Biology 251 Exam #2 Questions and
All Correct Answers.
When two neurons are communicating with each other at a chemical synapse, the ( ) neuron
releases neurotransmitters that diffuse across the synaptic cleft and bind to receptors on the
membrane of the ( ) neuron. - Answer presynaptic: postsynaptic
In neurons, where is neurotransmitter stored? - Answer within synaptic vesicles in the axon
terminal
Which of the following is a mechanism whereby neurotransmitters are rapidly removed from
the synaptic cleft thus terminating the signal? - Answer diffusion out of the cleft
degradation by enzymes
active reuptake back into the presynaptic neuron
What type of synapse occurs between an axon terminal of one neuron and the cell body of
another neuron? - Answer axosomatic
The influx of calcium into the axon terminal of a chemical synapse is responsible for which of
the following? - Answer movement of synaptic vesicles to the membrane of the axon
terminal and the release of neurotransmitter
Which of the following statements about inhibitory synapses is FALSE? - Answer the
membrane potential of the postsynaptic cell is depolarized
What is a change in the postsynaptic potential that brings that membrane potential closer to
threshold called? - Answer excitatory postsynaptic potential (EPSP)
What portion of the efferent branch of the peripheral nervous system controls glands and the
smooth muscle of many visceral organs? - Answer autonomic nervous system
Where do the preganglionic neurons of the sympathetic nervous system emerge from the spinal
cord? - Answer thoracic and lumbar regions
Where in the central nervous system do the preganglionic neurons of the parasympathetic
nervous system originate? - Answer brainstem and sacral region of the spinal cord
Dual innervation of organs by the autonomic nervous system refers to the observation that ( ) -
Answer both sympathetic and parasympathetic neurons innervate most organs
, Parasympathetic preganglionic neurons release the neurotransmitter ( ); sympathetic
preganglionic neurons release the neurotransmitter ( ). - Answer acetylcholine :
acetylcholine
Which of the following endocrine glands is innervated by sympathetic preganglionic neurons? -
Answer adrenal medulla
Parasympathetic postganglionic neurons release the neurotransmitter ( ); sympathetic
postganglionic neurons release the neurotransmitter ( ). - Answer acetylcholine :
norepinephrine
What structure in the eye is comprised of neural tissue that includes photoreceptors, bipolar
cells, and ganglion cells? - Answer retina
During visual accommodation, which division of the nervous system is activated to alter the
shape of the lens to increase the refractive power of the lens to focus close images onto the
retina? - Answer parasympathetic
The outer radial muscles of the iris of the eye are innervated by the ( ) nervous system and their
contraction causes pupillary ( ). - Answer sympathetic : dilation
Which of the following is/are a type of cholinergic receptor, i.e. a receptor that binds and is
activated by acetylcholine? - Answer both nicotinic and muscarine
Which of the following accurately describes adrenergic receptors of the autonomic nervous
system? - Answer they belong to alpha or beta subtypes
they are on target cells of the sympathetic nervous system
The somatic nervous system regulates the activity of - Answer skeletal muscle
What is the correct order for the steps of synaptic transmission at the motor end plate?
1. Acetylcholine binds to postsynaptic receptors on the skeletal muscle plasma membrane
2. Acetylcholine is released from the axon terminal
3. A graded depolarization is produced on the skeletal muscle membrane at the motor end plate
4. An action potential is produced on the muscle cell membrane which spreads over the muscle
cell
5. Channels that primarily allow diffusion of sodium into the skeletal muscle are opened
6. Voltage-dependent calcium channels of the axon terminal open
All Correct Answers.
When two neurons are communicating with each other at a chemical synapse, the ( ) neuron
releases neurotransmitters that diffuse across the synaptic cleft and bind to receptors on the
membrane of the ( ) neuron. - Answer presynaptic: postsynaptic
In neurons, where is neurotransmitter stored? - Answer within synaptic vesicles in the axon
terminal
Which of the following is a mechanism whereby neurotransmitters are rapidly removed from
the synaptic cleft thus terminating the signal? - Answer diffusion out of the cleft
degradation by enzymes
active reuptake back into the presynaptic neuron
What type of synapse occurs between an axon terminal of one neuron and the cell body of
another neuron? - Answer axosomatic
The influx of calcium into the axon terminal of a chemical synapse is responsible for which of
the following? - Answer movement of synaptic vesicles to the membrane of the axon
terminal and the release of neurotransmitter
Which of the following statements about inhibitory synapses is FALSE? - Answer the
membrane potential of the postsynaptic cell is depolarized
What is a change in the postsynaptic potential that brings that membrane potential closer to
threshold called? - Answer excitatory postsynaptic potential (EPSP)
What portion of the efferent branch of the peripheral nervous system controls glands and the
smooth muscle of many visceral organs? - Answer autonomic nervous system
Where do the preganglionic neurons of the sympathetic nervous system emerge from the spinal
cord? - Answer thoracic and lumbar regions
Where in the central nervous system do the preganglionic neurons of the parasympathetic
nervous system originate? - Answer brainstem and sacral region of the spinal cord
Dual innervation of organs by the autonomic nervous system refers to the observation that ( ) -
Answer both sympathetic and parasympathetic neurons innervate most organs
, Parasympathetic preganglionic neurons release the neurotransmitter ( ); sympathetic
preganglionic neurons release the neurotransmitter ( ). - Answer acetylcholine :
acetylcholine
Which of the following endocrine glands is innervated by sympathetic preganglionic neurons? -
Answer adrenal medulla
Parasympathetic postganglionic neurons release the neurotransmitter ( ); sympathetic
postganglionic neurons release the neurotransmitter ( ). - Answer acetylcholine :
norepinephrine
What structure in the eye is comprised of neural tissue that includes photoreceptors, bipolar
cells, and ganglion cells? - Answer retina
During visual accommodation, which division of the nervous system is activated to alter the
shape of the lens to increase the refractive power of the lens to focus close images onto the
retina? - Answer parasympathetic
The outer radial muscles of the iris of the eye are innervated by the ( ) nervous system and their
contraction causes pupillary ( ). - Answer sympathetic : dilation
Which of the following is/are a type of cholinergic receptor, i.e. a receptor that binds and is
activated by acetylcholine? - Answer both nicotinic and muscarine
Which of the following accurately describes adrenergic receptors of the autonomic nervous
system? - Answer they belong to alpha or beta subtypes
they are on target cells of the sympathetic nervous system
The somatic nervous system regulates the activity of - Answer skeletal muscle
What is the correct order for the steps of synaptic transmission at the motor end plate?
1. Acetylcholine binds to postsynaptic receptors on the skeletal muscle plasma membrane
2. Acetylcholine is released from the axon terminal
3. A graded depolarization is produced on the skeletal muscle membrane at the motor end plate
4. An action potential is produced on the muscle cell membrane which spreads over the muscle
cell
5. Channels that primarily allow diffusion of sodium into the skeletal muscle are opened
6. Voltage-dependent calcium channels of the axon terminal open
