Exam 2 - Nervous, Sensory, & Immune Systems Flashcards
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.
True
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
tropomyosin
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
t-tubule
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.
5,3,2,1,4
Sound energy is transferred from the tympanic membrane to the oval window by the
ossicles
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?
bitter
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 _____________.
macrophages
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
