Exam 2 - Nervous, Sensory, & Immune Systems Flashcards Preview

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Flashcards in Exam 2 - Nervous, Sensory, & Immune Systems Deck (30)
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An inhibitory postsynaptic potential (IPSP) occurs in a membrane made more permeable to

potassium ions


When several EPSPs arrive at the axon hillock from different dendritic locations, depolarizing the postsynaptic cell to threshold for an action potential, this is an example of

spatial summation


A neuron has a membrane potential of -70 mV, a threshold of -40 mV, and equilibrium potentials for K, Cl and Na of -90 mV (EK), -50 mV (ECl) and +60 mV (ENa), respectively. To generate an action potential in this cell, which of the following channels would you have to open?

Na channel


What factors determine the direction of movement of ions across a biological membrane?

both membrane potential and concentraton gradient


All action potentials are preceded by graded potentials.



For a typical neuron like that shown, in what zone would you expect to find the myelin sheath?

I cant upload the pic but if the neuron looked like O----K it'd be in the --- part


In an action potential, which of the following events happens first?

voltage-gated Na+ channels open


In what direction would K flow in a cation selective channel that is opened by a ligand?

Out of the cell


The equilibrium potential (EK) for K+ ions in a normal neuron is -92 mV and the resting membrane potential (VM) is -70 mV. If K+ channels in this neuron were to open, what would happen?

K+ ions would move out of the cell and the cell would hyperpolarize


The typical stimulus that activates a mechanosensitive channel is:

membrane stretch


Which event represents the physiological basis for the THRESHOLD?

opening of voltage-gated Na+ channels


The detection of pitch (frequency of sound) is generally most dependent upon the physical properties of what specific structure?

basilar membrane


The protein that physically interferes with the binding between actin and myosin at rest is



In phototransduction, what is most directly responsible for the dark current?

Na+ ions moving in through the cGMP-gated channels


This structure carries action potentials deep into the interior of skeletal muscle cells. It is called a



Which of the following is the correct sequence that occurs during the excitation and contraction of a muscle cell?
[1] Tropomyosin shifts and unblocks the cross-bridge binding sites.
[2] Calcium is released and binds to the troponin complex.
[3] Transverse tubules depolarize the sarcoplasmic reticulum.
[4] The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP.
[5] An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.



Sound energy is transferred from the tympanic membrane to the oval window by the



When a vertebrate photoreceptor responds to light, what is the cellular response?

the photoreceptor hyperpolarizes and releases less neurotransmitter


As the stapes pushes on the oval window, fluid waves travel down the cochlea causing vibrations in specific regions of the basilar membrane, which in turn leads to activation of specific hair cells in the organ of Corti. Which of the following statement is true about this process?

the movement of the basilar membrane pushes the hair cells against the tectorialmembrane


In terms of its functional role in taste (nutrient detection vs. toxin avoidance), which of the following basic tastes is unlike the other three?



this one is too long but it's asking about the properties of rods and cones

sorry :|


Muscle contraction is controlled in part by a rise in Ca2+ in the sarcoplasm. Where does this Ca2+ come from?

from the sarcoplasmic reticulum via Ca2+ release channels


Which of the following is considered a first line of defense against pathogens?

acidic secretions from the nasal cavity


Why might it be a bad idea to take aspirin to reduce a moderate fever?

B and T cells are more active at high temperatures


An autoimmune disease is one is which:

your body's immune system begins to attack its own tissues


Which of the following differentiates T cells and B cells?

T cells but not B cells can directly attack and destroy invading pathogens


What effect do the perforins on pathogenic bacteria?

they lead to the formation of pores in bacteria, effectively killing them


The cells in the immune system that have the greatest phagocytic activity are the _____________.



Natural killer cells are considered part of

innate immunity


Which of the following cell types directly interacts with and kills infected or cancerous cells?

Cytotoxic T cells