GIT motility Flashcards by Iseoluwa Ojo

List the 4 Steps of motility and describe them

Ingestion-taking food into the mouth
Mastication:chewing
Swallowing: degluttition
Peristalsis:wavelike movement through git

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motility In the upper region is controlled directly by—-

CNS

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mixing and slow propulsion is mainly controlled by —-

myogenic, neural, or hormonal mechanism

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electric potentials generated in the git are unique because they have—— that are produced by——

slow waves

interstitial cells of cajal (ICC)

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interstitial cells of cajal (ICC) are located where???

ICC is located between longitudinal and circular muscles

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The ionic basis for the slow waves is ——

Na/K atpase activity

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——acts as a pacemaker of the slow waves

ICC

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Slow waves are also called—-

basic electrical rhythm

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slow waves(basic electrical rhythm) can be propagated over long segments of the tracts owing thanks to ——?

Gap junctions

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Area of the GIT that lack smooth muscle

pharynx, upper one third of esophagus and external sphincter muscle which is striated muscle

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Chewing, voluntary or involuntary

Majorly voluntary

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Swallowing reflex is initiated once food touches the——

posterior wall and soft palate

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swallowing reflex is coordinated by swallowing center in——

medulla and lower pons

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Swallowing involves which cranial nerves

5
9
10
12

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due to the—— nerves, respiration and swallowing are closely integrated

vagal

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Mention the STEPS IN SWALLOWING REFLEX

close nasopharynx

palatopharyngeal fold moves medially
glottis closes larynx and vocal cord
inhibit breathing
open the upper sphincter

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Mention and describe the PHASES OF SWALLOWING

oral : when food touches the receptor

pharyngeal: when breathing is inhibited
oesophageal:primary peristalsis wave is generated

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PERISTALSIS can be initiated by——

distension or irritation

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Mention the Types of esophageal peristalsis waves and what initiates them

primary:
Initiated by swallowing

secondary:
Initiated by presence of food within the gut

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What controls the esophageal peristaltic waves

Primary: vagal nerves
Secondary: INS

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List the types of smooth muscle contractions

PHASIC/RHYTHMIC

TONIC

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Define the types of smooth muscle contractions

Phasic: contraction followed by relaxation

Tonic: maintained contraction

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Common Location of phasic and tonic contractions in the git

Phasic: found in antrum , esophagus and small intestine

Tonic: cardiac sphincter ;lower esophageal sphincter, ileocecal and internal anal sphincter

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Causes of tonic contractions

caused by repetitive spike potentials

-caused by hormones or continuous entry of calcium ions

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Relationship between Ca’s effect om tonic contractions and the smooth muscle‘s membrane potential

Nothing. They are not associated

GIT SMOOTH MUSCLE Function as a syncytium | T/F

A smooth muscle fiber is about —- length and —- diameter

200-500um in length; 2-10um in diameter

Types of electrical waves in smooth muscles

slow waves and spikes

mV range of slow waves is

-70 and -80mV

Slow waves cause contraction and AP | T/F

Threshold for smooth muscle is —-

-40mV

slow waves are depolarized due to influx of—— through—— channels

calcium ions voltage-gated

The calcium binds to what ——-

Calmodulin

``` Frequency of slow waves in : Stomach Ileum Duodenum Proximal colon Distal colon ```

``` 3/min 10/min 12/min 3/hour ; 11/min 10/hour; 17/min ```

Chewing reflex center is coordinated in the —-

Brainstem

Describe achalasia

loss of ENS in the lower part of esophagus

Achalasia always involves——

lower esophageal sphincter

Achalasia. Common or uncommon

Uncommon

What causes Achalasia

No clue

Treatments of achalasia are??

- intervention with nitrites or calcium channel blockers like Isosorbide dinitrite and (nifedipine and Verapamil) respectively are used but with little efficacy - primary treatment is by balloon dilation of cutting up the sphincter called oesophagomyotomy

Negative side effect of oesophagomyotomy

allows gastric reflux

List the 3 main functions of gastric motility

Storage Mixing Emptying

Storage in the stomach is accomplished by 2 mechanism

Receptive relaxation | Accommodation

During storage in the stomach —— enlarges

Fundus(orad ) region

Mixing occurs in the —-region

occurs in caudal region like body and antrum

Mixing results from——

peristaltic waves /contraction

Slow waves in the stomach are due to change in membrane potential from -mV to -mV

30-60mV

Velocity of BER is more in the body or antrum of the stomach

Antrum

—— sphincter ensures a thorough mixing before emptying

pyloric

Gastric emptying usually takes how long

3-4hours after eating

During INTESTINAL MOTILITY , chyme is mixed with ——

Intestinal juice and bile

INTESTINAL MOTILITY propels chyme from —— to——-

duodenum colon

Types of movements associated with intestinal motility

Segmentation : alternate contraction and relaxation Peristalsis Migrating motor complex

Migrating motor complex spread over the intestine during the ——- every —— and lasts for ——-

