference between tunica serosa and tunica adventitia from a histological perspective?
Tunica serosa = simple squamous epithelium
(squamous are very flat cells)
What is a special feature of tunica serosa cells?
all of the cells secrete SEROUS SECRETE!
simple squamous epithelium
What is serous secrete? What is its function?
- watery substance
- small fraction of proteins and other molecules
- necessary for the lubrication of outer surfaces
What lubricates internal organs?
tunica serosa cells
Where is tunica serosa found?
ONLY IN CAVITIES!
- pelvic
- abdominal
- thoracic
ser tylko w brzuchu = cavities
What is constant in all organs in a cavity?
- lubrication!
- covered by tunica serosa!
Explain the structure of tunica adventitia. What is its function?
- based on loose connective tissue
- attaches organ with the adjacent structure
Explain the surrounding layer of the esophagus.
Esophagus is located in the neck = not a cavity!
- highly attached to adjacent structures (muscles)
- surrounded by tunica adventitia
Explain the structure of the external layer of tissue of the digestive tract.
tunica serosa- simple squamous epithelium
tunica adventitia- loose connective tissue
State the functions of the external layer of the digestive tract.
Tunica adventitia:
- attaches organ to adjacent structures
Tunica serosa:
- prevents attachment
- provides lubrication + sliding movements
What layer comes after tunica serosa/adventitia?
Tunica muscularis (Muscular layer)
What is tunica muscularis based on?
smooth muscle cells
What is tunica muscularis based on?
2 layers!
1) Circular muscle layer
2) Longitudinal muscle layer
Which muscle layer is typically located on the inner side? Which on the outer side?
Inner- circular muscle layer
Outer- longitudinal muscle layer
Why are the two muscle layers necessary in the digestive tract?
Circular and longitudinal contractions provide the digestive tract with “PERISTALTIC MOVEMENTS”.
- allow food to move through the digestive tract