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GI > Physio - GI motility (edited) > Flashcards

Physio - GI motility (edited) Flashcards

0
Q

How are smooth muscle cells in GI tract functionally coupled?

A
  • are connected by nexus that allow fast communiction bw cells and enables them to contract together
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1
Q

2 different types of contraction of GI tract

A
  1. Phasic– Short contraction (peristalsis) 2. Tonic– Can last for hours until inhibited (sphincters)
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2
Q

T/F. Chewing is both voluntary & reflexive.

A

TRUE (stretch reflex) *we dont have to continuously think about chewing when eating

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3
Q

3 Functions of chewing

A
  1. Break down food 2. Lubricate with saliva 3. Increase surface area for chemical digestion
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4
Q

When bolus contacts the back of the pharynx, ________ contract.

A

Superior constrictor muscles -> afferent innervation sends signal to swallowing center in medulla -> sends efferent signals via nonvagal nuclei to contract muscles of pharynx & esophagus

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5
Q

As food moves through pharynx, ____ is closed off by epiglottis & bolus enters the _____.

A

Trachea; esophagus *Peristaltic movement is initiated in esophagus

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6
Q

The esophagus closes once bolus has passed through to prevent _____.

A

Reflux of material back into esophagus *Inferior constrictor muscles

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7
Q

Upper esophageal sphincter pressure is greater/less than atmospheric pressure.

A

Greater.

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8
Q

Below UES through diaphragm, the pressure is greater/less than atmospheric pressure.

A

Less. *thorax has negative pressure

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9
Q

Below diaphragm, the pressure is greater/less than the atmospheric pressure.

A

Greater.

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10
Q

Primary peristalsis

A

Initiated by a swallow

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11
Q

Secondary peristalsis

A

Not initiated by a swallow e.g. to clear any residual obstructions not cleared by the primary peristaltic wave

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12
Q

Gastric Esophageal Reflux Disease (GERD)

A

Acid reflux from stomach into esophagus - mucosa of stomach is unaffected by acid but the esophagus is susceptible to acid damage. *heart burn

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13
Q

Some causes of GERD

A

Hiatal hernia Pregnancy Failure of secondary peristalsis

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14
Q

Orad area of the stomach

A

Few & weak contractions Primary function is storage Contains oxyntic glands

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15
Q

Pyloric gland area of the stomach

A

Very strong muscular contractions

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16
Q

Achalasia

A

Due to absence of ganglion in esophagus that contains VIP. Becomes contracted and material doesn’t move through it. Also possible in colon.

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17
Q

Functional areas of the stomach

A

Orad (oxyntic gland) and Antrum.

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18
Q

Where in the stomach has NO contractions?

A

Fundus

19
Q

Reflexive relaxation

A

Drop in fundus pressure allows the stomach to receive food Vago-vagal reflex -> VIP release causes NO release -> relaxation of the stomach

20
Q

Gastric motility contraction increases/decreases in strength and rate as it goes distally

A

Increases

21
Q

Gastric slow wave

A

Sets the maximum rate of contraction rate of the stomach 3-5 contractions/min **cannot be changed

22
Q

What creates the slow wave potentials in the stomach?

A

Interstitial cells of cajal.

23
Q

Amplitude of the wave is regulated how?

A

neural & hormonal activity *determines the strength of the contraction

24
Q

Which empties faster from stomach? Liquid or solid?

A

Liquid. DUH!!! Also greater the volume, the more rapid the rate of emptying.

25
Q

What empties fastest? Hypotonic, isotonic, or hypertonic?

A

ISOTONIC Saline Hypo-hypertonic inhibit emptying

26
Q

Acid stimulates/inhibits emptying.

A

inhibits *needs time to neutralize before entering the gut

27
Q

Why does fat take longer to empty from stomach?

A

Not water soluble -> longer to digest Triggers CCK release -> slows down gastric emptying

28
Q

Failure to empty in stomach can be caused by…

A

Vagotomy (no vago-vagal reflex to cause peristalsis) Obstruction (ulcer or cancer)

29
Q

Symptoms of failure to empty

A

Fullness, loss of appetite, and nausea

30
Q

Increased emptying can be caused by…

A

Inadequate regulation

31
Q

Symptoms of increased emptying

A

diarrhea duodenal ulcer

32
Q

Almost all significant absorption occurs where?

A

Small intestine -> very slow progression through small intestine

33
Q

Motor patterns of small intestine

A

Segmentation Peristalsis

34
Q

Motilin release is stopped when?

A

Once feeding begins -> causes migratory motor complex to halt

35
Q

Intestinal contraction requires ___ on slow waves.

A

Spikes!!! *no contraction without spike Like the stomach, the frequency of slow waves do not change, but the frequency of the spiking can change!

36
Q

There is no change in amplitude of the contractions in small intestine/stomach.

A

Small intestine!!! Only the frequency of spiking changes

37
Q

Max frequency of contraction in S.I. is greater proximally/distally.

A

Proximally *decreases distally

38
Q

Function of the colon

A

Fluid & electrolyte absorption

39
Q

Colon is innervated by…

A

Vagus n. til 2/3 transverse colon The rest is innervated by pelvic n.

40
Q

Ileocecal sphincter is the junction btw

A

Ileum & Cecum

41
Q

If ileum is distended, what happens to the ileocecal sphincter?

A

Relaxes and allows material into colon from ileum

42
Q

What happens to the ileocecal sphincter if colon is distended?

A

Ileocecal valve contracts and prevents reflux of material from colon into small intestine.

43
Q

Ileocecal sphincter normally has what type of contraction? Tonic or phasic?

A

Tonic! Not vagal.

44
Q

What is the cause of the urge to poop?

A

2-3 times a day, haustrations in portions of colon disappear and cause peristalsis Also Rectum contracts and internal rectosphincter relaxes

45
Q

What type of movement does the colon have?

A

MASS MOVEMENT

46
Q

If conditions are not right for defecation, what happens?

A

External sphincter contracts and prevents defecation. Innervation via dorsal segments (pudendal n.)

GI (40 decks)

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