Neurophysiology (Test 1) Flashcards
What cells are responsible for myelination?
oligodendrocytes and Schwann cells.
Which channels mediate transmitter release at the presynaptic terminal?
Ca2+ channels.
What is the ion and direction of flow in the action potential phase 3:
Na+ ions flow into cell.
What is the order of the types of synapse in escape response in terms of fast?
Gap junction, ligand-gated, G-protein-coupled.
What is the main fast inhibitory transmitter in the nervous system?
GABA.
What is the structure circled in the picture? From where is it derived?
Thalamus, diencephalon
What are the neurotransmiters of the preganglionic neuron and the postganglionic neuron of sympathetic nervous system?
Acetylcholine, norepinephrine.
What nervous system’s function is refer to as ‘Fight or flight’?
Sympathetic nervous system.
What are the functions of the cerebellum?
Movement, posture, balance.
Is the autonomic nervous system voluntary or involuntary?
involuntary
How any types of synapse does the autonomic nervous system consist of?
Two, Cholinergic and adrenergic.
Sensory afferents that cross immediately when entering the spinal cord carries___________ information and ascends in which pathway?
Pain and temperature; spinothalamic tract.
What is the only sensory information that doesn’t first synapse in the thalamus before reaching the cortex?
Olfactory.
Where is the tonotopic organization of the auditory system originates from?
Basilar membrane.
What is the depolarization of taste cells in response to a salty taste mediated?
Na+ ions flowing through an amilioride-sensitive Na+ channel.
What types of the sensory receptor cells of the visual system are?
Rods and cones.
What is the equilibrium potential of an ion dependent on?
Valence of the ion, temperature and intra- and extracellular concentration of the ion.
What is the main excitatory neurotransmitter in the brain?
glutamate
In general, by which root the sensory afferents enter and motor efferents exit the spinal cord?
Sensory afferents enter the spinal cord dorsally and motor efferents exit the spinal cord ventrally.
What makes cerebrospinal fluid?
Choroid plexus
What are the functions of cranial nerve X (Vagus Nerve)?
The vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech (via the recurrent laryngeal nerve) and keeping the larynx open for breathing.
What is the area of the body or visual space that when stimulated leads to activity in a primary sensory neuron called?
Receptive field.
After crossing in the medulla, ascending sensory information travels in what structure to reach the thalamus?
Medial lemniscus.
What ion in the endolymph surrounding cilia of the hair cells generates the endocochlear potential?
High K+ concentration.
What kind of shape change of the lens in near-sighted vision.
Rounded.
What is the intensity of a sensory stimulus encoded by?
The frequency of action potentials fired.
What is the “dark current” (depolarizing current) in photo sensory cells mediated by?
A continual influx of Na+ ions.
What is the neurotransmitter of postganglionic neurons in the parasympathetic nervous system?
Acetylcholine.
Most sensory information synapses in what structure where neurons then send axons on to the cortex?
Thalamus.
What causes congenital birth defects such as anencephaly and spina bifida?
Failure of the neural tube to close.
What current is responsible for repolarizing the cell during action potential?
A slow-onset and continuous outward K+ current.
If the capacitance of a membrane is increased, it will have what affect on the time course (i.e., time constant τ) of membrane response to current pulses?
increase
What factors will influence the threshold for ‘two-point discrimination’ sensory tasks?
Receptor density, size of receptive field and lateral inhibition.
What is the cellular response to light falling on a photoreceptor?
Hyperpolarize and refrain from releasing transmitter in amounts corresponding to the light intensity
What is the function of cholinesterase inhibitors?
The inhibition of break-down of acetylcholine in the synaptic cleft.
Reuptake of autonomic monoamine neurotransmitter is an important physiological regulation on synapse function. List three mechanisms that mediate the reuptake of these neurotransmitters.
(1) serotonin transporter (SERT), blocked by selective serotonin reuptake inhibitors (SSRI) (2) norepinephrine transporter (NET), blocked by tricyclic antidepressant (TCA) (3) dopamine transporter (DAT), blocked by amphetamines cocaine blocks all three.
What is the function Wernicke’s area and Broca’s area of the cerebral cortex?
Wernicke’s area is involved in the understanding of written and spoken language. Broca’s area is involved the production of language.
