Biology 161 Exam 2

Which of the following types of neurons will pass through a spinal cord dorsal root ganglion?

A: afferent

B:efferent

A: afferent

What structures are likely to be found in nerves?

A. Dendrites

B. Axons

C. Cell bodies

D. Ganglia

E. Myelin sheaths

B and E

Which of the following structures are part of the brainstem?

A. Cerebrum

B. Cerebellum

C. Midbrain

D. Pons

E. Medulla

C, D, and E

Which part of the neuron typically receives signals from other neurons?

Dendrites

An action potential is more likely to travel

A. from axon hillock to dendrite

B. from axon terminal to soma

C. from soma to axon terminal

C

Injured tissue releases chemicals which activate platelets in the blood. Activated platelets release chemicals to attract MORE platelets, eventually forming a blood clot. Which of the following is this an example of?

A. Negative feedback

B. Positive feedback

C. Neither

B

What is another name for soma?

cell body

The long, unbranched process of many typical neurons is called the

A. axon

B. dendrites

C. cell body

D. axon hillock

A

The epineurium is a tough, protective outer covering of a nerve. Which of the following connective tissues make the epineurium?

A. Adipose

B. Areolar

C. Dense irregular

D. Dense regular

E. None of the above

C

Which of the following structures is not part of the CNS?

A. Axon

B. Spinal cord

C. Ganglion

D. Dendrites

E. Brain

C

Which of the following classes of neurons are responsible for detecting sensory information?

A. Interneuron

B. Afferent neuron

C. Efferent neuron

D. Motor neuron

B

In thinking about a negative feedback loop, which class of neurons will form a synapse with a target tissue? The action of this class of neurons will cause a response in the target tissue to bring the body back to a setpoint.

A. Interneuron

B. Afferent neuron

C. Efferent neuron

D. Sensory neuron

C

Epidural analgesia is the injection of a drug into the space outside the dura mater, that numbs the spinal nerves. If the epidural is correctly placed, will the drug mix with the circulating CSF that surrounds the spinal cord?

A.Yes, it will

B.No, it will not

B

Pseudounipolar neurons are associated with which of the following spinal cord structures?

A. Ventral horn

B. Dorsal root

C. Ventral root

D. Lateral horn

B

You step on a thumb-tack. Which statement is TRUE about the neuron that carries the sensation of pain back to your central nervous system?

A.Its cell body is located in the dorsal root ganglion and its axon travels through the ventral root of the spinal nerve.

B.Its cell body is located in the ventral root ganglion and its axon travels through the ventral root of the spinal nerve.

C.Its cell body is located in the dorsal root ganglion and its axon travels through the dorsal root of the spinal nerve.

D.Its cell body is located in the spinal cord and its axon travels through the ventral root of the spinal nerve.

C

What types of structural neurons are the following: sensory neurons, interneurons, and motor neurons?

Sensory neurons are pseudounipolar and the other two are multipolar.

Which class of neurons function in integration of information?

Interneurons

Which part of the neuron communicates an electrical signal to target tissue?

A. Dendrites

B. Cell body

C. Axon

D. Nucleus

C

Afferent and efferent neurons are located completely within the central nervous system (CNS).

True/false

False

Motor neurons are which type of neuron?

Pseudounipolar

Multipolar

Bipolar

Multipolar

Smoking can damage the taste receptor cells that are normally stimulated by chemicals in our food. Which part of the neural circuit are these cells directly associated with?

A. afferent

B. efferent

C. interneurons

A

Sodium and potassium ion are both positively charged (cations).

True/false

True

Ions can cross a membrane without the help of an integral membrane protein.

True/false

False

Sodium potassium pumps require the use of energy to move ions.

True/false

True

Sodium potassium pumps move ions down their concentration gradient - from high concentration to low concentration.

True/false

False

Electronic spread requires the use of energy.

True/false

False

The change of potential due to electrotonic spread will get larger the further away from the starting point it travels.

