L20, 21 & 22: Organisation of the nervous system Flashcards
(150 cards)
1
Q
What are the two components of the central nervous system?
A
Brain and spinal cord
2
Q
What are the to neuron types that make up the peripheral nervous system?
A
Motor neurons and sensory neurons
3
Q
Which part of the nervous system controls voluntary movements?
A
Somatic
4
Q
Which part of the nervous system controls involuntary responses?
A
Autonomic nervous system
5
Q
Which division of the autonomic nervous system controls “rest and digest” functions?
A
Parasympathetic
6
Q
Which division of the autonomic nervous system controls “fight or flight” functions?
A
Sympathetic
7
Q
What areas are innervated by cervical nerves (C1-C8)?
A
Head, neck, upper limb, diaphragm
8
Q
What areas are innervated by thoracic nerves (T1-T12)?
A
Chest muscles and abdominal muscles
9
Q
What areas are innervated by lumbar nerves (L1-L5)?
A
Leg muscles
10
Q
What areas are innervated by sacral nerves (S1-S5)?
A
Bowel, bladder, sexual function
11
Q
What is cranial nerve (I)? What does it innervate?
A
(I) Olfactory
Sensory: Nose
12
Q
What is cranial nerve (II)? What does it innervate?
A
(II) Optic
Sensory: Eye
13
Q
What is cranial nerve (III)? What does it innervate?
A
(III) Occulomotor
Motor: Most eye muscles
14
Q
What is cranial nerve (IV)? What does it innervate?
A
(IV) Trochlear
Motor: Superior oblique muscle
15
Q
What is cranial nerve (V)? What does it innervate?
A
(V) Trigeminal
Sensory: Face, teeth, sinuses, etc.
Motor: Muscles of mastication
16
Q
What is cranial nerve (VI)? What does it innervate?
A
(VI) Abducent
Motor: External muscle
17
Q
What is cranial nerve (VII)? What does it innervate?
A
(VII) Facial
Motor: Muscles of the face
18
Q
What is cranial nerve (VIII)? What does it innervate?
A
(VIII) Vestibulocochlear
Sensory: Inner ear
19
Q
What is cranial nerve (IX)? What does it innervate?
A
(IX) Glossopharyngeal
Motor: Pharyngeal musculature
Sensory: Posterior part of tongue, tonsil, pharynx
20
Q
What is cranial nerve (X)? What does it innervate?
A
(X) Vagus
Motor: Heart, lungs, bronchi, GI tract
21
Q
What is cranial nerve (XI)? What does it innervate?
A
(XI) Accessory
Motor: Sterno-cleidomastoid and trapezius muscles
22
Q
What is cranial nerve (XII)? What does it innervate?
A
(XII) Hypoglossal
Motor: Muscles of the tongue
23
Q
Fill in the gap:
Somatic (voluntary) efferent nerves carry impulses from CNS to __1__ only.
A
skeletal muscles
24
Q
True or false:
There is a third division of the peripheral nervous system (in addition to SNS and ANS) called the enteric nervous system.
A
True
25
Which of the following is/are true of somatic motor neurons?
A. Effector is striated muscle
B. Usually 2 neurons with synapse (ganglion) between
C. Neurotransmitter is always stimulatory
D. Ach and noradrenaline released at synapses
E. No firing at rest
F. Effector at rest is flaccid
A. Effector is striated muscle
C. Neurotransmitter is always stimulatory
E. No firing at rest
F. Effector at rest is flaccid
(B is incorrect because somatic motor pathways use a single motor neuron from spinal cord to target organ; D is incorrect because somatic motor neurons only use Ach)
26
How many neurons are involved in an autonomic motor pathway?
Usually 2 neurons with a synapse (ganglion) between
27
Are neurotransmitters on an autonomic motor pathway stimulatory or inhibitory? Is this the same for somatic?
Autonomic: NTs can be stimulatory or inhibitory (NT's will be either ACh or noradrenaline)
Somatic: NT's always stimulatory (and always ACh)
28
Which motor pathway has baseline firing?
Autonomic.
While the somatic has no firing at rest, the autonomic has baseline firing which speeds up when stimulated.
