Lecture 20 Flashcards
What is the primary function of the GI System?
Bring nutrients into the internal environment so they can be used
What are features of the general structure of the GI System?
- Long tube with outgrowths
- Closed off at both ends (sphincters)
- Lined by epithelium
How are epithelia classified>
Shape, number of layers and specialisations
Where is Satisfied squamous epithelium found?
Mouth/Oral cavity, esophagus and Anal canal
Role of stratified squamous epithelium?
Protection from abrasion
Where is simple columnar epithelium found?
Stomach, small intestine and large intestine
What is the role of simple columnar epithelium?
Secretion and absorption
Where are goblet cells located?
In between columnar epithelium of the small intestine
Features of Goblet cells?
Columnar
Goblet shape
Apical mucous granules
Basal nucleus
What are multicellular glands?
Epithelium that invaginate to form glands.
What are the two types of multicellular glands?
Simple - gland with single duct (stomach and small intestine).
Compound - gland with 2 or more ducts (salivary glands)
What are the four layers of the gut tube?
Mucosa
Submucosa
Muscularis
Adventitia `
What does the mucosa consist of?
Epithelium
Lamina propria
Muscularis Mucosae
sometimes glands
What does the submucosa contain?
Glands
Blood vessels
How is secretion regulated in the sub-mucosa?
Submucosal nerve which is part of the enteric nervous system
What are the main components of the muscularis?
Smooth muscle
- Inner circular
- outer longitudinal
Myenteric plexus
What is the Myenteric plexus?
Part of the enteric nervous system.
In. between muscle layers.
Regulates Motility
What is the Serosa?
An additional outer covering for organs in the peritoneal cavity but not included as one of the four layers.
What is the adventitia made up of ?
Fibrous connective tissue
What is the peritoneum?
A serous membrane, consists of parietal layer that lines the body wall and visceral layer that lines the organs. Between these layers is a fluid filled space.
What does retroperitoneal mean?
Posterior to the peritoneum.
What is a mesentery?
Double layer of visceral peritoneum that connects organ to body wall.
What is the omenta?
Double layer of visceral peritoneum that connects an organ to another organ.
What are the three pars of salivary glands connected to oral cavity via ducts?
Parotid - serous fluid with amylase
Sublingual - Mucous only
Submandibular - Mixed
Structure of Salivary glands?
Compound secretory glands.
Cells in clusters - acinus
What do Acinar cells secrete?
Acinar cells secrete enzymes (amylase)
What do Duct cells secrete?
Duct cells secrete bicarbonate (buffering)
Location of esophagus?
Posterior to the Trachea, extends from pharynx to stomach
Role of Epiglottis?
Ensures that food enters the esophagus and not the trachea
Structure of esophagus?
Basic Tube modified to pass food. Highly fold submucosa and mucosa so it has the capacity to expand.
What is the role of the Muscularis in the esophagus?
Move food bolus
What types of muscle are found in the esophagus?
First 1/3 skeletal
Middle 1/3 A mixture
Last 1/3 smooth muscle
Why is mucosa important in the esophagus?
Lubrication and Protection
How is the mucosa in the esophagus different?
No goblet cells, instead have glands with ducts to surface