True/false

False

Which of the following ratios represent the movement of ions from OUT of a neuron to INSIDE a neuron due to the sodium potassium pump?

A. 3 sodium ions out : 3 potassium ions in

B. 2 sodium ions out : 2 potassium ions in

C. 3 sodium ions out : 2 potassium ions in

D. 2 sodium ions out : 3 potassium ions in

C

Which of the following characteristics contribute to sodium passively entering a neuron if the membrane is permeable to sodium (like through a channel)? Choose all that apply.

A. The inside of the cell is more negative than the outside

B. The inside of the cell is more positive than the outside

C.There are more sodium ions outside the cell compared to inside the cell.

D. There are fewer sodium ions outside the cell compared to inside the cell.

A & C

Which of the following structures helps to transmit information from the spinal cord to the extremities of the body?

A. Dorsal root

B. Ventral root

C. Dorsal root ganglion

B

The soma of psuedounipolar neurons is found in the gray matter of the spinal cord.

True/false

`False

The cell body of motor neurons is located in the

A. Dorsal root

B. Ventral horn

C. Dorsal root ganglion

D> White matter

B

Which layer of the meninges will be closest to the bone of the vertebrate?

A. Pia mater

B. Dura mater

C. Arachnoid Mater

B

Signals being transmitted by neurons in a circuit enter the spinal cord via the dorsal root and exit the spinal cord via the ventral root.

True/false

True

A drug binds to and inhibits protein pumps of a cell. What is one result of this event?

A. Passive transport will not occur.

B. Solutes will not move down their concentration gradient.

C. Active transport will not occur.

D. Facilitated diffusion will not occur.

C

Creation of the chemical gradient requires the use of energy?

True/false

True

Action of the Na+/K+ pump causes the ICF to be slightly more ________compared to the ECF

A. positive

B. negative

B

If the membrane is permeable to potassium ions via leak channels, which way will they diffuse based on chemical gradient?

A. Into the cell

B. Out of the cell

C. Both directions

B

If the membrane is permeable to sodium ions via leak channels, which way will they diffuse based on chemical gradient?

A. Into the cell

B. Out of the cell

C. Both directions

A

Which statement is true in regards to the electrochemical gradient of neurons?

A. Pumps do not require energy to create concentration gradients.

B. Sodium ions tend to diffuse into a neuron because of their concentration AND electrical gradients.

C. Neurons are more permeable to sodium ions so the resting membrane potential is negative.

D. Large anions are trapped outside of neurons.

B

The change of potential due to electrotonic spread will get larger the further away from the starting point it travels.

True/false

False

In which type of potential do voltage-gated channels play a role?

A. Electrotonic (local/graded) potentials

B. Action potentials

B

What event occurs next if the electrotonic spread causes a change of potential from -70mV (at rest) to -55mv?

A. Voltage-gated potassium channels open.

B. Voltage-gated sodium channels open.

B

The axon hillock is the location of large quantity of voltage-gated channels.

True/false

True

An action potential helps to "boost" electrotonic potential so that it can spread further (like down an axon) without losing strength.

True/false

True

If a chemical binds to a chemical-gated Na+ channel in the membrane of a neuron, which way will sodium diffuse?

A. Out of the cell

B. Into the cell

C. Both in and out of the cell

B

As Na+ diffuses into the cell, what will happen to the membrane potential (the difference in charge between the ICF and the ECF)?

A. The potential will approach 0 (become more positive, less of a difference b/w ICF and ECF)

B. The potential will move further away from zero (become more negative, greater difference b/w ICF and ECF )

C. The potential will not change

A

What type of channels may be stimulated in the PNS to initiate a graded potential?

A. mechanical-gated

B. chemical-gated

C. voltage-gated

D. all of the above

E. A and B only

E

Local potentials can be excitatory or inhibitory.

A. True

B. False

True

It is more likely to find chemical-gated channels in the membrane of an axon compared to a dendrite.

A. True

B. False

B

A strong excitatory stimulus will result in a larger depolarization of the cell membrane compared to weak excitatory stimulus.

