Neurophysiology Review Flashcards
What is the general rule with size of neurons and their membrane potential?
The bigger they are, the more negative they are (i.e. Skeletal muscle and large neurons are -70 and -90 mV respectively)
What are the two ways that the membrane potential is maintained?
- Na/K ATPase
2. Selective permeability
Which two ions cannot pass the membrane at rest but do so through channels?
- Potassium (leak channels)
2. Chloride
Describe the phases of a fast action potential (include which gates are open/closed).
- Rapid depolarization (Voltage-gated Na Channels are open)
- Repolarization (Inactivation of Na Channels and opening of Voltage-Gated K Channels)
- @ Completion (Both Na and K Channels are closed)
- Activity of the Na/K ATPase returns concentration gradients
Describe the phases of a slow action potential (include which gates are open/closed).
- Depolarization (voltage-gated Ca Channels are open)
- Repolarization (K efflux and Ca channels are closing)
- @ Completion (both channels are closed)
- Na/K ATPase and Ca ATPase are required
Which refractory period cannot elicit an action potential?
Which gates are involved?
When does it occur?
Absolute Refractory Period
Voltage-Gated Na channels are open or inactive
Occurs during an on-going action potential
Which refractory period requires greater stimulation to produce an action potential?
Which gates are involved?
When does it occur?
Relative Refractory Period
At least some Voltage-gated Na channels are closed (others are in the inactive state-that’s why it is harder)
Occurs during repolarization and a bit after the on-going action potential has completed
What is the term when a neuron (or muscle cell) is forced to remain in a depolarized state for too long?
Describe how this works?
Voltage Inactivation (Depolarization Block)
In the inactive state, depolarization no longer opens the Na Channels
If the channel is open, the gradient for Na and/or K is abolished
What is the end result of Voltage Inactivation?
Depolarization block prevents the cell from releasing NT once the block has occured.
Essentially the cell is STUCK in the absolute refractory period!
What is the term used when an action potential jumps from node of Ranvier to node?
Saltatory Conduction
Which process is going to be decreased in patients with Multiple Sclerosis?
Saltatory Conduction
Explain how you increase your conduction velocity with Saltatory Conduction.
Myelin Sheath prevents the Na from leaving the cell!
Nodes have Voltage-Gated Channels and the rest of the axon does not have as many
What are Post-Synaptic densities?
Likely Neurotransmitter receptors on the post-synaptic terminal
Put these steps in order:
- Fusion of vesicle with cell membrane creates opening
- Depolarization of terminal by action potential causes the Voltage-Gated Ca channels to open.
- NT released in synaptic trough
- NT diffuses to post-synaptic cell and binds to its receptor.
- Ca binds to docking proteins
- Influx of Ca
- Docking proteins have vesicles associated with them and Ca will trigger a conformational change that will bring the vesicle to the plasma membrane
- NT must be removed from the synapse
2 - 6 - 5 - 7 - 1 - 3 - 4 - 8
Ca/Na can create a EPSP at the Post-Synaptic Membrane. Cl/K can create an IPSP at the post-synaptic membrane. What is the name of the receptor that they bind to?
Ionotropic
What are the names of the receptors that are located on the post-synaptic cell linked to GPCRs?
Metabotropic
Dopamine, Epinephrine and Norepinephrine all the same precursor named _________ .
Tyrosine
What is the precursor for histamine?
Histidine
What is the precursor for Serotonin?
Tryptamine
Which neurotransmitter is responsible for mood/affect?
Serotonin
Which neurotransmitter is responsible for Parkinson Disease/Mood/Affect/emotional experience?
Dopamine
Which neurotransmitter is responsible for awareness and memory/Alzheimer Disease?
Acetylcholine
Which neurotransmitter is inhibitory in nature and allows Cl into the cell? It is also used for general anesthesia and its activation is used to reduce spasticity.
GABA
Which neurotransmitter is inhibitory and stays in the spinal cord?
Glycine
Which NT is used in for pain relief/addiction?
Opiods
Which NT is related to vasodilation?
Nitric Oxide
Glutamate/Aspartate are which type of amino acids?
Excitatory
Which ion do NMDA receptors allow in?
Ca2+
Which receptor is going to have excess activation after a seizure/stroke/TBI?
NMDA receptors
Which NTs are going to be involved in consciousness, seizure disorders, excitatory effects of stroke/seizures/etc…?
Excitatory Amino Acids
Which NT is released at the synapse between the preganglionic and postganlgionic fibers?
