Lecture 41: Principles of viscera

Question 1

What are the 4 listed functions of viscera?

Answer 1

SEAD - secretion, excretion, absorption, digestion

Question 2

What are the two types of viscera

Answer 2

Hollow/tubular and solid

Question 3

What part of the body do most organ systems NOT involve?

Answer 3

The back

Question 4

What are the three layers of hollow viscus?

Answer 4

From interior to exterior:

(Lumen), Mucosa, Muscularis, Serosa

Question 5

What is the role of the serosa?

Answer 5

Minimizes the friction

Question 6

What are waves of smooth muscle called?

Answer 6

Peristalsis

Question 7

What structural feature may the mucosa have to increase surface area?

Answer 7

Folds

Question 8

What are the two structural parts of a hollow organ?

Answer 8

Constrictions and dilations

Question 9

Give an example of how knowing where constrictions are in an organ is useful?

Answer 9

Estimate where a caculus could become lodged in the urethra, ie restrictions in size such as constrictions

Question 10

Where is a calculus likely to be lodged?

Answer 10

The orific

Question 11

What two ducts do gallstones have to pass through to get to the bowls?

Answer 11

Cystic ducts and common bile duct.

Question 12

What are the two types of smooth muscle?

Answer 12

Longitudinal and circular

Question 13

What 2 features of smooth muscle is important for bladder control?

Answer 13

1. Smooth muscle can be stretched without loosing any tension (important for storage and excretion) and can contract to force urine out to the exterior
2. Motility

Question 14

What are the two subdivisions in a secretory solid viscus?

Answer 14

Outer cortex and inner medulla

Question 15

What structural feature is typical of solid viscus?

Answer 15

Solid viscera tend to have impressions/marks from adjacent structures.

Question 16

What are the two types of sphincters?

Answer 16

Anatomical and functional

Question 17

What are the 2 main roles of a sphincter?

Answer 17

Prevents reflux of contents and control passage of contents.

Question 18

What can happen to a sphincter if a drug causes it to lose tone?

Answer 18

Anything that alters tension/tone of smooth muscle can cause unchecked flow of contents

Question 19

What is a functional sphincter?

Answer 19

A tube that enters the wall of a muscle obliquely so that when the muscle contracts it closes the tube and prevents back flow, eg the ureter entering the bladder or in the esophagus entering the stomach via the diaphragm

Question 20

What is the key difference between an anatomical sphincter and a functional sphincter?

Answer 20

No localized muscle thickening around a functional sphincter.

Question 21

Are autonomic sphincters under involuntary or voluntary control?

Answer 21

Autonomic sphincters are under involuntary control

Question 22

Are voluntary sphincter made of skeletal or smooth muscle?

Answer 22

Skeletal

Question 23

Which line of defense are the voluntary and involuntary sphincters? (Think ‘rectum’)

Answer 23

1st - involuntary

2nd - voluntary

Question 24

What are the serous membranes of the thorax and abdomen?

Answer 24

Thorax - pleura

Abdomen - peritoneum

Question 25

What is the parietal layer of the serous membrane?

Answer 25

The layer against the body cavity.

Question 26

What is the viscus layer of the serous membrane?

Answer 26

The layer against the viscera.

Question 27

With what structure(s) does the viscus layer of serous membrane share its vascular and nerve supply?

Answer 27

The viscera it surrounds.

Question 28

What is the fold of peritoneum that suspends viscera in the peritoneal cavity called?

Answer 28

Mesentery

Question 29

What are the two roles of the mesentery?

Answer 29

• Provides pathway for nerves, etc, to viscera

- Provides viscera with mobility within the body cavity

Question 30

Structures with mesentery are in danger of what kind of injury?

Answer 30

Torsion/twisting?

Question 31

Visceral pain is often called ‘what’ pain?

Answer 31

Referred pain

Question 32

Do paired viscera share the same nerve supply?

Answer 32

Yes

Question 33

To what side of the body is paired visceral pained (relative to the inflamed viscus)?

Answer 33

The same side as the viscus.

Question 34

To where does unpaired viscera refer pain?

Answer 34

The midline, ie its developmental origin.

Question 35

When is pain from unpaired viscera referred to overlying skin?

Answer 35

When local somatic nerves are involved.