Principles of Organization of Organs- Histology Flashcards
(49 cards)
What are ‘hollow’ organs?
These are the body tubes that connect with the outside of the body (the digestive, respiratory, and urogenital tracts)
Hollow organs are all lined by what?
a mucosa or mucus membrane
What do mucous membranes consist of?
consists of the surface epithelium, the underlying connective tissue (called the lamina propria).
NOTE: In the GI tract, there is also a layer of smooth muscle, which is called the muscularis mucosa.
T or F. Muscularis externa lies external to the mucosa in the GI tract
T
What does muscularis externa consist of?
1-3 layers of smooth muscle. (typically 2 in GI tract)
External to muscularis externa in hollow organs is what?
loose connective tissue.
For organs not situated within a body cavity, the outer layer outside the connective tissue is called the adventitia and attaches the organ to adjacent structures.
For organs situated within a body cavity, this connective tissue is covered by mesothelium (i.e. simple squamous epithelium); together they are called the serosa.
Some organs have an additional layer of connective tissue between lamina propria & muscularis externa, which is termed the submucosa.
a collection of tissues joined in a structural unit to perform a common function is called what?
an organ
What are three main architectural types of organs?
hollow (tubular)
glands
solid
Name 5 examples of tubular organs
- Digestive tract – esophagus, stomach, small intestine, large intestine
- Respiratory tract – trachea, bronchi, bronchioles
- Urinary tract – ureters, urinary bladder, urethra
- Female reproductive tract – oviduct, uterus, cervix, vagina
- Male reproductive tract – ductus deferens, urethra
What are the four layers of most hollow organs? Note that some others have additional layers
epithelium
lamina propria
muscularis externa
adventitia or serosa
Note that some others have additional layers
What is mucosa?
the lining of the body tubes that connect with the outside of the body (i.e. digestive, respiratory, and urogenital tracts).
What two layers make up the mucosa?
epithelium and lamina propia (term used for the underlying connective tissue)
Some organs have an additional submucosa layer. Where is this layer?
between lamina propia and muscular external
it is connective tissue
T or F. All hollow organs have muscularis externa
T
T or F. All hollow organs have muscularis mucosa
F. Only present in the GI tract
For organs situated within a body cavity, this outer layer is comprised of loose connective tissue covered by mesothelium (i.e. simple squamous epithelium). What is this layer called?
serosa
Adventitia – for organs not situated within a body cavity, the outer layer is made up of connective tissue that attaches the organ to adjacent structures.
In the GI, the muscular externa typically exists as how many layers? What are those layers?
2 layers
inner circular and outer longitudinal
NOTE: can exist as 1,2, or 3 layers
contraction of circularly-arranged muscle in the GI results in what?
narrowing of the lumen
contraction of longitudinally-arranged muscle in the GI results in what?
shortening of the tube
In the GI tract, contraction of smooth muscle is controlled by what?
Post-synaptic sympathetic fibers & parasympathetic ganglion neurons present and modulate the contraction of smooth muscle
What kind of neurons modulate smooth muscle contraction in the GI tract?
enteric neurons
Where are enteric neurons typically found in the GI tract?
typically grouped in small clusters, mostly in submucosa and between smooth muscle layers of muscularis externa.
the submocusa contains of what kind of tissue?
dense irregular CT
Sometimes contains glands – e.g. esophagus, duodenum, trachea
What are the layers of mucosa?
epithelium
lamina propria
(also muscularis mucosa in GI tract)