Acetycholine
Which NT is released at the synapse between the postganlgionic fibers and the effector organ in sympathetic/parasympathetic?
Sympathetic: Norepinephrine
Parasympathetic: Acetylcholine
Which structure mainly controls the ANS?
Hypothalamus
What is produced by the Choroid Plexus?
Cerebrospinal Fluid
True or False. CSF has low Mg, protein, glucose and K when compared to blood.
FALSE
HIGH Mg2+ (but everything else is right)
Tight junctions between capillary endothelial cells and podocytes from glial cells make up __________ .
Blood Brain Barrier
___________ is responsible for moving many drugs/other substances from CSF to the Blood.
P-glycoprotein
What is it called when you get an accumulation of CSF in the CNS?
Hydrocephalus
Which Glucose transporter is involved in maintenance of the Blood Brain Barrier and is also insulin-independent?
GLUT-1
Which transporter’s activation is tied to K+ levels?
Na/K/2Cl Transporter
Related cerebral blood flow to the activity of neurons.
Direct Relationship
More active neurons = more metabolites = more blood flow due to vasodilation
If systemic blood pressure goes too high, activation of ____________ receptors on cerebral vasculature causes vasoconstriction which will prevent the high blood pressure from damaging the capillaries involved in the Blood-Brain Barrier.
alpha-adrenergic (probably alpha 1)
If the brain blood flow is compromised, the brain will activate pressor regions in the _________ which will drive __________ up to force blood through to the brain.
Medulla
Systemic Pressure
What is the “fun fact” about the innervation of the vasculature in the brain that does not occur anywhere else in the body?
Innervated by Nociceptors!
Why do you feel pain/headache when the cerebral vasculature is distended, torqued, or twisted?
Cerebral Vasculature is Innervated by Nociceptors!
Increases in __________ can lead to a tremendous increase in __________ as the brain tries to maintain perfusion.
Intracranial Pressure
Systemic Blood Pressure
When dealing with Brain Arousal Mechanisms, if sleep cycles are present but consciousness is not, what do we say that is?
Awake
When dealing with Brain Arousal Mechanisms, if we are considering different levels of consciousness, what we say that is?
Aware
Which cutaneous receptors have the highest threshold?
Bare Nerve Endings
Which sense takes the path of Dorsal Columns / Spinothalamic Tract?
Cutaenous Sensation
When talking about the processing of Sensory information, if a stimulus is strong enough, it will pass through to the cortex. Which region in the cortex is responsible for the initial processing and identification of the characteristics of what activated the receptor?
S1
Which region in the cortex has the ability to recognize an unseen object by touch (stereognosis), compare two objects and ties it to memory?
S2
Which region in the cortex is in the association cortex and is responsible for naming objects?
PTO
_________ can produce disruptions in sensory processing, leading to numbness.
Strokes
Which receptors contain bare nerve endings that can be slightly myelinated (A delta fibers) or unmyelinated (C fibers)?
Nociceptors
Which two chemicals can activate nociceptors? What happens when these two chemicals activate the nociceptors?
- Bradykinin
- Substance P
This leads to sensitization of the nociceptors and increased activation with similar stimulus (the pain perceived increases)
The Spinothalamic tract is used for which type of pain?
Fast/Sharp Pain (A delta fibers)
The Spinoreticuluothalamic path is used for which type of pain?
Slow/Dull pain (C fibers)
Prescribed opiods work to reduce pain transmission by activating which pathway?
Spinoreticulothalamic Pathway
The Spinoreticulothalamic pathway is important because there is a synapse in the spinal cord at the level where the afferent enters the spinal cord. The __________ is a non-nociceptive input from A beta fibers (cutaneous) that inhibits painful inputs via presynaptic inhibition. Descending opioid inputs via the __________ also act to decrease transmission at this synapse.
Gating Mechanism (gate theory of pain)
Raphne Nuclei
In the cortex, __________ is responsible for coordinating autnomic responses to pain.
Insular Cortex
What is the term used when painful inputs are recognized as painful, but not perceived as unpleasant?
Asymbolia
Chronic (neuropathic) pain results from changes in the _______________.
Periphery
Where does most of the refraction of light occur and remains constant?
Cornea
Where does variable refraction of light occur?
Lens
Cloudiness in lens that interferes with light passage is known as _________ .
Cataract
The inability to change the shape of the lens due to stiffness or inflexibility is known as __________ .
Presbyopia
True or False. A Flatter lens is required to see objects closer to us.
