1. What two structures make up the CNS?
Brain and Spinal cord
2. Describe the roles of the three types of neurons in the spinal cord (sensory, motor,
and interneuron).
Sensory neurons:
a. about 10 million
b. delive
...
1. What two structures make up the CNS?
Brain and Spinal cord
2. Describe the roles of the three types of neurons in the spinal cord (sensory, motor,
and interneuron).
Sensory neurons:
a. about 10 million
b. deliver information to CNS
Motor neurons:
c. about 1/2 million
d. deliver commands to peripheral effectors
Interneurons (AKA - association neurons):
a. about 20 billion
b. interpret, plan, and coordinate signals in and out
3. Draw AND label (including the functions of the regions that you label) of a spinal cord
cross section. The more detail that you provide, the better! Here are some regions
that you should not forget to include:
Sensory info
Dorsal root ganglion
Dorsal ramus
Ventral ramus
Somatic sensory nuclei
Visceral sensory nuclei
Motor info
Sympathetic ganglion
Dorsal ramus
Ventral ramus
Sensory motor nuclei
Visceral motor nuclei
Sympathetic nerve (preganglionic and postganglionic fibers)
4. Diagram AND label the five steps that occur in a neural reflex. Make sure to keep the
sensory and motor neurons straight!
Step 1: Arrival of stimulus, activation of receptor
a. physical or chemical changes
Step 2: Activation of sensory neuron
b. graded depolarization
Step 3: Information processing by postsynaptic cell triggered by neurotransmitters
Step 4: Activation of motor neuron action potential
Step 5: Response of peripheral effector triggered by neurotransmitters
5. Compare and contrast innate and acquired reflexes.
a. innate reflexes:
i. basic neural reflexes
ii. formed before birth
b. acquired reflexes:
i. rapid, automatic
ii. learned motor patterns
iii. tripping and falling but catching yourself
6. Compare and contrast somatic and visceral reflexes.
a. somatic reflexes:
i. involuntary control of nervous system
1. superficial reflexes of skin, mucous membranes
2. stretch reflexes (deep tendon reflexes) e.g., patellar reflex
b. visceral reflexes (autonomic reflexes):
i. control systems other than muscular system
7. Compare and contrast monosynaptic and polysynaptic reflexes.
a. monosynaptic - sensory neuron synapses directly onto motor neuron
b. polysynaptic - at least 1 interneuron between sensory neuron and motor
neuron
8. Compare and contrast spinal reflexes and cranial reflexes.
a. spinal reflexes:
i. occurs in spinal cord (many of the reflexes that happen in the body)
(majority)
b. cranial reflexes:
i. occurs in brain (not as many reflexes hat occur in the brain)
9. Diagram AND label a monosynaptic spinal reflex, using the stretch reflex as an
example
10. Explain the roles of intrafusal and extrafusal muscle fibers in the stretch reflex as well
as the adjustment of muscles tension in postural reflexes.
Bundles of small, specialized intrafusal muscle fibers:
a. innervated by sensory and motor neurons
Surrounded by extrafusal muscle fibers:
b. which maintain tone and contract muscle
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