TOB: Internal surfaces of the body Flashcards
What is a mucous membrane?
Membrane which line certain internal tubes which OPEN to the exterior
Where can mucous membranes be found?
Alimentary/ GI tract
Respiratory tract
Urinary tract
These mucosal bear mucus-secreting cells to varying degrees
What is a serous membrane?
Thin, two-part membranes which line certain CLOSED body cavities. They envelop the viscera.
Where can serous membranes be found?
Lining the:
Peritoneum
Pleural sacs - envelop the lungs
Pericardial sac - envelops the heart
What layers make up a mucous membrane?
- Epithelium: lining the lumen of the tube
- Lamina propria: an adjacent layer of connective tissue
- Muscularis mucosae (in GI tract only) - a layer of smooth muscle cells (not involved in peristalsis)
What is the function of serous membranes?
They secrete a lubricating fluid which promotes relatively friction-free movement of the structures they surround.
What layers make up a serous membrane?
- Simple squamous epithelium (mesothelioma) which secretes a watery lubricating fluid
- A thin layer of connective tissue which attaches the epithelium to adjacent tissues (also carries blood vessels and nerves) - epithelium don’t have blood vessels
List the four layers of the gut from innermost to outermost
- Mucosa (epithelium, lamina propria and muscularis mucosae)
- Submucosa
- Muscularis externae
- Serosa ((mesothelium) simple squamous epithelium and a thin layer of connective tissue)
In what layer of the gut are Peyer’s patches located?
Lamina propria
What does the submucosa contain?
A layer of connective tissue containing:
Glands, arteries, veins and nerves
How many layers of muscle is there in the muscularis externa of the gut?
Two layers of smooth muscle: outer longitudinal layer and inner circular layer
What is the function of the muscularis externa of the gut?
To create successive peristaltic waves to move luminal contents along the gut
Name the four layers that make up the oesophagus from innermost to outermost
- Mucosa(stratified squamous non-kerratinised epithelium, lamina propria and muscularis mucosae)
- Submucosa
- Muscularis externa (2 layers - inner circular and outer longitudinal)
- Adventitia - thin outermost layer of connective tissue (no peritoneal enfolding of the is portion of the GI tract)
How does the internal surface of the oesophagus differ from that of the gut?
It is not surrounded by serosa (a serous membrane), instead it has a thin covering of connective tissue called the Adventitia
How many layers of muscularis externa does the oesophagus have?
Two: inner circular and outer longitudinal
How does the muscularis externae of the stomach differ from that of the rest of the GI tract?
It has three layers of smooth muscle: oblique, circular and longitudinal.
What are the temporary folds of the stomach called?
Rugae: folds of gastric mucosa forming longitudinal ridges in the empty stomach
What are the permanent folds of mucosa and submucosa present in the small intestine called?
Plicae circulares