29
If an effector has an intrinsic resting tone, which motor pathway is it on?
Autonomic
30
What are the names of the two motor neurons used in ANS pathways?
Preganglionic and postganglionic
31
Where is the cell body and axon of a preganglionic ANS motor neuron located?
Cell body (soma) is in the brain or the spinal cord (lateral horns). The axon exits the CNS as part of a cranial or spinal nerve (small diameter type B fibre)
32
Where does a preganglionic ANS motor neurone synapse?
It synapses with a postganglionic neuron at the autonomic ganglion
33
Where is the cell body and axon of a postganglionic ANS motor neuron located?
Whole neuron lies outside the CNS. Cell body is in the autonomic ganglion, axon leaves as a type C fibre, relaying information to visceral effectors
34
Where in the spinal cord would you find preganglionic cell bodies?
Lateral horns of grey matter in the thoracolumbar division (12 thoracic segments and first 3 lumbar segments)
35
In the sympathetic division of the ANS, what are the types of ganglia (synapse regions)?
Two types: Sympathetic trunk ganglia (innervate above the diaphragm) and prevertebral ganglia (innervate below the diaphragm)
36
In the sympathetic division, preganglionic nerves can synapse with how many postganglionic neurones?
20+ (divergence, many sympathetic responses are whole body)
37
In the parasympathetic division of the ANS, what are the types of ganglia (synapse regions)?
Just 1 type: Terminal ganglia (close to effector)
38
In the parasympathetic division, preganglionic nerves can synapse with how many postganglionic neurones?
Only synapse with 4-5 postganglionic neurons, all in the same visceral organ
39
In the parasympathetic division, where do preganglionic neurons originate?
Cell bodies in nuclei of 4 cranial nerves: III (oculomotor), VII (facial motor), IX (glossopharyngeal), X (valgus).
And S2, S3, S4
40
Why is the parasympathetic division very targeted and not controlled by hormones?
You don't want to start switching off organ systems in mass!
41
Which ANS division's preganglionic neurons originate from T1-L2?
Sympathetic
42
Which ANS division's preganglionic neurons originate from cranial nerves III, VII, IX, X and spinal cord segments S2-S4?
Parasympathetic
43
Which ANS division is associated with sympathetic root ganglia and prevertebral ganglia?
Sympathetic
44
Which ANS division is associated with terminal ganglia?
Parasympathetic
45
Which ANS division is associated with ganglia that are close to the CNS and distant from visceral effectors?
Sympathetic (sympathetic trunk ganglia and prevertebral ganglia)
46
Which ANS division is associated with ganglia that are typically near or within wall of visceral effectors?
Parasympathetic (terminal ganglia)
47
Which ANS division is associated with short preganglionic neuron axons, and long postganglionic neuron axons?
Sympathetic
48
Which ANS division is associated with long preganglionic axons and short postganglionic axons?
Parasympathetic
49
Which ANS division is associated with the presence of rami communicantes?
Sympathetic
50
Which ANS division is associated with the absence of rami communicantes?
Parasympathetic
51
Which ANS division is associated with the neurotransmitter acetylcholine?
Both sympathetic and parasympathetic
52
Which ANS division is associated with the neurotransmitter noradrenaline?
Sympathetic
53
Describe the locations of the sympathetic trunk ganglia, prevertebral ganglia and terminal ganglia. Which type of autonomic neurones synapse in each type of ganglion?
Terminal ganglia (parasymp.) are locate near or within their visceral effector. Sympathetic trunk ganglia (symp.) are above the diaphragm. Prevertebral (symp.)are below the diaphragm.
54
Which neurotransmitter would be used by a postganglionic neuron that was stimulating cardiac muscle?
Noradrenaline
55
True or false: A single preganglionic neuron can cause sympathetic innervation of the adrenal medulla
True
56
What neurotransmitter is used by postganglionic neurons in the somatic system?
Trick question! Somatic system only uses one neuron, so there isn't a postganglionic neuron. The somatic neuron use ACh with a nicotinic receptor on the effector.
57
What is the neurotransmitter and receptor used in the ganglia of the autonomic systems?
