Neurotransmission Flashcards

Question

What are the roles of hairs?

Answer 1

Hair cells Inner Hair Cells- Mechanical transduction Outer Hair Cells- fine tuning Base attached to basilar membrane Stereocillia anchored to tectorial membrane. Shearing forces at the stereocillia

Answer 2

Displacement of the basilar membrane causes movement of specialized mechanical transducing cells

Answer 3

Endolymph - stereocilium (K+) Perilymph - Afferent and efferent - blood? (Depolarize here - Ca 2+)

Answer 4

Movement of the sterocillia Rapid response required Mechanically gated K+ channels opened causing depolarization ( K+ rich endolymph) Depolarization results in opening of voltage gated Calcium channels Release of neurotransmitter- Glutamate (plus others) Repolarization through K+ efflux ( into K+ poor perilymph)

Answer 5

Each nerve responds maximally at a specific frequency. But our ability to discriminate different frequencies is not fully explained by this theory. Outer Hair Cells can alter the stiffness of the basilar membrane to ensure maximal stimulation at one site and dampened response at another. Increased resolution

Answer 6

Sound analysed to encode in formation for neural transmission FREQUENCY (PITCH) Encoded in nerves by location along the basilar membrane INTENSITY (LOUDNESS) Encoded in nerves by numbers responding and by firing rate SOUND TRANSDUCTION Inner Hair Cells (and OHCs) AMPLIFICATION Outer Hair Cells

Answer 7

Auditory fibre – spiral ganglion. Spiral Ganglion to Cochlear nerve ( VIII) Central auditory pathway

Answer 8

Cochlea -> 8th nerve -> 2. cochlear nucleus -> 3. superior Oliver’s complex -> 4. lateral leminiscus - 5. inferior colliculus -> medial geniculate body -> auditory cortex Numbered - unsure of order - check!!!!

Answer 9

Sound Localization...

Answer 10

Sound source Sound wave Rough estimate of ITD Left, right ear arrival time Perceived azimuth in this case

Answer 11

MSO neurons are coincident detectors responding to only when excitatory signals arrive simultaneously Anatomically differences in connectivity allow each MSO neuoron to be sensitive to sound source from particular location 1. Sound reaches left ear first 2. Action potential begins travelling toward MSO 3. Sound reach right ear a little later (at right ear) 4. Action potential from right ear begins travelling toward MSO (at right ear) 5. Action potentials converge on an MSO neuron that responds most strongly of their arrival is coincident (middle)

Answer 12

Eighth Nerve Cochlear Nucleus Olive Lateral Leminiscus Inferior Colliculus

Answer 13

Defective outer/middle ear =CONDUCTIVE HEARING LOSS Defective Inner Ear = SENSORINEURAL HEARING LOSS

Answer 14

Treatment depends on the cause...Improve conduction Improve amplification - hearing aids

Answer 15

Stimulate e.g. auditory brainstem implant - stimulus cochlear nucleus

Answer 16

Neurones and glia Differentiated glia: - oligodendrocytes - microglia - Astrocytes Others e.g. glial stem cells, oligodendrocytes precursors, ependymal cells

Answer 17

Specialised for electrical signalling • Inputs via dendrites • Action potentials propagate along the axon from the axon hillock • Mainly formed during development

Answer 18

Tissue sections can be stained with histological stains • e.g. H&E: - Haemotoxylin, stains nucleic acids blue - Eosin – stains proteins red

Answer 19

Neurons communicate via synapses - 2 types • Chemical – majority – via neurotransmitters (glutamate, GABA, dopamine, serotonin, etc.) • Electrical – less abundant – via direct flow of ions - enable synchronized electrical activity, e.g. brainstem (breathing) & hypothalamus (hormone secretion)

Answer 20

Neurons communicate via synapses - 2 types • Chemical – majority – via neurotransmitters (glutamate, GABA, dopamine, serotonin, etc.) • Electrical – less abundant – via direct flow of ions - enable synchronized electrical activity, e.g. brainstem (breathing) & hypothalamus (hormone secretion)

