BIOD152 Final Exam Study Guide with Alternative Questions
Question 1
True or False; If false, explain why the statement is false: Bipolar neurons have a central cell body with
two extensions
Answer: True
Note: Structurally, neurons are classified according to the number
of extension from their cell body, as multipolar, bipolar, and
unipolar neurons. Multipolar neurons have three or more
extensions from the cell body. Multipolar neurons have one axon
and many dendrites. They can be called motor neurons. Bipolar
neurons have a central cell body with two extensions. Bipolar
neurons are found within the body as special receptor cells in the
visual and olfactory systems. Unipolar neurons
(pseudounipolar) have one extension off the cell body that
branches into two: one central process running to the CNS and
another peripheral process running to the sensory receptor. These neurons are sensory neurons in the
peripheral nervous system.
***CAN ALSO ASK
Fill in the Blanks: The ____________ are the receiving end of a neuron, while the ____________
conducts nerve impulses away from the cell body.
Answer: Dendrites; axon
Note: Neurons are nerve cells that conduct electrical
impulses and relay information throughout the body.
All neurons have three basic parts: the dendrites, cell
body, and axon. Neurons do not undergo mitosis (cell
division). Neurons can survive a person’s entire
lifetime, which is why brain and spinal cord damage is
so serious. Any neurons that die due to brain damage
cannot be replaced. Neurons can survive just minutes
without oxygen.
The neuron cell body, which synthesizes all nerve cell
products, consists of a large nucleus with surrounding
cytoplasm containing the normal organelles.
Information is received and sent in the same direction within a neuron. The dendrites are the receiving
end of a neuron. Dendrites are numerous short extensions that emanate from the cell body,
which receive information from other neurons and conduct those nerve impulses toward the cell body.
The single axon conducts nerve impulses away from the cell body to its axon terminals. Axons can vary
in length, being very short or very long, up to three feet. Axons are composed of cell components like
,the cell body but lack rough endoplasmic reticulum. The axon depends upon the neuron’s cell body to
send the necessary proteins down the length of the axon.
The cell body contains the nucleus and other organelles typically found in cells, except for centrioles,
which are not capable of mitosis. One of the main functions of the cell body is to manufacture
neurotransmitters. Neurotransmitters are chemicals stored inside secretory vesicles (axon terminal
vesicles) at the end of the axon terminals. When neurotransmitters are released by the axon terminal
vesicles, they carry the transmission of the nerve impulse from one neuron to another.
Neurotransmitters are emitted across a synapse to the dendrite of another neuron. A synapse is a gap
between two neurons, as neurons do not physically touch one another. A presynaptic
neuron means before the synapse. A postsynaptic neuron is a neuron that is found after the synapse.
Neurotransmitters are sent from a presynaptic neuron through the synapse to the postsynaptic neuron.
The message continues in this same manner from one neuron to the next.
***CAN ALSO ASK
The neuron pictured below, is best described as
Answer: Multipolar
***CAN ALSO ASK
Identify the parts of the neuron shown in the diagram below
, A. dendrite
B. cell body
C. nucleus
D. axon/axon hillock
E. myelin sheath
F. Schwann cell/Schwann cell nucleus
G. Node of ranvier
H. Axon terminal
Question 2
List the phases of an action potential in order
Phase 1: Resting Potential- During the resting phase, both sodium and potassium gates are closed.
At rest, the plasma membrane is said to be polarized, meaning that one side has a different charge than
the other side. When the axon is not conducting an impulse, this difference in electrical charge is
called resting potential, or the resting state of a neuron, and is equal to about -70mV (millivolts). The
charge is negative because the charge on the inside of the axon's cell membrane is 70 millivolts less than
the outside of the membrane.
Phase 2: Depolarization- The sodium gates open, and sodium rushes into the axon during the
depolarization phase of the action potential. Voltage travels to zero and then on up to +40 mV.
Phase 3: Repolarization- The sodium gates close, and potassium gates open allowing potassium to rush
out of the axon. This returns a negative voltage to the inside of the axon.
Phase 4: Afterpolarization, also called hyperpolarization. Potassium gates are slow to close, and there
is an undershoot of the potential. The voltage drops below -70mV and then returns to -70mV as the
resting state begins.
