4/29: Colon

Question 1

What does pressure and chemical irritation do?

Answer 1

Relax sphincter and excite peristalsis

Question 2

What does fluidity of contents promote?

Answer 2

Emptying

Question 3

What does pressure or chemical irritation in cecum do?

Answer 3

Inhibits peristalsis of ileum and excites sphincter

Question 4

Where is the absorbing colon?

Answer 4

Proximal 1/2

Question 5

What is the function of the absorbing colon?

Answer 5

Absorption of water and electrolytes from chyme to form solid feces

Question 6

Where is the storage colon?

Answer 6

Distal 1/2

Question 7

What is the function of the storage colon?

Answer 7

Storage of fecal matter until it can be expelled

Question 8

What does poor motility cause?

Answer 8

Greater absorption and hard feces in transverse colon cause constipation

Question 9

What does excess motility cause?

Answer 9

Less absorption and diarrhea or loose feces

Question 10

What is the longitudinal muscle?

Answer 10

Teniae coli

Question 11

How long does it take to move contents from ileocecal valve to anus?

Answer 11

8-15 hours

Question 12

What are mixing movements?

Answer 12

Haustrations

Question 13

Describe haustrations

Answer 13

• Fecal material slowly dug into and rolled over
• All fecal material gradually exposed to mucosal surface
• Facilitates absorption of water and dissolved substances
• Movement of material from cecum through ascending colon

Question 14

What are propulsive movements?

Answer 14

Mass movements

Question 15

Descrive propulsive movements

Answer 15

• 1-3x each day
• Transverse to Sigmoid
• Occurs throughout colon for 10 min.
• Force feces into rectum
• Gastrocolic and Duodenocolic Reflexes
• Irritation can stimulate

Question 16

What promotes growth of colon bacteria?

Answer 16

Slow motility

Question 17

What valve keeps bacteria in colon?

Answer 17

Ileocecal valve

Question 18

What do colon bacteria ferment?

Answer 18

Undigested carbs to short chain fatty acids

Question 19

Describe short chain fatty acids that are fermented

Answer 19

– Soluble and easily absorbed.
– Nutrient salvage
– Evidence obesity associated with biasing microbes to species efficient at nutrient salvage

Question 20

What do colon bacteria produce?

Answer 20

Vitamin K (vital since amount in diet not sufficient)

Question 21

What do colon bacteria increase risistence of?

Answer 21

the intestinal mucosa to colonization with pathogenic microorganism

Question 22

What does colon bacteria produce?

Answer 22

Flatus

Question 23

What is the defecation reflex?

Answer 23

Muscles from the colon move stool towards the rectum

Question 24

What is the function of the pudendal nerve?

Answer 24

controls the movement of your: Anal sphincter muscles, which help you hold in or release feces (poop)

Question 25

What nerves control the descending and sigmoid colon?

Answer 25

Parasympathetic nerve fibers (pelvic nerves)

Question 26

What nerves control the rectum?

Answer 26

Afferent nerve fibers

Question 27

What nervces control the internal anal sphincter?

Answer 27

Parasympathetic nerve fibers

Question 28

What nerves control the external anal sphincter?

Answer 28

Skeletal motor nerves from conscious cortex