Module 6:  Interactive Physiology:  Nervous System

Nervous System I:  Anatomy Review

1. Neurons can communicate because of their anatomical design and because they are _________________________.

 

2. Neurons communicate with other neurons, muscles and ____________________________________.

 

3. ______________________________ receive signals from other neurons and send them toward the axon.

 

4. The conducting region of the neuron is the ___________________________________.

 

5. What is transmitted the length of the axon to a target cell is an _________________________________________.

 

6. Axons vary in size from 1 mm to over 1 __________________________________.

 

7. The junction between neurons where one neuron communicates with another neuron is a ____________________.

 

8. Action potentials are generated at the ______________________________________________ .

 

9. Action potentials are conducted along the axon to the end of the axon called the _____________________________.

 

10. Axons in the PNS are myelinated by ________________________________ cells.

 

11. Gaps in the myelin sheath (between Schwann cells) are called __________________________________________.

 

12. The receptive and integrative regions of the neuron are the dendrites and the _______________________________.

 

 

Nervous System I:  Ion Channels

1. Ion channels are selective based on their size and ____________________________.

 

2. Non-gated channels are also called ______________________________ channels.

 

3. In terms of charge, the outside of a neuron’s membrane is slightly __________________________.

 

4. The difference in charge across the membrane produces a voltage called the ______________________ potential.

 

5. Voltage gated channels open and close during an _______________________________________.

 

6. Neurotransmitter binds to receptors on ________________________________ channels and causes them to open.

 

7. Voltage gated channels are found on the axon hillock and all along the _____________________________.

 

8. Non-gated channels are responsible for the _______________________________________ potential.

 

9. Chemically gated channels are responsible for ___________________________________ potentials.

 

10. Voltage gated channels are responsible for ____________________________________ potentials.

 

 

Nervous System I:  The Membrane Potential

1. Na+ is more abundant ______________________________ cells and is balanced in charge by Cl-.

 

2. K+ is more abundant ______________________________ cells and is balanced in charge by intracellular proteins.

 

3. Neurons are selectively permeable to Na+, Cl- and ________________________________.

 

4. The permeability of a cell for a given ion _____________________ when gated channels for that ion are opened.

 

5. Ions diffuse _______________________________ their concentration gradients.

 

6. Resting membranes are very permeable to ______________ and only slightly permeable to ______________.

 

7. More K+ leaks out of the cell than Na+ leaks in causing the inside of the membrane to be

 

8. The resting membrane potential for neurons is _________________________ mv.

 

9. The Na+-K+ pump keeps pumping _______­­­________out of the cell in exchange for ________________ into the cell.

 

10. Since the Na+-K+ pump moves ions against their electrochemical gradients it requires ________________________.

 

 

Nervous System I:  The Action Potential

1. Nerve impulses are the signals between neurons. They are also called ___________________________________.

 

2. Action potentials result from a rapid change in permeability of the neuron membrane to _________ and _________.

 

3. The stimulus must reach ____________________ for an action potential to be generated.

 

4. Action potentials are generated at the ____________________________________________.

 

5. The depolarization phase of an AP is caused by voltage gated channels opening and _________ rushing into the cell.

 

6. The depolarization phase ends with the inactivation of voltage gated __________________ channels.

 

7. As voltage gate Na+ channels become inactivated, voltage gated ____________ channels open.

 

8. As K+ moves out of the cell this causes the _____________________________________.

 

9. When an excess of K+ moves out of the cell this causes a ______________________________________.

 

10. The _________________ refractory period is the time during and action potential when another cannot be generated.

 

11. A stronger than threshold stimulus can generate another AP during the ____________________ refractory period.

 

12. Conduction velocity is the speed at which APs are ________________________________________.

 

13. APs travel faster on axons with greater __________________________ and axons that are ____________________.

 

14. APs in myelinated axons jump from node to node. This is fast and is called _________________________________.

 

Nervous System II:  Anatomy Review

1. Neurons form synapses with other ______________________________ glands and muscles.

 

2. Skeletal muscle is stimulated by neurons of the ________________________________ nervous system.

 

3. Cardiac muscle, smooth muscle and glands are stimulated by neurons of the __________________ nervous system.

 

4. Neurons can excite or _______________________________ other neurons.

 

5. The most common type of synapse is the ____________________________ synapse.

 

6. The signal transmitted from one neuron to another is by way of __________________________________.

 

7. The neuron conducting an action potential toward the synapse is called the _______________________ neuron.

 

8. The neuron receiving the signal is called the __________________________________ neuron.

 

 

Nervous System II:  Ion Channels

 

1. Neurotransmitters bind to a ___________________________ on the postsynaptic neuron.

 

2. An EPSP is produced when the movement of ions makes the inside of the cell membrane more ________________.

 

3. An IPSP is produced when the movement of ions makes the inside of the cell membrane more _________________.

 

4. EPSPs depolarize the neuron by allowing _______________ to flood into the cell.

 

5. IPSPs hyperpolarize the neuron by allowing _______________ to flood into the cell.

 

6. EPSPs promote _______________________ and IPSPs inhibit ___________________________ from happening.

 

 

Nervous System II:  Synaptic Potentials and Cellular Integration

1. Synaptic potentials are small compared to _________________________________________.

 

2. The amplitude of synaptic potential depends on the influx of _________________ into the presynaptic terminal.

 

3. The greater the influx of Ca++, the greater the release of _________________ and the greater the synaptic potential.

 

4. Presynaptic inhibition can result due to an ____________________ synapse. This decreases the amplitude of the synaptic potential

 

5. Because synaptic potentials vary in amplitude, they are said to be _______________________ potentials.

 

6. Synaptic potentials travel only a small distance because they __________ as they move along the neuron membrane.

 

7. Temporal summation occurs because a series of EPSPs can _________________________ at the same synapse.

 

8. ____________________ summation occurs because EPSPs at multiple synapses can summate.

 

9. Many EPSPs are required to ________________________________ a neuron to threshold.

 

10. IPSPs can also summate and have an __________________________________ effect.

 

11. IPSPs reduce the magnitude of _________________________________ making it harder to reach threshold.