Smith: Visceral Affarents 2014 Flashcards Preview

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Flashcards in Smith: Visceral Affarents 2014 Deck (57)
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1
Q

The gut communicates with the (blank)

A

CNS

2
Q

(blank) innervation inhibits peristalsis and secretion, while (blank) innervation stimulates peristalsis and secretion

A

sympathetic; parasympathetic

3
Q

a condition with microbial imbalances on or inside the body

A

dysbiosis

4
Q

Vagal affarents synpase in the (blank), while pelvic afferents synapse in the (blank)

A

nodose; dorsal root ganglia

5
Q

Gastric input to the CNS is represented in the brainstem and thoracic spinal cord by (blank) and (blank) inputs

A

vagal; splanchnic

6
Q

(blank) percent of nerve fibers in the vagus nerve are sensory

A

80%

7
Q

Three pathways connecting the gut to the CNS

A
  1. vagal afferents
  2. pelvic afferents
  3. splanchnic afferents
8
Q

Make up 80% of nerve fibers, signal mainly from upper GI regions

A

vagal afferents

9
Q

Regulate colon, rectum and internal anal sphincter

A

pelvic afferents

10
Q

Throughout the GI tract, many are thought to be nociceptive

A

splanchnic afferents

11
Q

Extrinsic afferents reach the gut via these four nerves

A

vagus
splanchnic
pelvic
pudendal

12
Q

Differences between a generator potential and an action potential.

A
  1. generator potential does not propagate
  2. generator potential is “graded”–>larger when more transmitters are attached
  3. no refractory period
13
Q

The spinal reflex arc that changes activity in an effector (5 steps)

A
  1. visceral afferent neuron plus sensory receptor
  2. interneuron
  3. preganglionic neuron
  4. postganglionic neuron
  5. effector
14
Q

Information about conditions of the gut are signaled through extrinsic (blank) afferents to the brain stem and (blank) afferents to the spinal cord

A

vagal; spinal

15
Q

Mechanical stimuli (stretch, pressure, distortion and shearing forces) can activate spinal, vagal and intrinsic primary afferents (IPANs) (blank) without intermediary cells.

A

directly

16
Q

Function as detectors that analyze luminal contents, survey the mucosal status and activate afferent neurons

A

endocrine cells in the GI tract

17
Q

release Cholecystokinin (CCK) in response to fat and protein digestion

A

I cells in the duodenum

18
Q

release secretin from EC cells in response to duodenal acidification to enhance pancreatic exocrine secretion and bile flow

A

S cells of the stomach and intestine

19
Q

Release ~20 different neuropeptides that can stimulate vagal afferents in a paracrine fashion, or when released into the circulation they can exert an endocrine effect

A

EE cells

20
Q

Mechanical and chemical stimulation releases 5-HT to activate both intrinsic (peristalsis) and extrinsic afferent neurons to cause receptive relaxation of the stomach

A

EC cells

21
Q

includes antigen-sampling M cells, macrophages, eosinophils, neutrophils, and mast cells

A

lymphoid tissue

22
Q

(blank) nerve stimulation elicits severe pain in conscious humans, whereas (blank) nerve stimulation doesn’t produce pain

A

splanchnic; vagal

23
Q

Afferents regulating visceral tone, distension, motility and secretion accompany the (blank) efferent nerves

A

parasympathetic

24
Q

Most visceral afferent nerve fibers mediating sensation and nociception (pain) accompany the (blank) nerves

A

sympathetic

25
Q

Bottom line: (blank) afferent nerve fibers cause pain, (blank) afferent nerve fibers do not.

A

sympathetic; parasympathetic

26
Q

There are many more mechanosensory neurons than visceral sensory neurons, so visceral sensations are (blank) difficult to (blank).

A

diffuse; localize

27
Q

(blank) afferents are considered to convey to the CNS the sensations of discomfort and pain.

