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Flashcards in Phys 1 Deck (35)
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1
Q

The ANS consists of motor neurons that:

A
  • Innervate smooth and cardiac muscle and glands
  • Make adjustments to ensure homeostatic environment
  • Operate via involuntary control
  • Have viscera as most of their effectors
2
Q

Role of the Parasympathetic Division

A

“rest and digest”

  1. keeping body energy use low
  2. the D activities: digestion, defecation, diuresis
  3. BP, HR, and RR are low
  4. GI activity is high
  5. skin is warm and pupils are constricted
3
Q

Parasympathetic Division is illustrated by…

A

a person who reads after a meal

4
Q

Role of the Sympathetic Division

A

“fight or flight”

  1. the E activities: exercise, excitement, emergency, and embarrassment
  2. blood flow to organs is reduced, flow to muscles is increased
  3. HR increases, breathing is rapid and deep
  4. skin is cold and sweaty, pupils dilated
5
Q

Sympathetic Division is illustrated by…

A

a person who is threatened

6
Q

Somatic effectors

A

skeletal muscle

7
Q

ANS effectors

A
  1. cardiac muscle
  2. smooth muscle
  3. glands
8
Q

Characteristics of somatic nervous system neurons

A
  • Thick, heavily myelinated
  • One neuron leaves CNS, reaches effector
  • Without ganglia
9
Q

Characteristics of autonomic nervous system neurons

A
  • Preganglionic thinly myelinated
  • Two neuron systems
  • Ganglion
  • Postganglionic neuron usually unmyelinated
10
Q

All somatic motor neurons release…

A

Acetylcholine (ACh), which has an excitatory effect

11
Q

In the ANS, what do the fibers release (preganglionic vs. postganglionic)?

A
  • Preganglionic fibers release ACh

- Postganglionic fibers release norepinephrine or ACh and effect is either stimulatory or inhibitory

12
Q

Comparison of Somatic and ANS

A
  • Higher CNS centers regulate and coordinate both somatic and visceral activities
  • There is overlap and integration of both systems
13
Q

Parasympathetic Outflow

A
  • Cranial outflow via cranial nerves

- Sacral outflow forming splanchnic nerves

14
Q

Parasympathetic cranial outflow - oculomotor (CN III)

A
  • Synapse in ciliary ganglion
  • Sphincter of iris: contraction or miosis
  • Ciliary muscles: contract- accommodation
15
Q

Parasympathetic cranial outflow - facial (CN VII)

A
  1. Pterygopalatine: lacrimal glands-contraction
  2. Sphenopalatine ganglia: nasal glands, nasal mucosa- contraction
  3. Submandibular ganglia: salivary glands (submandibular and sublingual)- contraction
16
Q

Parasympathetic cranial outflow - glossopharyngeal (CN IX)

A

Otic ganglia: parotid salivary glands- contraction

17
Q

Parasympathetic cranial outflow -vagus (CN X)

A
  • 90% of preganglionic PSNS fibers
  • serve neck and organs of thoracic and abdominal cavities
  • via nerve plexuses

*when in doubt, choose vagus.

18
Q

What organs does the parasympathetic cranial outflow go to?

A
  • heart
  • lung
  • gallbladder
  • stomach
  • pancreas
  • SI and proximal colon
19
Q

Parasympathetic cranial outflow: heart

  • locations
  • effects
A
  • SA node, A and V, SA node and Purkinje fibers

- to reduce HR, contractility and conduction velocity

20
Q

Parasympathetic cranial outflow: lung

-effects

A

bronchial smooth muscle contraction

21
Q

Parasympathetic cranial outflow: gallbladder

-effect

A

Contraction

22
Q

Parasympathetic cranial outflow: stomach

-effects

A
  • increase gastric secretions & motility

- relax sphincters

23
Q

Parasympathetic cranial outflow: pancreas

-effects

A

increase secretions

24
Q

Parasympathetic cranial outflow: SI and proximal colon

-effects

A

increase secretions & motility

relax sphincters

25
Q

ParasympatheticOutflow: Sacral

  • origin
  • exit
  • branch
  • synapse
A
  • Originate in lateral gray matter of spinal cord
  • Exit via ventral root
  • Branch to form pelvic splanchnic nerves (which pass thru inferior hypogastric plexus)
  • Synapse in intramural ganglia of organ
26
Q

Parasympathetic sacral outflow: distal colon

-effects

A
  • increase secretions & motility

- relax sphincters

27
Q

Parasympathetic sacral outflow: ureter

-effects

A

Contractions

28
Q

Parasympathetic sacral outflow: urinary bladder

-effects

A
  • detrusor muscle contraction

- relax sphincter

29
Q

Parasympathetic sacral outflow: reproductive organs

-effects

A

clitoris and penis vasodilation

30
Q

Sympathetic outflow - preganglionic fibers arise from…

A
  • All SNS preganglionic fibers arise from preganglionic cell bodies in spinal cord segments T1 – L2 (AKA thoracolumbar outflow)
  • Sympathetic neurons form the lateral horns of gray matter
31
Q

Sympathetic outflow - preganglionic fibers exit…

A
  • SNS preganglionic fibers exit spinal cord via ventral root
  • Pass thru white rami communicans
  • Enter paravertebral ganglia of sympathetic trunk
32
Q

Three possible sympathetic preganglionic pathways

A
  1. Synapse in adjacent ganglion
  2. Ascend or descend to synapse in different ganglion
  3. Exit without synapsing to form splanchnic nerves then synapse in prevertebral ganglia
33
Q

If the SNS preganglionic pathway exits via grey communicans…

A
  • Synapse at local, adjacent ganglion
  • Postganglionic nerve exits with adjacent SN via ramus
  • Distributed to sweat glands, arrector pili MM, and smooth muscle of blood vessels
34
Q

Pathway of sympathetic preganglionic fibers of T1 –T5

A
  • Exit via white communicans
  • Ascend or descend chain to synapse in different ganglion
  • Postganglionic nerve exits with adjacent SN via ramus
  • Serve head, neck, heart, and lungs
35
Q

Pathway of sympathetic preganglionic fibers of T5-L2

A

-Exit via white communicans without synapsing

-These fibers form splanchnic nerves (greater, lesser, and
lumbar)

  • Synapse in a collateral or prevertebral ganglion
  • -Celiac ganglion
  • -Superior mesenteric ganglion
  • -Inferior mesenteric ganglion
  • Postganglionic fiber serves target
  • -Liver, GI tract, kidney, reproductive organs