Lecture 01a: Introduction to the Autonomic Nervous System Flashcards
1
Q
What are the two main functions of the nervous system?
A
- receiving and processing information from the environment
- coordinating and executing appropriate actions in response to stimuli
2
Q
What is the nervous system comprised of?
A
neurons and neuroglia
3
Q
What kind of cells are neurons?
A
excitable nerve cells
4
Q
What kind of cells are neuroglia?
A
non-excitable supporting cells
5
Q
What is the nervous system structurally divided into?
A
the CNS and PNS
6
Q
What makes up the CNS?
A
brain + spinal cord (tracts + nuclei)
7
Q
What makes up the PNS?
A
everything outside of the CNS (nerves + ganglia)
8
Q
What are tracts?
A
white matter components
9
Q
What are nuclei?
A
gray matter components
10
Q
What is the peripheral nervous system divided into?
A
motor (efferent) and sensory (afferent) components
11
Q
What do efferents do?
A
they carry signals from the CNS to muscles and glands
12
Q
What do afferents do?
A
they carry signals from tissues and organs to the CNS
13
Q
What is the motor component of the PNS divided into?
A
somatic and autonomic nervous systems
14
Q
What is the function of the somatic nervous system?
A
it innervates skeletal muscle
15
Q
What is the function of the autonomic nervous system?
A
it innervates smooth/cardiac muscle and most glands
16
Q
What is the autonomic nervous system divided into?
A
the sympathetic and parasympathetic nervous systems
17
Q
What is the sympathetic nervous system?
A
“fight or flight”
18
Q
What is the parasympathetic nervous system?
A
“rest and digest”
19
Q
What are the components of the enteric nervous system?
A
digestive organs only
20
Q
Examples of somatic sensory
A
temperature, pain, touch, pressure, proprioception
21
Q
Examples of visceral sensory
A
heart rate, nausea, hunger
22
Q
Examples of somatic motor
A
contraction of skeletal muscle: movement at joints
23
Q
Examples of visceral motor
A
glandular secretion, vasodilation/vasoconstriction
24
Q
Where does sensory stimuli come from in the visceral nervous system?
A
from the internal environment
25
What kind of motor responses come from in the visceral nervous system?
motor control of smooth and cardiac muscle
26
What are visceral structures?
thoracic, abdominal and pelvic organs
27
Where are the cell bodies found in the somatic nervous system?
the ventral horn
28
Where do the cell bodies exit in the somatic nervous system?
through the ventral rootlet and roots into the spinal nerve
29
What neurotransmitter is released at the neuromuscular junction in somatic efferents?
acetylcholine
30
How does information travel in somatic efferents?
a single axon that goes from the CNS into peripheral tissues to innervate skeletal muscle
31
Where are cell bodies found in the visceral nervous system?
the lateral horn
32
Where do cell bodies exit in the visceral nervous system?
through the ventral rootlets and roots into the spinal nerve
33
Is the preganglionic neuron myelinated or unmyelinated in the visceral nervous system?
myelinated
34
What is released once the preganglionic neuron reaches the autonomic ganglion?
acetylcholine
35
What is activated when acetylcholine is released?
the postganglionic neuron
36
Is the postganglionic neuron myelinated or unmyelinated in the visceral nervous system?
unmyelinated
37
What do postganglionic neurons release when they reach their target muscle?
either acetylcholine or norepinephrine
38
What do visceral neurons innervate?
smooth muscle, cardiac muscle and glands
39
What kind of innervation does the skin and adrenal gland receive?
sympathetic innervation
40
What is another name for the sympathetic division?
thoracolumbar outflow T1-L2
41
What are the 3 characteristics of the preganglionic sympathetic neurons?
(where are their cell bodies found, what are their sizes, what do they release)
1. cell bodies in the lateral horns of the spinal cord
2. short, myelinated axons
3. release acetylcholine
42
What are the 3 characteristics of the postganglionic sympathetic neurons?
(where are their cell bodies found, what are their sizes, what do they release)
1. cell bodies in the sympathetic ganglia
2. long, unmyelinated axons
3. release norepinephrine
43
What are sympathetic chains (paravertebral ganglia)?
interconnected ganglia lateral to vertebral column
44
What are the 3 collateral ganglia?