Interdigestive state 60-90min for 10sec

Which hormones reduces the amplitude of slow waves in the intestine

Secretin and glucagon

Which hormones increase the amplitude of slow waves in the intestine

Insulin, CCK, gastrin, motilin , serotonin

Which hormone controls the migrating motor complex

Motilin

What can cause peristaltic rush

presence of irritants can cause rapid and powerful peristalsis

Major functions of the colon motility

to absorb water and electrolyte from chyme | -to store fecal matter until it can be expelled

Types of movements in colon motility

Peristalsis Haustra shuttling Mass movement

Receiving segment of propulsion: | Propulsive segment of propulsion:

Receiving: long contracts; circular relaxes Propulsing: long relaxes; circular contracts

HIRSCHSPRUNG DISEASE. Congenital or not

Congenital

Describe HIRSCHSPRUNG DISEASE

loss of ENS in distal colon | -involves internal anal sphincter

HIRSCHSPRUNG DISEASE always involves —— sphincter

internal anal sphincter

Effect of drugs in HIRSCHSPRUNG DISEASE

drugs are useless

Effective treatment of HIRSCHSPRUNG DISEASE

-removal of the aganglionic segment usually fixes the issue

Vomiting center is located in the——

medulla

- and - precedes vomitting

Salivation and retching

during retching , contents reach ——because—-

the esophagus but not the mouth of a closed lower sphincter

Factors that can cause vomitting

- presence of irritant in stomach or small intestine - head injury - abnormal stimulation of vestibula organ

——sensed by—— in—— of brain can also lead to vomitting

systemic irritant chemoreceptor trigger zone fourth ventricle

DIARRHOEA occurs when ———through the colon

chyme and faecal matter move too quickly

DIARRHOEA can be due to——- or just——-

irritation of the lower git or a disease nervous stress

Types of diarrhea

Osmotic and secretory

The most common type of diarrhea is ——-

Osmotic diarrhea

Gap junctions are —- resistance pathways

Low

Depolarization phase of slow waves is by -influx Plateau phase is by - influx Repolarization phase is by -efflux

Ca Ca K

Chewing reflex center is in the—-

Brainstem

Swallowing is accelerated by gravity | T/F

Layers of the stomach

Outer long Middle circ Inner oblique

Which has thicker walls? | Orad or caudad region of the stomach

Caudad

Vagotomy aids receptive relaxation. | T/F

Contractions in the stomach increase in strength as they approach the ——

Pylorus

_ is the movement of chyme back from the pylorus to the body of the stomach and back ..to and from

Retropulsion

To enter the duodenum, solids must be reduced to particles of—— or less

1 mm3

Effect of enkephalins and neuropeptides Y in GIT

Opiates: contraction of smooth muscle and decease intestinal secretion Neuropeptides:relaxation of smooth muscle and decrease intestinal secretion

Effect of serotonin on intestinal motility

AIDS peristalsis

In the colon: | Segmentation Contractions is to ——- as mass movement is to ——

Ascending and transverse Transverse and descending

Mass movements occur anywhere from——- times per day.

1 to 3

List the gastrointestinal peptides classified as hormones

CCK secretin Gastrin GIP

Full meaning of GIP

Glucose-Dependent Insulinotropic Peptide

List the gastrointestinal paracrines

Somatostatin and histamine but histamine isn’t a peptide

In between meals —-gastrin is secreted | During meals, ——-gastrin is secreted

G34 | G17

Which amino acids are the most potent for stimulating gastrin

Phenylalanine and tryptophan

Actions of gastrin

It stimulates H+ secretion by gastric parietal cells, and (2) it stimulates growth of the gastric mucosa,

Difference between CCKa and CCKb receptors

CCKA receptors are selective for CCK, while CCKB receptors are equally sensitive to CCK and gastrin.

CCK is secreted in response to triglycerides | T/F

``` Which cells secrete the following Gastrin CCK Secretin GIP Somatostatin ```

``` G I S K D ```

the only gastrointestinal hormone that is secreted in response to all three types of nutrients: glucose, amino acids, and fatty acids is ——?

Glucose-Dependent Insulinotropic Peptide

When is GIP secreted

Only by oral glucose.. not intravenous

Effect of GIP on H+ secretion

Inhibits H+ secretion

Function of pancreatic polypeptide

Inhibits pancreatic secretion of HCO3- and enzymes

Full meaning of GLP | Function of GLP

Glucagon-like peptide | Stimulates insulin production

Examples of Incretins

GIP | GLP

Somatostatin is secreted in the —- and ——

Hypothalamus and delta cells of the pancreas

Effect of opiates and neuropeptides on appetite

Anorexigenic neurons release pro-opiomelanocortin (POMC) and cause decreased appetite; orexigenic neurons release neuropeptide Y and cause increased appetite.

``` Effect of the following on appetite Leptin Insulin GLP-1 Ghrelin Peptide YY ```

``` Decrease Decrease Decrease Increase Decrease ```

GIT motility Flashcards

(107 cards)