Questions Flashcards
Who showed calcium is required for neurotransmitter release
Katz and Miledi
What is the name given to the non-specific region of the brain that is particularly developed in man to receive inputs from multiple regions of multiple modalities
Association cortex
What is the name given to fibres that project from the cerebellum and link to non cortical areas
Projection fibres
Which areas of the brain are linked by association fibres
Regions within the same same hemisphere - e.g. longitudinal fasciculi
What are the key roles of the cerebellum
Maintaining muscle tone Motor coordination Motor error checking and learning
Gap junctions allow for _______________ between cells in structure called electrical synpases
Rapid communication
Because the squid was cold blooded did the giant axon require inncubation
No
How is the synapse an example of an adhesion molecules
Adhesion proteins between neurones, pre and post synaptic neurons bound together
How does light result in a signal being detected by the optic nerve
Light causes hyperpolarisation of the rod cell which leads to the ceasing of glutamate release and no inhibition of the bipolar cell thus an EPSP is generated in the bipolar cells
What cells absorb the CSF
Arachnoid villi
Do neuropeptides only activated GPCRs
Yes
CN I (NAME)
Olfactory
Define an action potential
Fixed size change in membrane potential from negative to positive that is all or nothing and travels along the axis of a neuron
What route brings motor information out of the spinal cord
Ventral
GABA is the most …
Important inhibitory neurotransmitter in the brain
What is the nucleus ruber
Motor coordination
What structures make up the mesencephalon
Cerebral peduncles Tectum Sustantia nigra Nucleus ruber
Where is the cerebellum located
Underneath the occipital lobe on the root of the fourth ventricle
What are muscle spindles
Proprioreceptors located in skeletal muscle near tendons which detect strech of musxle
Name the primary brain vesicles
Prosencephalon Mesencephalon Rhombencephalon Spinal cord
What role do the opiate receptors in the periaqueductal grey have
Regualtion of pain sensation
What is the function of the PNS myelin protein components
P0 - is adhesion molecule for compaction of the myelin layers PMP-22 - is involved in the spacing between the layers of wrapping
What are the three types of unencapsulated nerve endings
Free nerve endings, tactile discs, hair receptors
What is the cause of cataracts
Caused by low ocular pressue
What is the pineal gland
Unpaired structure consisting of an endocrine gland that makes and secretes melatonin and serotonin
Where is ACh found within the brain
Basal forebrain and hippocampus
What are the four types of sensory information transmitted by sensory receptors
Modality Intensity Duration Location
What is the role of the Canal of Schlemm
Drains aqueous humour from anterior chamber
What is miosis
Constriction of the pupil of the eye
Define the autonomic nervous system
The efferent division of the visceral nervous system
Typical values of intra and extrcellular K+ and Na+
Na i - 15mM Na o - 140 mN K i - 100 mM K o - 5 mM`
What is the main role of the horizontal cells
Enhance contrast and sensitivity
What aspects are lateralised to the right hemisphere
Creativity Artistic Spatial
Define multiple sclerosis
Conditions that lead to the degredation of CNS myelin followed by periods of relapse and remission
What do peripheral nerves contain
ONLY axons NO dendrites
What are the 3 meninges of the brain
Pia Arachnoid layer Dura mater
What types of receptor are the opiate receptors
GPCRs
What are the two main photoreceptive pigements
Rhodopsin Photopsin
What type of disease is MS
Primary demyelination disease - axon sparing only the myelin is degraded
What macroglia myelinate in the CNS how is this achieved
Oligodendrocytes Send out processes so can myelinate multiple axons
What equation is uses to calculate equillibrium potentials
Nernst
What is the difference between temporal and spatial summation
Temporal summation is the result of multiple action potentials adding up in time where the size of the post synaptic potential depends on the amount of action potentials received. Spatial summation occurs when multiple presynaptic neurons bring action potentials to the synpase at the same time
