Nervous System Flashcards
(138 cards)
1
Q
Functions of the brain
A
Communication - between parts of the body
Regulation - controls everything - heart rate, breathing, gut motility and movement, temperature.
Behavioural - sociatal interaction and with environment
Storage - holds memories, long and short term
Sensations - Pain, touch, temperature and our feelings. Emotional state, arousal, alertness and sleep.
2
Q
What are spinal nerves
A
31 pairs that are named after where they come off the spinal cord
3
Q
What are cranial nerves
A
12 pairs that come off brain and brainstem
4
Q
Define somatic cell
A
cell of the body, not a germline cell
5
Q
Define Visceral
A
internal organs in main cavities of the body
6
Q
what divides the 2 cerebral hemisphere
A
groove called longitudinal fissue
7
Q
what can we call the bumps and grooves in the cerebrum
A
gyri - upwards
sulci - downwards
8
Q
What does the cerebellum control
A
Movement, coordination, precision with integration of sensory systems
9
Q
What does the brainstem contain and control
A
Midbrain, pons and medullla
responsible for breathing and heart rate
any swelling of the brain pressures the brainstem and has an impact on cardio and resp systems - this is called coning
10
Q
What is the telencephalon
A
Cerebrum
11
Q
What is the diencephalon
A
thalamus and hypothalamus
T - relay station of sensory and motor neuronsmonitors sleep and consciousness
H- Regulates endocrine system via pituitary gland
12
Q
What doe the telencephalon and diencephalon make up
A
the forebrain
13
Q
What is the mesencephalon
A
Midbrain
Vision
hearing
motor function
arousal state
14
Q
What is the rhombencephalon
A
Hindbrain
developmental organisation
15
Q
Functions of the frontal lobe
A
executive functions = long term memory
speech
movement
personality
16
Q
fucntions of the parietal lobe
A
sensory integration
language interpretation
spatial/visual perception
17
Q
function of occipital lobe
A
visual processing (colour light)
18
Q
fcuntion of temporal lobe
A
primary auditory cortex
memory
understanding language
19
Q
which lobe is which
A
frontal - anterior
parietal - superior
occipital - posterior
temporal - inferior
20
Q
What are Astrocytes
A
Cells involved in nutrient supply to neurons in the CNS. Structural support and form brain-blood barrier
21
Q
What are Microglia
A
Cells with a defense role: phagocytic
22
Q
What are ependymal cells
A
Cells involved in the production
e.g. cerebrospinal fluid (CSF)
23
Q
What are oligodendrocytes
A
Cells involved in neuronal support and myelin formation in the CNS
24
Q
What are schwann cells
A
Cells involved in neuronal support and myelin fprmation in the PNS
25
Where is the Conus Medullaris
region of spinal cord found Lower end of the spinal cord at L1/2
26
What is the Cauda equina
Nerve rootlets comprised of L2-5. Sits in a space called Lumbar Cistern (formed by subrachnoid space)
27
What is the Pia mater
innermost layer of meninges and is delicate and allows blood to pass through and nourish the brain
28
What is the Arachnoid mater
does not pass into gyri and sulci and sits above blood vessels pressed against the dura
29
What is the dura mater
thick membrane made of dense irregular connective tissue. composes the periosteal and meningeal. Thick dura layer between left and righ cortex is called Falx Cerebri
30
What is the meninges
3 layers that wrap around the brain and spinal cord.
31
What is the Brachial Plexus
Provides motor and sensory information to the upper limb - C5-T1
32
What is the cranial plexus
C1 - C8
33
What are dermatomes
areas of skin supplied by one nerve
34
What are myotomes
Blocks of muscle supplied by motor axons
35
Describe pseudo-unipolar sensory neurons
1 extension from its cells body and splits into 2 branches - one goes peripherally and the other centrally
36
Describe the somatic multipolar motor neuron
single axon and many dendrites - typically motor neurons
37
Describe autonomic multipolar motor neurons
Has a synapse between 2 neurons (within autonomic ganglion)
38
What is the 1st pair of cranial nerves
Olfactory - Smell
39
What is the 2nd pair of cranial nerves
Optic - vision
40
What is the 3rd pair of cranial nerves
oculomotor - eye movements
41
What is the 4th pair of cranial nerves
Trochlear - eye movements
42
What is the 5th pair of cranial nerves
trigeminal - motor to muscles of mastication and general sensory to the face
43
What is the 6th pair of cranial nerves
Abducens - eye movements
44
What is the 7th pair of cranial nerves
Facial - muscles of facial expression
45
What is the 8th pair of cranial nerves
vestibulocochlear - hearing and balence
46
What is the 9th pair of cranial nerves
glossopharyngeal - swallowing, taste
47
What is the 10th pair of cranial nerves
vagus - wandering nerve supplying heart, lungs
## Footnote
gut
48
What is the 11th pair of cranial nerves
spinal accessory - neck muscles
49
What is the 12th pair of cranial nerves
hypoglossal - muscles of the tongue
50
Two types of visceral efferent fibres
sympathetic - thoracumbular T1-L2
parasympathetic - craniosacral S2 - S4
51
Other name for autonmic nervous system
visceral nervous system
52
What is in grey matter of brain
More cell bodies, dendrites
53
What is in white matter of brain
more axons (myelinated), glial cells (oligodendrocytes); blood vessels
54
3 components of brain stem in superior to inferior levels
Mid brain
Pons
Medulla Oblingata
55
What happens if Broca's area is damaged
Impaired speech; still comprehends speech
56
What happens in Wernicke's are is damaged
Fluent speech but no meaning; impaired speech comprehension
57
Function of limbic system
Emotions and e otional behaviour (amygdala)
learning and memory (hippocampus)
58
Fucntions of Basal glanglia
Reward circuit
control of movement
59
Functions of thalamus
sensory relay centre between spinal cord and cerebral cortex
60
Functions of hypothalamus
Temperature regulation; other homeostasis (endocrine gland)
61
Corpus callosum
White matter tracts, communication between two hemispheres
62
Where is sympathetic tone from
nerves T1-12
63
Where is parasympathetic tone from
The cranial nerves and S4
64
What are spinal cord tracts
Bundles of nerve fibres that run up/down spinal cord (rostral/caudral)
- ascending or descending
- autonomicsensory
- motor
in the PNS this is called a nerve not a tract
65
Function of spinothalamic tract
Sensory, pain and temperature
Ascending
66
Function of corticospinal tract
Motor
voluntary movement
descending
67
Define decussate
cross over
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define ipsalateral
same side
69
define contralateral
opposite side
70
What is Dura mater composed of
fibrous connective tissue
71
What are arachnoid and pia maters both composed of
Membrane
72
Where does the two layers of fused dura mater separate
To form venous sinuses for drainage
73
What would cause an epidural potential space to form
Rupture of meningeal arteries - haematoma
74
What would cause a subdural potential space
Bridging veins connecting to venous sinuses ruprure - haemotoma
75
What lies under the arachnoid mater (before pia mater)
Subarachnoid space filled with CSF
cerebral arteries and veins as well as arachnoid connective trabeculae
76
Differences in spinal cord meninges
Dura is 1 layer
Epidural space (not potential!) contains fat tissue and venous plexus
77
What is meningitis
Inflammation of pia mater, arachnoid mater and subarachnoid space
usually viral or bacterial infection
can cause brain damage; cerebral oedema; raised intracranial pressure can cause herniation.
78
Testing for meningitis
Lumbar puncture at L4/5 would show increases WBCs in CSF
done at this level as only risks damage to nerves not cord
79
What fills the ventricles of the brain
CSF
80
Function of CSF
Cushions brain against impact/movement and own weight ('floats')
Provides stable chemical environment for brain
Nutrient & waste exchange between nervous tissue and blood
Age: reduced turnover of CSFmetabolic waste buildup may contribute to neurodegenerative disease
81
Where is CSF produced
By choroid plexus in lateral and 4th ventricles
82
where is CSF resorbed into
venous system
Arachnoid granulations
Circulation is driven by new production
- Excess CSF/flow obstruction - hydrocephalus
83
Composure of CSF
colourless liquid
Very few cells
Similar to plasma but much lower protein' different electrolyte levels (low potassium level for example)
Very few cells
Similar to plasma but much lower protein' different electrolyte levels (low potassium level for example)
84
Describe the blood-brain barrier
Several features that prevent harmful substances getting into brain and spinal cord from blood.
85
capillary components of blood-brain barrier
Capillaries in nervous tissue
- Tight junctions between endothelial cells restrict movement
- Thick continous basement mebrane
- Astrocytes' processes cover vessel
86
Ependymocyte components of blood brain barrier
E cells line ventricles and spinal canal
- Tight junctions restrict movement
87
What are circum ventricular organs
Areas of blood-brain barrier that have a higher permeability
Examples:
Medulla - area postream - vomiting centre detects toxins and initiates vomiting reflex
88
What is an impulse
Wave of altered charge across nerve cell membranethat sweeps alont the axon
AKA depolarisation and action potential
89
Ratios of Chlorine, Sodium and potassium across plasma membrane at resting potential
Cl- : more outside
Na+ : more outside
K+ : more inside
90
What is the refractory period
Time immediately following action potential when a new action potential cannot be initiated in the same are of membrane
91
How does an action potential start
If overall membrane potential reaches threshold volatge (nrormally -55mV)
Multiple inputs from multiple dendrites
- Excitatory pre-synaptic potentials (EPSPs)
- Inhibitory pre-synaptic potentials (IPSPs)
92
What is spatial summation
Summation of inputs from differe areas of cell
ie, from different dendrites
93
What is temporal summation
Input occurs multiple times from the same are/dendrite
Repeated inputs in short time period
APs generated more or less frequently
94
What does the autonomic system control
Cardiovascular
digestion
micturition
stress response
95
What is a ganglion
Connection of nerve endings
juction box
passing of nerve impulses
96
Origin of sympathetic output
Thoracolumbar origins
97
Pre ganglionic synapse neurotransmitter
Acetylcholine
98
Post ganglionic synsapse neurotransmitter
Noradrenaline
99
Physical effects of stress reposne
Eye dilation
dry nose (gets more oxygen)
dry mouth (no saliva)
100
What happens in renal system during stress response
1. Vasoconstriction
2. Increase renin
3. Further vasoconstriction (increases cardiac output)
101
Which ganglia doesnt originate from thoracolumbar region
Cervical ganglia - sweating of head and pupil dilation
102
Post-ganglionic neurotransmitter in sweat glands and deep muscle vessels (not usual)
Acetylcholine
103
Two receptor types in autonomic nervous system
Alpha and Beta
2 of each
104
Describe alpha receptors
Vascular
Alpha 1 - Arteriole constriction
Alpha 2 - Coronary and venous vasoconstriction
105
Describe the beta receptors
Beta 1 - in heart increases HR and contractility
Beta 2 - in Lungs
Uterus and Skeletal muscle blood vessels. Increases relaxation, dilation etc
106
Clinical Example of B2 agonist
Salbutamol - Used in inhalers for asthma, causes relaxtion, also used in premature labour
107
Clinical example of B1 receptor antagonist
Atenolol - Lowers blood pressure, tacchyarrthymia, secondary MI prevention.
Essentially blocks noradrenaline to reduce risk of cardiac failure if heart is sped up too much ???
108
Physical effects of parasympathetic system
Pupillary constriction - improves near vision
Nasal engorement - maximise sensory absorption
Excess salivation
Increases gastric secretions and blood flow
Slows heart rate
Broncho constrictor
Micturatedefecate and ejaculate
109
origins of parasympathetic nervous system
Craniosacral outflow
110
Post and Pre synapse Neurotransmitters of parasympathetic NS
Acetylcholine
111
Cranial nerves involved in parasympathetic NS
3 - Occulomotor (pupillary constriction)
7 - Facial (Salivary glands)
9 - Glossopharyngeal (Saliva)
10 - Vagus nerve (supplies everything else)
112
Ganglia of 3rd cranial nerve
Ciliary Ganglia
113
ganglia of 7th Cranial nerve
Optic
114
Ganglia of 9th cranial nerve
Petrosal ganglia
115
2 receptors of Parasympathetic NS
Muscarinic or Nicotinic
116
Locations of M receptors in Parasympathetic NS
M1 - brain
M2 - heart
M3 - salivary glands, gut, bladder, blood vessel, eye
M4 - brain
M5 - brain
117
Clinical example of M2 receptor antagonist
Atropine - blocks Acetylcholine on heart, increases HR
118
Clinical examples of M3 receptor antagonists
Lungs - Tiotropium / ipratropium
Bladder - Oxybutinin
Gut - Mebervine
Eyes - Pilocarpine
119
Clinical example of M1 receptor agonist
Xanomeline - potential treatment of Alzheimer's and schizophrenia
120
Where are N1 receptors
neuromuscular junctions
121
Describe N2 receptors
Mainly in autonomic ganglia, some in brain
Ganglion blockers
122
Clincial example of N1 agonist
Succinylcholine - Intense relaxation of muscles
Could be used as poison - paralysis
it breaks down so wont be detected
123
Clinical example of N1 antagonist
Bungarotoxin - irreversible muscle relaxation
used to paralyse animals
124
Describe sacral outflow of parasympathetic NS
S2, 3, 4 Innervates from middle of transverse colon
Innervation of genitourinary tract
sexual organs
Some cross innervation with vagus
125
Features of autonomic dysfucntion
Excess salivation
Flushing
excess sweating
Visual disturbances
dread of panic
Wheezing
Erectile dysfunction
126
First sign of coning
Dilated pupil
127
Basilar stroke
Single vessel supply to brain stem
if stroke occurs it can be removed but would result in 'locked-in' syndrome
128
Approxiamate size of synapse
100nm
129
Describe neurotransmitters
Chemical signals that can be excitatory or inhibitory
130
Main excitatory NT in CNS
Glutamate
131
Main inhibitory NT in CNS
GABA
132
Describe Catercholamines
Monoamines derived from Tyr
e.g. dopamine, serotonin
used to treat depression and anxiety
133
Explain GABA binding
When binded to GABA-A receptor (ion channel receptor) it causes a conformational change that opens the ion channel.
Allows Cl- ions into cell
making the inside more negative. Hyperpolarisation - harder to reach threshold voltage for AP formation in post-synaptic cell.
134
How can the signal at a synapse be switched off
Re-uptake transporters
Degradation enzymes
135
Describe the action of acetylcholine at NMJ
ACh binding allows Na+ entry
Na+ influx - depolarisation of muscle cell membrane
Depolarisation initiates contraction
Acetylcholinesterase in cleft removes ACh ('switch-off')
136
Clinical example of Acetylcholine at NMJ
Myasthenia gravis (muscle weakness)
- Autoimmune antibodies attack ACh receptors at NMJ
- Treatment: AChE inhibitors used to enhance NMJ transmission. They block the breakdown of acetylcholine once its been released. This enhances transmission of signal by ACh NT across teh NMJ
137
Describe electrical signalling via gap junctions
Connexin proteins hold two adjacent cells together.
Connexin proteins form connnection with channel
Ions carry charge from one cell to another via diffusion through the channel
Examples: Cardiac Myocytesrare cases where there are 'electrical synapses' between neurons
138
What causes a heartbeat
Electrical impulse travels across heart tissue causing contraction.
Specialised cells with neuron-like properties spread charge
Ion clow between adjacent muscle cells (myocytes)
