Chpt. 10.1 - 10.5 - Nervous System, Neurons, Synapes

Question 1

Function of the Nervous System

Answer 1

• Detects changes
• Makes decisions
• Stimulates muscles and glands to respond
• Maintains homeostasis

Question 2

Neuroglia

Answer 2

• Surround and support neurons
• Nourish neurons
• Send & receive messages
• Help maintain blood-brain barrier

Question 3

Sensory Function of Nervous System

Answer 3

• Nervous System receives information
• Sensory receptors gather information by detecting changes
• Information is carried to the CNS

Question 4

Integrative Function of Nervous System

Answer 4

• Nervous system coordinates sensory information to create sensations, memories, thoughts
• Nervous system makes decisions on body’s response to sensory information

Question 5

Motor Function of Nervous System

Answer 5

• Decisions are acted upon
• Impulses are carried to effectors
• Somatic: voluntary
• Autonomic: involuntary

Question 6

Bipolar / Unipolar / Multipolar Neurons

Answer 6

Bipolar:
-two processes
-eyes, ears, nose
Unipolar:
-one process
-ganglia of PNS
-sensory
Multipolar:
-99% of neurons
-Many processes
-Most neurons of CNS

Question 7

Sensory / Inter/ Motor Neurons

Answer 7

Sensory Neurons:
-afferent neurons
-carry impulses to CNS
-most are unipolar
Interneurons:
-Association neurons
-Link neurons
-Multipolar
-Located in CNS
Motor Neurons:
-Multipolar, efferent
-Carry impulses away from CNS
-Carry impulses to effectors

Question 8

Astrocytes

Answer 8

• In CNS
• Connect neurons to blood vessels; exchange nutrients and growth factors
• form scar tissue
• aid metabolism of substances
• regulate ion concentrations, such as K+
• Part of Blood Brain Barrier

Question 9

Oligodendrocytes

Answer 9

-Myelinate CNS axons; also provide structural support

Question 10

Microglia

Answer 10

• In CNS

- Phagocytic cell; also provides structural support

Question 11

Ependyma

Answer 11

• Line central canal of spinal cord & ventricles of brain, cover choroid plexuses
• Help regulate composition of cerebrospinal fluid
• cuboidal/columnar cells; ciliated

Question 12

Schwann Cells

Answer 12

• In PNS
• encase axon in lipid-sheets
• composed of myelin; myelin sheath
• neurilemma: surrounds myelin sheaths; contains the cytoplasm and nuclei

Question 13

Nodes of Ranvier

Answer 13

-narrow gaps in myelin sheath between Schwann cells

Question 14

Gliotransmission

Answer 14

• Communication between neurons and glial cells due to the release of gliotransmitters
• usually induced from Ca2+ signaling
• Neuronal activation of astrocytic Gq GPCR-mediated Ca2+ elevations
• Neuromodulation by Ca2+-dependent release of gliotransmitters

Question 15

Neuron Regeneration in the PNS

Answer 15

1) Axon separated from cell body and its myelin sheath degenerates
2) Schwann cells and neurilemma remain
3) Remaining Schwann cells provide guiding sheath for growing axon
4) If axon re-establishes connection, function will return

Question 16

Neuron Regeneration in the CNS

Answer 16

• CNS axons lack neurilemma to act as guiding sheath
• Oligodendrocytes do not proliferate after injury
• REGENERATION UNLIKELY

Question 17

Impulse Pathway

Answer 17

Axon terminal on pre-synaptic neuron > dendrite of post-synaptic neuron > body of post-synaptic neuron > axon of post-synaptic neuron

Question 18

Synaptic Transmission

Answer 18

1) Impulse reaches synaptic knob of pre-synaptic neuron
2) Voltage-gated Ca2+ channels open in synaptic knob in response to pre-synaptic impulse
3) Causes neurotransmitters to be released from synaptic vesicles into synaptic cleft
4) Neurotransmitters will either exert excitatory or inhibitory effect on postsynaptic neuron