Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Gastrointestinal > General Principles Of GI > Flashcards

General Principles Of GI Flashcards

1
Q

Key sphincters in the GI tract

A

1) Upper esophageal sphincter (UES)
- separates the mouth from the esophagus

2) Lower esophageal sphincter (LES)
- separates the esophagus from the stomach

3) pyloric sphincter
- separates the stomach from the duodenum

4) illocecal sphincter
- separates the terminal ileum from the cecum (beginning of large intestine)

5) internal and external anal sphincters
- both function to separate anus from terminal colon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Esophagus primary function

A

Conduit from the mouth to the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Stomach broad functions

A

Temporarily stores food and also initiates digestion by churning and secreting proteases and acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Small vs large intestine functions

A

Small

  • serves for absorption of nutrients from food
  • aids in digestion with stomach

Large

  • serves as fluid and electrolyte absorption
  • aids in producing and storing fecal matter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Accessory organs in the GI tract

A

Salivary glands

Pancreas

Liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pancreas broad function

A

Secretes digestive enzymes into the duodenum to aid in further break down and nutrient absorption

Secretes HCO3- into the duodenum to neutralize remnant gastric acid from the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Liver broad function

A

Secretes bile which the gallbladder stores for delivery to duodenum when needed in the presence of fatty foods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

General theme of GI wall anatomy

A

Layers (external -> internal)

1) Serosa
2) Muscularis Externa
- outer longitudinal layer
- inner circular layer
3) Submucosa
4) Muscularis Mucosae
5) Mucosa
- Lamina propria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Serosa layer

A

Most superficial layer of the Gut

- Enveloping layer of connective tissue that is made up of squamous epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Muscularis externa layer

A

Consists of two layers and is just deep to the mucosa layer

  • outer externa = outer longitudinal layer
  • inner externa = inner circular layer

Also contains enteric neurons sandwiched between the two muscle layers

  • also called “myenteric (Auerbach)plexus”
  • responsible for peristalsis of the GI tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Submucosa layer

A

Layer of GI tract that is deep to the muscularis externa

  • consists of loose CT and blood vessels
  • also contains glands that secrete material into the GI lumen

Contains the submucosal (Meissener) plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Inner Mucosa layer

A

Consists of epithelium and loose CT called the lamina propria

  • contains capillaries enteric neurons and immune cells
  • also contains microvilli/villi and “crypts/glands”

Also conditions the muscularis mucosae
- thin layer of smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are crypts in the inner mucosa layer of the GI?

A

Invaginated folds of mucosa in the GI tract to increase surface area for digestion and absorption of nutrients/minerals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Enzymes that are found in the mouth and the macronutrients that are digested

A

Salivary amylase
- (a-amylase/ptyallin)

Lingual lipase

Both are used to initiate the breakdown of lipids and carbohydrates for the GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Gastric enzymes and types of macronutrients it breaks down

A

Contains gastric proteases and gastric lipases

  • initiates protein digestion
  • continues fat digestion

does NOT do any carbohydrate digestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pancreatic enzymes include that?

A

Lipase
- essential for final fat metabolism

Chymotrypsin
- essential for final protein metabolism

Amylase
- essential for final carbohydrate metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Small intestine enzymes

A

Disaccharidases
- completes carbohydrate digestion

Dipeptidases
- completes protein digestion

both are found in the brush border of the small intestine and is referred to as “membrane digestion”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Two plexus of the enteric nervous system

A

Submucosal plexus
- found in the proximal small intestines -> terminal large intestines

Myenteric plexus

  • located between circular and longitudinal muscle layers of the muscularis externa
  • found from the proximal esophagus-> the rectum
19
Q

Sensory/Afferent neuron function in the enteric nervous system

A

Monitor changes in luminal activity such as

  • distention
  • smooth muscle tension
  • chemistry (pH/osmolality)
  • levels of specific nutrients
  • levels of mechanical stimulation
20
Q

Is parasympathetics of sympathetics more in control of the GI system?

A

Parasympathetic

21
Q

What induces acinar cells in the pancreas to release bicarbonate and lipase/amylase?

