Organ Architecture I - Hollow Organs

Question 1

What is mucosa?

Answer 1

epithelial layer that faces the lumen. May need to protect the underlying layers, absorb, secrete, etc. This depends on location in the body. Mainly it forms a barrier and mediates exchange.

Question 2

What is the lamina propria?

Answer 2

The loose CT layer underneath the epithelium. This supports the epithelium and is part of the mucosal layer.

Question 3

What is the submucosa?

Answer 3

A denser CT layer underneath the mucosa. This is also a supportive layer and contains VASCULATURE.

Question 4

What is the muscularis?

Answer 4

Muscular layer under the submucosa. This facilitates peristalsis in the digestive tract but also regulates BP and blood flow in the circulatory system and helps keep airways open in the respiratory system.
Usually two layers of smooth muscle, circular and longitudinal.

Question 5

What is the serosa?

Answer 5

This is the outer layer covering of any hollow organ that is inside a body cavity, like the stomach and intestines. It was a Smooth appearance. It is loose CT covered with mesothelium.
SEROSA=SMOOTH

Question 6

What is adventitia?

Answer 6

Loose CT that serves as a connection for the structure to other nearby structures when not in a body cavity. Adventitia connects the esophagus to the nearby structures, aorta, vena cava, etc.

Question 7

Compare the layers of a medium artery or vein with the layers of hollow organs (such as the digestive tube).

Answer 7

Medium arteries and veins have three layers similar to the layers of the digestive tube:

• Tunica initma (similar to mucosal layers)
• Tunica Media (similar to muscularis)
• Tunica adventitia (outer layer)

Question 8

Describe the structure of bronchi

Answer 8

• large lumens with rings of cartilage for support
• pseudostratified columnar epithelium, ciliated (mucosa)
• muscular layer has smooth muscle to restrict the airway (for coughing)
• the submucosa contains seromucous glands
• the combination of mucus and cilia beating upward is the mucociliary elevator
• cartilage is in the adventitia, to hold the airway open

Question 9

Describe the structure of bronchioles

Answer 9

• smaller openings with no cartilage and a relatively thick epithelium
• no gas exchange needed, no seromucous glands here either
• no need for mucus secretion since it is too deep in the lungs
• smooth muscle tension holds these airways open

Question 10

Describe the structure of alveoli

Answer 10

• open sacs, very thin epithelium (alveolar septa allows gas exchange from capillary to alveolus)
• bubble-like
• very thin basal lamina separating capillaries from alveoli