ToB - Internal Surfaces

Question 0

What do serous membranes secrete, where and what do they consist of?

Answer 0

Secrete a watery fluid for lubrication
Consist of simple squamous epithelia and a thin CT layer
There are 2 layers (parietal and visceral) which line closed body cavities
- peritoneal
- pericardial sac
- pleural sac

Question 1

What are the 2 types of membranes that may cover internal surfaces?

Answer 1

Serous

Mucous

Question 2

What do mucous membranes secrete, where and what do they consist of?

Answer 2

Secrete mucous
Consist of epithelia, layer of CT (lamina propria) and in the GI tract, muscularis mucosae.
Can be found:
- GI tract
- respiratory tract
- urinary tract

Question 3

What are the layers of the GI tract like?

Answer 3

Oesophagus, stomach, jejeunum and colon.

All have:
Epithelia
Lamina propria
Muscularis mucosae (thin in the colon)
Submucosa
Muscularis externa (3 layers in stomach though)

Question 4

How is the internal surface of the stomach adapted?

Answer 4

The gastric mucosa is folded into rugae = increases s.a.

Question 5

How is the internal surface of the jejeunum adapted?

Answer 5

It has plicae circulares, folds of mucosa and submucosa to increase s.a.
The epithelia also have villi for this function

Question 6

What are the crypts of lieberkühn and where are they found?

Answer 6

Found on the colon. These contain:

• goblet cells which produce mucous
• peyers patches which contains lymphoid tissue = fight microbes
• absorbative cells which can take in electrolytes and water.

Question 7

What are the 2 main parts of the urinary tract and their internal surface structure?

Answer 7

Ureter

• transitional epithelia
• lamina propria (containing elastic fibres)
• mucularis externa

Bladder

• transitional epithelia
• lamina propria (containing smooth muscle)
• 3 layers of muscularis externa

Question 8

How is the bladder kept impermeable to urine?

Answer 8

Thick membrane of epithelia with tight intercellular junctions.

Question 9

What are the 4 parts of the respiratory tract and what are their internal surfaces made of?

Answer 9

1) . Trachea
- epithelia (p)
- lamina propria
- submucosa (with seromucous glands to kill microbes)
- cartilage
- adventitia

2) . Bronchus
- epithelia (p)
- lamina propria
- muscularis mucosae
- submucosa (with seromucous glands to kill microbes)
- cartilage

3) . Bronchioles
- epithelia (scc)
- lamina propria
- muscularis mucosae
- Clara cells (produce surfactant that protects bronchioles lining)

4) . Alveoli
- epithelia (sse)
- macrophages as cuboidal cells produce surfactant, not mucus.