Sympathetic: ACh, nicotinic receptor
Parasympathetic: ACh, nicotinic receptor
58
In each ANS division, what is the neurotransmitter and receptor used by postganglionic neurons and their effectors?
Sympathetic: Ach for sweat gland innervation; NA for all others (adrenergic receptor).
Parasympathetic: ACh only, with a muscarinic receptor
59
Which receptor is found on all postganglionic cell bodies and the adrenal medulla?
Nicotinic
60
Which receptor is found on all effectors of parasympathetic and sweat glands of sympathetic?
Muscarinic
61
Is noradrenaline (NAd) a neurotransmitter or a hormone?
Both.
NAd can be released as a neurotransmitter or as a hormone by chromaffin cells of adrenal medulla
62
Which type of adrenergic receptor is inhibitory?
A. alpha-1
B. alpha-2
C. beta-1
D. beta 2
B. alpha-2
63
Which type(s) of adrenergic receptor is/are postsynaptic?
A. alpha-1
B. beta-1
C. beta-2
D. All of the above
D. All of the above
64
Which type of adrenergic receptor is associated with renin secretion, hunger, and the heart?
A. alpha-1
B. alpha-2
C. beta-1
D. beta 2
C. beta-1
65
What are some of the key functions performed by the parasympathetic division?
```
SLUDD:
Salivation
Lacrimation
Urination
Digestion
Defecation
```
3 decreases:
Heart rate
Diameter of airways
Diameter of pupils
66
Which ANS division promotes erection of genitals? Which promotes ejaculation and vaginal contractions?
Erection: parasympathetic
Ejaculation/vaginal contractions: sympathetic
67
Children with congential analgesia can't __?__
Feel pain
68
What treatment sometimes works on congenital analgesia?
Naloxone - degrades endorphins to try and restore sensation
69
In what circumstances does naloxone work to help those with congenital analgesia?
When the condition is caused by overproduction of endorphins.
If the problem is caused by a mutation affecting the voltage gated-sodium channels, naloxone wont have an effect.
70
Where does perception take place?
Cerebral cortex
71
True or false: Sensory receptors can detect multiple types of stimulus
False, each sensory receptor responds to only one kind of stimulus (e.g. touch, pain, vision, hearing)
72
What are the special senses?
Smell, taste, vision, hearing, balance
73
What does the term "proprioception" refer to?
Movement and limb position
74
Free nerve endings detect what type of stimuli?
Pain and temperature
75
Encapsulated nerve ending detect what type of stimuli?
Touch (e.g. pacinian corpuscles)
76
Sensory pathways have how many neurones?
3 - a primary, secondary and tertiary neuron
77
Where do nociception, temperature, and coarse touch cross the midline?
In the spinal cord
78
Where do fine touch, proprioception, and vibration cross the midline?
In the medulla
79
In sensory pathways, which neuron carries the impulse across the midline (at either the medulla or in the spinal cord)?
The secondary sensory neuron
80
True or false: All sensory pathways synapse in the spinal cord
False, only the primary and secondary neurons for nociception, temperature and coarse touch synapse in the spinal cord.
Fine touch, proprioception, and vibration synapse in the medulla
81
True or false: All sensory pathways synapse in the thalamus
True. All secondary and tertiary sensory neurons synapse in the thalamus.
82
Where does the tertiary sensory neurone pick up the impulse?
In the thalamus
83
Where does the tertiary sensory neuron take the impulse?
To the primary somatic sensory cortex, where it is processed and a 'feeling' is generated
84
Put these in the order that they would receive a sensory impulse:
Dorsal grey column
Thalamic nuclei
Dorsal root ganglia
1. Dorsal root ganglia
2. Dorsal grey column
3. Thalamic nuclei
85
Sensory receptors produce __?__ potentials
graded
86
Is an action potential graded or not graded?
Not graded.
An action potential is an all-or-nothing impulse
87
What sensory receptor feature is associated with pain, thermal, tickle, itch, and some touch sensations?
Free nerve endings
88
What sensory receptor feature is associated with touch, pressure, and vibration?
Encapsulated nerve endings
89
What sensory receptor feature is associated with special senses?
