*A&P 1 Unit 12 (Lab) [The Nervous System: Nervous Tissue]

Question 1

Name the two cell types found in nervous tissue.

Answer 1

• Neurons
• Neuroglial Cells

Question 2

Which cells are responsible for sending the electrical messages called action potentials?

Answer 2

Neurons

Question 3

What is another name for action potentials?

Answer 3

Nerve impulses

Question 4

The 3 Structural Areas of a Neuron

Answer 4

• Cell Body
• Axon
• Dendrites

Question 5

Which structure contains the nucleus?

Answer 5

Cell Body

Question 6

Which structure receives messages from other neurons?

Answer 6

Dendrites

Question 7

Which structure produces and transmits the action potential?

Answer 7

Axon

Question 8

What do nuclei and ganglia have in common? How are they different?

Answer 8

• Nuclei- clusters of cell bodies in Central Nervous System (CNS)
• Ganglia- clusters of cell bodies in Peripheral Nervous System (PNS)

Question 9

What is the axolemma?

Answer 9

An axon’s plasma membrane

Question 10

Where does a neuron store its synaptic vesicles containing neurotransmitters?

Answer 10

Axon Terminal

Question 11

When an action potential travels “down” (along) an axon and arrives at the axon terminals, they release the neurotransmitters by exocytosis. What is the prupose of neurotransmitter release?

Answer 11

Sends to another target across the synaptic cleft, which can be another neuron.

Question 12

Describe the function of dendrites.

Answer 12

Receive messages from other neurons. They transmit these messages to the neuron’s cell body, but they are not capable of generating action potentials.

Question 13

Can dendrites produce action potentials?

Answer 13

No

Question 14

3 Structural Classifications of Neurons

Answer 14

• Bipolar
• Unipolar
• Multipolar

Question 15

Which type of neurons has more than two processes (extensions) from its cell body? Is its axon the longer process or its dendrites?

Answer 15

Multipolar

Axon is longer

Question 16

Which type of neurons has only one process- a very short one- extending directly from its cell body? And what structure branches in both directions (T’s) from this single process?

Answer 16

Unipolar

Axon

Question 17

Which type of neurons has two processes branching from its cell body? And name these two processes.

Answer 17

Bipolar

Axon and Dendrite

Question 18

Which are the most common type of neuron?

Answer 18

Multipolar

Question 19

Which types of neurons are less common and associated with sendory functions?

Answer 19

Bipolar and Unipolar

Question 20

What is the function of the synapse?

Answer 20

Neurons communicate with one another and with their target cells at this junction.

Question 21

Presynaptic Neuron

Answer 21

The neuron that sends the message. It contains neurotransmitters packaged in synaptic vesicles in its axon terminals.

Question 22

Synaptic Cleft

Answer 22

The two neurons in a neuronal synapse are separated by this small space. This space is filled with extracellular fluid through which the neurotransmitters diffuse when they are released from the synaptic vesicles.

Question 23

Postsynaptic Neuron

Answer 23

The neuron that receives the message. Its plasma membrane contains receptors for neurotransmitters. When the neurotranmitters bind to these receptors, the membrane potential of the postsynaptic neuron chenges.

Question 24

Which cell type is smallest?

Answer 24

Neuroglial Cells

Question 25

Which cell type is most abundant?

Answer 25

Neuroglial Cells

Question 26

Neuroglia Located in the PNS

Answer 26

* Schwann Cells * Satellite Cells

Question 27

Which neuroglia of the PNS surround neuronal cell bodies in the PNS? What is thought to be thier function?

Answer 27

Satellite Cells Believed to enclose and support the cell bodies, althogh their precise function is unknown.

Question 28

Which neuroglia of the PNS form the myelin sheath along the axon in the PNS?

Answer 28

Schwann Cells

Question 29

How do Schwann Cells form the myelin sheath?

Answer 29

Wrapping clockwise around the axon.

Question 30

Does a myelinated axon have one or many Schwann Cells wrapping its axon?

Answer 30

Many Schwann Cells

Question 31

What is the general function of myelination?

Answer 31

The myelin sheath protects and insulates the axons and speeds up conduction of action potential.

Question 32

Name the spaces between the Schwann Cells where the axon is exposed.

Answer 32

Nodes of Ranvier

Question 33

Neuroglia Located in the CNS

Answer 33

* Astrocytes * Oligodendrocytes * Microglial Cells * Ependymal Cells

Question 34

Astrocytes

Answer 34

The most numerous neuroglial cell type in the CNS. These star-shaped cells have many functions, including anchoring neurons and blood vessels in place with processes called perivasculaer feet and regulating the environment of the brain. In addition, they faciliate the formation of the blood-brain barrier, created by tight junctions in the brain cappilaries that prevent many substances in the blood from entering the brain tissue.

Question 35

Oligodendrocytes

Answer 35

Have long extensions that wrap around the axons of certain neurons in the CNS to form the myelin sheath. Note that one oligodendrocyte can myelinate several axons.

Question 36

Microglial Cells

Answer 36

The small microglial cells are very active phagocytes that clean up debris surrounding the neurons. Microglia also degrade and ingest damaged or dead neurons.

Question 37

Ependymal Cells

Answer 37

The ciliated ependymal cells line the hollow spaces of the brain and spinal cord. They assist in forming the fluid that bathes the brain and spinal cord, cerebrospinal fluid, adn circulate it with their cilia.

Question 38

Which neuroglia of the CNS performing a "cleaning" activity similar ro specific white blood cells? What is this activity called?

Answer 38

Microglial Cells Phagocytosis

Question 39

Which neuroglia of the CNS process and circulate cerebrospinal fluid (CSF)? What cellular structures do these neuroglia use to move the CSF?

Answer 39

Ependymal Cilia

Question 40

Which neuroglia of the CNS help position neurons in relation to blood vessels?

Answer 40

Astrocytes

Question 41

Which neuroglia of the CNS form the myelin sheath along CNS axons? Does each of these neuroglia wrap one or many axons? How does this compare to Schwann Cells of the PNS?

Answer 41

Oligodendrocytes Several Axons Schwann Cells can only wrap one axon.