What are ON bioplar cells
Glutamate inhibits Hyperpolarised in the dark light causes loss of inhibition Metabotrophic
What is lens accommodation
Ciliary muscle contraction to decrease lens size, relaxation of the suspensory ligaments to release radial tension causing the lens to form a more spherical shape with a higher refractive power
Which areas of the brain are linked by commissural fibres
Regions in different hemispheres - e.g. corpus callosum
TRUE OR FALSE Neuropeptides are synthesised in the cell body and stored in secretory granuels whereas other neurotransmitters are synthesised at the synaptic vesicles and packaged into synaptic vesicles
True
What does the prosencephalon give rise to
Telencephalon Optic vesicles Diencephalon
Where are tactile discs found and what modalities do they detect
Stratum basale of the epidermis Sense light, touch, texture, edges and shape
Recall the catecholamine synthesis pathway
Tyrosine L-Dihydroxyphenylalanine (L-Dopa) Dopamine Noradrenaline Adrenaline
What are OFF bipolar cells
Glutamate excites Depolarised in the dark Light causes loss of excitation Ionotrophic
What do AChE inhibitors do
Prevent ACh breakdown Nerve gases
How can Gullian Barre be treated
Intravenous Igs - attack and destory autoimmune antibodies Plasmapheresis - separation of blood plasma cells to remove harmful antibodies
Which vesicles give rise to the hindbrain
Metencephalon Myelencephalon
Does the dorsal root contain sensory neuronal cell bodies
Yes
What is the role of the thalamus
Processing and relay centre Senesory information is passed on to higher brain centres
What is the role of cerebrosides in myelin formation
Aid in the compaction of myelin Knockout mice exhibit peeling of the layers leading to vacuoles and paralysis
Name the 3 divisions of the ANS
Sympathetic Parasympathetic Enteric
How many neurons in the brain
10^10-10^12
In the spinal cord where do neuronal cells bodies occur
Grey matter
CN V (NAME)
Trigeminal
Define graded potentials
Localised changes in membrane potential of any variable size that does not travel over long distances and that usually occurs in the dendrites
What are names given to spinal nerve branches
Rami
What are the four types of encapsulated nerve endings
Tactile corpuscles, Krause end bulbs, lamellated corpuscles, ruffini corpuscles
Where do most motor neurones cross
Medulla oblongata
What is meant by the term, postsynaptic density
Region where neurotransmitter binds to the postsynaptic membrane
Which regions of the brain contain NA neurones
Locus coeruleus, thalamus and hypothalamus
What are the primary roles of the medulla oblongata
CV and resp patterning
What are symptoms of Parkinsons
Shuffling gate Stooped shoulders Slurred monotonous speech Akinesia
What region of damage is brocas aphasia linked to
Left frontal lobe damage
Which enzymes metabolises catecholamines in the cytoplasm
Catechol-O-Methyltransferase
What enzyme that converts glutamate to GABA
Glutamic acid decarboxylase (GAD)
What is an inhibitory graded potential
Hyperpolarising graded potential caused by influx of Cl- into the cell shifting Vm more negative
What are the four layers of the cerebellum
Molecular Purkinje Granular White matter
How is Guillian Barre similar and different to MS
Primary demyelination PNS myelin damaged Develops after bacterial/viral infection
What is the role of the iris
Regulates light levels by pupillary constrictior
What are the 6 lobes of the cerebrum
Frontal lobe Parietal lobe Occipital lobe Central lobe Temporal lobe Limbic system
What is Dales principle and is it always correct
Only one type of NT present in the pre sy term NO peptide containing neurons usually have amino acid/amine neurotransmitters (or a co transmitter)
In both divisions of the ANS what is the NT and receptor of the ganglionic neurone
Acetlycholine N2 NAChR
What is convergence of the eyes
When the eyes move close together
Do nerves contain swellings
Yes - swellings are called ganglia
Is the AMPA involved in fast transmission via glutamate and is often independent from the NMDA receptor