1. celiac ganglion
2. superior mesenteric ganglion
3. inferior mesenteric ganglion
45
Where are collateral ganglia found?
anterior to the spinal cord
46
What is the exception in the sympathetic division?
the adrenal medulla
47
Why is the adrenal medulla the exception of the sympathetic division?
because it receives direct innervation from preganglionic sympathetic neurons
48
Why does the adrenal medulla receive direct innervation from preganglionic sympathetic neurons?
because it produces norepinephrine itself
49
What are the divisions of the sympathetic system?
1. white ramus communicans
2. grey ramus communicans
3. sympathetic chain
4. splanchnic nerves
50
What passes through the white ramus communicans?
preganglionic neuron
51
What passes through the grey ramus communicans?
postganglionic neuron
52
What kind of axons are found in the sympathetic chain?
ascending/descending axons
53
Where do splanchnic nerves synapse?
in collateral ganglia
54
What happens during sympathetic pathways towards cranial, cervical and thoracic viscera?
preganglionic neurons synapse in superior ganglia of sympathetic chain; postganglionic neurons continue as named sympathetic nerves to target organs
55
What happens during sympathetic pathways towards abdominal and pelvic viscera?
preganglionic neurons pass through sympathetic chain ganglia and create splanchnic nerves; synapse in collateral ganglia then to target organs
56
What do postganglionic sympathetic fibers contribute to?
large visceral plexus near target organs
57
What is another name for the parasympathetic division?
craniosacral outflow (brainstem + S2-S4)
58
What carries the parasympathetic division?
4 cranial nerves + S2-S4
59
What are the 4 cranial nerves used in the parasympathetic division?
CN III, CN VII, CN IX, CN X (3, 7, 9, 10)
60
What nerve is CN III?
oculomotor nerve
61
What nerve is CN VII?
facial nerve
62
What nerve is CN IX?
glossopharyngeal nerve
63
What nerve is CN X?
vagus nerve
64
What are the 3 characteristics of the preganglionic parasympathetic neurons?
(where are their cell bodies found, what are their sizes, what do they release)
1. cell bodies found in the lateral horns of the spinal cord
2. long, myelinated axons
3. release acetylcholine
65
What are the 3 characteristics of the postganglionic parasympathetic neurons?
(where are their cell bodies found, what are their sizes, what do they release)
1. cell bodies found in parasympathetic ganglia
2. short, unmyelinated axons
3. release acetylcholine
66
Where are the visceral ganglia found in the parasympathetic system?
near or within the walls of target organs
67
What are the 5 major functions of the parasympathetic nervous system?
1. salivation
2. lacrimation
3. urination
4. digestion
5. defacation
68
What kind of system is responsible for cutaneous structures like blood vessels, sweat glands and hair follicles?
only the sympathetic nervous system
69
What kind of system is responsible for the dilation of the pupil (increasing the size)?
sympathetic nervous system
70
What kind of system is responsible for the constriction of the pupil (decreasing the size)?
parasympathetic nervous system
71
Does the sympathetic nervous system have single or multiple connections between pre- and post-ganglionic neurons?
multiple connections (widespread influence)
72
Does the parasympathetic nervous system have single or multiple connections between pre- and post-ganglionic neurons?
it has one or two (localized actions)
73
Are visceral afferents part of the autonomic nervous system?
no
74
What do visceral afferents carry?
pain and sensation from organs
75
What is the structure of visceral afferents?
collections of pseudo unipolar neurons with cell bodies in sensory ganglia
76
What are dermatomes?
an area of skin innervated by sensory fibers in a single spinal nerve
77
How are dermatomes distributed?
unilaterally
78
What are the 4 key dermatomes?
C5-T1: upper limbs
T4: nipples
T10: belly button
L2-S2: lower limbs
79
What is the definition of referred pain?
tissue injury/other painful stimulus in one area is perceived as pain elsewhere
80
Why does referred pain happen?
because sensory neurons from visceral and somatic tissues from their dermatomes share similar pathways and may synapse on the same interneurons or higher order neurons
81
Referred pain pattern for the heart
T1-T4
82
Referred pain pattern for the diaphragm/lung
C3, C4, C5
83
Referred pain pattern for the kidneys
T11/T12-L3