Question 1
True or False; If false, explain why the statement is false: Bipolar neurons have a central cell body with
two extensions
Answer: True
Note: Structurally, neurons are classified according to the number
of extension from their cell body, as multipolar, bipolar, and
unipolar neurons. Multipolar neurons have three or more
extensions from the cell body. Multipolar neurons have one axon
and many dendrites. They can be called motor neurons. Bipolar
neurons have a central cell body with two extensions. Bipolar
neurons are found within the body as special receptor cells in the
visual and olfactory systems. Unipolar neurons
(pseudounipolar) have one extension off the cell body that
branches into two: one central process running to the CNS and
another peripheral process running to the sensory receptor. These neurons are sensory neurons in the
peripheral nervous system.
***CAN ALSO ASK
Fill in the Blanks: The ____________ are the receiving end of a neuron, while the ____________
conducts nerve impulses away from the cell body.
Answer: Dendrites; axon
Note: Neurons are nerve cells that conduct electrical
impulses and relay information throughout the body.
All neurons have three basic parts: the dendrites, cell
body, and axon. Neurons do not undergo mitosis (cell
division). Neurons can survive a person’s entire
lifetime, which is why brain and spinal cord damage is
so serious. Any neurons that die due to brain damage
cannot be replaced. Neurons can survive just minutes
without oxygen.
The neuron cell body, which synthesizes all nerve cell
products, consists of a large nucleus with surrounding
cytoplasm containing the normal organelles.
Information is received and sent in the same direction within a neuron. The dendrites are the receiving
end of a neuron. Dendrites are numerous short extensions that emanate from the cell body,
which receive information from other neurons and conduct those nerve impulses toward the cell body.
The single axon conducts nerve impulses away from the cell body to its axon terminals. Axons can vary
in length, being very short or very long, up to three feet. Axons are composed of cell components like
,the cell body but lack rough endoplasmic reticulum. The axon depends upon the neuron’s cell body to
send the necessary proteins down the length of the axon.
The cell body contains the nucleus and other organelles typically found in cells, except for centrioles,
which are not capable of mitosis. One of the main functions of the cell body is to manufacture
neurotransmitters. Neurotransmitters are chemicals stored inside secretory vesicles (axon terminal
vesicles) at the end of the axon terminals. When neurotransmitters are released by the axon terminal
vesicles, they carry the transmission of the nerve impulse from one neuron to another.
Neurotransmitters are emitted across a synapse to the dendrite of another neuron. A synapse is a gap
between two neurons, as neurons do not physically touch one another. A presynaptic
neuron means before the synapse. A postsynaptic neuron is a neuron that is found after the synapse.
Neurotransmitters are sent from a presynaptic neuron through the synapse to the postsynaptic neuron.
The message continues in this same manner from one neuron to the next.
***CAN ALSO ASK
The neuron pictured below, is best described as
Answer: Multipolar
***CAN ALSO ASK
Identify the parts of the neuron shown in the diagram below
, A. dendrite
B. cell body
C. nucleus
D. axon/axon hillock
E. myelin sheath
F. Schwann cell/Schwann cell nucleus
G. Node of ranvier
H. Axon terminal
Question 2
List the phases of an action potential in order
Phase 1: Resting Potential- During the resting phase, both sodium and potassium gates are closed.
At rest, the plasma membrane is said to be polarized, meaning that one side has a different charge than
the other side. When the axon is not conducting an impulse, this difference in electrical charge is
called resting potential, or the resting state of a neuron, and is equal to about -70mV (millivolts). The
charge is negative because the charge on the inside of the axon's cell membrane is 70 millivolts less than
the outside of the membrane.
Phase 2: Depolarization- The sodium gates open, and sodium rushes into the axon during the
depolarization phase of the action potential. Voltage travels to zero and then on up to +40 mV.
Phase 3: Repolarization- The sodium gates close, and potassium gates open allowing potassium to rush
out of the axon. This returns a negative voltage to the inside of the axon.
Phase 4: Afterpolarization, also called hyperpolarization. Potassium gates are slow to close, and there
is an undershoot of the potential. The voltage drops below -70mV and then returns to -70mV as the
resting state begins.