NO first part part correct but coexists with NMDA
What role did BF skinner play in early neuroscience
Developed operant conditioning (positive and negative reinforcement)
Describe saltatory conduction
Action potentials generated the Nodes of Ranvier due to localisation of Na+ ion channels. Depolarisation at one Node is suffiicent to induce depolarisation at the next node, AP jumps from node to node without decay
What are the equilibrium potentials for Na and K
Na - +62mV K - -80mV
Where are the free nerve endings found and what modalities do they detect
Epithelia and connective tissue Sense pain and heat
What is the role of the pigment epithelium
Maintenance of the rod and cone cells and stimulation of retinal regeneration
Describe emmetropia
When the eye is in a relaxed state focussed on an object 6m away
What are the names of the six layers of the cortex
Molecular External granular External pyramidal Internal granular Internal pyramidal Fusiform layer
What are the two main protein components of CNS myelin
Myelin basic protein Proteolipid protein
What are some of the MS risk factors
Immunological factors Enviro factors Vit D linked Genetic predisposition
Name some molecules that have effects of DA
L-dopa increases DA production Amphetamines increase DA release Cocain blocks DA reuptake D2 receptor agonists treat parkinsons MAO-B inhibitors prevent DA metabolism
At what Vm are the Na+ channels open and clased
Closed -65mV Open -40mV
Name the secondary brain vesicles
Telencephalon Optic vesicles Diencephalon Metencephalon Mylencephalon Spinal cord
What is meant by duplicity theory
Cant have a high sensitivity and high resolution in a single receptor
Four types of retinal neurones
Bipolar, ganglion, horizontal and amacrine cells
What is the role of the ciliary body
Specialised region of muscle that secretes aqueous humour
Name the endogenous opiate compounds
Endorophin, encephalin, dynorphin
Describe the state of the rod cell in the dark
Depolirised and inhibits ganglion cells
What role to do the opiate receptors in the amygdala have
Emotional response to pain
What is the mechanism for ACh synthesis
Choline + ACoA –> ACh + CoA ENZYME: Acetyltransferase
CN X (NAME)
Vagus
MS treatments methods
Steroids Interferons to damp down the response Immunosupressants Vit D
Symptoms of Wernickes aphasia
Inappropriate or contrived words whilst grammar and syntax is still conserved
Which components of the eye make up the tunica vasculosa
Choroid, ciliary body, iris
Can damage to the frontal lobe can cause changes in personality?
Yes
Describe the pathology of PD
Diminished SNc Decreased dopamine synthesis and connection Less inhibition of inhibitory effects of striatum More inhibition of motor activity by striatum - nigrostriatcal pathway
Tetraethylammonium is a _________________—
Non specific K+ ion channel blocker
What type of aphasia is Broca’s
Expressive
Who showed how axons grow in their work on frogs/toads
Harrison
What structures make up the diencephalon
Thalamus Hypothalamus Pineal gland
CN II (NAME)
Optic
What are the three tunics of the eye (from outer to inner)
Tunica fibrosa Tunica vasculosa Tunica interna
Is the glutamate the most important excitatory NT the PNS
NO it is in the CNS
What order are bipolar cells
!st
What is the roles of the hypothalamus
Controlling centre Hunger Thirst Arousal Body temperature
Are Na+ ion channels more localised in axons or dendrites
Axons
CN VIII (NAME)
Vestibulocochlear / Auditory vestibular
What are two ways action potentials can travel
Orthodomically Antodromically
How many pairs of peripheral nerves
43
Which demographics show an increased risk
Caucasian Women
Where is a lumbar puncture carried out
Between the 3rd and 4th lumbar vertebrae
Name and locate each of the brain ventricles
Lateral ventricles - within the cerebral hemisphere 3rd ventricle - centre of the diencephalon 4th ventricle - within the pons/medulla
The diencephalon is part of which region of the brain and what does it do
Part of the forebrain and links the cerebrum to the midbrain
What are diffuse neurotransmitters
Neurotransmitters that have widespread, non-specific effects over large regions of the brain
How many spinal nerves? How many pairs?
