Term
| Describe the events that occur at an active chemical synapse. |
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Definition
1. AP reaches presynaptic terminal
2. Ca2+ enters presynaptic terminal
3. Vesicles move to membrane & release NTs
4. NTs bind to postsynaptic receptors
5. Membrane channel changes shape & ions enter |
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Term
| 2 factors affecting the strength of a stimulus? |
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Definition
| Total number of APs and duration of the stimulus |
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Term
| What is a local depolarization of postsynaptic potential that opens Na+ and Ca2+ channels? |
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Definition
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Term
| What is a local hyperpolarization of postsynaptic potential that opens Cl- and K+ channels? |
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Definition
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Term
| When a presynaptic axon releases NTs that slightly depolarize the axon terminal of a 2nd neuron this is called... |
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Definition
| Facilitation (More Ca2+ --> more release) |
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Term
| When a presynaptic axon releases NTs that slightly hyperpolarize the axon terminal of a 2nd neuron this is called... |
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Definition
| Inhibition (Less Ca2+ --> less release) |
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Term
| What do direct neurotransmitters do? Speed of action? |
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Definition
| Activate ion channels, fast-acting |
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Term
| What do indirect NTs do? Speed? |
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Definition
| Activate proteins in the postsynaptic neuron, slow acting |
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Term
| These substances act at a distance away from the synaptic cleft and are released into ECF. What are they and what is the speed of their effect? |
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Definition
| Neuromodulators, slow-acting |
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Term
| This NT plays a major role in transmitting PNS information. Can be fast acting (muscle fibers) or slow acting (autonomic function, control of movement, attention in CNS). |
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Definition
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Term
| List 4 amino acids that act as fast-acting NTs. Are they excitatory or inhibitory? |
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Definition
Excitatory --> glutamate, aspartate
Inhibitory --> glycine, GABA |
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Term
| This slow-acting amine NT controls motor activity, cognition and behavior. Associated w/ pleasure & reward. |
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Definition
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Term
| This slow-acting amine NT controls attention to sensory info and is associated with vigilance, sleep, fear, panic disorders & PTSD. |
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Definition
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Term
| This slow-acting amine NT controls mood and perception of pain. It is associated w/ alertness, REM sleep, depression & suicidal behavior. |
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Definition
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Term
| This slow-acting amine NT is concentrated in the hypothalamus and affects hormonal function and arousal. |
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Definition
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Term
| This NT stimulates nerve endings at the site of injury, carries info between SC and brain, and acts as a neuromodulator to intensify signals perceived as pain (allodynia). |
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Definition
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Term
| This NT regulates the vascular system and is active in the brain. It works as a diffusible agent and does not bind to receptors. |
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Definition
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Term
| What 3 mechanisms do postsynaptic receptors use to transduce signals? |
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Definition
Directly (opening ion channels, fast)
Indirectly (opening ion channels, slow)
Activates cascade of intracellular events, including activating genes (slow) |
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Term
| In a second messenger system, what substances act as the first & second messengers, respectively? |
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Definition
1st: neurotransmitter (remains outside cell)
2nd: cAMP (produced inside cell) |
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Term
| Name 2 types of ACh receptors. |
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Definition
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Term
| These receptors open ligand-gated ion channels in the NMJ, autonomic ganglia, and CNS. |
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Definition
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Term
| These G-protein receptors are found in autonomic effectors cells of the heart and brain. |
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Definition
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Term
| Name 2 glutamate receptors that activate ion channels. |
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Definition
AMPA, kainite (fast)
NMDA (voltage and ligand-gated, slow) |
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Term
| Name a glutamate receptor that activates a G-protein pathway. |
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Definition
| Metabotropic glutamate receptors |
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Term
| This type of receptor has positive roles in development and learning and abnormal roles leading to neuronal cell death (causing chronic pain, depression, PD, schizophrenia, and injury ass. w/ stroke). |
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Definition
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Term
| GABA receptors are typically excitatory or inhibitory? Name the two subtypes and how they work. |
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Definition
Inhibitory
GabaA --> opens Cl- channel
GabaB --> second-messenger system |
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Term
| Name 3 types of amine receptors and what system do they utilize? |
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Definition
Dopamine --> 2nd messenger system
Norepinepherine --> G-protein system
Serotonin --> G-protein & ligand-gated |
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Term
| A decrease in the number of receptors at a synapse caused by overstimulation? |
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Definition
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Term
| The switching off of synaptic receptors by phosphorylation? |
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Definition
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Term
| A disease in which antibodies destroy voltage-gated Ca2+ channels in the presynaptic terminal. |
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Definition
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Term
| A disease in which antibodies attack & destroy nicotinic receptors on muscle cells |
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Definition
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Term
| A disease involving dysfunction of ion channels causing some cases of epilepsy & migraine headaches. |
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Definition
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Term
| Put in order from darkest to lightest on a CT scan: CSF, air, white matter, gray matter, bone, fat, freshly congealed blood, water |
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Definition
1. Air
2. Fat
3. Water
4. CSF
5. White matter
6. Gray matter
7. Freshly congealed blood
8. Bone |
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Term
| Structures that form the tops of the "sideways T" shape on a CT and structures that form the stems? |
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Definition
Tops: superior frontal gyrus & superior parietal lobule
Stems: precentral and postcentral gyri |
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Term
| 4 intracranial abnormalities a CT would reveal? |
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Definition
| Hemorrhages, acute cerebral infarctions, neoplasms, mass effects |
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Term
| How would a fresh intracranial hemorrhage appear on a CT scan? After a week? After 2-3 weeks? |
