CNS Flashcards
0
Q
How may a UMN synapse onto a LMN?
A
Directly or via interneurons
1
Q
Are UMNs inhibitory or excitatory to LMNs?
A
Inhibitory
2
Q
UMNs to LMNs supplying flexor muscles travel in which funiculi of the spinal cord?
A
Lateral
3
Q
UMNS to LMNs supplying extensor muscles travel in which funiculi of the spinal cord?
A
Ventral
4
Q
Which neurotransmitter is present between LMNs and muscle cells?
A
Acetylcholine
5
Q
What is the difference between a reflex and a response?
A
Reflex-innate reaction to a stimulus, is present from birth
Response-a learned behaviour
6
Q
In a LMN injury, what happens to the muscle?
A
Will lose reflexes, will atrophy (lose bulk) and will lose tone
RAT (Reflexes, Atrophy, Tone)
7
Q
In a UMN injury, what will happen to the muscle?
A
Reflexes are normal or increases, as is tone
Any atrophy is mild
Decreased coordination
Normal strength
8
Q
Which tract is known as the pyramidal tract?
A
Corticospinal
9
Q
What does the pyramidal tract enable?
A
Fine, voluntary movements
10
Q
What does the extrapyramidal tract do?
A
Controls posture
Enables subconscious, rhythmic movements
11
Q
What is the function of the cerebellum?
A
Coordinates and integrates sensory input (vestibular) and input from the cerebral cortex
Can’t initiate movement
12
Q
What are the 3 layers of the spinal meninges?
A
Pia mater (inner) Arachnoid mater (middle) Dura mater (outer)
13
Q
What is the foramen magnum?
A
Large hole at base of skull through which spinal cord passes
(Further back in dogs than humans as relates to walking on 4 legs)
14
Q
List the spinal vertebrae
A
Cervical C1-C7 Thoracic T1-T13 Lumbar L1-L7 Sacral S1-S3 Caudal Cd1-Cd5
15
Q
Where is an ideal place for injecting anaesthetic into the spinal cord?
A
Epidural space
16
Q
Where is a good place for sampling CSF in the spinal cord?
A
Lumbar cistern
17
Q
What do somatic motor neurons innervate?
A
Skeletal muscle
18
Q
What do autonomic motor neurons innervate?
A
Cardiac muscle, smooth muscle and glands
19
Q
What kind of neurons do dorsal root ganglions contain?
A
Sensory neurons
20
Q
Which spinal cord segments make up the cervical intumescence?
A
C6-T2
21
Q
Which spinal cord segments make up the thoracolumbar region?
A
T3-L3
22
Q
Which spinal cord segments make up the lumbar intumescence?
A
L4-S3
23
Q
What is a dermatome?
A
An area of skin supplied by nerves from a single spinal root
24
Where do sensory nerve tracts travel?
From the skin and musculoskeletal system to the cerebral cortex (spinocortical)
25
Where do motor nerve tracts travel?
From the cerebral cortex to skeletal muscle (corticospinal)
26
What function does the lateral column of a spinal cord segment have?
Mixed (motor and sensory)
27
What function does the ventral column of a spinal cord segment have?
Motor
28
What function does the dorsal column of a spinal cord segment have
Sensory
29
What does the neural tube give rise to?
CNS (brain and spinal cord)
30
What does the neural crest give rise to?
Cells in the PNS (including dorsal root ganglia, sensory neurones of cranial nerves, autonomic ganglion neurones)
31
How is spina bifida caused, and in which animals is it common?
Failure of caudal fusion of the neural tube (neuropore). Vertebral arches are unfused above the spinal cord.
Common in tailless breeds (eg manx cat, bulldog)
32
What cells is the notochord made up of?
Mesodermal
33
What is glia?
Connective tissue of the nervous system
34
When the neural tube closes, what 3 layers does it consist of?
```
Ventricular zone (innermost)
Mantle layer (forms grey matter)
Marginal layer (forms white matter)
```
35
Which signalling factors do the roof and floor plate each secrete?
Roof plate=BMPs (bone morphogenetic proteins)
| Floor plate=SHH (sonic hedgehog)
36
What does white matter consist of?
Myelinated axons
37
What does grey matter consist of?
Neuronal cell bodies and some unmyelinated axons
38
What are the 2 subdivisions of the dorsal funiculus/column?
```
Gracile funiculus (medial; hindlimb and caudal trunk fibres)
Cuneate funiculus (lateral; forelimb, cranial trunk and neck fibres)
```
39
What does the dorsal horn contain?
Receives axons of both somatic and visceral SENSORY (afferent) neurones
(Cell bodies reside in dorsal root ganglia)
40
What does the ventral horn contain?
Cell bodies of preganglionic autonomic motor neurones (VE)
41
What does the ventral horn contain?
