LS Motility (edited) Flashcards

1
Q

When does MMC begin?

A

3-4 hours after a meal

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1
Q

where is the MMC active?

A

mid stomach through the terminal ileum

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2
Q

what is the purpose of the MMC?

A
  • housekeeping, sweeps undigested food and bacteria into colon - preventing bacterial growth and damage to villus lining of SI (easy to damage)
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3
Q

What stimulates phase 3?

A

Motilin

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4
Q

What happens secondary peristalsis?

A

Stuck food initiates the enteric system to increase secretions and peristalsis

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5
Q

2 types of propulsion involved in swallowing?

A

Primary and secondary esophageal Peristalsis

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6
Q

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

A

Vegal stimulation

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7
Q

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

A

induces gastric juice secretion

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9
Q

Why function does the narrowing of the antrum have?

A
  • enables some mixing and mechanical digestion of chyme (breaks it up). Ensures that food particles are small enough to enter duodenum
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10
Q

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

A

-60mV

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10
Q

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

A

high acidic meals, then lipids

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11
Q

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

A

Resting memb potential in the form of slow waves

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13
Q

rate of slow waves in the stomach?

A

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

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14
Q

rate of slow waves in the ilium?

A

12 per minute

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14
Q

what is the action potential threshold ?

A

-40mV

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15
Q

Frequency of slow waves in the colon?

A

1 every 3 hours

16
Q

What type of nerve stimulation induces depolarizaiton?

A

parasympathetics

17
Q

What controls the force of contraction?

A

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

18
Q

What hormone induces depolarization?

A

Gastrin

19
Q

What functions does gastrin have?

A

Depolarization of smooth muscles, stimulates HCl secretion

20
Q

What secretes Gastrin and where are they located?

A

G cell in the antrum and duodenum

22
Q

What are the things that help depolarize the GI muscles?

A

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

22
Q

What hyperpolarizes smooth muscles in the GI?

A

NE, sympathetics, VIP, NO

23
Q

Another name for substance P

A

Tachykinin

24
Q

What does aborally mean?

A

away from the mouth

26
Q

What is the function of segmentation?

A

movement and mixing of chyme

26
Q

What 2 things stimulate peristalsis?

A

stretch and parasympathetics

27
Q

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

A

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

28
Q

Under what control is segmentation?

A

probably enteric

29
Q

What two controls initiate contraction of the gall bladder?

A

CCK and vegal stimulation

30
Q

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

A

sphincter of oddi

31
Q

What stimulates the relaxation of the sphincter of Oddi?

A

CCK, vagal

32
Q

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

A

Taenia coli

34
Q

What are mass movements? Cause?

A
  • 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
Q

What is the reflex that induces mass movements?

A

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

36
Q

What is hirshprung’s disease?

A

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

37
Q

How can fever or hyperthyroidism cause diarrhea?

A

?