Neurochem iRAT 1.1-2.1

37 y/o Female: severe allergy medication makes her drowsy. Which cell type in the CNS is most responsible for forming the Blood Brain Barrier (BBB)?

Astrocyte

45 y/o Male: Intraparenchymal brain tumor w/ myelin elements. From what cell in the CNS did this tumor likely arise?

Oligodendrocyte

21 y/o Male: Ruptured aneurysm, CT scan + lumbar puncture is performed, bloody CSF is found. Where was this bloody CSF obtained from?

Subarachnoid space

25 y/o Female: K+ 2.8 mEq/L (normal: 4.0 mEq/L). How would the physician expect the hypokalemia to affect the resting membrane potential of the nerves?

No effect on the resting MP

47 y/o Female: Paresthesia, intracellular potential is measured as -65 m/V (normal). What relative ionic concentrations are responsible for maintaining this membrane potential?

[Na+]out > [Na+]in , [K+]out < [K+]in

What cellular mechanism is most responsible for maintaining the resting potential?

Na+/K+ ATPase

Med students is studying the effects of Ouabain in action potential of neurons. What will happen to the neuronal action potential once ouabain is applied?

Depolarization of membrane potential and insufficient energy of action potentials

52 y/o Male: Ate unusual fish delicacies and then had trouble breathing. The voltage-gated channel of which ion is blocked by the fish toxin and what is the toxin?

Sodium & tetrodotoxin

30 y/o Male: MRI reveals Multiple Sclerosis. Which substance is damaged by this disease and causes the findings on the brain MRI?

Myelin

Curare blocks the endplate potential because it is a competitive inhibitor of ______, the transmitter released at the presynaptic terminal.

Acetycholine

How does the endplate potential propagate?

Passively and with decrement

What factor(s) control the duration of the EPSP at the neuromuscular junction?

Diffusion and Ach-ase

An endplate potential in a skeletal muscle cell could in principle be produced by a decreased permeability to which of the following ion(s)?

K+

What are the fundamental differences between the process of synaptic transmission in the CNS versus the neuromuscular junction?

CNS uses different neurotransmitter & NMJ have larger action potentials

Consider a motor neuron that receives two inputs. An active potential produced in a sensory neuron 1 produces a 1 mV EPSP and a a single action potential in sensory neuron 2 also produces a 1 mV EPSP. If action potentials are produced simultaneously in sensory neuron 1 and 2, the EPSPs summate to produce a summated EPSP which is twice that of the individual ESPS. This is called spatial summation. T or F?

True

What does IPSP stand for?

Inhibitory PostSynaptic Potential

Which neurotransmitter is released by the inhibitory neurons?

Glycine & GABA

Gap junctions are associated with?

Electrical

Which on of the following toxins behaves similarly to curare?

alpha - bungarotoxin

The presence of Choline acetyltransferase (CAT) is the “marker” that a neuron is?

Cholinergic

The level of serotonin in the brain is regulated principally by the amount of?

Tryptophan

How does black widow spider venom effect the neuromuscular junction?

Increases the release of neurotransmitters

The first step in the synthesis of catecholamines is the hydroxylation of the tyrosine to form?

Dopa

The muscarinic receptors can?

All of the above

Which of the follow is effective in increasing the level of acetylcholine in the synapse of neuromuscular junction?

Inhibiting AChE

At synaptic junctions released ACh is rapidly hydrolyzed by the enzyme?

AChE

Which one of the following receptor is linked only to the G protein?

Histamine

GABA and glycine ionotropic receptor are selectively permeable to K+ (reverse potential near -70 mV). When they open, they can cause the neuron to hyperpolarize and therefore drive the membrane potential away from the threshold for firing an action potential. T or F?

False only GABA

GABA mediates the majority of inhibitory synaptic actions in the CNS. GABA is synthesized from glutamate in a reaction catalyzed by glutamic acid decarboxylase (GAD). T or F?

True

Limbic is a Latin term for?

Border

Outputs(s) or efferent(s) from hippocampus pass to?

All of the above

The mild hearing loss and its effect on speech may suggest damage to the?

Temporal lobe

Wernicke’s are is located in?

Parietal/temporal lobe

Nearly half of all US pregnancies are unplanned, so the risk of alcohol exposure in pregnancy is significant. T or F?

True

Neural tube expands in the front of the embryo to form the five subdivisions. Which one of the following subdivisions differentiates to form the substantia nigra?

Mesencephalon

Hindbrain develops into which one of the following structures?

Cerebellum, pons, and medulla

Which one of the following is the major input to the hippocampus?

Entorhinal cortex

Which one the following is not part of the limbic system?

Broca’s

What does hippocampus mean in Greek?

Seahorse

The striatum is involved with memories for skills and habits. T or F?

True

Which one of the following terms refers to the loss of old memories?

Retrograde amnesia

What is the advantage of using Aplysia in neuroscience studies?

All of the above

Sensitization is defined as the enhancement of the response to a test stimulus as a result of delivering strong generally noxious stimulus to the animal. T or F?

True

Learning is due to a reorganization of the nervous system or the growth of new neurons. T or F?

False

What part of the brain is involved with emotional memories?

Amygdala

Whereas H.M. had a great difficulty forming new memories for facts and events, he still had all of his old memories for facts and events. This type of memory deficit is called?

Anterograde amnesia

The process by which an initially labile memory is transformed into a more enduring form is called?

Consolidation

The word NURSE is recognized more quickly following the word DOCTOR than following the word BREAD. This is an example of _____ that involves the neocortex.

Priming

Classical conditioning is an example of?

Implicit memory

Exposing the skin to controlled heat makes it possible to measure the threshold for pain. When the temperature of the skin reaches _____ ± 1*C, subject reports pain. This temperature denatures tissue protein ad elicits damage in all subjects.

45*C

Two sequential pain sensations in short time intervals is the result of the sudden painful stimulation. The first one is immediately after the damage. It is followed several seconds later with additional pain sensation. These two separate sensations are several seconds apart because a fast transmitting information sensation is carried via C fibers and is followed several seconds later with slow transmitting pain information via A delta fibers. This is known as “double pain sensation”. T or F?

False, sharp is by delta fibers, slow is by c fibers.

Which of the following fact DOES NOT activate nociceptors?

Glycine

Nociceptors are sensory receptors that detect signals from damaged tissue or the threat of damage and indirectly also respond to the chemicals released from the damaged tissue. Nociceptors are free nerve endings found in the skin, muscle, joints, bone, and viscera. Recently, it was found that nerve endings contain _____ channels that sense and detect damage.

TRP

Allodynia is pain resulting from a stimulus that does not normally produce pain.

True

No nociceptors are found inside the CNS. T or F?

True

The cell bodies of the primary afferent pain neurons from the body, face, and head are located in the dorsal root ganglion (DRG) and in the trigeminal ganglion respectively. T or F?

False, it’s spino & trigeminal

Which of the following pathway does not transmit pain information to the CNS?

Medial lemniscal does not transmit to the CNS

C fibers comprise 10% of all the fibers carrying noxious input. T or F?

False

Skin nociceptors may be divided into different categories based on function. Which one of the following belongs to the skin nociceptor category?

Skin muscles, all of the above

What is true for cone photoreceptors?

What type of cone constitutes the majority of the cones in the eye?

Which neuron contributes to the production of sharper images?

Why do rods contain more photopigment than cones?

Which statement describes ON bipolar cells?

How do rods differ from cones?

How many different types of cones exist in the human eye?

ON bipolar cells received their name because?

Which activity most likely requires the use of rods?

There are two different types of photoreceptors in the human eye, rods and cones. In contrast to cones, rods?