Separate cells
90
Interoceptors are found:
A. In blood vessels
B. Near the body surface
C. In muscles
D. In the inner ear
A. In blood vessels
91
Which class of receptor provides information about muscle length and tension?
A. Exteroreceptors
B. Interoceptors
C. Proprioceptors
D. Osmoreceptors
C. Proprioceptors
92
How would you recognise that you are in a cold shower? (what type of sensory neurone would detect the stimulus?) Give an overview of the pathway by which the signal would be sent.
Temperature detected by thermoreceptor, sensation transmitted along primary sensory neuron to the dorsal root ganglion, where it is picked up by the secondary neuron, crosses the midline in the spinal cord, and propagated up tot he thalamus where it is picked up by the tertiary neuron and taken to the primary sensory cortex.
93
What does a Merkel disk detect. Is it slow or rapid adapting?
Merkel disk, touch, slow adapting
94
What does a Ruffini corpuscle detect? Is it slow or rapid adapting?
Ruffini corpuscle, touch, slow adapting
95
What does a Meissner corpuscle detect? Is it slow or rapid adapting?
Meissner corpuscle, touch, rapid adapting
96
What does a hair root plexus detect? Is it slow or rapid adapting?
Hair root plexus, touch, rapid
97
What does a nociceptor detect?
Pain
98
What does a pacinian corpuscle detect?
Pressure
99
Which receptor(s) is/are found in the dermal papillae?
Nociceptors (pain), Merkel discs (slow touch), Meissner corpuscles (rapid touch)
100
Which receptor(s) is/are found mid-dermis?
Ruffini corpuscles (slow touch)
101
Where are pacinian corpuscles located?
At the base of the dermis
102
True or false: the CNS interprets signals from all 6 of the skin receptors
True, this is important in order for you to identify the stimuli and coordinate an appropriate response
103
Conscious proprioception for limbs, trunk, neck and posterior head is conducted along which somatic sensory pathway?
Posterior column-medial lemniscus pathway
104
Pain, temperature and itch from the limbs, trunk, neck, and posterior head are conducted along which somatic sensory pathway?
Spinothalamic
105
Neurons of the spinothalamic tract cross the midline in which region?
A. Spinal cord
B. Medulla oblongata
C. Thalamus
D. Primary somatosensory cortex
A. Spinal cord
106
Describe the route of the trigeminothalamic pathway
1. Primary neurons extend into the pons through the trigeminal (V) nerves. Cell bodies are located in the ganglion.
2. Synapse with 2nd order neurons in the pons and medulla.
3. 2nd order neurons cross over and ascend trigeminothalamic tract to the thalamus.
4. 2nd order neurons synapse with 3rd order neurons, which project into cerebral cortex.
107
Which is the only somatic sensory pathway that uses the pons?
Trigeminothalamic
108
What sensations use the trigeminothalamic pathway?
Somatic sensation from face and teeth
109
What causes Wallenberg syndrome?
Stroke
110
In Wallenbergs syndrome, infarction in one side of their brain causes a loss of temperature and pain sensation on the __1__lateral side of their body and __2__lateral side of their face.
1. contralateral
| 2. ipsilateral
111
Syphilis causes debilitating neurological problems by degerating which portions of the spinal column?
Posterior portions
112
Syphilis causes a person to lose somatic sensations, and their gait becomes jerky. Why is this?
Impulses fail to reach the cerebellum
113
The nose contains 10 million to 100 million receptors for the sense of smell in the olfactory epithelium. What does olfactory epithelium consist of?
Olfactory receptors, supporting cells, and basal cells.
114
What are the supporting cells in the olfactory epithelium?
Columnar epithelial of mucous membrane lining the nose
115
What are olfactory basal cells?
Stem cells that can become olfactory receptors or supporting cells. Olfactory receptors live for just 1 month.
116
How does an olfactory receptor generate an action potential?
Odorant molecule binds to protein receptor, ATP converts adenylate cyclase to cAMP, cAMP acts on sodium channel, causing influx that generates potential. Continued influx of Na+ depolarises olfactory cell and triggers action potential.