31 5 pairs
What is an example of a specialized astrocytes
Retinal Muller cells Radial Bergman glia in the cerebellum
What gene is mutated in shiverer mouse
MBP - problems in synthesis
Why aren’t all neurones myelinated
Metabolic and volume costs of myelination
Which type of spinal column deals with sensory information
Ascending columns
What aspects are catecholamines associated with
Mood movement attention and visceral fucntion
What are the factors which influence conduction velocity along an axons
Axon diameter (Resistance is inversely proportional to the inverse of the CSA) Myelination (saltatory conduction)
Do rod cells contact ganglion cells directyl
No they are connected via horzontal and amacrine cells
Name some effects of diffuse NTS
Dopamine Adrenaline (Nora) ACh 5-HT
T/F?? Hodgkin, Huxley and Katz were involved in studying the giant squid axon and determination of ion flow potentials
T by JZ young also involved
Main components of the brainstem
Fibre tracts Housekeeping nuclei
What is an en passant synpase
Synapse made along the length of the axon
Do all Schwann cells wrapped around an axons actually myelinate
No
Put these in order from axon –> fassicle –> nerve Peri/epi/endo neurium
Endo Peri Epi
How are sensory receptors classified
Modality, origin and distribution
Name other CNS myelin proteins
MOG MAG Clyclic nucleotide phosphodiesterase Carbonic anhydrase
What are three methods of transmission termination
Reuptake Breakdown Diffusion
On which model organism did Nichole le Dourain work on
The chicken
What type of glial cells are involved in the formation of the blood bran barrier
Astrocytes cause the induction of very tight junctions between the endothelial cells
Describe the sclera
White of the eye
What is periodicity and how does it vary throughout the nervous system
Distance between layers of protein and layers lipids Is less in the CNS
Where is the aqueous humour found
Anterior and posterior chambers
Which type of glial cell are derived from circulating monocytes and have phagocytic properties
Microglia - short spikey processes
Where are the hair receptors found and what modalities do they detect
Around hair follicle, sense hair movement
CN XII (NAME)
Hypoglossal
Ho does the NMDA receptor act as a biological AND-hate
Voltage dependent magnesium block that sits in the channel preventing the passage of Ca2+ through unless glutamate has bound to the receptor and depolarisation of the membrane has occured
Major roles of astrocytes
Forming the blood-brain barrier Spatial buffering - functional syncytium removing K+ to prevent damage to neurons Neurotransmitter uptake - responsible for uptake of GABA and enzyme for GABA–>Glutamate Glucose metabolism - Neurones prefer 3C molecules store some as glycogen but can convert some to lactate for neuronal cells
Which regions make up the forbrain
Hemispheres, diencephalon
What is the role of ependyma
Create the epithelial lining of the ventricles and spinal canal and choroid epithelium producing the CSF
What is EPSP shunting
EPSPs can be shunted by an inhibitory synapse closer to the cell body, this causes the dissipation and no change in Vm in the stom. Thus dendrites closer to the stoma have a greater influence on action potential generation
Where is the vitreous humour found
Between lens and retina
Is myelin metabolically active
Yes- undergoing lipid synthesis
Outline stages of neural tube formation
Formation of the neural plate Neural fold rises up Neural fold fuses around the neural groovee
What has to happen before a voltage gated ion channel can participate in another action potential
Channel inactivation –> Channel de-inactivation (consisting of activation gate closure and inactivation gate reopening)
What is the name given to the region where neurotransmitters are released from secretory vesicles/granules
Active zone
What are interneurones and why are they important
Connect sensory and motor neurones and are important in reflexes
Difference between pre and post gang neurons
Post gang unmyelinated Pre always myelinated
Why is lidocaine used as local anesthetic
Lidocaine blocks voltage gated Na+ channels preventing depolarisation occurs , therfore no action potential can occur
What is hydrocephalus
Abnormal accumulation of CSF causing raised intercranial pressure
What is the cause of Glaucoma
Caused by high ocular pressure
Main NTs of the ANS
Acetylcholine and noradrenaline
Do mice with PLP knockout have same phenotype as the jimpy mouse
No, not toxic PLP produced leads to RUMPSHAKER phenotype
Which regions of the brain contain DA nuerons