Answer 21

On dendritic spines ER in spines - some proteins are made in spine

Answer 22

Neural plasticity - changes in neuronal/synaptic structure and function in response to neural activity - basis of learning and memory • Spines are dynamic structures – number, size, composition • Spine remodelling linked to neural activity • Relevant to disease – e.g. schizophrenia & Alzheimer’s - ↓spine density

Answer 23

Neurons differ in their: • Size • Morphology • Neurotransmitter content • Electrical properties • E.g. neocortex (right)

Answer 24

Betz cells = upper motor neurons – large, excitatory (glutamatergic,) long projections, pyramidal cells • Vulnerable in MND Medium spiny neurons = striatal interneurons – small, inhibitory (GABAergic) • Vulnerable in Huntington’s disease

Answer 25

E.g. cerebellar purkinje cell

Answer 26

Myelinating cells of the CNS • Unique to vertebrates • Myelin insulates axon segments, enables rapid nerve conduction • Myelin sheath segments interrupted by nodes of Ranvier – saltatory conduction • Provide metabolic support for axons

Answer 27

Formed by wrapping of axons by oligodendrocyte processes (membranes) • Highly compacted – 70% lipid, 30% protein • Myelin specific proteins, e.g. myelin basic protein (MBP) can be used as “markers”

Answer 28

Resident immune cells of the CNS • Originate from yolk sac progenitors that migrate into the CNS • “Resting” state, highly ramified, motile processes survey environment (2-3 μm/min) • Upon activation (e.g. by ATP), retract processes, become “amoeboid” & motile • Proliferate at sites of injury - phagocytic

Answer 29

Immune surveillance • Phagocytosis – debris/microbes • Synaptic plasticity – pruning of spines • “Bad” (M1) & “good” (M2) microglia

Answer 30

Star-like cells” • Most numerous glial cells in the CNS • Highly heterogeneous – not all star-shaped • Common “marker” glial fibrillary acidic protein (GFAP)

Answer 31

Anti-GFAP immunostaining for astrocytes – cell bodies & processes coating capillaries Dual immunostaining with second astrocyte marker AQP4 reveals more of the vascular network: GFAP Aquaporin 4 (water channel – necessary due to the blood- brain barrier – see later)

Answer 32

Structural - define brain micro-architecture • Envelope synapses – “tripartite synapse” – buffer K+, glutamate, etc. • Metabolic support – e.g. Glutamate-Glutamine shuttle • Neurovascular coupling – changes in cerebral blood flow in response to neural activity • Proliferate in disease = gliosis or astrocytosis

Answer 33

Radial glia – important for brain development Bergmann glia (cerebellum) - green Muller cells (retina)

Answer 34

Motor neurone disease – adult-onset neurodegenerative disease characterised by loss of upper (motor cortex) and lower (spinal cord) motor neurones • Multiple sclerosis – autoimmune demyelinating disease where immune cells attack the myelin sheath of oligodendrocytes 25

Answer 35

Abundance of neuronal cell bodies in nuclei • Axons gathered into tracts • Tracts that cross midline = commissures • Grey matter abundant in neural cell bodies & processes – neuropil contains few cell bodies • White matter contains abundance of myelinated tracts & commissures

Answer 36

Cell bodies & supporting cells located in ganglia – e.g. dorsal root ganglia (DRGs) • Axons bundled into nerves • Many PNS axons are enveloped by Schwann cells (myelinating cells of the PNS – neural crest derived c.f. oligodendrocytes, derived from CNS- resident neural progenitors)

Answer 37

• Dyes injected into blood penetrate most tissues, but not the brain • Dyes injected into CSF – brain stains → specialised blood-brain barrier • Formed by endothelial cell tight junctions, basement membrane (few fenestrations), astrocyte end feet & pericytes (contractile, aid blood flow) • Sensitive to inflammation, hypertension, trauma, ischaemia • Problem for drug delivery!