A. True

B. False

A

Some neurons of the CNS contain Cl- pumps that create a chloride gradient, ECF>ICF. The same cells also have chemical-gated Cl- channels (shown in image) that bind to a neurotransmitter called GABA.

If this type of neuron binds to GABA, what is the result? (Hint - what ion is diffusing and how will it change the charge inside the cell)

A. The cell will depolarize

B. The cell will hyperpolarize

C. There is no change to the potential

B

Some neurons of the CNS contain Cl- pumps that create a chloride gradient, ECF>ICF. The same cells also have chemical-gated Cl- channels (shown in image) that bind to a neurotransmitter called GABA.

If a person has a mutated GABA receptors in their CNS so that the channels have difficulty binding to GABA and do not open as quickly to normal levels of GABA, what is the result?

A. The person's CNS neurons are likely to be more positive (excited) compared to normally functioning neurons.

B. The person's CNS neurons are likely to be more negative (inhibited) compared to normally functioning neurons.

A

Many common sedativedrugs (Ambien, Valium) bind to the same channel and ENHANCE the effect of GABA binding to the channel.

If a person has mutated GABA receptors AND is treated with Valium (assume normal GABA levels are present), what is the result?

A. The person's CNS neurons are likely to be more positive more (excited) compared to a normal functioning neurons.

B. The person's CNS neurons are likely to be more negative (inhibited) compared to a normal functioning neurons.

C. The person's CNS neurons are will be at the about the same level of excitement/inhibition compared to normal functioning neurons.

C

A local potential reaches -55mV. Which of the following events immediately occur?

A. Potassium ions enter the cell

B. Sodium voltage-gated channels close

C. Potassium voltage-gated channels open

D. Sodium ions enter the cell

D

Which of the following protein channels are NOT directly involved in graded (local) potentials?

A. voltage-gated channels

B. chemical-gated channels

C. mechanical-gated channels

A

Which of the following channels open during the depolarization phase of an action potential?

A. K+ voltage-gated channel

B. Na+ voltage-gated channel

B

Which of the following channels open primarily during the repolarization phase of an action potential?

A. K+ voltage-gated channel

B. Na+ voltage-gated channel

A

Na+/K+ pumps function during the duration of an action potential.

True/false

True

An action potential will continue to "boost" itself down the entire axon of a neuron; therefore after an action potential is initiated it is irreversible and will result in communication to the next neuron or tissue of the circuit.

True/false

True

Activation (opening) of K+ chemical- or mechanical-gated channels during a graded potential will lead to an action potential.

True/false

False

Which of the following channels may be involved with a change of potential more negative than the value of resting membrane potential? Another way of thinking about this question is to consider when a neuron may have a potential below threshold and WHY that has occurred? Choose all that apply.

A. voltage gated Na+ channels

B. chemical gated Na+ channels

C. voltage gated K+ channels

D. chemical gated K+ channels

C & D*

You step on a thumb-tack. Which statement is TRUE about the neuron that carries the sensation of pain back to your central nervous system?

a

Its cell body is located in the dorsal root ganglion and its axon travels through the ventral root of the spinal nerve.

b

Its cell body is located in the ventral root ganglion and its axon travels through the ventral root of the spinal nerve.

c

Its cell body is located in the dorsal root ganglion and its axon travels through the dorsal root of the spinal nerve.

where are the axons of motor neurons found?

Anterior/Ventral Horn

Pseudounipolar neurons are associated with which of the following spinal cord structures?

dorsal root

At one postsynaptic neuron, the total EPSP change from RMP is +25mV and the total IPSP change from RMP is -15mV. Will an action potential be triggered? Assume RMP equals -70mV and threshold is -35mV.  (Hint – remember that EPSPs and IPSPs are happening at the same time.)

no

Epidural analgesia is the injection of a drug into the space outside the dura mater, that numbs the spinal nerves. If the epidural is correctly placed, will the drug mix with the circulating CSF that surrounds the spinal cord?

no it will not