Top brainstem Frontal lobe Striatum Substantia nigra Ventral tegmental area
Recall enxymes associated with catcehcolamine synthesis
Tyrosine hydroxylase Dop decarboxylase Dopamine-beta hydroxylase Phentolamine N-methyltransferase
CN XI (NAME)
Spinal accessory
CN VII (NAME)
Facial
Why is inhibition important
Dendrites with excitation inputs but inhibitory synapses can knock down excitation
At rest the membrane is permemable to ____ and not very permeable to _____
K Na
What is unusual about swear gland innervation
Sympathetic but postganglioic uses acetly choline
What is the pyramidal tract
Carries mainly motor information from the cerebral cortex which crosses the medulla
CN IX (NAME)
Glossopharyngeal
What is the consensual light reflex
Changes in light intensity in one eye causes an effect in both eyes
What is the effect of increasing membrane permeability to Cl-
Little/no effect on the Vm but does make it harder for the Vm to change
CN VI (NAME)
Abducens
Which components of the eye make up the tunica interna
Retinal, optic nerve (CNII)
What three factors leads to the the establishement of the resting potential
Selectively permeable membrane Unequal distrubution of ions and physical forces
Describe the pathology of MS
No definite cause, autoimmune, leading to destruction of oligodendrocytes in the CNS through macrophage and protease activity
Name some example molecules that make up the lipid composition of myelin
Cerebrosides, sulfatides, sphingomyelin
What are common symptoms of Broca aphasia
Poor grammar, syntax error and incorrect word structure
What is meant by quantal release
Vesicles are usually of a certain size Allows you to calculate the number of vesicles and amount of neurotransmitter that caused a specific size of response
The olives are found in the ________________ where to they project to
Medulla oblongata Cerebellum
What specilaised regions are part of the tunica fibrosa
Sclerea Cornea
What is meant by tonic and phasic responses
Phasic -Short burst Tonic - Continuously firing, slowly adapting
What is an excitatory graded potentials
Depolarising graded potential caused by NT arrival at postsynaptic membrane resulting in opening of a ligand gated ion channels allowing Na+ in to the neuron
There dura splits into two what are the names
Endosteal and menningeal
CN III (NAME)
Oculomotor
State the equation for ionic driving force
IDF proportional to (Vm - Eion)
What disease is associated with defects P0 or PMP-22
Carcot-Marie-Tooth syndrome Loss of muscle tisue and touch sensation
Where is the mechanism for ACh brekadown
ACh –> Chloine + Acetate ENZYME: Acetylcholinesterase
Does glutamate act as an exitatory NT during photoreception
No release from a depolarised rod cells causes an IPSP in the bipolar cell
What macroglia myelinate in the PNS how is this achieved
Schwann cells Myelinate individual axons by flattening down and wrapping around the axons with swellings as the Nodes of Ranvier
What are the main types of synapse
Axodendritic Dendrodendritic Axoaxonic Axosomatic
During which age is MS usually onset at?
20-40
What are three subtypes of macroglia
Astrocytes Schwann cells Oligodendrocytes
How many more glial cells than neurones
10x
What is the term given for crossing over of pathways
Decussation
Are spinal nerves sensory or motor
They’re mixed
In what regions does the CSF flow
Ventricles, central-canal and sub arachnoid space
List the 5 sets of spinal nerves
Cervical Thoracic Lumbar Sacral Coccygeal
What are the protein components of PNS myelin
P0 MBP PMP-22
What can be used to prevent some neural tube defects
Folic acid
How does the pons connect to the cerebllum
Via the cerebral peduncles
Name some examples of toxins that interfere with ACh release
Botulinum toxin and black widow spider venom
What type of aphasia is Wernickes aphasia
Receptive
What type of cells produce CSF
Choroid plexus
What does the rhombencephalon give rise to
Metencephalon Myelencephalon
What structures are contained within the tectum and what are they involved in
Superior (visual reflexes) and inferior (auditory reflexes) colliculi
What aspects are lateralised to the left hemisphere
Analysis Calculation Speech
What are the three ways which nerves can fire action potentials
Consistently - same rate Slowly adapting - rate decreasing Rapidly adapting - fire a few times and then stop
What does the lymbic system consist of
Hippocampus Amygdala Thalamus Hypothalamus
Are ganglion cells 1st or 2nd order
2nd
What role do the opitate receptors in the brainstem (medulla) have?
