Biology 12
Name:
Nervous System Practice Exam
Study Card 1: Types of Neurons and Reflex Arcs
1. Identify the parts of the following motor neuron:
2.
Describe the roles of the following
a. Myelin:
Helps speed up nerve impulses + protects neurons
b. Node of Ranvier:
Helps speed up nerve impulses because the nerve impulse jumps from node to node.
3.
Label the following on the diagram below: THIS IS A GOOD CHOICE FOR SHORT ANSWER.
Sensory receptor, sensory neuron, interneuron, motor neuron, effector
4. Describe the function of the following parts of a reflex arc. (Note: the parts are given in the CORRECT
ORDER) THIS IS A GOOD CHOICE FOR SHORT ANSWER.
Component
Sense receptor
Function
Detects stimulus + Starts nerve impulse
Sensory neuron
Sends nerve impulse to interneuron
Interneuron
Sends nerve impulse to motor neuron
Motor Neuron
Sends nerve impulse to effectors
Effector
Cause a body action - example: effectors can be heart, diaphragm, muscles etc.
5.
Label the following diagram.
W
Y = dendrite of sensory neuron
W = cell body of sensory neuron
X = axon of interneuron
Z = axon of motor neuron
6.
In the diagram, X indicates the
a) dendrite of an interneuron
b) cell body of the motor neuron
c) axon of a sensory neuron
d) dendrite of a motor neuron
7.
Neurons which carry nerve impulses toward the central nervous system are called
a) inter neurons
b) motor neurons
c) sensory neurons
d) sympathetic neurons
8.
In the diagram, X indicates
a) Cell body of motor neuron
b) Cell body of interneuron
c) Cell body of sensory neuron
d) Axon of sensory neuron
9.
A collection of cell bodies in the location labeled as X is called
a) Ventral root
b) Dorsal root ganglion
c) Spinal cord
d) Medulla oblongata
10. Considering the direction of the nerve impulse, what is structure X?
a) dendrite
b) synapse
c) cell body
d) axon
11. Considering the direction of the nerve impulse,
what is structure Y?
a) dendrite
b) synapse
c) cell body
d) axon
12. Considering the direction of the nerve impulse, what type of cell is the second neuron?
a) sensory neuron
b) motor neuron
c) interneuron
d) schwaan cell
Study Card 2: Action Potential and Nerve Impulse
13. Explain the transmission of a nerve impulse through a neuron, using the following terms:
Term
Description
Resting potential
inside neuron is -60 mVolts and Na+ is pumped to the outside of the
neuron and K+ pumped to the inside of the neuron
Action potential
Na+ diffuses into the neuron and K+ diffuses out of the neuron.
(depolarization + repolarization)
Depolarization
Na+ gate opens and Na+ diffuses into the neuron
Repolarization
K+ gate opens and K+ diffuses out of the neuron
Recovery (refractory) period
Na+ is pumped to the outside of the neuron and K+ pumped to the
inside of the neuron - this requires the Na+/K+ pump which requires
ATP.
A nerve impulse will be generated if the neuron is depolarized to a
threshold value.
Threshold (all or none
response)
14. What is the role of myelin in a myelinated nerve fibre?
Protects neurons and helps speed up nerve impulse – nerve impulse jumps from node to node.
15. Name and describe the events at each stage of the graph below
1 = resting potential: inside neuron is -60 mVolts and Na+ is pumped to the outside of the neuron and
K+ pumped to the inside of the neuron – requires Na+/K+ pump and ATP
2 = depolarization: Na+ gate opens and Na+ diffuses into the neuron (+40 mvolts)
3 = repolarization: K+ gate opens and K+ diffuses out of the neuron (-60 mvolts)
4 = recover (refractory) phase: Na+ is pumped to the outside of the neuron and K+ pumped to the
inside of the neuron - this requires the Na+/K+ pump which requires ATP.
16. Explain how a nerve impulse (action potential) is transmitted along a neuron.
Action potential travels like a wave down a neuron
17. In the diagram of a nerve impulse above, the area from 5-6 milliseconds would represent
a) sodium gates opening and sodium ions leaving the neuron cytoplasm
b) sodium gates opening and sodium ions entering the neuron cytoplasm
c) potassium gates opening and potassium ions leaving the neuron cytoplasm
d) active transport of sodium and potassium ions
18. The diagram shows part of a dendrite. A role of structure X is to
a) Secrete the myelin sheath.
b) Identify the cell to phagocytes.
c) Move sodium across the membrane.
d) Release calcium at the synaptic ending.
19. If potassium ions could not diffuse out of the axon, which of the following would result?
a) Repolarization would not occur.
b) A neurotransmitter would be released.
c) The length of the recovery phase would be reduced.
d) The frequency of action potentials would be increased.
20. Why can an impulse traveling along an axon not reverse its direction?
a) The myelin sheath will only permit one-way travel of an impulse.
b) Sodium gates remain closed until the impulse reaches the synapse.
c) The threshold required to create an action potential behind the impulse is increased.
d) The sodium-potassium pump has not restored the resting potential immediately behind the action
potential.
21. Use the graph below to describe how a neuron would respond to increased stimulation of the
membrane.