Answer 38

CSF also drains via perineural routes and via meningeal lymphatics

Answer 39

Epithelial-like, line ventricles & central canal of spinal cord • Functions - CSF production, flow & absorption • Ciliated – facilitates flow • Allow solute exchange between nervous tissue & CSF

Answer 40

Frond-like projections in ventricles • Formed from modified ependymal cells - villi form around network of capillaries → highly vascularised with a large surface area • Main site CSF production by plasma filtration driven by solute secretion • Gap junctions between ependymal cells form blood- CSF barrier

Answer 41

Neurons are highly specialised, heterogeneous cells which are supported by glia • Patient symptoms typically reflect loss of neuronal function

Answer 42

• Glia are important in health and disease: - initiation of disease (e.g. multiple sclerosis) - progression of neurodegenerative diseases (e.g. MND) - research as alternative target for therapy

Answer 43

Cognitive analyses - frontal cortex - response suppression Context - hippocampus and septum - amygdala - conditional emotional responses Complex neutral stimuli - sensory cortex - amygdala - conditional emotional responses Neutral stimuli - thalamus - amygdala - conditional emotional responses Species specific threat stimuli - midbrain and hypothalamus - species specific responses (freeze/flight/fight) Sudden distal stimuli - hindbrain - startle response Noxious or contact stimuli - spinal cord - reflexive withdrawal All stimuli - sensory input - leave as a motor, autonomic and endocrine output

Answer 44

Brain, spinal cord (skull?)

Answer 45

Somatic nerves system - interacts with the external environment: Skin muscles, joints, eyes, ears etc (Afferent nerves - sensory signal)-> CNS Opposite way = efferent nerves (motor command) - from CNS

Answer 46

Autonomic nervous system (unconscious/automatic): Internal organs -(afferent)—> CNS Opposite - efferent Regulates body’s internal environment

Answer 47

Division located outside of skull and spine

Answer 48

Cervical region - head and neck, diaphragm and arms and hands Thoracic region - chest muscles, breathing and abdominal muscles Lumbar region - legs and feet Sacral region - bowel bladder control, sexual functions

Answer 49

Dorsal RootAfferent (affected by the world) Ventral Root RootEfferent (having an effect on the world) [MOTOR]

Answer 50

Forebrain - telencephalon and diencephalon Midbrain - mesoncephalon Hindbrain - metencephalon and myelencephalon

Answer 51

Telencephalon - Cerebral cortex, basal ganglia and limbic system Diencephalon - thalamus and hypothalamus

Answer 52

Tegmentum and tectum

Answer 53

Metencephalon (pons, cerebellum) Myelencephalon (medulla)

Answer 54

Old brain, involved in autonomic and low level sensorimotor control Medulla (myelencephalon): Contains tracts carrying signals between the rest of the brain and the body. Contain caudal part of the reticular formation ("little net"): low level sensorimotor control – e.g. balance Involved in variety of vital functions: Sleep/Wakefulness Motor Plant: movement, maintenance of muscle tone Various cardiac, circulatory, respiratory, excretory reflexes

Answer 55

- Relay from cortex and midbrain to the cerebellum - Contains millions of neuronal fibers - Pontine reticular formation (pattern generators) – e.g. for walking

Answer 56

Smaller than the brain but contains as many neurons as all the rest of the CNS. “Motor errors” between intended movement and actual movement – adjusts synaptic weights to eliminate error. Online correction can take place during the movement : motor learning. Thought exclusive for motor coordin-ation – recently implicated in cognitive and affective/emotional function. [‘hijacked’ for its computational power??]

Answer 57

Tectum – visual/spatial and auditory frequency maps Also called: colliculi ("little hills") Superior Colliculus - Sensitive to sensory change – orienting/defensive movements Inferior Colliculus - Similar, but for auditory events

Answer 58

Three colourful structures - The Periaqueductal Gray - red nucleus - Substantia nigra

Answer 59

Role in defensive behavior Role in pain (ascending and descending signals) Role in reproduction From tegmentum

Answer 60

- target of cortex and cerebellum projects to spinal cord - Role in pre-cortical motor control (especially arms and legs) From tegementum

Answer 61

- Substantia nigra pars compacta (Dopamine cells) – basal ganglia, Input…Parkinson’s disease - Substantia nigra pars reticulata – basal ganglia output part of basal ganglia)

Answer 62

Relay structure from diencephalon Specific nuclei : relay signals to cortex/limbic system for all sensations (but smell...). Non-specific nuclei : Role in regulating state of sleep and wakefulness and levels of arousal Important relays from basal ganglia and cerebellum back to cortex