Depression of respiration and cough reflex
What is a subdural haematoma
Where blood vessels have ruptured and blood has collected between the dura and arachnoid layer
Name an agonist and an antagonist of the opiate receptors
Ag - Morphine Antag - Naloxone
Which myelin components contribute to the intraperiod line and the major period line
Intra - protein - light banding Major - lipid - dark
What type of control centre is found in the pons
Respiratory
What are the three regions of the brainstem
Medulla oblongata Pons Mesencephalon
Four divisions of the human brain
Cerebrum Diencephalon Brainstem Cerebellum
What is the crtieria for a neurotransmitter
Present in pre sy terminal Released in repsonse to stimuli Interact with post sy receptors Rapid removal
Name the structures which make up the basal ganglia
Nucleus accumbens Globus palidus Striatum (putamen and caudate nucleus) Substantia nigra Sub-thalamic nucleus
What are the two main sub-types of astrocytes and where are they found
Protoplasmic - in the grey matter and contain few IF Fibrous - in the white matter contain lots of IF
What are four types of retinal ganglion cells
W X Y Melanopsin RGCs
Explain the pathology of the jimpy mouse mutation
Mutation of PLP PLP produced incorrectly and is toxic to oligodendrocytes –> profound loss of macroglia
Which MAOenzyme metabolises NA and serotonin in the outer mitochondrial membrane
MAO-A MAO-B –> Metabolises dopamine
What secondary vesicles give rise to the forebrain
Telencephalon Diencephalon
CN IV (NAME)
Trochlear
Explain the phototransduction pathway
Light activates rhodopsin This activates transducin (transducin GDP-transucing GTP) Activated transducin activates phosphodiesterase Activated PDE catalyses the conversion of cGMP to GMP Increased GMP causes closure of the Na+ ion channels This decreases the intracellular levels of Na+ and Ca2+ Decreased Ca2+ activates recoverin Recoverin activates guanylyl cyclase which causes GMP -> cGMP a re opens the Na+ channels
What are the problems of long term L-dopa treatment
Chronic L-dopa syndrome - induced dyskinesia Sudden and severe immobility Req peripheral domaine decraboxylase to treat side effects
What is the role of the substantia nigra
Control of voluntary movement
Are majority of axons myelinated or unmyelinated
Un-myelinated
Who demonstrated impriting in chicks
Lorenz
Describe the process that leads to transmission of the action potential at a synapse
Action potential arrives at the presynaptic terminal Depolarisation causes opening of voltage gated Ca2+ channels due to positive Vm Calcium causes vesicle fusion and NT release Small volume of the cleft causes concentration of NT to rise to the mM range
What three things occur when an object is brought closer to the eye
Convergence Miosis Lens accomodation
How do action potentials vary from graded potenital
Change in Vm doesnt spread very far from site of stimulation with effect decreasing with distance can be either excitatory or inhibtory
How is choline taken back into the neurone
Choline transporter
Is the lens living
Yes
List some distinguishing features of Rod cells
High convergence and sensitivitiy, low accuity and fuction best at low light intensities
What is autoinhibition
Where neurones interact with their own receptors creating a short discrete release period and a tight signal
What route brings sensory information into the spinal cord
Dorsal
From which germ layers is the NS derived from
Ectoderm
