Lec 16 - Organology Flashcards
What are the four concentric layers or tunics found in most tubular organs?
The four tunics are:
1. Tunica mucosa
2. Tunica submucosa
3. Tunica muscularis
4. Tunica adventitia (or tunica serosa when mesothelial investment is present).
Describe the function and structure of the lamina epithelialis mucosae.
The lamina epithelialis mucosae is the epithelial layer of an organ that forms the innermost layer of the tunica mucosa.
It is a consistent layer of epithelial cells that rests on the basal lamina, serving as the lining of the lumen.
What is the primary role of the lamina propria mucosae in the tunica mucosa?
The lamina propria mucosae is the connective tissue layer beneath the epithelium.
It provides structural support, contains small blood vessels, nerves, and, in some organs, lymphatic nodules and glands.
How does the lamina muscularis mucosae contribute to the structure of the tunica mucosa?
The lamina muscularis mucosae consists of smooth muscle cell.
It may have an inner circular and outer longitudinal muscle layer, although it is not always present.
It serves as a sharp demarcation line between the lamina propria mucosae and the tunica submucosa.
What is the difference between the tunica submucosa and the lamina propria mucosae?
The tunica submucosa is a more coarsely arranged connective tissue layer containing larger blood vessels, nerve plexi, and sometimes glands. In contrast, the lamina propria mucosae is a finer, supportive connective tissue layer that underlies the epithelium of the tunica mucosa.
What is the significance of the tunica muscularis in tubular organs, and how are its layers arranged?
The tunica muscularis is responsible for the tone, size of the lumen, and movement of materials through the organ.
It typically consists of two layers of smooth muscle: an inner circular layer and an outer longitudinal layer, with vascular structures, nerve plexi, and autonomic ganglia separating them.
In what way does the tunica adventitia contribute to the support of tubular organs?
The tunica adventitia is a loose connective tissue layer surrounding the organ that contains blood vessels, nerves, ganglia, and adipose tissue. It helps suspend the organ by attaching it to surrounding tissues or structures.
What is the difference between tunica adventitia and tunica serosa in terms of their structure and function?
The tunica adventitia consists of loose connective tissue, while the tunica serosa has a mesothelial layer (simple squamous epithelium) surrounding it.
The tunica serosa is typically found in organs within coelomic cavities.
How do the tunica mucosa and tunica submucosa work together when the lamina muscularis mucosae is absent?
When the lamina muscularis mucosae is absent, the lamina propria mucosae blends with the tunica submucosa, and the two layers may collectively be referred to as the “tunica mucosa-submucosa.”
What is the study of organology, and what does it focus on?
Organology is the study of the morphology (structure) of the organ systems of the body.
How are organs formed in the body according to organology?
Organs are formed by a combination of one or more basic tissues.
What are parenchymatous organs, and what are they composed of?
Parenchymatous organs are solid organs composed of a combination of one or more basic tissues.
They are primarily made up of the parenchyma (functional component) and the stroma (supportive tissue).
How are the components of parenchymatous organs categorized?
The components of parenchymatous organs are divided into two subgroups:
• Parenchyma: the specific functional component of the organ.
• Stroma: the supportive tissue that includes connective tissue, vasculature, nerves, and lymphatics.
How are small groups of parenchyma organized and surrounded by connective tissue within an organ?
Small groups of parenchyma are surrounded by a fine meshwork of areolar or reticular connective tissue that contains vessels and nerves.
These groups may be grouped as a unit and surrounded by more coarse areolar connective tissue. The connective tissue can be continuous with DWFCT of the capsule.
How do mucous membranes differ from serous membranes in terms of structure and function?
Mucous membranes include some or all of the components of the tunica mucosa and are kept moist by secretions from cells within the lamina epithelialis or glands located in the lamina propria mucosae or tunica submucosa.
In contrast, serous membranes consist of a layer of mesothelium and associated connective tissue, lining the coelomic cavities. They secrete fluids, such as peritoneal fluid in the peritoneal cavity.
What is the main structural difference between tubular and parenchymatous organs?
Tubular organs consist of a wall and a lumen, typically organized into four concentric tunics, while parenchymatous organs are solid and composed of one or more basic tissues, divided into parenchyma and stroma.
