Overview of Nervous System

Question 1

Speech production result of interaction of 5 systems

Answer 1

1. Nervous (master planner)
2. Respiratory (power source)
3. Phonatory (sound source)
4. Articulatory (sound shaper)
5. Auditory (sound converter)

Question 2

As “master planner,” the nervous system:

Answer 2

1. Develops thoughts into words
2. Converts words into muscle movements or motor plans
3. Send those motor plans to muscles
4. Monitors execution of plans
5. Monitors and interprets ongoing conversation

Based on neural events, a series of muscular and structural events will lead to acoustic events resulting in perceptual moments resulting in communication

Question 3

Nervous System Biological Roles

Answer 3

1. To monitor internal (inside the body) and external (outside the body) environments
2. Integrate info from these environments
3. And respond as needed

Question 4

The nervous system divides into:

Answer 4

• central nervous system
• peripheral nervous system

Question 5

central nervous system (CNS)

Answer 5

• includes brain and spinal cord
• located within skull and vertebral column
• integrates info from and responds to external environment

Question 6

peripheral nervous system (PNS)

Answer 6

• includes cranial and spinal nerves
• located outside skull and vertebral column
• conveys neural info from external environment to CNS and from CNS to external environment

Question 7

autonomic nervous system (ANS)

Answer 7

• part of PNS
• maintains and controls internal environment
• consists of sympathetic and parasympathetic divisions

Question 8

sympathetic divison of ANS

Answer 8

associated with energy expenditure, such as increased heart rate and breathing during exercise

Question 9

parasympathetic division of ANS

Answer 9

• associated with energy conservation, such as rest and digest
• has nerves connecting to muscles in the head

Question 10

basic cell types

Answer 10

• neurons
• glial cells/ glia

Question 11

Role of neuron:

Answer 11

to convey information

Question 12

basic structure of a neuron

Answer 12

• cell body
• dentrites
• axon
• note: vary in structure and size and designed for receiving and transferring info

Question 13

cell body

Answer 13

• life-sustaining needs of neuron
• gray matter

Question 14

dendrites

Answer 14

• receive info from other neurons or structures
• gray matter

Question 15

axon

Answer 15

• conduct info to other neurons or structures
• white matter

Question 16

myelin

Answer 16

insulate axon, accelerate info transfer

Question 17

presynaptic ending

Answer 17

• axons end here (axon terminal)
• form synapses with other neurons or structures

Question 18

synapse

Answer 18

location of info transfer from one neuron to another

Question 19

postsynaptic endings

Answer 19

• are on receiving end of synapse
• Usually consist of dendrite of another neuron/structure, such as a muscle or gland (ex: salivary glands)

Question 20

Functional Types of Neurons

Answer 20

1. Sensory neurons
2. Motor neurons
3. interneurons
   - note: all 3 provide basis for transferring info for CNS and PNS functions

Question 21

sensory neurons

Answer 21

• aka afferent = carry into
• Convey information to the CNS from PNS, including information related to skin, muscles, and joints
• reside primarily in PNS

Question 22

motor neurons

Answer 22

• aka efferent = carry away from
• Convey instructions to muscles from CNS to body
• reside primarily in PNS

Question 23

interneurons

Answer 23

• means “between 2 parts”
• Reside entirely in CNS and link other neurons
• Some have short axons; thus, remain local and connect small areas of the CNS
• Other have long axons; thus, project to different areas of CNS
• Most numerous type of neuron (99% of all neurons)
• highlight info exchange as a basic principle of NS

Question 24

Gray Matter

Answer 24

• think FUNCTION
• made up of cell bodies and dendrites
• Most obvious gray matter in CNS is the cortex - layered surface of brain, thus entire brain surface represents CNS functions
• also areas of gray matter within CNS called nuclei
• in PNS, clumps of gray matter are called ganglia

Question 25

White Matter

Answer 25

• think PATHWAY, where info is being transferred somewhere
• made up of axons, appear white because they have myelin sheath, which is comprised of lipids - thus, fatty, white appearance
• Much of CNS is comprised of white matter
• Visible white matter indicates pathways connecting various functional areas of NS

Question 26

Glia

Answer 26

• the most numerous cell type in NS
• play several roles in supporting neuron function

Question 27

types of glia

Answer 27

1. oligodendrocytes
2. astrocytes
3. ependymal cells
4. microglia

Question 28

oligodendrocytes

Answer 28

• produce myelin sheath that surrounds CNS axons
• Schwann cells perform the same role in PNS

Question 29

astroctyes

Answer 29

• cover all exposed surfaces of neuron/ regulate extracellular environment of neuron
• have end-feet that are applied to CNS blood vessels
• This provides them with two regulatory roles:
  
  1. Regulate the transfer of oxygen and glucose between blood and neuron
  2. Trigger increase in blood vessel diameter in response to increased neuron activity
• Glioblastomas (brain tumors) often arise from astrocytes and are highly malignant because reproduce quickly and have access to blood vessels

Question 30

ependymal cells

Answer 30

• line ventricles (system of cavities in CNS filled with cerebrospinal fluid)
• CSF provide extracellular environment essential to normal neuron function
• most neuroscientists no longer consider ependyma to be glial cells

Question 31

microglia

Answer 31

• “custodians” of NS
• main role is to consume pathogens (ex. bacteria) and neuronal waste
• Also play role in NS response to injury
• play role in eliminating unused synapses; thus, shaping neural connections
• “Rogue” microglia may play role in multiple sclerosis (progressive demyelinating disorder) by attacking oligodendrocytes