Phys 63-64: GI Principles and Propulsion Flashcards

1
Q

GI Wall muscle layers (out to in)

A

1) Serosa
2) Longitudnal
3) Circular
4) Submucosa
5) Mucosa

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2
Q

What happens in a muscle that functions as syncytium

A

Action potential in one area travels in all directions of muscle

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3
Q

Two types of electrical waves in GI muscle

A

Slow wave

Spike

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4
Q

Slow waves are caused by _____

A

Undulating changes in resting membrane potential

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5
Q

Electrical pacemakers of smooth muscle cells aka

A

Interstitial cells of cajal

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6
Q

Ion channels in nerve fibers (which ions?) (in GI*)

A

Calcium-sodium channels

Lots of calcium and sodium

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7
Q

Factors that depolarize GI smooth muscle membrane

A

1) Stretching of muscle
2) Stimulation by acetylcholine
3) Simulation by specific GI hormones

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8
Q

Factors that make GI smooth muscle membrane less excitable

A

1) Norepi/Epi
2) Sympathetic

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9
Q

Calcium ion influx into smooth muscle causes

A

Contraction.

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10
Q

Tonic contraction characteristics

A

Non-rhythmic. Continous and last several minutes-hours

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11
Q

Myenteric vs submucosal plexus

A

Myenteric: GI movement
Submucosal: Secretion

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12
Q

Enterogastric reflexes

A

Intestine tells stomach to chill

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13
Q

Gastrocolic reflex

A

Stomach tells colon to move

(la de hoy empuja la de ayer)

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14
Q

Gastrin secretion site

A

G Cells of antrum

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15
Q

Gastrin action

A

stimulates gastric acid secretion and mucosal growth

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16
Q

Secretin site of secretion

A

S cells

17
Q

Secretin function

A

Stimulates pepsin secretion, pancreas and gall bladder

Inhibits gastrin

18
Q

Glucose-dependent insulinotropic peptide site of secretion

A

K cells (duodenum and jejunum)

19
Q

Glucose-dependent insulinotropic peptide action

A

Stimulates insulin release

Inhibits acid secretion

20
Q

Motilin site of secretion

A

M cells (duodenum and jejunum)

21
Q

Substance secreted due to vagal stimulation of gastric mucosa

A

Gastrin-releasing peptide

22
Q

Cholecystokinin actions

A

Contracts gallbladder, slows gastric emptying. Inhibits apetite

23
Q

Stimulus for peristalsis

A

Gut distention

24
Q

liver sinusoids lined by ______. Function?

A

Reticuloendothelial cells

Funcion is to remove bacteria from portal circulation

25
Q

mechanics of the pharyngeal stage of swallowing:

A

The trachea is closed, the esophagus is opened, and a fast peristaltic wave initiated by the nervous system of the pharynx forces the bolus of food into the upper esophagus

26
Q

Sensory impulses in mouth go to

A

Tractus solitarious

27
Q

Areas in medulla/pons controlling swalloing

A

Deglutition

Swallowing center

28
Q

Primary vs secondary esophagus peristalsis

A

Primary: Follows first wave of food down

Secondary: remaiing food distends esophagus and initiates second wave

29
Q

Waves that mix food in stomach

A

Constrictor waves/ mixing waves

30
Q

Maximum segmental contraction frequency determined by

A

Frequency of slow waves in intestinal wall

31
Q

gastroileal reflex

A

intensifies peristalsis in the ileum and forces the remaining chyme through to large intestine.

32
Q

Longitudnal strips of muscle in colon AKA

A

Teniae coli

33
Q

External anal sphincter controlled by

A

Pudendal nerve

34
Q

Parasympatheic defecation reflex

A

Chyme in rectum stimulates nerves that synapse at spine and then return via pelvic nerves to cause peristalsis

35
Q

Peristalsis during peritonitis

A

Inhibited