Answer 63

From diencephalon - Regulates the pituitary gland which regulates hormonal secretion: interface between brain and hormones ► Role in hormonal control of motivated behavior …including hunger, thirst, temperature, pain,

Answer 64

Subcortical (under the cortex) portions: Basal Ganglia Limbic system

Answer 65

- group of structures - loop organization These structures thought to be involved in motor function since involved in movement disorders

Answer 66

Group of structures These structures involved in emotion, motivation and emotional association with memory limbic system influences the formation of memory by integrating emotional states with stored memories of physical sensations

Answer 67

Amygdala Hippocampus Fornix Cingulate gyrus Septum Mammillary body

Answer 68

Amygdala Hippocampus Fornix Cingulate gyrus Septum Mammillary body

Answer 69

Amygdala ("Almond"): Involved in associating sensory stimuli with emotional impact Hippocampus ("Sea Horse"): Involved in memory (long term) / Involved in spatial memory

Answer 70

Mammillary body: Breast shaped Important for the formation of recollective memory – amnesia Fornix: C-shaped bundle of fibers, Carries signals from the hippocam-pus to the mammillary bodies and septal nucleus

Answer 71

Mammillary body: Breast shaped Important for the formation of recollective memory – amnesia Fornix: C-shaped bundle of fibers, Carries signals from the hippocam-pus to the mammillary bodies and septal nucleus

Answer 72

Cingulate gyrus (Limbic cortex) - Linking behavioural outcomes to motivation and autonomic control – atrophied in schizophrenia Septum:"something that encloses" Involved in defense and aggression

Answer 73

Frontal lobe, parietal, temporal, occipital Pre and post central gyrus around the central sulcus

Answer 74

Gray matter (6 layers) : cell bodies White matter: fibers / axons Biggest part of the brain in Primates

Answer 75

Contain the precentral gyrus from which motor instructions (particularly for fine motor control) that are sent to muscles controlling hands and feet. Primary motor cortex: contains many of the cells giving origin to the descending motor pathways - it is involved in the initiation of voluntary movements. Premotor and supplementary motor areas: higher level motor plans and initiation of voluntary movements.

Answer 76

•Involved in - i.e. lesions disrupt…. •“Executive" planning – generating models of the consequences of actions • Judgmental roles • Emotional modulation •Working memory: short-term information (rather than long-term factual data) •Control of behavior that depends upon context or setting •Prefrontal cortex: generating sophisticated behavioural options that are mindful of consequences

Answer 77

Contains the post central gyrus which receives sensation from the rest of the body Primary somatosensory cortex: Maintains representations of the body's and of the head's position in space. •Permits complicated spatio-temporal predictions – e.g. catching something when you are moving

Answer 78

Contains the primary auditory cortex Inferotemporal cortex recognition faces and objects Plays an important role in integrating sensory information from various parts of the body Interface between cortex and limbic system - association of affect/emotion with things

Answer 79

Contains visual cortices Dorsal stream Vision for movement - where (is it in relation to us - note path towards motor areas) Ventral stream Vision for identification What [does it mean to us – note path towards temporal/limbic areas]

Answer 80

Therefore all our actions will engage a bit of cortex interacting with a bit of basal ganglia, cerebellum and hippocampus…all directing the brainstem on what to do

Answer 81

Approximately 100 billion (109) neurons in the ‘average’ brain •But, 0.15 quadrillion (1015) connections between them (synapses)

Answer 82

Basic cellular unit of the nervous system •Huge range - specialised for different functions •All have same basic components •Dendrites •Cell body/soma •Axon •Presynaptic terminals

Answer 83

Multipolar, bipolar, pseudo-unipolar and unipolar E.g. Different Types of Neurons. A. Purkinje cell B. Granule cell C. Motor neuron D. Tripolar neuron E. Pyramidal Cell F. Chandelier cell G. Spindle neuron H. Stellate cell (Credit: Ferris Jabr; based on reconstructions and drawings by Cajal)

Answer 84

Multipolar, bipolar, pseudo-unipolar and unipolar E.g. Different Types of Neurons. A. Purkinje cell B. Granule cell C. Motor neuron D. Tripolar neuron E. Pyramidal Cell F. Chandelier cell G. Spindle neuron H. Stellate cell (Credit: Ferris Jabr; based on reconstructions and drawings by Cajal)

Answer 85

Transmission of information from location A to location B – Axonal transmission • Integration/processing of information and transmission between neurons – synaptic transmission

Answer 86

At rest – the inside of the neuron has a negative electric charge…why is this ?