117
Which of the following are true of olfactory receptors:
A. Have a low threshold
B. Initial adaptation occurs rapidly
C. Slowly adapting after the first second
D. All of the above
D. All of the above
118
What term describes the inability to detect odours?
Anosmia
119
What term describes a decreased ability to detect odours?
Hyposmia
120
What term describes a distorted identification of smell?
Dysosmia
121
What term describes an altered perception of smell in the presence of an odour (usually unpleasant)?
Parosmia
122
What term describes the perception of smell without an odour present?
Phantosmia
123
What term describes the inability to classify or contrast odours, although able to detect odours?
Agnosia
124
What is the function of spinal white matter?
Impulse propagation (contains sensory and motor tracts).
White matter tracts are highways for nerve impulse propagation. Sensory inputs travel along these to the brain; motor inputs travel along these to the effectors
125
What is the function of spinal grey matter?
Integrates incoming and outgoing information.
Integrates excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs)
126
How can you tell whether a spinal tract is motor or sensory?
The name tells you the direction the impulse is travelling. Sensory impulses travel towards the CNS, motor impulses travel away from the CNS.
127
Sensory neurons always go through the __?__ ganglion
dorsal
128
Give the general components of a reflex arc
1. Sensory receptor
2. Sensory neuron
3. Integrating centre (CNS)
4. Motor neuron
5. Effector
129
What does the stretch reflex control?
Muscle length
130
True or false: in the stretch reflex, the effector is the same muscle that stimulated the reflex.
True.
Meanwhile, that muscle's antagonist is inhibited.
131
# Fill in the gaps:
The stretch reflex is a __1__ reflex arc that uses __2__ junctions. __3__ triggers action potential. It is an __4__ reflex, which means the sensory nerve impulse enters the spinal cord on the __5__ side as the motor neurons that leave it.
1. monoynaptic
2. neuromuscular
3. Acetylcholine
4. ipsilateral
5. same
132
At the same time as the stretch reflex, a __?__ reflex arc inhibits the antagonistic muscles.
polysynaptic
133
When a reflex stimulates one muscle and inhibits the antagonistic muscles, it is called __?__ innervation.
reciprocal
| This prevents conflict by opposing muscles
134
What does the tendon reflex control?
Muscle tension, allows relaxation to prevent tendon damage
135
Which is more sensitive, stretch or tendon reflex?
Stretch
Although it is less sensitive, the tendon reflex can override the stretch reflex
136
IS the tendon reflex ipsilateral or contralateral?
Ipsilateral
137
In the tendon reflex, where are the sensory receptors located?
Tendon organs
138
Regarding tendon reflex:
As tension increases, frequency of __?__ impulses increases, relaxing the muscle.
inhibitory
139
Flexor (or withdrawal) reflex is NOT:
A. Contralateral
B. Polysynaptic
C. Intersegmental
D. Linked with crossed extensor reflex
A. Contralateral
Flexor reflex is ipsilateral
140
What is the stimulus and response for the flexor reflex?
Stimulus = pain
Effect: Flexor muscles contract to withdraw from source of pain
141
What other reflex is activated along with the flexor reflex?
Crossed extensor reflex
142
What connects the flexor reflex to the crossed extensor reflex?
Interneurons that cross the midline.
143
Is the crossed extensor reflex ipsi- or contra- lateral?
Contralateral
144
What might be indicated by the absence of a patellar reflex?
(Use patellar reflex test to check stretch reflex)
No response indicates damage to sensory or motor neurons or to the integration centres in 2nd, 3rd, or 4th lumbar segments. Often absent in chronic diabetes.
145
What can the Achilles reflex test indicate?
Tertiary neurosyphilis, diabetes, alcoholism, subarachnoid haemorrhage
146
Why is it hard to test most autonomic reflexes?
It is difficult to stimulate visceral effectors
147
Which autonomic reflex can be easily tested?
Pupillary light reflex
148
Paralysis from the waist down suggests damage to which spinal section?
Lumbar
149
Paralysis from the mid-chest down suggests damage to which spinal section?
Thoracic
150
Paralysis from the neck down suggests damage to which spinal section?
Cervical
