Chapter 9 Anatomy Quiz

18. List the events that occur during an action potential.

3 steps: 1. the membrane permeability to sodium suddenly changes 2. as the sodium changes channels open and sodium ions come in and the cell depolarizes. 3. at the same time potassium channels open allowing potassium to LEAVE the membrane causing it to become re polarized. This all happens very rapidly.

19. Choose the correct sequence of an axon: A. B. C. D.

C or D????

3. Explain the relationship between CNS and the PNS

CNS- Central Nervous System is the brain and spinal cord and PNS- Peripheral Nervous System is the nerves and stuff that travel to the spinal cord and brain.

10. Distinguish among sensory neurons, interneurons, and motor neurons

Sensory carries impulses from PNS to CNS, most are unipolar. Interneurons links sensory to motor only in CNS and they are multipolar. Motor neurons carries impulses from CNS to PNS.

16. Define resting potential.

The electrical potential of a neuron when not stimiulated

4. List the general functions of the nervous system.

Sensory function- gather information from inside the body and and the outside environment. Interpretative function- turns information into thoughts Motor function- makes your nerves follow through on those thoughts

12. Define synapse.

The junction between two communicating neurons

20. Explain why a myelin sheath covering an entire axon (with no nodes of Ranvier) would inhibit conduction of an impulse.

This happens because the myelin sheath prevents the impulse from jumping node to node.

6. Describe three structures found in neurons that are also in other cell types, and describe two structures that are unique to neurons.

Three structures in other cell types: Multipolar- many processes and lies within the brain or CNS Unipolar-single process, function as a single axon, two branches one in the PNS and one in the CNS Bipolar-have only two processes, one is an axon and the other is a dendrite; in the ears, eyes, nose, PNS Two structures unique to neurons: Axon and Dendrite

8. Distinguish between myelinated and unmeylinated axons.

Unmyelinated axons conduct action potentials along their entire lengths. Myelinated axons conduct impulses more rapidly.

14. Explain how a membrane becomes polarized.

When there are unequal positive and negative ions distributed between sides of the membrane

13. Explain how information passes from one neuron to another.

Within a neuron an impulse travels from a dendrite to a cell body and then moves along the axon to the end

7. The part of a Schwann cell that contributes to the myelin sheath is the _________, and the part that contributes to the neurilemma is the _____________.

_____cell membrane____ and _____cytoplasm_____

17. Explain the relationship between threshold potential and an action potential.

the membrane potential reaches a level called the threshold potential which approximately -55 millivolts, if the threshold is reached, an action potential results.

1. The general function of a neuron is to ________ where as the general functions of a neuralgia are to ____________.

transmit information providing insulation, physical support, and nutrients for nuerons

2. Match the neuron part on the left to its description on the right. 1) dendrite 2) axon 3) cell body

1-B 2-A 3-C BAC!!!!

5. Match the types of neuralgia to their functions 1) ependymal cells 2) oligodendrocytes 3) astrocytes 4) Schwann cells 5) microglial cells

1-C 2-E 3-D 4-A 5-B CEDAB

15. Describe how ions associated with nerve cell membranes are distributed.

It is determined in part by pore or channels in those membranes. The channels can either can be open all the time or sometimes open and sometimes closed.

11. Distinguish between ganglia and nuclei

Nuclei is a cluster of neuron cell bodies found only in the CNS but the ganglia is a cluster of neuron cell bodies found only in the PNS and the brain

9. Distinguish among multipolar, bipolar and unipolar neurons.

Bipolar: two processes, one axon, and one dendrite; found in eyes, nose and ears Unipolar: one process, divides into to branches (PNS and CNS) functions as a single axon and has ganglia Multipolar: many processes, many dendrites, but one axon and includes most of the CNS neurons