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Definition
Hyperdense
Isodense
Hypodense |
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Term
| How does an acute cerebral infarction appear on a CT? How long does it take to appear in the scan? |
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Definition
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Term
| How does a neoplasm appear on a CT? |
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Definition
| Hypo/iso/hyper dense. Areas of calcification, hemorrhage, cysts, or edema. |
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Term
| What term refers to anything that distorts the brain's usual anatomy by displacement and can be detected by localized compression of the ventricles, effacement of sulci, or distortion of other brain structures? |
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Definition
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Term
| Intravenous contrast material contains what chemical that is denser than brain? How does It appear in areas of increased vascularity or breakdown of the BBB? |
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Definition
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Term
| What method of contrast enhancement allows better radiological visualization of nerve roots and abnormal impingements? |
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Definition
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Term
| Which is better at showing images of basilar structures including the brainstem, cerebellum, and pituitary fossa, MRI or CT? |
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Definition
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Term
| Which is better at showing fresh hemorrhages and bony structures, MRI or CT? |
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Definition
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Term
| Which imaging method if preferred for showing low-contrast lesions? |
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Definition
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Term
| What 3 properties determine the intensity of MRI signals? |
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Definition
| Proton density, T1 (longitudinal relaxation time) and T2 (transverse relaxation time) |
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Term
| What MRI property is aligned with the z-axis parallel to the magnetic field and lasts 300-2000ms? |
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Definition
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Term
| What MRI property is aligned in the x-y plane perpendicular to the magnetic field and lasts 30-150ms? |
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Definition
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Term
| What are the two properties of spin echo (SE) pulse sequence and what do they determine? |
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Definition
Repetition time (TR) - determines T1
Echo time (TE) - determines T2 |
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Term
| A (short/long) TR and a (short/long) TE enhance T1 contrast maximally. (T1-weighted) |
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Definition
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Term
| A (short/long) TR and (short/long) TE enhance T2 contrast maximally (T2-weighted) |
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Definition
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Term
| A (short/long) TR and (short/long) TE enhance proton density |
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Definition
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Term
| Which weighted image looks like anatomical brain sections and is useful for identifying anatomy? |
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Definition
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Term
| Which weight image looks like a film negative and is better for detecting pathological changes? |
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Definition
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Term
| In T1 images, which appears dark and which appears bright: water and fat. Does it have better resolution or better contrast? |
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Definition
Water - dark
Fat - bright
Better resolution |
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Term
| In T2 images, which appears dark and which appears bright: wqater and fat. Does it have better resolution or better contrast? |
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Definition
Water - bright
Fat - dark
Better contrast |
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Term
| 5 Factors affecting the intensity of MRI? |
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Definition
1. Proton density
2. Paramagnetic substance
3. Gadolinium use for intravenous contrast
4. Flow artifact
5. Metallic impacts |
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Term
| How do abnormal areas of increased fluid appear on T1 weighted images versus T2 weighted images? |
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Definition
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Term
| What type of imaging is used to detect distortions in blood vessel patterns such as aneurysms and arteriovenous malformations? |
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Definition
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Term
| What arteries are the radio-opaque iodinated contrast material injected into in cerebral angiography? |
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Definition
| Carotid and vertebral on both sides |
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Term
| What imaging technique is used to measure flow and lumen diameter of large BVs in the head and neck and assessing the proximal portions of arteries? |
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Definition
Neuroangiography ultrasound
Cannot detect aneurysms, vascular abnormalities |
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Term
| What imaging technique takes advantage of the change in MR signal that occurs in areas of flow due to protons moving into and out of the region? Detects regions of decreased or absent arterial BF and is useful for detecting some aneurysms and vascular abnormalities. |
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Definition
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Term
| What imaging technique uses rapid injection of IV contrast used with helical CT to obtain fast images of BVs? |
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Definition
| Spiral CT angiography (CTA) |
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Term
| What interventional neuroradiology technique uses sedative medication infused to localize the side of language and memory function for surgery? |
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Definition
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Term
| What imaging technique is used to locate abnormalities in large regions of the brain that produce abnormal or asymmetrical waveforms in epilepsy or other widespread abnormalities of brain function? |
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Definition
| EEG, has low sensitivity and spatial resolution |
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Term
| What is called when brain electrical signals are recorded in response to specific stimuli? |
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Definition
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Term
| What imaging technique uses SQUID to detect very weak magnetic signals? |
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Definition
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Term
| Name some techniques that measure brain metabolic activity. |
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Definition
Xenon regional cerebral BF mapping
PET
SPECT
Perfusion MRI
BOLD MRI |
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Term
| What imaging technique is able to map local consumption of glucose and local binding of NTs? |
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Definition
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Term
| What imaging technique uses rapid injection of gadolinium and rapid measurements with echo planar imaging to reproduce an image of dynamic blood volume? |
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Definition
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Term
| What imaging technique measures changes in oxy- and deoxyhemoglobin? |
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Definition
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Term
| What imaging technique uses rapid echo planar imaging and strong gradients to measure diffusion coefficient of water? |
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Definition
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