Site of cell bodies of somatic motor neurones (efferent)
42
What are the 3 parts of the brain called during early development?
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
43
Which is the only cranial nerve which emerges dorsally from the brainstem?
Trochlear
44
How is the dura mater attached to the spinal cord?
Cranial end: Attached at the rim of the foramen magnum
| Caudal end: Attached to the dorsal vertebral canal of a caudal vertebra via the filum terminale ligament
45
What is the name of the space between the arachnoid membrane and dura mater?
Subdural space
| Contains a tiny volume of lymph-like fluid
46
What is the name of the space between the arachnoid membrane and the pia mater?
Subarachnoid space
| Filled with circulating CSF and crossed by trabeculae (spider's web appearance)
47
Which of the meninges provides blood supply to the neural tissue?
Pia mater
48
How do the paired lateral ventricles communicate with the third ventricle?
Via the interventricular foramen
49
Which 2 sites are ideal for CSF sampling?
Lumbar cistern
| Atlanto-occipital junction (between atlas and skull)
50
What are the 5 main artery pairs off the cerebral arterial circle?
```
Rostral cerebral
Middle cerebral
Caudal cerebral
Rostral cerebellar
Caudal cerebellar
```
51
What are the 4 possible sources of arterial blood for the cerebral arterial circle?
Internal carotid
Basilar artery
Maxillary artery
Vertebral artery
52
What are the functions of the rete mirabile?
Gives off a vessel which supplies the cerebral arterial circle
Cool blood down
Reduce blood pulsation before it enters the brain
53
How does ritual slaughter affect welfare of cows?
Involves slashing throat with no prior stunning
Sheep-carotids are severed therefore so is maxillary, therefore blood supply to brain is interrupted
Cow-still sufficient blood supply reaching brain from vertebral artery to maintain consciousness for up to 85 seconds afterwards
54
Which (dorsal) sinuses sit within the falx cerebri?
Dorsal sagittal sinus
| Straight sinus
55
Which (dorsal) sinuses sit within the tentorium cerebelli?
Left and right transverse sinuses
56
When the dorsal sinuses join, what do they form?
| What does this do?
Caudal confluence of sinuses
Drains into veins
Connects with the ventral sinus system
57
What do the cavernous sinuses drain into?
Dorsal and ventral petrosal sinuses
58
Where do the confluence of sinuses drain into?
Maxillary veins
Jugular veins
Occipital vein and/or vertebral vein
59
How is the venous system of the CNS a potential route for seeding of tumours and infection?
Blood flow is slow, bilateral and intermittent
60
Where does the optic cup develop from?
Diencephalon (forebrain)
61
Failure of the choroid fissure to close can lead to what?
Haemorrhage and blindness in collies
62
What do rods detect?
```
Low light (night vision)
Black and white
```
63
What do cones detect?
```
Bright light (day vision)
Colour
```
64
Which ares of the eye is the area of greatest visual clarity (acuity)?
Fovea
| Bipolar and ganglion cells are displaced, easier for light to pass through
65
Which cells are present at the fovea?
Cones only
66
What is the ora serrata?
Point where photoreceptors end
67
What 3 processes are involved with image formation?
Refraction of light
Accommodation of pupil
Constriction of pupil
68
How is aqueous humor formed?
Filtration of blood plasma by the ciliary processes.
69
How does fluid return to the circulatory system from the aqueous humour in the anterior chamber?
Via venous plexus at the transition between the cornea and sclera (limbus)
70
What is the function of sclera?
Support layer
Provides strength in all directions
Highly fibrous, elastic, contains loose connective tissue
Continuous with cornea
71
What kind of muscles constrict the pupil?
Circular muscles of iris
72
What kind of muscles dilate the pupils?
Radial muscles of iris
73
What are the 3 kinds of strabismus?
| Which cranial nerve is dysfunctional in each?
Ventrolateral (CN3)
Extorsional (CN4)
Medial (CN6)
74
Which cells are the only special sense receptors that are primary sensory cells and why?
Olfactory receptor cells, as they have their own axons
75
```
Name the stimuli of each receptor type, and give examples of where they're found in the body
Mechanoreceptors
Chemoreceptors
Thermoreceptors
Photoreceptors
Electroreceptors
Magnetoreceptors
Nociceptors
```
Mechanoreceptors: Mechanical; inner ear, skin, muscles, heart
Chemoreceptors: Chemical; mouth, nose, brain, large blood vessels
Thermoreceptors: Temperature; skin, brain
Photoreceptors: Light; eyes
Electroreceptors: Electric fields; skin (fish)
Magnetoreceptors: Magnetic fields; location unknown
Nociceptors: Intense, harmful stimuli leading to pain; most parts of body
76
What do rapidly adapting sensory neurons detect?
Pressure, touch, smell
77
What do slowly adapting sensory neurons detect?