Answer 87

Neuronal cell membrane - semi-permeable Some substances which are electrically charged (+ve or –ve) cross readily – potassium (K+) and chloride (Cl-) •Some cross with difficulty – sodium (Na+) •Some not at all – large organic proteins (-ve charge)

Answer 88

Diffusion – the force driving molecules to move to areas of lower concentration Electrostatic attraction/repulsion: Electrostatic pressure - ions (like magnets) move according to charge – Like ions repel and unlike attract Ions: A- (anions - protein) Na+ (sodium ions) K+ (potassium ions) Cl- (chlorine ions)

Answer 89

Diffusion + electrostatic pressure Ions A- (anions - protein) - restricted to inside of cell Na+ (sodium ions) - mostly outside neuron K+ (potassium ions) - mostly inside neuron Cl- (chlorine ions) - mostly outside neuron

Answer 90

Sodium-potassium pump •Active process to transport Na+ ions out of neuron & K+ in •Three Na+ for every two K+ •Require energy supplied by ATP

Answer 91

Final resting potential –70mV •Result is NA+ high concentration outside but with both forces pushing in •Membrane and pump resists Na+ inward movement •K+ & Cl- can move backward and forward across membrane so reach steady state determined by opposing forces of diffusion and electrostatic pressure •Some sodium leaks back in but is expelled by the pump

Answer 92

The Action Potential •Neuron fires – a sudden pulse where the negative resting potential is temporarily reversed •Transmits information i.e. the message [digitally / all or none / 0 or 1] •Events within the action potential –Depolarization & threshold –Reversal of membrane potential –Repolarisation to resting potential –Refractory period

Answer 93

The membrane potential remains in this resting ‘stable’ state until something disturbs the balance: Neurotransmitters initiate such changes at the dendrites of neurons •Neurotransmitters activate receptors on dendrites / soma •Receptors open ion channels •Ions cross plasma membrane, changing the membrane potential •The potential changes spread through the cell •If the potential changes felt at the axon hillock are positive (+mV), and large enough, an action potential is triggered

Answer 94

The membrane potential: Depolarisation more +ve V than -70 Polariser at -70mV = RMP Hyperpolarised more -ve V than -70 Excitatory neurotransmitters depolarise the cell membrane - increases probability of AP being elicited -cause an excitatory post synaptic potential (EPSP) Inhibitory neurotransmitters hyperpolarise the cell membrane - decreases probability of an action potential being elicited - cause an inhibitory post synaptic potential (IPSP) An action potential will be elicited if the membrane potential is depolarised beyond the threshold of excitation

Answer 95

EPSP Temporal/spatial summation

Answer 96

EPSPs begin to depolarise cell membrane •Threshold ~ -60mV –When reached Na+ channels open (Na+ rushes in) and polarity reverses to +30 inside •Membrane potential reverses with the inside

Answer 97

The voltage changes are caused by the opening or closing of ion channels •In the cell membrane there are channels which are opened by voltage changes…thus voltage changes control the ion channels which control the voltage changes…….... The action potential is therefore self perpetuating

Answer 98

depolarisation of each and every segment of the axon in turn is SLOW, need faster conduction than this…

Answer 99

Myelination greatly speeds up axonal conduction Myelin comes from oligodendrocytes in the CNS and from Schwann cells in the PNS

Answer 100

Myelination greatly speeds up axonal conduction Myelin comes from oligodendrocytes in the CNS and from Schwann cells in the PNS

Answer 101

Signal loss due to lack of insulation –could be overcome by continual opening of next ion channel •But SLOW due to time to activate each channel. •Mainly short axon interneurons Saltatory conduction

Answer 102

Saltatory Conduction •Decremental conduction between nodes (but ‘re-boosted’ each time) •But very fast along axon. •Most CNS neurons.