False
Which photoreceptors are responsible for color/light?
Presence of Color - Cones
Presence of Light - Rods
True or False. When light hits a photoreceptor, it causes the cell to become depolarized.
False. (Hyperpolarized)
When light hits a photoreceptor, you will have a _________ in _________ release into the synapse.
Decrease
Glutamate
Which cell is going to dictate the actions of the Ganglion Cell?
Bipolar Cell
Put the following components in order as they go to the brain:
- Lateral Geniculate Body
- Optic Nerve
- V2/V4
- Ventral/Dorsal Visual Pathway
- Primary Visual Cortex
- Optic Chiasm
2 - 6 - 1 - 5 - 3 - 4
Which part of the vision pathway is responsible for allowing the eyes to move together, detect motion and the initial processing of visual information?
Lateral Geniculate Body
Which part of the vision pathway is responsible to create an outline map of the visual field and initial color processing?
Primary Visual Cortex
Which part of the vision pathway is responsible for depth perception?
V2
Which part of the vision pathway is responsible for color perception?
V4
Which part of the vision pathway is responsible for the use of visual information in motion?
Dorsal Visual Pathway
Which part of the vision pathway is responsible for naming objects?
Ventral Visual Pathway
Which -lymph in the cochlea is similar to the ECF (High Na/Low K)?
Perilymph
What is the composition of Endolymph?
High K and Low Na
Put the following in order in regards to auditory information traveling to the brain:
- Primary Auditory Cortex
- Superior/Inferior Colliculus
- Auditory Association Cortex
- Superior Olive
4 - 2 - 1 - 3
Which part of the auditory pathway is responsible for localizing the source of the sound?
Superior Olive
Which part of the auditory pathway is responsible for suppressing information from echoes?
Inferior Colliculus
Which part of the auditory pathway is responsible for creating a 3D map of where the sound is?
Superior Colliculus
Which part of the auditory pathway is responsible for creating a tonotopic map of sound (i.e. Loudness)?
Primary Auditory Cortex
Which part of the auditory pathway is responsible for creating a complex map of sound (i.e. harmonies).
Auditory Association Cortex
The utricle and saccule are responsible for detecting which type of information?
Utricle - Horizontal
Saccule - Verticle
The semicircular canals (horizontal, anterior and posterior) are responsible for detecting which type of movement?
Angular Acceleration
- Horizontal - Turning in circle
- Anterior - Falling Forward
- Posterior - Falling Backward
With vestibular central processing, you are going to be ___________ the reflexes.
Suppressing
Which reflex is able to detect when a force that is being developed during a muscle contraction is too strong and provides a strong inhibitory signal to stop the contraction?
Golgi Tendon Reflex
Which reflex is involved in muscle contraction due to the stretching of the muscle spindle?
Myotactic Reflex
Which afferent neuron in the muscle spindle is responsible for the length and rate of change? Which one is JUST the change in length?
Afferents Ia: Length and rate
II: Length
Activity of the gamma motorneuron is controlled via the ______________ .
Brainstem
The brainstem inhibitory region is going to inhibit _______ and it requires ________ by the _______ .
Gamma motor neuron
Activation
Cortex
The brainstem facilitatory region is going to ________ gamma motorneurons and is _________ active.
Activate
Spontaneously
Spasticity results from damage to the cortical regions that activate the _______________ .
Brainstem Inhibitory Area
In regards to voluntary motion, which area will relate the desired action to the LMNs to activate the muscles?
Primary Motor Cortex
In regards to voluntary motion, which area is responsible for planning of motions and postural control?
Supplementary and premotor cortex
Which part of the cerebellum is responsible for postural control?
Medial Spinocerebellum
Which part of the cerebellum is responsible correcting ongoing motion?
Lateral Spinocerebellum
Which part of the cerebellum is responsible planning of complex motion and motor memory?
Cerebrocerebellum
Which part of the cerebellum is responsible eye movements and postural movements for future motions?
Vestibulocerebellum
Which disease results from a loss of dopaminergic inputs and is characterized by bradykinesia?
Parkinson’s Disease
Which disease results from loss of the indirect basal ganglia pathway and results in excess motion?
Huntington’s Disease
Which pathway in the basal ganglia is releasing dopamine from the substantia nigra; thus, allowing motion to occur?
Direct Pathway
Which pathway in the basal ganglia allows Ach to activate GABAergin input; thus, inhibiting motion?
Indirect Pathway
