29 Questions
What type of signal molecules bind to receptors in the cytosol?
Lipophilic
What is the function of transducers in signal pathways?
To convert extracellular signals into intracellular messages
Which type of receptor is involved in slower responses related to changes in gene activity?
Nuclear receptor
What is the result of the receptor-ligand complex activation?
Activation of an amplifier enzyme
What is the function of the amplifier enzyme (AE) in signal pathways?
To amplify the signal
What is the location of integrin receptors?
Cell membrane
What determines the intensity of a stimulus in the CNS?
The frequency of impulses
What is the main function of the absolute refractory period?
To ensure one-way transmission of nerve impulses
During the relative refractory period, which of the following is true?
Most Na+ channels have returned to their resting state
What happens during the depolarization phase of an action potential?
Na+ enters the cell
What is the main difference between the absolute and relative refractory periods?
The possibility of generating another action potential
What is the primary cause of the depolarizing phase of an action potential?
Opening of voltage-gated Na+ channels
What is the result of the positive feedback during the depolarizing phase of an action potential?
Reversal of membrane polarity to +30 mV
What is the primary function of the sodium-potassium pump in neurons?
To maintain the resting ionic conditions of the neuron
What is the result of the slow inactivation of Na+ channels during the repolarizing phase?
Decreased membrane permeability to Na+
What is the direction of the local currents that occur during the propagation of an action potential?
Away from the point of origin
What is the result of the hyperpolarization phase of an action potential?
An undershoot of the resting membrane potential
What percentage of stimuli is filtered out by the RAS?
99%
What is the result of severe injury to the RAS?
Permanent unconsciousness
What type of motor functions are regulated by the reticular autonomic centers?
Visceral motor functions
What is the purpose of the EEG?
To record the electrical activity that accompanies brain function
What is the function of the ascending general sensory tracts?
To transmit sensory information from the spinal cord to the brain
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
What is the primary function of the blood-brain barrier?
To separate neurons from some bloodborne substances
What triggers the activation of enzymes that modify proteins in the postsynaptic terminal?
The influx of calcium
What is the role of astrocytes in the blood-brain barrier?
To provide signals to endothelium for the formation of tight junctions
What is the result of the binding of glutamate to NMDA receptors?
The increase of synaptic strength
What is the role of CREB in the molecular basis of memory?
To trigger postsynaptic gene activation for synaptic protein synthesis
What is the composition of the blood-brain barrier?
A continuous endothelium of capillary walls, basal lamina, and feet of astrocytes
Test your knowledge of signal pathways, including receptor locations, types of signal molecules, and the effects of ligand-receptor complexes on cellular responses.
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