Answer 103

Axonal transmission failure: Multiple Sclerosis Most common disease of NS in young adults

Answer 104

Symptoms: •Eye movements – uncontrolled, seeing double •Speech – slurred •Paralysis – partial/complete, any part of body •Tremor •Co-ordination – lost •Weakness – tired •Sensory – numbness, prickling, pain

Answer 105

Prognosis: •Initial symptoms – slight with remission… •….becoming more numerous, frequent and severe •Difficult to diagnose: •Early symptoms slight – person doesn’t go to doctor •Other diseases have similar symptoms •No definitive test: repeated presentation of symptoms combined with MRI

Answer 106

•Who gets MS ? •Young adults 20-40 •Slightly more women than men •Temperate zones •Areas with high standards of sanitation

Answer 107

Transmission of information from location A to location B – Axonal transmission • Integration/processing of information – synaptic transmission

Answer 108

Disrupts normal synaptic neurotransmission for the neurotransmitter acetylcholine

Answer 109

Ca2+ channels Exocytosus Postsynaptic membrane Chemical synapse Synaptic cleft

Answer 110

Acetylcholinesterase is the name of the enzyme that breaks down the neurotransmitter acetylcholine

Answer 111

Would remain active in synapse if it wasn’t for: 1.Enzymatic Degradation 2.Reuptake AChE inhibitor - novichok

Answer 112

Inhibiting breakdown of a neurotransmitter means it will stay active in the synapse •So it will continue to have whatever effects it has, long after these would normally be terminated

Answer 113

It is the key neurotransmitter at the neuromuscular junction – it activates muscles •Not just skeletal muscles (for voluntary movement), also heart, respiratory muscles, gastrointestinal tract, eye muscles, muscles around blood vessels………

Answer 114

Excessive activation of muscles (convulsions) initially •Subsequent paralysis as muscle cannot continually contract •Failure of heart muscles (heart failure) •Failure of muscles controlling respiration (asphyxsiation/drowning) •Failure of muscles in eye (pupils constricted / paralysis) •Failure of skeletal muscles (paralysis) •Failure of muscles of digestive tract (vomiting/diarrhoea)

Answer 115

Atropine is an ACh receptor blocker – but doses needed to be effective very high (side effects) •Drugs which can re-activate AChE may also be administered •Usually intensive life-support required (due to cardiovascular effects) •Long-term damage of neuromuscular function probable

Answer 116

Neurotransmitter release –Calcium ion channels open when action potential reaches pre-synaptic terminal –Ca++ ions cause vesicles to move to release sites – fuse with the cell membrane – and discharge their contents –Transmitter substance diffuses across synaptic cleft –Attach to receptor sites on post-synaptic membrane

Answer 117

Important to know because almost all the drugs that act on the brain – do so by interacting with one or more of these 5 processes 1.Manufacture – intracellular biochemical processes 2.Storage – vesicles 3.Release – by action potential 4.Interact with post-synaptic receptors – diffusion across the synapse 5.Inactivation – break down or re-uptake

Answer 118

Fast neurotransmitters – short lasting effects –Acetylcholine (ACh) –Glutamate (GLU) –Gamma-aminobutyric acid (GABA) •Neuromodulators – slower timescale –Dopamine (DA) –Noradrenalin (NA) (norepenephrine) –Serotonin (5HT) (5-hydroxytryptamine)

Answer 119

E.g. procaine and ligocaine Na+ channels blockers - particularly well absorbed through mucous membranes Blocks progress of action potential Used in medicine and dentistr

Answer 120

Transmitter at the neuromuscular junction, also used widely in brain and spinal cord –Affected by: •Cigarettes (nicotine - agonist) •Poison arrows (curare - antagonist) •Spider toxins (black widow - release) •Nerve gas (WW-I – blocks break-down)

Answer 121

Transmitter in peripheral (heart) and central nervous systems –Affected by: •Antidepressant drugs (Imipramine – blocks re-uptake) •Antidepressant drugs (MAO inhibitors – block break-down) •Stimulants (Amphetamine – increases release and blocks re-uptake)

