Chapter 11 - Nervous Tissue Organization

Question 1

Ganglion

Answer 1

Collection of neuron cell bodies outside the brain and spinal cord

Question 2

Plexus

Answer 2

Extensive network of axons, and sometimes neuron cell bodies, located outside the CNS

Question 3

Functions of the nervous system

Answer 3

-Maintain homeostasis
-Receiving sensory input
-Integrating information
-Controlling muscles and glands
-Establishing and maintaining mental activity

Question 4

Sympathetic division of ANS

Answer 4

Prepares body for physical activity

Question 5

Parasympathetic division of ANS

Answer 5

Regulates resting functions such as digesting food or emptying the bladder

Question 6

Enteric division of ANS

Answer 6

Plexuses within the walls of the digestive tract

Question 7

Nissl bodies

Answer 7

Rough ER of neurons

Question 8

Glial cells of the CNS

Answer 8

-Astrocytes
-Ependymal cells
-Microglia
-Oligodendrocytes

Question 9

Glial cells of the PNS

Answer 9

-Schwann cells
-Satellite cells

Question 10

Astrocytes

Answer 10

-Processes form feet that cover surfaces
-Regulate (blood brain barrier)
-Regulate extracellular brain fluid composition

Question 11

Ependymal cells

Answer 11

-Line brain ventricles and central canal
-Specialized versions form choroid plexus

Question 12

Choroid plexus

Answer 12

-Secrete CSF
-Cilia help CSF move through brain
-Long processes that extend through brain tissue, similar functions to astrocytes sometimes

Question 13

Microglia

Answer 13

Specialized macrophages

Question 14

Oligodendrocytes

Answer 14

-Form myelin sheaths of surrounding axon
-Can form sheaths around several axons

Question 15

Schwann cells

Answer 15

-Form myelin sheath around only one axon
-Wrap around many times

Question 16

Satellite cells

Answer 16

-Surround neuron cell bodies in sensory ganglia
-Provide support and nutrients

Question 17

Gray matter

Answer 17

-Unmyelinated axons
-Cell bodies
-Dendrites
-Glia
-Integrative functions
-Outer cortex in brain, deeper in spinal cord

Question 18

White matter

Answer 18

-Myelinated axons
-Nerve tracts propagate actin potentials from one area to another in CNS
-Deep to cortex in brain, outer part of spinal cord (forms nerve tracts)

Question 19

Ganglia

Answer 19

-PNS gray matter
-Groups of cell bodies

Question 20

What is the most common way neuron cells become depolarized?

Answer 20

Sodium ions - if the gated sodium channels open, sodium ions diffuse into the cells and the inside becomes more positive

Question 21

What is the most common way neuron cells become hyperpolarized?

Answer 21

Potassium ions - if their gated channels open, they diffuse out of the cell, and the inside of the cell becomes more negative

Question 22

Subthreshold stimulus

Answer 22

Does not cause a graded potential that is great enough to initiate an action potential

Question 23

Threshold stimulus

Answer 23

Causes a graded potential that is great enough to initiate an action potential

Question 24

Maximal stimulus

Answer 24

Just strong enough to produce a maximum frequency of action potentials

Question 25

Submaximal stimulus

Answer 25

All stimuli between threshold and the maximal stimulus strength

Question 26

Supramaximal stimulus

Answer 26

-Any stimulus stronger than maximal stimulus -These stimuli cannot produce a greater frequency of action potentials than a maximal stimulus

Question 27

Type A Nerve Fibers

Answer 27

-Large diameter -Myelinated -Motor neurons supplying skeletal and most sensory neurons

Question 28

Type B Nerve Fibers

Answer 28

-Medium diameter -Lightly myelinated -Part of ANS

Question 29

Type C Nerve Fibers

Answer 29

-Small diameter -Unmyelinated -Part of ANS

Question 30

Electrical synapse

Answer 30

-Cells connected by gap junctions -Found in cardiac and many types of smooth muscle -Where contractile ability among cells is important

Question 31

Major chemical classes of neurotransmitters

Answer 31

-Acetylcholine -Biogenic amines -Amino acids -Purines -Neuropeptides -Gases and lipids

Question 32

Excitatory postsynaptic potential

Answer 32

-Depolarization occurs and response is stimulatory -Depolarization may reach threshold and trigger action potential

Question 33

Inhibitory postsynaptic potential

Answer 33

-Hyperpolarization, response is inhibitory -Decreases likelihood of action potential occuring

Question 34

What ion is needed to release a neurotransmitter from the synaptic vesicles?

Answer 34

Calcium

Question 35

After the creation of an action potential when the refractory period is complete, the neuron...

Answer 35

Returns to its original polarity