A

spinal

28
Q

Types of vagal, pelvic and spinal afferents

A

intramuscular arrays
intraganglionic endings
mucosal intravillous arbors

29
Q

Located within the submucosal and myenteric plexuses

Activate enteric reflexes that regulate motility, secretion, and blood flow

A

intrinsic primary afferent neurons (IPANs)

30
Q

Two types of extrinsic primary afferent neurons

A

Vagal afferents

Spinal afferents

31
Q

Activated by mechanical, thermal and chemical stimuli

Cell bodies in nodose ganglion and central terminals to brainstem nucleus tractus solitarius

A

vagal afferents

32
Q

Activated by low and high intensity chemical stimuli
Cell bodies in DRG and central terminals in superficial dorsal horn of spinal cord
Convey info about painful stimuli

A

spinal afferents

33
Q

EC cells can release (blank) which can activate the vomiting center via vagal afferents directly, vagal afferents to the area postrema, or through the bloodstream to the area postrema

A

5HT

34
Q

a type of chronic inflammatory bowel disease. It involves the formation of areas of patchy inflammation, primarily in the small intestine (terminal ileus) but sometimes in other parts of the digestive tract

A

Crohn’s disease

35
Q

a form of IBD in which the inflammation is limited to the large intestine

A

Ulcerative colitis

36
Q

T/F: irritable bowl syndrome = IBD

A

FALSE, While IBS can be painful, it doesn’t lead to other health problems or damage the GI tract

37
Q

Inflammation sensitizes responses to gastric distension

A

visceral hyposensitivity

38
Q

Following injury, there is complex sensitization of pain (nociceptive) fibers caused by a (blank)

A

inflammatory soup (bradykinins, histamine, prostaglandins, substance P)

39
Q

Sensory (blank) channels sense how hot or mild different foods are.

A

TRP

40
Q

exaggerated pain in response to a painful stimulus

A

hyperalgesia

41
Q

pain in response to an innocuous stimulus

A

allodynia

42
Q

Sensitization of peripheral visceral sensory neurons is defined by an increase in the number of (blank) triggered by a stimulus, a decrease in the (blank) required for AP generation, and a lowering of the (blank) for AP generation

A

action potentials; stimulus intensity; threshold

43
Q

Sensitization of peripheral visceral sensory neurons may be associated with increase or change in (blank) release at central synapses or enhanced response of postsynaptic neurons

A

transmitter

44
Q

Sensitization of central visceral sensory neurons is associated with (blank) in response magnitude of central neurons, (blank) in size of are of referred sensation, and (blank) excitability of spinal neurons.

A

increase

45
Q

both somatic sensory fibers and visceral sensory fibers have the cell bodies in the same dorsal root ganglion and synapse on the same second-order neurons in the spinal cord causing (blank)

A

referred pain

46
Q

T/F: Visceral organs, such as the bladder and colon, can become cross-sensitized

A

True

47
Q

Theory attempting to explain why thoughts and emotions influence pain perception

A

gate control theory of pain

48
Q

Used to manage gut pain and can relieve diarrhea

A

opioids

49
Q

Some patients with inflammatory bowel disease (IBD) anecdotally report that they experience relief by smoking marijuana. What endogenous ligand is at work here?

A

cannabinoids

50
Q

T/F: Low innervation density and polymodal character of visceral sensory neurons explain the poor discriminatory ability of sensory input

A

true

51
Q

Convergence of different afferent input to higher order sensory neurons is responsible for (blank) pain

A

referred

52
Q

(blank) of sensory pathways during acute episodes of gastroenteritis contributes to the development of postinfectious functional GI disorders

A

sensitization

53
Q

Most gastric ulcers caused by a bacterial infection, usually (blank)

A

H. pylori

54
Q

Emesis occurs as a result of (blank) acting on nerves from the intestines to the vomiting center in the brain

A

5HT

55
Q

Detect stretch; are supplied by vagal afferents and innervate the smooth muscle layers of the GI tract

A

intramuscular arrays

56
Q

Detect mechanical changes; are supplied by vagal afferents and innervate

A

intraganglionic endings

57
Q

Sensitive to luminal chemicals and selective responses to fine tactile stimulation

A

vagal mucosal afferents