online week 4- neurobiology

Is the following statement true or false? "During an inhibitory graded potential, the membrane potential is inside less negative than the resting membrane potential." True False

False

______ are the cells of the nervous system which remove nervous tissue that is no longer functional. Oligodendrocytes Ependymal cells Astrocytes Microglial cells Cytotoxic T cells Neurons

Microglial cells

A resting neuronal membrane is polarized because the concentration of: Na+ is higher on the outside and K+ is higher on the inside Na+ is higher on the inside and K+ is higher on the outside Na+ and K+ ions are higher outside than inside the plasma membrane Na+ and K+ ions are higher inside than outside the plasma membrane

Na+ is higher on the outside and K+ is higher on the inside

What is/are the function(s) of the nervous system? detecting stimuli processing information sending a response to muscles or glands all of these choices are correct

all of these choices are correct

Both action potentials and graded potentials: begin at the axon hillock of a neuronal cell. begin in dendrites and the cell body of a neuronal cell. are deviations in membrane potential in a neuronal cell. are formed by the opening of voltage-gated sodium and potassium channels.

are deviations in membrane potential in a neuronal cell.

Is the following statement, true or false? "The plasma membrane typically has more K+ leak channels than Na+ leak channels, which contributes to the inside of the membrane being negatively charged." True False

True

The puffer fish, an expensive gourmet delicacy in Japanese cuisine, produces a potent neurotoxin called Tetrodotoxin (TTX). A chef must remove the tissues that produce TTX carefully before serving. When neurons are treated with TTX, graded potentials in the treated neurons are unaffected, but action potentials are blocked. What kind of gated-ion channels are inhibited by TTX? Ligand-gated ion-channels Voltage-gated ion-channels Mechanically-gated ion-channels

Voltage-gated ion-channels

Which of the following statements regarding potassium leak channels in neuronal plasma membranes is true? Potassium leak channels: are the most numerous open channels in the plasma membranes of resting (non-stimulated) neurons. allow any type of ion to pass through the plasma membrane more easily. only allow ions to move in a single direction across the plasma membrane. consume ATP to move potassium against a concentration gradient. make the plasma membrane less permeable to potassium.

are the most numerous open channels in the plasma membranes of resting (non-stimulated) neurons.

Graded potentials most often occur in the: dendrites and cell body dendrites and axon cell body and axon dendrites only myelin sheath axon and axon terminal

dendrites and cell body

The cerebrospinal fluid (CSF) is a clear, colorless fluid that circulates around the brain and spinal cord, and in the brain ventricles, to provide protective cushioning, circulate nutrients, and remove waste products. While examining a patient, you determine there is a lower than normal level of CSF being formed. Using your knowledge of the functions of each of the types glial cells, you surmise that the _______ are malfunctioning. oligodendrocytes microglial cells ependymal cells Schwann cells astrocytes

ependymal cells

Choose the statement below that accurately represents a significant feature of graded potentials. excitatory graded potentials can summate to reach the threshold voltage of a neuronal plasma membrane. excitatory graded potentials activate enzymes to excite the cell. excitatory graded potentials randomly occur all the time but are of no significance. excitatory graded potentials will subtract from each other to create a smaller graded potential.

excitatory graded potentials can summate to reach the threshold voltage of a neuronal plasma membrane.

In the human brain, the most abundant cell type is the: motor neuron. sensory neuron. glial cell. smooth muscle cell. endothelial cell. skeletal muscle cell.

glial cell

Which of the following statements regarding the sodium-potassium ATPase pump is false? The sodium-potassium ATPase pump: uses energy to move ions across the plasma membrane of a cell. moves three sodium ions for every two potassium ions. contributes to the establishment of a resting membrane potential around -70mV in most neuronal cells. is expressed exclusively in neuronal cells. actively moves potassium to the inside of a cell and sodium to the outside.

is expressed exclusively in neuronal cells.

The resting membrane potential of a neuron is due mostly to: open sodium leak channels. open potassium leak channels. open calcium leak channels. open chloride leak channels. closed sodium leak channels. closed potassium leak channels.

open potassium leak channels.

Which of the following statements regarding graded potentials is correct? Graded potentials: result when ion movement across a plasma membrane causes a minor change in the resting membrane potential. propagate down the entire lengths of an axon. occur when voltage-gated ion channels open. are associated with ion movement through leakage channels. are most often observed in axons.

result when ion movement across a plasma membrane causes a minor change in the resting membrane potential.

To study the role of Ca2+ in regulating biological processes, Roger Tsien and colleagues developed highly selective Ca2+ indicators, for example, the dye "Fura-2." Fura-2 becomes fluorescent in the presence of Ca2+. When ________ are loaded with Fura-2, an increase in cytoplasmic fluorescence is expected when the neuron is ________. axons; at rest synaptic terminals; at rest synaptic terminals; firing action potentials cell body; firing action potentials dendrites; at rest

synaptic terminals; firing action potentials

A scientist discovers that a neuron does not have adequate stores of neurotransmitter. What part of the neuron is she observing? the axon the axon terminal the dendrites the cell body

the axon terminal

Graded potentials are generated by: chemical reactions occurring near the cell membrane which change the cell's electrical state a sudden surge of ATP production on one side of the cell membrane feedback created in the axon of the neuron the momentary opening of mechanically-gated or ligand-gated channels

the momentary opening of mechanically-gated or ligand-gated channels

You are studying a sensory neuron that forms a synaptic connection with an interneuron in culture. When you stimulate the sensory neuron, you do not record a change in voltage in the interneuron. Which of the following can explain this result? the sensory neuron was stimulated below the threshold value stimulation of a sensory neuron can never generate a change in voltage in an interneuron the interneuron was stimulated below the threshold value the interneuron was stimulated above the threshold value the sensory neuron was stimulated above the threshold value

the sensory neuron was stimulated below the threshold value

Which of the following channels is NOT involved in the formation of graded potentials triggered by extracellular cues? voltage-gated ion channels ligand-gated ion channels mechanically-gated ion channels All of these ion channels are involved in graded potential formation.

voltage-gated ion channels

Which of the following ion channels are highly concentrated in neuronal axons? ligand-gated ion channels voltage-gated ion channels mechanically-gated ion channels All of these ion channels are located in neuronal axons.

voltage-gated ion channels

The threshold potential of a neuronal membrane refers to the voltage at which: the axon blows up. the neuronal plasma membrane breaks down. voltage-gated sodium and potassium channels are stimulated. a single graded potential stimulates an action potential in a neuron. graded potentials are generated.

voltage-gated sodium and potassium channels are stimulated.

Which of the following statements is/are correct concerning neuronal cells? The cell body is the metabolic center and contains the nucleus and other organelles. Dendrites receive chemical signals from other neurons. Axons conduct electrical signals in the form of action potentials. All of these responses are correct

The cell body is the metabolic center and contains the nucleus and other organelles.???? I think this one is incorrect, should be "all of these responses are correct"

Within a motor neuron, information moves from: dendrite to cell body to axon. axon to cell body to dendrite. cell body to axon to dendrite. axon to dendrite to cell body. dendrite to axon to cell body.

dendrite to cell body to axon.

Ions cross the plasma membrane through channels. What factors will affect the movement of the ions? concentration gradients only electrical gradients only pressure gradients only both chemical and electrical gradients pressure, chemical, and electrical gradients

both chemical and electrical gradients