Nervous System Flashcards

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1
Q

What are neuroglia cells?

A
  • AKA glial cells
  • Secrete myelin
  • Supply oxygen and nutrients to neurons
  • Protect and support neurons
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2
Q

What are the components of a neuron?

A

-Dendrite, cell body, axon

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3
Q

Dendrites…

A

…are cytoplasmic extensions that receive information and transmit to cell body.

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4
Q

Axons…

A

…transmit action potentials away from the cell body.

  • Mostly sheathed by myelin
  • End in synaptic terminal
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5
Q

What is the purpose of mylein sheath?

A
  • Prevent leakage of signal from axon

- Faster conduction of signal

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6
Q

Nodes of Ranvier…

A

…gaps between myelin sheath.

-Signal propagates by saltutory conduction

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7
Q

Oligodendrocytes…

A
  • Type of glial cells

- Produce myelin in CNS

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8
Q

What type of cell produces myelin in the PNS?

A

-Schwann cells

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9
Q

Where are neurotransmitters released?

A

-From axon terminals into synapse to an adjacent dendrite

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10
Q

What are astrocytes?

A
  • In CNS
  • Maintain integrity of blood-brain barrier
  • Regulate nutrient and dissolved gas conc
  • Absorb/recycle neurotransmitters
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11
Q

What are microglia?

A
  • In CNS

- Remove cell debris and pathogens

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12
Q

What are ependymal cells?

A
  • Line brain ventricles

- Make/maintain cerebral fluid

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13
Q

What are satellite cells?

A
  • In PNS

- Surround neuron cell bodies in ganglia (autonomic nervous system)

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14
Q

What is the resting potential of a neuron?

A
  • Polarized (-70mV)
  • Maintained by Na+/K+ pump
  • Membrane more permeable to K+, diffuse back out
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15
Q

Describe the transmission of action potentials.

A
  • Causes depolarization (more positive inside cell)
  • Reach threshold potential
  • Na+ to flow down gradient –> depolarize more of axon
  • Reach synaptic terminal –> Ca++ flow in
  • Exocytosis of synaptic vesicles with neurotransmitters
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16
Q

Describe repolarization.

A
  • High voltage causes K+ channels to open
  • K+ rush down gradient and out of cell
  • Voltage gated Na+ channel closes
  • Na+/K+ begins again
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17
Q

Describe hyperpolarization.

A
  • Repolarized past resting potential due to K+ still being permeable
  • Allows time for regeneration of neurotransmitters
  • Potential only moves forward
  • Refractory period
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18
Q

What is the stimulus intensity coded by?

A

-Frequency NOT magnitude of action potential

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19
Q

What are factors that allow faster propagation of stimuls?

A
  • More myelinated (only permeable to ions in Nodes of Ranvier)
  • Larger diameter of axon
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20
Q

What are the ways neurotransmitters are removed from the synapse?

A
  • Taken back up into the nerve terminal (reused/degraded)
  • Degraded by enzymes in synapse
  • Diffuse out of synapse
21
Q

What are afferent neurons?

A

-Carry sensory information from external/internal environment to brain/spinal cord

22
Q

What are efferent neurons?

A

-Carry motor commands from brain/spinal cord to body

23
Q

What are interneurons?

A
  • Participate only in local circuits

- Linking sensory and motor neurons

24
Q

Organization of nerves

A
  • Bundle of axons covered with connective tissue (nerves)
  • Nerve fibers = plexus
  • Neuronal cell body clusters = ganglia(PNS) or nuclei (CNS)
25
Q

What is the difference between gray and white matter?

A
  • Gray matter is outer portion of cell bodies

- White matter is inner portion of myelinated axons

26
Q

Forebrain

A

-Telencephalon and diencephalon

27
Q

Telencephalon

A
  • Cerebral cortex process/integrate sensory/motor
  • Memory/Creative thought
  • Olfactory bulb
28
Q

Diencephalon

A
  • Thalamus integrate spinal cord and cerebral cortex

- Hypothalamus controls visceral functions (hunger/thirst/sex/temp)

29
Q

Midbrain

A
  • Relay center for visual and auditory impulses

- Motor control

30
Q

Hindbrain

A

-Cerebellum, the pons, medulla

31
Q

Cerebellum

A

-Balance, hand-eye coordination, modulate motor impulses by cerebral cortex

32
Q

Pons

A

-Relay center to allow cortex to communicate with cerebellum

33
Q

Medulla

A

-Vital functions (breathing, HR, GI)

34
Q

What makes up the brainstem?

A

-Midbrain, pons, medulla

35
Q

Spinal Cord

A
  • Outer white matter, inner gray

- Can integrate motor responses itself

36
Q

How does sensory information enter spinal cord?

A

-Through the dorsal horn (dorsal root ganglia) and exits ventral horn

37
Q

What does the PNS consist of?

A

-Somatic and Autonomic

38
Q

Somatic Nervous System

A
  • Innervate skeletal muscles

- Voluntary movement and reflex arcs

39
Q

Autonomic Nervous System

A
  • Involuntary - cardiac and smooth muscles

- Sympathetic and parasympathetic

40
Q

Where is smooth muscles located?

A

-Blood vessels, digestive tract, bladder, bronchi

41
Q

Sympathetic Nervous System

A
  • “Fight or Flight”
  • Increase bp, HR, blood flow to skeletal muscle
  • Decrease gut motility
  • Dilate bronchioles to increase gas exchange
  • Norepinephrine
42
Q

What is the primary neurotransmitter for sympathetic nervous system? Parasympathetic?

A
  • Norepinephrine

- Acetylcholine

43
Q

Parasympathetic Nervous System

A
  • “Rest and digest”
  • Lowers hr, increase digestion
  • Vagus nerve - innervate thoracic and abdominal viscera
  • Acetylcholine
44
Q

What bends and focuses light?

A

-Cornea

45
Q

What controls the diameter of the pupil?

A

-Iris by responding to intensity of light

46
Q

Lens…

A

…focuses image onto retina.

47
Q

Describe the synaptic pathway of photoreceptors.

A

Synapse onto bipolar cells –> ganglion cells –> optic nerve –> brain

48
Q

What causes action potentials to transmit to brain in hearing?

A
  • Ossicles vibrate and exert pressure on inner ear fluid which stimulates hair cells in basilar membrane
  • Pressure –> action potential
49
Q

Motor unit

A

-All muscle fibers innervated by one nerve fiber