Flashcards in Class Test 3 Deck (92):
What causes Parkinson's Disease?
Loss of dopaminergic neurones in substantia nigria
Dorsal (muscle --> spinal cord)
What is not present at chemical synapses?
Difference between spatial and temporal summation
Spatial- multiple EPSPs
Temporal- same EPSPs
What do Tau proteins do?
Bind and stabilise cytoplasmic microtubules
What are in astrocytes cytoplasm?
Glial Fillary Acid Proteins
What do astrocytes provide?
Structural support for neurons in the brain and aid in neuronal repair
What do glial cells do?
Hold brain together
Occupy spaces between neurons
What is the process of ionophoresis?
Applying electrical current of the same polarity as the charged dye and hence expelled
What notion does arborisation of the neuron create?
Notion of how many connections a cell cn accomodate and to how many sites it sends its own processes
What do ganglion cells contain?
Around 400 nerve cells with distinctive shapes, sizes, positions and branching patterns
How are MRI scans formed?
From an oscillating magnetic field which causes protons in tissues to become excited and emit a radio frequency signal which is detected by a receiver
What composes grey matter and white matter?
Grey matter- nerve cell bodies
White matter- myelinated axonal processes and supporting glia
What is neuropil?
Where nerve cell bodies of grey matter are embedded
What makes up the spinal cord?
Centered H-shape core grey matter surrounded by white matter
What do vitementin positive cells contain?
Intermediate filament protein
What is used for labelling spinal cord sections?
Antibodies raised against several antigens
What is MAP2 (Microtubule Associated Protein 2) used to observe?
Soma and dendrites in the grey matter of the spinal cord
What is NP-NF (non-phosphorylated form of neurofilament protein) used to label?
Adult spinal cord
NP-NF used via fluorescently labelled NP-NF antibody
Only stains large cells in developing ventral horn
What is P-NF (phosphorylated form of neurofilament protein) used to label?
Immature spinal cord
Only labels axons
What is exocytosis?
Neurotransmitters released from axon terminal
What do inhibitory and excitatory neurotransmitters do?
Inhibitory- drives membrane potential away from critical firing level
Excitatory- reaches critical firing level and causes an action potential
What is a confocal laser scanning microscope used for?
Create 3D structures from obtained images
What synapses are predominantly found in mammals?
What is a synapse?
Axon terminal from one neuron and dendrite/cell body from another neuron
Are there delays for chemical and electrical synapses?
Chemical- .5 ms between impulse at pre-synaptic terminal and detection of post-synaptic potential change
How common are electrical synapses?
Not common in mammals
Few examples e.g. retina
How are tissues optically sectioned?
Immunocytochemistry combined with confocal microscopy
What does TEM (Transmission electron microscopy) or electrical recording from cells confirm?
Presence of an active synapse
Electron microscope- view synapse
What is lacking as you go down the spinal cord?
White matter relative to grey matter decreases
Sacral cord- loss of all white matter
What are Purkinje neurones?
Largest cells in the cerebral cortex
What are satellite cells?
Supportive cells which surround each neurone
What surrounds ganglions?
Fibrous connective tissue capsules
What is electronic spread?
Detriment and voltage faults
What affects conduction velocity?
Axon diameter (larger diameter, faster conduction)
Myelination (increases conduction)
What do Schwan cells form
Relies on voltage-gated channels at the nodes
Fast conduction between nodes and nodes
Gaps between myelin sheath
Soma of nerve cells
Dense voltage-gated channels
How is information contained in AP?
Frequency and pattern of activity
What does NMJ release?
How are action potentials generated?
Where are inhibitory synapses on the axon terminals?
What are IPSPs?
Makes postsynaptic neuron less likely to generate an action potential
Where are small molecule transmitters synthesised?
In axon terminals
Where are neuropeptides synthesised?
In the cell body
Where are autoreceptors?
What are modulators?
Type of neurotransmitters but aren't released in a synapse (e.g. released into tissue)
What makes up the spinothalamic pathway?
Motor control and voluntary movements
sub thalamic, caudate nucleus, thalamus
Initiation of movement
Motor control and cooridination
Sleep and wakefulness, body posture
Cortex - Spinal cord
Episodic and learning
Semantic and declarative
Auditory and Optic
Sensory, touch, taste
Diencephalon (Thalamus, hypothalamus, basal ganglia)
Forebrain (D and T)
Brainstem (midbrain, pons, medulla)
Hindbrain (cerebellum, pons (rostral) , medulla (caudal))
Links cortex and brain
Olfaction, emotions, memory
Complex cognitive functions
e.g. speech and language
Pre-motor cortex (motor map)
Pre-frontal cortex (decision)
What are excitation of muscle spindles responsible for?
Control reflex vs protective reflex
Control= Closed loop
What is protective reflex accompanied by?
Crossed extensor reflex
What do rods and cones differ in?
Link photoreceptors to ganglion cells
Mediate lateral responses
1 to 1 with bipolar and ganglion cells
Rods converge on
Roles of V1, V5, V4
V1- parcels out info
V5- motion analysis (akinetopsia)
V4- colour vision (achromotopsia)
Basal ganglia input and output
Input- Prefrontal cortex
Output- Pre-motor area
Corticospinal and rubrospinal
control of movement
Control of posture
What are collections of motoneurones in the ventral horn called?
Iconic and echoic memory duration?
Iconic- 1/2 secs
Echoic- 2-3 secs
Properties of LTP?
Co-operativity (2 weak inputs same time)
Associativity (1 weak 1 strong)
AMPA receptors and NDMA receptors
AMPA- Fast reliable transmission
Permeable for Na
NDMA- Permeable for Ca
Brain blood supply
Dorsal aorta gives rise to internal carotid and vertebral arteries
Vertebral arteries join to form one single basilar artery
Basilar artery and internal carotid arteries form circle of willis
3 major cerebral arteries
Left middle cerebral
Pathways across BBB
Transcellular lipophillic pathway
Receptor mediated endocytosis
Endothelium choroid plexus
What groups of cells are involved in voluntary movements?
Substantia nigra and red nucleus
Think about breathing
Locked in syndrome?
Can't make voluntary movements only eyes