Question

1. The soma sensory neurons are located in which of the following structures?
   1. Dorsal column
   2. Ventral root
   3. Dorsal root ganglion
   4. Gray matter
2. Bill has lost feeling in his left foot. Briefly describe 3 possible locations of injury that could result in this symptom and explain how each injury results in this symptom.

3. Briefly describe a major difference between the spatial-temporal summation of presynaptic inputs onto a postsynaptic neuron.

4. As the strength of the stimulus increases, the amplitude of action potentials generated by a sensory receptor

4. 1. Decreases
   2. Remains the same
   3. Increases
5. What type of sensory receptor detects pain resulting from tissue damage? (one-word answer)
6. A decrease in pH of cerebral spinal fluid will cause respiration rate to?
   1. Increase
   2. Remain the same
   3. Decrease
7. A sensory receptor that detects the light touch of the skin is an example of?
   1. Visceral receptor
   2. Mechanoreceptor
   3. All of these
   4. Enteroreceptor
   5. None of these
8. Membrane potentials for a postsynaptic neuron are recorded at its axon hillock (trigger zone). Resting potential for this cell is -80mv. Individuals stimulation of presynaptic neurons A,B and C results in the following changes in membrane potential at the axon hillock: +10 mV, -10mV mV and +20mV. If all 3 presynaptic neurons were stimulated at the same time, then the membrane potential at the postsynaptic axon hillock would be:
   1. -60mV
   2. None of these
   3. -40mV
   4. -100mV
9. Briefly describe one major difference between an inotropic receptor and a metabotropic receptor.
10. Which of the following neurons would have the fastest conduction velocity of an action potential?
    1. Myelinated axon that has a diameter of 1 micron
    2. Unmyelinated axon that has a dimeter of 3 microns
    3. Myelinated axon that has a diameter of 3 microns
    4. Unmyelinated axon that has diameter of 1 micron

11. Sensory receptors in which of the following locations play a role in regulating breathing rate?
    1. None of these
    2. All of these
    3. Lungs
    4. Aorta
    5. Brain
12. The effect of a neurotransmitter on a postsynaptic neuron is typically very brief because the concentration of the neurotransmitter in the synaptic cleft decreases rapidly soon after the transmitter is secreted by the presynaptic neuron. Describe 3 mechanisms by which the transmitter is removed.

Answer 1

Dorsal root ganglion is the site of sensory soma

- temporal summation occurs when one presynaptic neuron releases neurotransmitter over a period of time whereas spatial summation occurs when multiple presynaptic neurons release neurotransmitter and produce action potential.

- a decrease in pH of csf causes increase in respiratory rate

- ( -60mv)

[ (-80)+(+10)+(-10)+(+20)] = (-60mv)

- Ionotropic receptors form an ion channel pore whereas metobotropic receptors are not related to ions

- myelinated neurons with larger diameter are fastest

-stretch receptors of lungs, peripheral chemoreceptors in aorta and central receptors in brain control respiration

-transmitter is removed by reuptake, enzymatic degradation, and diffusion