A

Vagus nerve (parasympathetics)

  • vagus stimulation is initiated via*
  • conditioned stimuli
  • chewing
  • swallowing
  • hypoglycemia
22
Q

ANS physiological overview on the GI system

A

Sympathetics/parasympathetics leave via the spinal cord and bind to N2 receptors on the GI tract
- uses ACh as the main neurotransmitter

Sympathetics releases NE and induces GI muscle movements

Parasympathetics binds to muscarinic receptors on the GI system and increases secretion and motility

23
Q

Vasovagal reflex

A

A loop with parasympathetic afferent fibers and the medulla

  • stimulation from chemoreceptors/osmoreceptors and mechanoreceptors in the mucosa go to the medulla and are processed
  • medulla sends stimulation via the vagus nerve back to these receptors and changes things as needed
24
Q

What cells help signal to the pancreas the release of its enzymes via a vasovagal reflex

A

I cells

  • sense FA’s/AA’s and peptides in the duodenum
  • once sensed by I cells, releases CCK to the vagus nerve which in turn stimulates acinar cells in the pancreas to release enzymes and bicarbonate
25
Q

ACh affects on the GI tract

A

Contraction of smooth muscle in walls

Relaxes sphincters

Increases salivary/gastric secretion

Increased pancreas secretion

26
Q

NE effects on the GI tract

A

Relaxation of smooth muscle in the wall

Contraction sphincters

Increases salivary secretion

27
Q

Vasoactive Intestinal Peptide (VIP) effects on the GI tract

A

Relaxation of smooth muscle

Increases intestinal secretion

Increases pancreatic secretion

is co-secreted with VIP

28
Q

Nitric oxide (NO) effects on the GI system

A

Relaxes smooth muscles

29
Q

Gastric-releases peptide/Bombesin effects on the GI tract

A

Releases gastric secretion

arises from vagal neurons in the gastric mucosa

30
Q

Enkephalins (opiates) effects on the GI tract

A

Contraction of smooth muscle

Decreases intestinal secretion

31
Q

Neruopeptide Y effects on the GI tract

A

Relaxation of smooth muscle

Decreases intestinal secretion

32
Q

Substance P effects on the GI tract

A

Contraction of smooth muscle

Increases salivary secretions

con-secreted with ACh

33
Q

ACh and VIP effects

A

ACh

  • binds to M3 receptors and increases IP3/DAG pathway in capillary cells
  • stimulates production of endothelial nitric oxide
  • nitric oxide then binds and activates guanlayte Cyclase (G.C.) which in turn stimulates cGMP production and causes smooth muscle relaxation

VIP
- binds to VIP receptor directly on smooth muscle cells and decrease intracellular calcium levels in the muscles and causes smooth muscle cell relaxation

both result in smooth muscle cell relaxation

VIP is delayed effects, whereas ACh/nitric oxide pathway results in fast dilation

34
Q

Gastrin hormone effects

A

1) Stimulates gastric acid secretion and mucosal growth
2) stimulates gastric release

stimuli is presence of protein in the antrum/duodenum or jejunum, stomach distention.
- also controlled by nerve inputs

Secreted via the G cells of the antrum of the stomach, duodenum and jejunum

negative feedback with acid (prescence of acid in the antrum/duodenum and jejunum inhibit release

35
Q

Cholecystokinin (CCK)

A

1) Stimulates pancreatic enzyme secretion
2) pancreatic bicarbonate secretion
3) growth of gallbladder and exocrine pancreas
4) inhibits gastric emptying

stimuli is the presence of fat/protein and acid in the duodenum, jejunum and/or ileum

Secreted via I cells of the DJ-ill

36
Q

Secretin

A

1) Stimulates pepsin secretion
2) pancreatic enzyme secretion
3) pancreatic bicarbonate secretion
4) stimulates insulin release
5) growth of gallbladder and exocrine pancreas
6) inhibits gastric emptying

  • stimuli is the presence of fat and/or acid in the D.J.-ill

Secreted via the S cells of the D.J.-ill

first GI hormone discovered and is actually the most abundant as well

37
Q

Gastric inhibitory peptide

A

1) Stimulates insulin release
2) inhibits gastric acid secretion

stimulated release in the presence of protein/fat and/or carbohydrates in the duodenum or jejunum

Released via K cells of the duodenum and jejunum

38
Q

Motilin

A

1) Stimulates gastric and intestinal motility
- released in the presence of fat, acid in the jejunum
- also controlled released via nerves

Released from M cells of the duodenum and jejunum

39
Q

What is the only primary GI hormone released in the stomach

A

Gastrin

- from the antrum of the stomach

40
Q

What is the chief immune cell that helps neuroimmune regulation and motor function of the intestines?

A

Mast cells in the lamina propria

41
Q

What does it mean when the GI system has “substantial redundancy”?

A

Control of GI function from both the brain, organs and immune system has many of the same functions. This allows fine tuning of the regulation of digestive processes

Provides backup/fail safe measures in the time of disease for the function of the GI system

42
Q

What types of smooth muscle cells are found primarily in the GI smooth muscle?

A

Unitary smooth muscle cells
- when one is stimulated, all nearby cells will also be stimulated

Permits for coordinated contractions and “slow waves” of action potential.

43
Q

How does unitary GI smooth muscle cells fire together so well?

A

The interstitial cells of cajal (ICC)

- these cells act as pacemakers in the GI specific smooth muscle cells

Gastrointestinal (71 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions