BIOLOGY 251- EXAM 2 LATEST UPDATE QUESTIONS
WITH VERIFIED ANSWERS.
Afferent neurons: head towards the central nervous system.
Efferent neurons: head away from the central nervous system. - answer ✔✔-What is the difference
between afferent and efferent neurons?
Autonomic nervous system - answer ✔✔-What part of the peripheral nervous system controls internal
organs by innervating smooth muscle, cardiac muscle, and glands in these organs/tissues?
Preganglionic neurons - answer ✔✔-Which type of autonomic neuron originates somewhere in the
central nervous system?
Postganglionic neuron - answer ✔✔-Which type of autonomic neuron originates in an autonomic
ganglion?
Sympathetic: thoracic and lumbar regions of spinal cord
Parasympathetic: brainstem and sacral spinal cord - answer ✔✔-For both autonomic divisions, list
where the preganglionic cell bodies are located within the central nervous system
Bind to adrenergic receptors, synapses between postganglionic axons and target organs in autonomic
nervous system - answer ✔✔-Do postganglionic neurons form synapses with other neurons, or do they
synapse with target cells?
Along the vertebral column in a chain - answer ✔✔-Where are the sympathetic ganglia located?
In or near effector organs - answer ✔✔-Where are the parasympathetic ganglia located?
Sympathetic: Fight or flight response, prepare for emergency/stress/exercise, increase heart rate and
blood pressure, mobilize energy stores, pupillary dilation, decrease gastrointestinal/urinary functions
Parasympathetic: Quiet/relaxed states, increase gastrointestinal activities, decrease heart rate and
blood pressure - answer ✔✔-In general, what are the functions of the sympathetic and the
parasympathetic divisions of the autonomic nervous system?
Acetylcholine- binds to receptors on postganglionic cell, cause action potentials, released by
preganglionic neurons (sympathetic AND parasympathetic)
Norepinephrine- bind to receptors on target cells, effects vary, released by postganglionic neurons
(sympathetic) - answer ✔✔-What are the autonomic neurotransmitters involved at each different
synapse (for both autonomic divisions)?
Alpha (a1-a2) and Beta (b1-b3) - answer ✔✔-What are the types of adrenergic receptors found in the
sympathetic division of the autonomic nervous system?
Excitatory: a1, a2, b1, b3
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, Inhibitory: b2 - answer ✔✔-In general, which adrenergic receptors are excitatory, and which are
inhibitory?
Nicotinic receptors and muscarinic receptors - answer ✔✔-What are the types of cholinergic receptors
of the parasympathetic division?
Nicotinic: postganglionic neuron cell bodies
Muscarinic: target organs - answer ✔✔-Where is each type of cholinergic receptor located?
Sympathetic nervous system - answer ✔✔-Which division of the autonomic nervous system controls
the release of epinephrine (adrenaline) from the adrenal medulla.
Skeletal muscle cells - answer ✔✔-What types of cells do somatic motor neurons control?
Synapse between a motor neuron and a muscle fiber - answer ✔✔-What is a neuromuscular junction?
Acetylcholine - answer ✔✔-What is the neurotransmitter released at the neuromuscular junction?
Nicotinic receptors on the motor end plate - answer ✔✔-Acetylcholine released at the neuromuscular
membrane binds to what type of receptor on the muscle cell membrane
1. Action potential arrives at motor axon terminal
2. Voltage-gated calcium channels open
3. Calcium enters cell, triggering release of Ach
4. Ach diffuses across the cleft and binds to Nicotinic receptors on motor end plate
5. Ach triggers opening of fast ion channels for small cations - sodium and potassium
6. Net movement of positive charge into muscle cell → depolarization
7. EPSP causes action potential in muscle cell
8. Action potential spreads through muscle causing contraction - answer ✔✔-Describe the events that
occur during synaptic transmission at a neuromuscular junction
Rods and cones - answer ✔✔-What are the two major photoreceptors in the retina?
Cones - answer ✔✔-Which of the two types of photoreceptors is responsible for color vision?
Rods: highly sensitive to light, low acuity: not able to resolve fine detail, can't discriminate color
Cones: not as sensitive to light, high acuity: able to resolve fine detail, each cone has a slightly
different photopigment - answer ✔✔-How do the two types of photoreceptors differ with respect to their
sensitivity to light vs. acuity (resolution)?