Answer 122

Important transmitter in basal ganglia –Affected by: •Antipsychotic drugs (Chlorpromazine – receptor blocker) •Stimulants (Amphetamine/cocaine – increase release and block re-uptake) •Anti-Parkinson drugs (L-DOPA increases manufacture

Answer 123

Diverging projections in the brain – innervating many structures –Affected by: •Antidepressant drugs (Prozac – serotonin re-uptake inhibitor – SSRI) •Hallucinogens (LSD, psilocybin –5HT receptor agonist) •Ecstasy (MDMA, increase release, reduce reuptake)

Answer 124

Hallucinogenic drugs include LSD, Magic Mushrooms, Ketamine •They mimic serotonin, and can activate numerous different serotonin receptor subtypes •But the hallucinogenic effect itself appears to be specifically related to the way they target the serotonin ‘2a’ receptor (5-HT2a)

Answer 125

Main inhibitory transmitter –Affected by: •Anti-anxiety drugs (benzodiazepines - valium – inhibitory effect at GABA receptors •Anticonvulsant drugs (benzodiazepines – see above) •Anaesthetics (Barbiturates – potentiate the effect of GABA

Answer 126

A region of the brain engaged in a particular function uses several neurotransmission systems e.g. basal ganglia –Glutamate –GABA –Dopamine –Acetylcholine –Substance P –Enkephalin •Regions of the brain engaged in different functions use the same neurotransmission systems –Glutamate –GABA –Acetylcholine –Serotonin –Dopamine/Noradrenalin

Answer 127

GABA agonists –Anti-anxiety –Anti-convulsant –Anaesthetic •L-DOPA –Anti-parkinson –Causes psychosis at high doses •Dopamine blockers –Anti-psychotic –Causes Parkinson-symptoms at high doses

Answer 128

resting potential is established and perturbed to generate EPSPs, IPSPs and action potentials

Answer 129

PARSYMPATHETIC in simple terms: - The VAGUS Nerve (X) to Thorax & Abdomen - Cranial nerves to Head, Thorax & Abdomen - Sacral outflow to Pelvic organs Sympathetic: - The Sympathetic Chain - Other Ganglia - Post Ganglionic fibres - cranial nerves to eye

Answer 130

Voluntary Involuntary

Answer 131

Thermoregulation, Exercise, Digestion, Competition, Sexual Function Mictrurition?

Answer 132

PARASYMPATHETIC - CRANIAL OUTFLOW - SACRAL OUTFLOW 2. SYMPATHETIC Adrenal amplification 3. ‘ENTERIC N.S.’

Answer 133

hitches a ride’ on cranial nerves 3,7, 9, 10 2. Apart from sacral outflow, S1, 2 Symp: 1. White & Grey Rami communicates, Sympathetic chain 2. Splanchnic nerves to large thoraco-abdominal plexi

Answer 134

Rami communicantes

Answer 135

Cranial outflow: Preganglionic fibers run via: • Oculomotor nerve (III) • Facial nerve (VII) • Glossopharyngeal nerve (IX) • Vagus nerve (X) • Cell bodies located in cranial nerve nuclei in the brain stem

Answer 136

Enteric system can work independently from ANS Coordinates GI function

Answer 137

Enteric system can work independently from ANS Coordinates GI function

Answer 138

Symp - ACh, nicotine receptors, adrenergic receptors, NE Para: ACh, , nicotinic and muscarinic receptors

Answer 139

Symp - ACh, nicotine receptors, adrenergic receptors, NE Para: ACh, , nicotinic and muscarinic receptors

Answer 140

Nordarenaline ALPHA: alpha1, alpha2 BETA: beta 1, 2, 3

Answer 141

Carotid receptors

Answer 142

Heart Rate and Blood Pressure, preferably beat-by-beat Radial artery HUT - head up tilt test (Arterial) Baro-reflex testing- By Phenylephrine test - - Measure R-R interval after iv pressor agent Phenylephrine- (PE)

Answer 143

Pupillometry •Sweat measurement •Skin blood flow, thermoregulation •Gastric acid secretion •Sexual function