Alimentary System Flashcards
What does the mucosa of the ileum consist of
three layers: epithelium, lamina propria and muscularis mucosa
What are the two main cell types in the epithelium of the ileum
Absorptive and mucus secreting
What is the adventitia of the ileum lined by?
Simple squamous epithelium
How long does it take stem cells to migrate from the site of cell division to the apex of the villus
3-5 days
What are Paneth cells
Specialise defence cells found at the base of the crypt of Lieberkühn
They secrete antimicrobial substances which are contained in eosinophilic apical granules
There are a large number of cells in the loose connective tissue immediately below the epithelium of the ileum. What are these?
White blood cells, particularly lymphocytes
What are the large aggregates of lymphoid tissue in the small intestine called
Peyer’s patches
What is the main component of the submucosa
Collagen
True or false
Each smooth muscle cell in the muscularis propria is fusiform
True
What is each muscle fibre in the muscularis propria surrounded bye
A thin layer of connective tissue which transmits the force of contraction from fibre to fibre
What are the 2 main functions of the tunica serosa
To secrete a watery, lubricating fluid which allows the folds of the intestines to move easily
Extends as a double layer to form the mesentery by which the gut is suspended in the body Kapity
What are rugae
Substantial faults made up of large numbers of tubular glands in the mucosa
What shape are oxyntic cells
Pear shaped with a central nucleus
What are the three mechanisms of defence in the gastric mucosa
Mucus
Cells replaced by cell division
Rapid replacement of damaged surface
Describe the connective tissue layers of the oesophagus
Has a protective stratified squamous epithelium and the muscle layers show transition from striated to smooth-muscle along the organ
Describe the connective tissue of the body of the stomach
Has a glandular epithelium
The glands in the stomach are tubular
The muscle layers are well developed and made of smooth-muscle only
Describe the connected tissue layers of the pylorus of stomach
CThe mucosa shows deep gastric pits and glands lined by numerous mucus secreting cells
Gastrin secreting cells are found scattered and monks the mucus cells, typically at the base of the glands
Describe the connective-tissue of the duodenum
The epithelium covers the valley which project into the lumen and extend into Brunner’s glands.
These glands which are distinctive feature of the duodenum are present in large numbers in a submucosa beneath the muscularis mucosae
The two muscle layers are clearly distinguished
What is the function of Brunners glands
Protection of the mucosa by secretion of an alkaline mucus which neutralises the acidic chyme received from the stomach
How does the submucosa of the ileum differ from the duodenum
No submucosal glands present in ileum
Describe the connective-tissue of the colon
The mucosa is lined by numerous straight tubular glands which extends down to the muscularis mucosa and which have two main types of cells: goblet cells and absorptive cells
What is a distinctive feature of the oesophagus
Mucus secreting submucosal glands
Are there glands in the lamina propria of the oesophageal mucosa
Yes especially near the stomach
These protect against acid reflux by producing a neutral mucus
