Smith: Visceral Affarents 2014 Flashcards Preview

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

The gut communicates with the (blank)

CNS

2

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

sympathetic; parasympathetic

3

a condition with microbial imbalances on or inside the body

dysbiosis

4

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

nodose; dorsal root ganglia

5

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

vagal; splanchnic

6

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

80%

7

Three pathways connecting the gut to the CNS

1. vagal afferents
2. pelvic afferents
3. splanchnic afferents

8

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

vagal afferents

9

Regulate colon, rectum and internal anal sphincter

pelvic afferents

10

Throughout the GI tract, many are thought to be nociceptive

splanchnic afferents

11

Extrinsic afferents reach the gut via these four nerves

vagus
splanchnic
pelvic
pudendal

12

Differences between a generator potential and an action potential.

1. generator potential does not propagate
2. generator potential is "graded"-->larger when more transmitters are attached
3. no refractory period

13

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

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

14

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

vagal; spinal

15

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

directly

16

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

endocrine cells in the GI tract

17

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

I cells in the duodenum

18

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

S cells of the stomach and intestine

19

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

EE cells

20

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

EC cells

21

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

lymphoid tissue

22

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

splanchnic; vagal

23

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

parasympathetic

24

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

sympathetic

25

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

sympathetic; parasympathetic

26

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

diffuse; localize

27

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

spinal

28

Types of vagal, pelvic and spinal afferents

intramuscular arrays
intraganglionic endings
mucosal intravillous arbors

29

Located within the submucosal and myenteric plexuses
Activate enteric reflexes that regulate motility, secretion, and blood flow

intrinsic primary afferent neurons (IPANs)

30

Two types of extrinsic primary afferent neurons

Vagal afferents
Spinal afferents