general neurobiology Flashcards
what are the 5 divisions of the brain?
- frontal
- parietal
- temporal
- occipital
- cerebellum
what part of the brain is involved in memory?
hippocampus
what is the amygdala involved in?
emotions
what are the components of the brain stem?
pons, medulla, midbrain, hypothalamus, thalamus.
what is the role of the thalamus?
- to relay information between the spinal cord and the higher neural regions within the brain
what makes up white and grey matter?
grey matter contains many cell bodies and axon terminals whereas white matter contains neurons
what is the morphology of a neuromuscular junction?
there are terminal buttons that contain acetylcholine vesicles. These vesicles are released into the synapse, where they bind to acetylcholine receptors on the motor end plate.
how are vesicles released within the synaptic terminal?
- an action potential reaches the presynaptic terminal of a motor neuron, which depolarises the bouton and activates voltage-dependent calcium channels to allow calcium ions to enter the neuron. Calcium ions bind to sensor proteins on synaptic vesicles, triggering vesicle fusion with the cell membrane and subsequent neurotransmitter release form the MN into the cleft. at binds to ligand gated ion channels (nicotinic receptors) on the cell membrane of the myofiber,
what are the advantages of TaDa?
- cheap, doesn’t involve RNA or protein pulldown or immunoprecititaton, fast
what is the resting membrane potential of an axon?
-70 to -80
what does depolarisation of the membrane mean?
becoming less negative
what is the role of the sodium potassium pump and what does this do to the membrane potential?
the pump transports three sodium ions out of the cell and two potassium ions in. This results in the concentration of potassium iOS being higher inside and the concentration os sodium being lower inside. It uses ATP. This results in the intracellular space having a negate charge .
what is the role of the calcium sodium pump?
- keeps calcium levels low at the resting state
what is the reversal potential?
- the transmembrane voltage at which diffusive and electrical forces counterbalance. the transmembrane voltage exactly oppose the force of diffusion of the ion, such that there is no net current of ions across the membrane
how can the resting potential be calculated?
the goldman formula: a weighted average of the reversal potentials for the individual ion types, weighted by permeability. In most animal cells, the permeability to potassium is much higher in the resting state than the permeability to sodium. As a consequence, the resting potential is usually close to the potassium reversal potential.
describe how an action potential occurs
- a stimulus is received by the dendrites of a nerve cell. This causes Na+ channels to open . If the opening is sufficient to drive the interior potential l from -70 to -55mv, the process continues.
- having reached the threshold voltage, more Na+ channels open. the Na+ influx drives the cell membrane to about +30mV. The process at this point is called depolarisation.
- The sodium channels close (inactive) and the K+ channels open (they are delayed) and K+ move out, reducing the membrane potential but overshoots, causing hyper polarisation. this prevents the neuron from receiving another signal at this time.
what is the threshold potential?
around -55mV
what is saltatory conduction?
caused by nodes of ranvier and results in fast conduction from the cell body body (dendrite) to the axons.
in general what is the tripartite system ?
the idea that glial cells play a large role in regulating neural synapses
what 5 things have glial been implicated in?
- control of brain blood flow
- control neuronal survival
- regulate repair after injury
- neuropathic pain
- epilepsy
how are astrocytes thought to control blood flow
- thought they are linked to vessels and synapses, hey release glial-derived signalling molecules which constrict the vessels, or cause vasodilation to shit blood flow to the active areas.
what are microglia?
related to immune cells, they are constantly moving their processes and monitoring brain tissue.
- they are also thought to cause chronic pain
what is the neurotrophic theory?
- theory that initially an excess of neurons is produced but then pruned depending on how much neurotrophic factor is released from the target organ. initially glial cells support neural development
during neuromuscular junction formation, how do achR cluster?
-agrin is released from the end terminus which stimulates clustering maybe through musk?