Pain, body position, chemical composition of blood
78
Which receptor cells are abundant in footpads?
Expanded tip receptors
| Ruffini's corpuscle
79
Which receptors are present in each layer:
Epidermis
Dermis
Subcutaneous layer
Epidermis: nociceptors, merkel discs, meissner corpuscles (touch)
Dermis: ruffini corpuscle, pacinian corpuscle
Subcutaneous layer: pacinian corpuscle
80
Give examples of causes of acute and chronic pain
Acute: Cut, puncture
Chronic: Burning, aching, throbbing
81
What is the neurotransmitter released from gate cells?
Enkephalin
82
What is the molecular layer of the cerebellar composed of?
Granule cell axons
| Purkinje cell dendrites
83
What is the lens capsule?
Thick layer of collagen secreted by underlying epithelial cells
84
What is the pinna of the ear made of?
Elastic cartilage
85
What is the function of the middle ear?
Transmit sound waves from outer ear to inner ear
86
What is the function of the ear drum?
Conveys sound vibrations from ear canal to ossicles (small bones)
87
Which cranial nerve crosses the middle ear?
Facial
88
What are the functions of the auditory tube?
Connects nasopharynx to middle ear
| Equalises air pressure on both sides of ear drum
89
Which joints are present between the ossicles?
Synovial
90
What are the functions of the inner ear?
Hearing-converts middle ear vibrations into electrochemical signals
Balance-enable sensing of position of head in space
91
What are the fluids that separate the bony and membranous labyrinths of the inner ear?
Perilymph (outer tube)
| Endolymph (inner tube)
92
Where are the highest frequencies detected in the cochlea?
Close to the round window
93
How is it that the right and left auditory areas of the cortex receive nerve impulses from both sides?
Many auditory axons decussate (cross over) in the medulla
94
Which are the 3 main reflexes that govern posture?
Vestibular reflexes
Tonic neck reflexes
Righting reflexes
95
What is a gait?
A regularly repeating sequence of leg movements
96
Where is the pattern of a gait generated?
Spinal cord
97
What is the difference between a swing phase and a stance phase?
Swing phase= foot is airborne
| Stance phase= foot is in contact with the ground
98
What is an animal's span? What is its stride?
```
Span= distance the body moves while the foot is in contact with the ground
Stride= distance each foot travels between stance phases
```
99
How do you calculate an animal's speed?
Stride frequency x stride length
100
What is proprioception?
The sense of relative position of the body parts in space, and whether/how they are moving
101
What is conscious proprioception used for?
To plan and refine complex, voluntary and learned movements
102
What is subconscious proprioception used for?
To plan and refine movements such as sitting, standing, scratching, chewing, breathing, and basic locomotion
103
What is ataxia?
Alteration in the rate, range and force of movements
104
Dorsal root nerves:
Function?
Contain which fibres?
Innervate structures derived from what?
Mixed function
Contain fibres of SA, AA, AE, SVE
Innervate structures derived from pharyngeal arches
105
Ventral root nerves:
Function?
Contain which fibres?
Innervate structures derived from what?
Motor function
Contain only SE fibres
Innervate structures derived from somites
106
Which cranial nerves are sensory only?
Olfactory, optic, vestibulocochlear
107
Which epithelium covers the tongue?
Stratified squamous
108
What are the 3 types of gustatory papillae?
Vallate
Fungiform
Foliate
109
What are the 3 types of mechanical papillae?
Filiform
Conical
Lenticular
110
The lingual tonsil is made of which kind of papillae?
Conical
111
Which nerves innervate the tongue? (Sensory and taste)
Caudal third: Sensory=glosso-pharyngeal and vagus
Taste=glossopharyngeal and vagus
Rostral two thirds: Sensory=trigeminal mandibular, lingual branch
Taste=chorda tympani of facial, SVA
112
What are tastants?
Chemicals that stimulate gustatory receptor cells
113
Why do foods taste different?
The patterns of nerve impulses in the taste neurons differ, ie patterns of activity code the taste
114
Give the path of the nerve impulses in the gustatory pathway
Tongue -> Medulla oblongata (gustatory nuclei) -> Thalamus, or limbic system and hypothalamus -> Primary taste area in the parietal lobe of the cerebral cortex
115
Fibres leaving the olfactory bulbs travel in which 2 routes?
Subcortical and thalamic-cortical
116
What collective name is given to the regions that make up the 'olfactory brain'?
Rhinencephalon
117
Which area of the brain controls appetite?
Hypothalamus
118
Which modulating signals affect appetite and satiety centre?
```
Glucose
CCK
Gastrointestinal filling
Body fat reserves
Smell
Vision
```
119
What does the limbic system coordinate?
Motivation
Emotion
Homeostasis
120
What is the hippocampus important for?
Memory formation
121
What are the effects of a lesion in the limbic system/forebrain?