Frequency of nerve impulses would
increase
22. If X is an interneuron, Y must be?
a)
b)
c)
d)
effector
sensory neuron
motor neuron
myelin
Study Card 3 - Synapse
23. Identify the major components of a Synapse. (THIS IS A GOOD CHOICE FOR SHORT
ANSWER)
24. Explain the process by which impulses are transmitted across a Synapse. Include the role of excitatory
and inhibitory neurotransmitters and the role of enzymes. (THIS IS A GOOD CHOICE FOR
SHORT ANSWER)
1. When an action potential reaches a synaptic ending it causes the vesicles with neurotransmitters to fuse
with the pre synaptic membrane and neurotransmitters are released through exocytosis.
Government exam Writers: the action potential causes calcium ions to diffuse into the pre-synaptic
ending. The calcium ions interact with contractile proteins which causes them to pull the synaptic
vesicles to the edge of the membrane where they then burst to release their contents.
2. Neurotransmitters diffuse across the cleft and attach to receptor sites on the post synaptic membrane in
a lock and key manner.
3.
Neurotransmitters can have either an excitatory or inhibitory effect.
excitatory effect - action potential generated in post synaptic membrane.
(Na+ gates (channels) open on post synaptic membrane)
inhibitory effect - action potential does not continue in post synaptic membrane.
(K+ gates (channels) open causing hyperpolarization of post synaptic membrane)
4. Enzymes on the post synaptic membrane, breakdown the neurotransmitters from the synaptic cleft and
the receptor sites. This stops excitatory or inhibitory stimulation of postsynaptic membranes.
25. Explain why neurons carry an impulse (action potential) in only one direction.
Only axon has vesicles with neurotransmitter and receptor sites found only on post synaptic
membrane.
26. To which other neuron(s) would the action potential be passed if neuron 2 were stimulated at point X?
a) 1 only
b) 3 only
c) 1 and 3
d) neither 1 nor 3
27. How does the molecule indicated by X move across the space below?
a) Osmosis.
b) Diffusion.
c) Active transport.
d) Facilitated transport.
28. In order for a nerve impulse to be transmitted across the synapse, the amount of excitatory
neurotransmitter must exceed the amount of inhibitory neurotransmitter.
Which of the following conditions would reach the threshold and cause the firing of a neuron?
Neuron C – (75 + 20 = 95 inhibitory) and (55 + 45 = 100 excitatory)
Type of Synapse
Amount of Neurotransmitter Released
inhibitory
75 units
inhibitory
20 units
excitatory
55 units
excitatory
45 units
Study Card 4: The brain and autonomic nervous system
29. Contrast the locations and functions of the Central and Peripheral Nervous Systems.
Nervous System
Components
Central
Brain + spinal cord
Peripheral
Spinal + cranial nerves
Autonomic
Motor neurons
Types of neurons
Spinal cord – relays sensory impulses to the
brain and relays motor nerve impulses to
effectors
Brain – thinking, learning etc.
Spinal nerves + cranial nerves – contain
sensory + motor neurons to take nerve
impulses to and from the CNS
Motor nerves to smooth muscle and internal
organs
involuntary
30. Differentiate between the functions of the Sympathetic and Parasympathetic Divisions of the
Autonomic Nervous System.
Autonomic Nervous
Functions
System Divisions
promotes reaction to “fight or flight” situations or emergency
Sympathetic
accelerate heart beat (rate)
increase breathing rate
dilation of pupils
inhibit digestion
decrease peristalsis
decrease enzyme secretion
decrease blood flow to intestines
promotes all those internal response we associate with a relaxed state
Parasympathetic
slow heart beat (rate)
slow breathing rate
contraction of pupils
digestion of food
increase peristalsis
increase enzyme secretion
increase blood flow to intestines
31. Identify the source gland for adrenalin (epinephrine) and explain its role in the "fight or flight"
response.
Trigger - sympathetic nervous system
Source - adrenal gland (adrenal medulla - inner part of adrenal gland)
Action - fight or flight responses
32. Identify and give functions for each of the following brain structures:
(THIS IS A GOOD CHOICE FOR SHORT ANSWER)
Structure
Medulla oblongata
Cerebellum
Thalamus
Hypothalamus
Pituitary gland
Corpus callosum
Cerebrum
Cerebral cortex
Function
Control reflexes – heart rate, breathing rate
Controls balance and muscle coordination
Gatekeeper – relays sensory nerve impulses to correct area of brain
Control body temperature
Produces and releases hormones
Produces and releases hormones
Bridge between right and left hemispheres of cerebrum
Connects the 2 hemispheres of cerebrum
Thinking, speech, hearing, personality
Right hemisphere controls left side of body, left hemisphere controls right side of
body
Top layer of cerebrum – higher level thinking
33.
A drug was observed to have the following effects:
• accelerated heart rate
• dilation of pupils
• reduced peristalsis
The nervous system affected by this drug is the
a) central
b) somatic
c) peripheral
d) sympathetic
34.
A person shows signs of uncoordinated movements. The part of the brain affected is the
a) cerebrum
b) cerebellum
c) medulla oblongata
d) thalamus
35.
Which of the following activities would be the most difficult for a person with a damaged
cerebellum?
a) reading
b) breathing
c) gymnastics
d) conscious thought