Signal Pathways and Receptor Locations

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What type of signal molecules bind to receptors in the cytosol?

Lipophobic

Lipophilic (correct)

Hydrophobic

Hydrophilic

What is the function of transducers in signal pathways?

To inhibit the signal

To convert extracellular signals into intracellular messages (correct)

To terminate the signal

To amplify the signal

Which type of receptor is involved in slower responses related to changes in gene activity?

Integrin receptor

Nuclear receptor (correct)

G protein-coupled receptor

Receptor-enzyme

What is the result of the receptor-ligand complex activation?

Activation of an amplifier enzyme Signup and view all the answers

What is the function of the amplifier enzyme (AE) in signal pathways?

To amplify the signal Signup and view all the answers

What is the location of integrin receptors?

Cell membrane Signup and view all the answers

What determines the intensity of a stimulus in the CNS?

The frequency of impulses Signup and view all the answers

What is the main function of the absolute refractory period?

To ensure one-way transmission of nerve impulses Signup and view all the answers

During the relative refractory period, which of the following is true?

Most Na+ channels have returned to their resting state Signup and view all the answers

What happens during the depolarization phase of an action potential?

Na+ enters the cell Signup and view all the answers

What is the main difference between the absolute and relative refractory periods?

The possibility of generating another action potential Signup and view all the answers

What is the primary cause of the depolarizing phase of an action potential?

Opening of voltage-gated Na+ channels Signup and view all the answers

What is the result of the positive feedback during the depolarizing phase of an action potential?

Reversal of membrane polarity to +30 mV Signup and view all the answers

What is the primary function of the sodium-potassium pump in neurons?

To maintain the resting ionic conditions of the neuron Signup and view all the answers

What is the result of the slow inactivation of Na+ channels during the repolarizing phase?

Decreased membrane permeability to Na+ Signup and view all the answers

What is the direction of the local currents that occur during the propagation of an action potential?

Away from the point of origin Signup and view all the answers

What is the result of the hyperpolarization phase of an action potential?

An undershoot of the resting membrane potential Signup and view all the answers

What percentage of stimuli is filtered out by the RAS?

99% Signup and view all the answers

What is the result of severe injury to the RAS?

Permanent unconsciousness Signup and view all the answers

What type of motor functions are regulated by the reticular autonomic centers?

Visceral motor functions Signup and view all the answers

What is the purpose of the EEG?

To record the electrical activity that accompanies brain function Signup and view all the answers

What is the function of the ascending general sensory tracts?

To transmit sensory information from the spinal cord to the brain Signup and view all the answers

What is the role of the RAS in 'fight or flight' situations?

To send impulses to the cerebral cortex to keep it conscious and alert Signup and view all the answers

What is the primary function of the blood-brain barrier?

To separate neurons from some bloodborne substances Signup and view all the answers

What triggers the activation of enzymes that modify proteins in the postsynaptic terminal?

The influx of calcium Signup and view all the answers

What is the role of astrocytes in the blood-brain barrier?

To provide signals to endothelium for the formation of tight junctions Signup and view all the answers

What is the result of the binding of glutamate to NMDA receptors?

The increase of synaptic strength Signup and view all the answers

What is the role of CREB in the molecular basis of memory?

To trigger postsynaptic gene activation for synaptic protein synthesis Signup and view all the answers

What is the composition of the blood-brain barrier?

A continuous endothelium of capillary walls, basal lamina, and feet of astrocytes Signup and view all the answers