Nervous System

Question 1

What are neuroglia cells?

Answer 1

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

Question 2

What are the components of a neuron?

Answer 2

-Dendrite, cell body, axon

Question 3

Dendrites…

Answer 3

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

Question 4

Axons…

Answer 4

…transmit action potentials away from the cell body.

• Mostly sheathed by myelin
• End in synaptic terminal

Question 5

What is the purpose of mylein sheath?

Answer 5

• Prevent leakage of signal from axon

- Faster conduction of signal

Question 6

Nodes of Ranvier…

Answer 6

…gaps between myelin sheath.

-Signal propagates by saltutory conduction

Question 7

Oligodendrocytes…

Answer 7

• Type of glial cells

- Produce myelin in CNS

Question 8

What type of cell produces myelin in the PNS?

Answer 8

-Schwann cells

Question 9

Where are neurotransmitters released?

Answer 9

-From axon terminals into synapse to an adjacent dendrite

Question 10

What are astrocytes?

Answer 10

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

Question 11

What are microglia?

Answer 11

• In CNS

- Remove cell debris and pathogens

Question 12

What are ependymal cells?

Answer 12

• Line brain ventricles

- Make/maintain cerebral fluid

Question 13

What are satellite cells?

Answer 13

• In PNS

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

Question 14

What is the resting potential of a neuron?

Answer 14

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

Question 15

Describe the transmission of action potentials.

Answer 15

• 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

Question 16

Describe repolarization.

Answer 16

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

Question 17

Describe hyperpolarization.

Answer 17

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

Question 18

What is the stimulus intensity coded by?

Answer 18

-Frequency NOT magnitude of action potential

Question 19

What are factors that allow faster propagation of stimuls?

Answer 19

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

Question 20

What are the ways neurotransmitters are removed from the synapse?

Answer 20

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

Question 21

What are afferent neurons?

Answer 21

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

Question 22

What are efferent neurons?

Answer 22

-Carry motor commands from brain/spinal cord to body

Question 23

What are interneurons?

Answer 23

• Participate only in local circuits

- Linking sensory and motor neurons

Question 24

Organization of nerves

Answer 24

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

Question 25

What is the difference between gray and white matter?

Answer 25

- Gray matter is outer portion of cell bodies | - White matter is inner portion of myelinated axons

Question 26

Forebrain

Answer 26

-Telencephalon and diencephalon

Question 27

Telencephalon

Answer 27

- Cerebral cortex process/integrate sensory/motor - Memory/Creative thought - Olfactory bulb

Question 28

Diencephalon

Answer 28

- Thalamus integrate spinal cord and cerebral cortex | - Hypothalamus controls visceral functions (hunger/thirst/sex/temp)

Question 29

Midbrain

Answer 29

- Relay center for visual and auditory impulses | - Motor control

Question 30

Hindbrain

Answer 30

-Cerebellum, the pons, medulla

Question 31

Cerebellum

Answer 31

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

Question 32

Pons

Answer 32

-Relay center to allow cortex to communicate with cerebellum

Question 33

Medulla

Answer 33

-Vital functions (breathing, HR, GI)

Question 34

What makes up the brainstem?

Answer 34

-Midbrain, pons, medulla

Question 35

Spinal Cord

Answer 35

- Outer white matter, inner gray | - Can integrate motor responses itself

Question 36

How does sensory information enter spinal cord?

Answer 36

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

Question 37

What does the PNS consist of?

Answer 37

-Somatic and Autonomic

Question 38

Somatic Nervous System

Answer 38

- Innervate skeletal muscles | - Voluntary movement and reflex arcs

Question 39

Autonomic Nervous System

Answer 39

- Involuntary - cardiac and smooth muscles | - Sympathetic and parasympathetic

Question 40

Where is smooth muscles located?

Answer 40

-Blood vessels, digestive tract, bladder, bronchi

Question 41

Sympathetic Nervous System

Answer 41

- "Fight or Flight" - Increase bp, HR, blood flow to skeletal muscle - Decrease gut motility - Dilate bronchioles to increase gas exchange - Norepinephrine

Question 42

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

Answer 42

- Norepinephrine | - Acetylcholine

Question 43

Parasympathetic Nervous System

Answer 43

- "Rest and digest" - Lowers hr, increase digestion - Vagus nerve - innervate thoracic and abdominal viscera - Acetylcholine

Question 44

What bends and focuses light?

Answer 44

-Cornea

Question 45

What controls the diameter of the pupil?

Answer 45

-Iris by responding to intensity of light

Question 46

Lens...

Answer 46

...focuses image onto retina.

Question 47

Describe the synaptic pathway of photoreceptors.

Answer 47

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

Question 48

What causes action potentials to transmit to brain in hearing?

Answer 48

- Ossicles vibrate and exert pressure on inner ear fluid which stimulates hair cells in basilar membrane - Pressure --> action potential

Question 49

Motor unit

Answer 49

-All muscle fibers innervated by one nerve fiber