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Flashcards in LS Motility (edited) Deck (37):
1

When does MMC begin?

3-4 hours after a meal

1

where is the MMC active?

mid stomach through the terminal ileum

2

what is the purpose of the MMC?

- housekeeping, sweeps undigested food and bacteria into colon - preventing bacterial growth and damage to villus lining of SI (easy to damage)

3

What stimulates phase 3?

Motilin

4

What happens secondary peristalsis?

Stuck food initiates the enteric system to increase secretions and peristalsis

5

2 types of propulsion involved in swallowing?

Primary and secondary esophageal Peristalsis

6

What stimulates the stomach into a relaxed state to accept food?

Vegal stimulation

7

What else does vegal stimulation do to the stomach beside relaxation?

induces gastric juice secretion

9

Why function does the narrowing of the antrum have?

- enables some mixing and mechanical digestion of chyme (breaks it up). Ensures that food particles are small enough to enter duodenum

10

what is the usual resting potential of muscles in the intestines?

-60mV

10

What are the types of food that take the longest to clear the stomach?

high acidic meals, then lipids

11

What is the underlying nerve function that controls the rate of contraction in GI tract?

Resting memb potential in the form of slow waves

13

rate of slow waves in the stomach?

every 20 seconds * contractions are most likely in stomach than in SI or colon

14

rate of slow waves in the ilium?

12 per minute

14

what is the action potential threshold ?

-40mV

15

Frequency of slow waves in the colon?

1 every 3 hours

16

What type of nerve stimulation induces depolarizaiton?

parasympathetics

17

What controls the force of contraction?

level of depolarization, NOT the slow waves more depolarization above -40, more APs more depolarized AP = stronger contractions

18

What hormone induces depolarization?

Gastrin

19

What functions does gastrin have?

Depolarization of smooth muscles, stimulates HCl secretion

20

What secretes Gastrin and where are they located?

G cell in the antrum and duodenum

22

What are the things that help depolarize the GI muscles?

stretch receptors, parasympathetics, gastrin, seratonin, substance P/tachykinin

22

What hyperpolarizes smooth muscles in the GI?

NE, sympathetics, VIP, NO

23

Another name for substance P

Tachykinin

24

What does aborally mean?

away from the mouth

26

What is the function of segmentation?

movement and mixing of chyme

26

What 2 things stimulate peristalsis?

stretch and parasympathetics

27

during peristalsis, what happens to the muscles behind and ahead the bolus?

behind bolus: muscles get depolarized - contract ahead of bolus: muscles get hyper-polarized - relax

28

Under what control is segmentation?

probably enteric

29

What two controls initiate contraction of the gall bladder?

CCK and vegal stimulation

30

What is the sphincter called at the bottom of the bile duct?

sphincter of oddi

31

What stimulates the relaxation of the sphincter of Oddi?

CCK, vagal

32

What are the longitudinal muscles that propel chyme through the large intestine?

Taenia coli

34

What are mass movements? Cause?

- Periods of hyperpolarization/relaxation in the colon followed by strong peristaltic contractions (making feces to make room for new food) - caused by gastrin and vegal stimulation

35

What is the reflex that induces mass movements?

Gastrocolic reflex - eating more food, trying to push out digested food in colon

36

What is hirshprung's disease?

Inability to relax the internal rectal sphincter, which leads to megacolon

37

How can fever or hyperthyroidism cause diarrhea?

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