What are the clinal signs?
Changes in behaviour and emotional responses, eg changes in personality, attitude, reaction to environment
Clinical signs: pacing, lethargy, depression, destructive behaviours
122
What is epilepsy?
Spontaneous discharge of activity by hippocampal neurons
123
Why can't an animal sleep if hungry or in pain?
Reticular formation neurons receive info from sensory organs and neurons commanding skeletal muscle. Continuous sensory information will cause RF to bombard cortex and keep animal awake.
124
What are the 5 levels of consciousness?
1. Normal
2. Obtunded (dull)
3. Stuporous (sleepy)
4. Comatose
5. Braindead
125
What is the definition of memory?
Storage of information in the nervous system
126
What are the 2 kinds of long term memory?
Procedural- provides info on how something is done with regards to movements. Cerebellum
Declarable- info about what something is and what has happened. Cerebral cortex
127
What are the 3 forms of memory?
Short term
Long term
Working
128
What is the neurotransmitter used in the somatic nervous system?
Acetylcholine
129
What are the 4 stages of anaesthesia?
1. Analgesia
2. Excitement
3. Surgical anaesthesia
4. Medullary depression
Aim is to keep patient in stage 3.
130
How do drugs affect the nervous system?
Influence the transmission of action potentials by:
- Increasing/decreasing amount of neurotransmitter at the synaptic //cleft
- Affecting the affinity of receptor complexes
- Affecting the ion channels
131
The sympathetic nervous system has preganglionic axons from which spinal segments?
Thoracic and lumbar spinal segments
132
Sympathetic supply to the thoracic viscera (lungs, heart) is via which ganglion?
Stellate ganglion
| Formed by fusion of the vertebral ganglia C7-T3
133
Where do parasympathetic pre-ganglionic axons arise from?
Brainstem and sacral spinal segments
134
Parasympathetic system
| In which cranial nerves are the cranial pre-ganglionics?
Cranial nerves 3, 7, 9, 10
135
What are the 2 types of acetylcholine receptors?
Nicotinic and muscarinic
136
In the ANS, what types of acetylcholine receptor is present on:
Post-ganglionic receptor
Target organ receptor
Nicotinic
| Muscarinic
137
Where are alpha 1 and 2 receptors found? What do they cause?
| What is the associated transmitter?
Arterioles and veins
Cause vasoconstriction
Noradrenaline/adrenaline
138
Where are beta 1 receptors found?
What do they do?
What is the associated transmitter?
Cardiac myocytes
Increase heart rate
Noradrenaline/adrenaline
139
Where are beta 2 receptors found?
What do they do?
What is the associated transmitter?
Coronary and skeletal muscle arterioles
Vasodilation
Noradrenaline/adrenaline
140
Where are M2 receptors found?
What do they do?
Transmitter?
Cardiac myocytes
Decrease heart rate
Acetylcholine
141
Where are M3 receptors found?
What do they do?
Transmitter?
Coronary, genital and skeletal muscle arterioles
Vasodilation
Acetylcholine
142
How do drugs affect the nervous system?
Influence the transmission of action potentials by:
- Increasing/decreasing amount of neurotransmitter at the synaptic //cleft
- Affecting the affinity of receptor complexes
- Affecting the ion channels
143
The sympathetic nervous system has preganglionic axons from which spinal segments?
Thoracic and lumbar spinal segments
144
Sympathetic supply to the thoracic viscera (lungs, heart) is via which ganglion?
Stellate ganglion
| Formed by fusion of the vertebral ganglia C7-T3
145
Where do parasympathetic pre-ganglionic axons arise from?
Brainstem and sacral spinal segments
146
Parasympathetic system
| In which cranial nerves are the cranial pre-ganglionics?
Cranial nerves 3, 7, 9, 10
147
What are the 2 types of acetylcholine receptors?
Nicotinic and muscarinic
148
In the ANS, what types of acetylcholine receptor is present on:
Post-ganglionic receptor
Target organ receptor
Nicotinic
| Muscarinic
149
Where are alpha 1 and 2 receptors found? What do they cause?
| What is the associated transmitter?
Arterioles and veins
Cause vasoconstriction
Noradrenaline/adrenaline
150
Where are beta 1 receptors found?
What do they do?
What is the associated transmitter?
Cardiac myocytes
Increase heart rate
Noradrenaline/adrenaline
151
Where are beta 2 receptors found?
What do they do?
What is the associated transmitter?
Coronary and skeletal muscle arterioles
Vasodilation
Noradrenaline/adrenaline
152
Where are M2 receptors found?
What do they do?
Transmitter?
Cardiac myocytes
Decrease heart rate
Acetylcholine
153
Where are M3 receptors found?
What do they do?
Transmitter?
Coronary, genital and skeletal muscle arterioles
Vasodilation
Acetylcholine
