Biology: Chapter 3: The Nervous System Flashcards

1
Q

What are neurons

A

Highly specialized cells responsible for the conduction of impulses

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2
Q

What are the two ways which neurons communicate

A

Electrical and Chemical

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3
Q

What are the parts of a neuron

A

Dendrites
Axon
Axon Hillock
Soma
Nerve Terminal

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4
Q

What are the Nodes of Ranvier

A

Exposed areas in the myelin sheath that permit saltatory conduction

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5
Q

What creates myelin in the CNS

A

Oligodendrocytes

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6
Q

What creates myelin in the PNS

A

Schwann Cells

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7
Q

Nerves vs Tracts

A

Nerves carry multiple types of information (sensory, motor, both) while tracts only carry one

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8
Q

What are clusters of neurons called in the CNS

A

Nuclei

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9
Q

What are clusters of neurons called in the PNS

A

Ganglia

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10
Q

What are Astrocytes

A

Glial cells that nourish neurons and form the Blood Brain Barrier which controls transmission of solutes from the blood stream into nervous tissue

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11
Q

What are Ependymal Cells

A

Glial cells that line the ventricles of the brain and produce cerebrospinal fluid which supports the brain and serves as a shock absorber

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12
Q

What are Microglia

A

Glial cells that are phagocytic meaning they ingest and break down waste products and pathogens in the CNS

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13
Q

What is the resting membrane potential

A

-70 mV

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14
Q

How is resting membrane potential maintained

A

selective permeability of ions and Na/K ATPase

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15
Q

What is the ratio of ions transported by Na/K ATPase

A

3 Na ions out for every 2 K ions in

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16
Q

What do Excitatory signals do to neurons

A

depolarize

17
Q

What do Inhibitory signals do to neurons

A

Hyperpolarize

18
Q

What is temporal summation

A

Integration of multiple signals near each other in time

19
Q

What is spatial summation

A

Integration of multiple signals near each other in space

20
Q

What is the first step of an action potential

A

Threshold is reached, voltage gated Na ion channels open causing Na influx which depolarized the cell

21
Q

What is the second step of an action potential

A

Once the cell is depolarized to 35 mV Na channels are inactivated and K channels open causing the cell to repolarize

22
Q

What is the third step of an action potential

A

K channels cause the cell to become hyperpolarized which then closes K channels and the refractory period begins while Na/K ATPase restores the membrane potential

23
Q

what are the phases of the refractory period

A

Absolute and Relative

24
Q

How is neurotransmitter released

A

Once the AP reaches the nerve terminal voltage gated Ca channels open causing an influx of Ca which causes NT vesicles to fuse with the presynaptic membrane which are then released into the synaptic cleft

25
Q

How are neurotransmitters removed from the synaptic cleft

A

Degradation
Re-uptake
Diffusion

26
Q

What are the three types of neurons

A

afferent (sensory), efferent (motor), interneurons

27
Q

What is white matter in the CNS

A

consists of myelinated axons

28
Q

What is gray matter in the CNS

A

consists of unmyelinated cell bodies and dendrites

29
Q

What is the organization of white matter/gray matter in the spinal cord vs the brain

A

brain –> white matter deeper than gray matter
spinal cord –> gray matter is deeper than white matter

30
Q

What are the divisions of the PNS

A

somatic and autonomic

31
Q

What is the somatic division

A

control voluntary function (muscles and skeleton)

32
Q

What is the autonomic division

A

controls involuntary function

33
Q

What are the divisions of the autonomic division

A

parasympathetic and sympathetic

34
Q

What does the parasympathetic system control

A

rest and digest

35
Q

What does the sympathetic system control

A

fight or flight

36
Q

What is a monosynaptic reflex arc

A

sensory neuron fires onto the motor neuron directlyw

37
Q

What is a polysynaptic reflex arc

A

sensory neuron may fire onto a motor neuron as well as interneurons that fire onto other motor neurons