Photoreceptors release a neurotransmitter that inhibits bipolar cells and ganglion cells. Bipolar and
ganglion cells produce action potentials that travel to visual centers. - answer ✔✔-How is light
converted to electrical impulses in neurons (phototransduction)?
Sensitivity of rods is low due to light "bleaching". Retinal and opsin re-associate and make new
photopigment. Can detect light again, but takes a few minutes. - answer ✔✔-What is meant by dark
adaptation?
In small changes in light intensity, pupillary dilation and constriction are enough to compensate. Larger
changes in light intensity requires changes in photopigment levels in photoreceptors. - answer ✔✔-
What is meant by light adaptation?
Accommodation: increasing curvature of lens to focus light from near objects on retina - answer ✔✔-
How is the amount of light entering the eye regulated?
Dilation - answer ✔✔-How does the sympathetic nervous system affect pupil diameter?
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WITH VERIFIED ANSWERS.
Afferent neurons: head towards the central nervous system.
Efferent neurons: head away from the central nervous system. - answer ✔✔-What is the difference
between afferent and efferent neurons?
Autonomic nervous system - answer ✔✔-What part of the peripheral nervous system controls internal
organs by innervating smooth muscle, cardiac muscle, and glands in these organs/tissues?
Preganglionic neurons - answer ✔✔-Which type of autonomic neuron originates somewhere in the
central nervous system?
Postganglionic neuron - answer ✔✔-Which type of autonomic neuron originates in an autonomic
ganglion?
Sympathetic: thoracic and lumbar regions of spinal cord
Parasympathetic: brainstem and sacral spinal cord - answer ✔✔-For both autonomic divisions, list
where the preganglionic cell bodies are located within the central nervous system
Bind to adrenergic receptors, synapses between postganglionic axons and target organs in autonomic
nervous system - answer ✔✔-Do postganglionic neurons form synapses with other neurons, or do they
synapse with target cells?
Along the vertebral column in a chain - answer ✔✔-Where are the sympathetic ganglia located?
In or near effector organs - answer ✔✔-Where are the parasympathetic ganglia located?
Sympathetic: Fight or flight response, prepare for emergency/stress/exercise, increase heart rate and
blood pressure, mobilize energy stores, pupillary dilation, decrease gastrointestinal/urinary functions
Parasympathetic: Quiet/relaxed states, increase gastrointestinal activities, decrease heart rate and
blood pressure - answer ✔✔-In general, what are the functions of the sympathetic and the
parasympathetic divisions of the autonomic nervous system?
Acetylcholine- binds to receptors on postganglionic cell, cause action potentials, released by
preganglionic neurons (sympathetic AND parasympathetic)
Norepinephrine- bind to receptors on target cells, effects vary, released by postganglionic neurons
(sympathetic) - answer ✔✔-What are the autonomic neurotransmitters involved at each different
synapse (for both autonomic divisions)?
Alpha (a1-a2) and Beta (b1-b3) - answer ✔✔-What are the types of adrenergic receptors found in the
sympathetic division of the autonomic nervous system?
Excitatory: a1, a2, b1, b3
GRADESMORE.COM
, Inhibitory: b2 - answer ✔✔-In general, which adrenergic receptors are excitatory, and which are
inhibitory?
Nicotinic receptors and muscarinic receptors - answer ✔✔-What are the types of cholinergic receptors
of the parasympathetic division?
Nicotinic: postganglionic neuron cell bodies
Muscarinic: target organs - answer ✔✔-Where is each type of cholinergic receptor located?
Sympathetic nervous system - answer ✔✔-Which division of the autonomic nervous system controls
the release of epinephrine (adrenaline) from the adrenal medulla.
Skeletal muscle cells - answer ✔✔-What types of cells do somatic motor neurons control?
Synapse between a motor neuron and a muscle fiber - answer ✔✔-What is a neuromuscular junction?
Acetylcholine - answer ✔✔-What is the neurotransmitter released at the neuromuscular junction?
Nicotinic receptors on the motor end plate - answer ✔✔-Acetylcholine released at the neuromuscular
membrane binds to what type of receptor on the muscle cell membrane
1. Action potential arrives at motor axon terminal
2. Voltage-gated calcium channels open
3. Calcium enters cell, triggering release of Ach
4. Ach diffuses across the cleft and binds to Nicotinic receptors on motor end plate
5. Ach triggers opening of fast ion channels for small cations - sodium and potassium
6. Net movement of positive charge into muscle cell → depolarization
7. EPSP causes action potential in muscle cell
8. Action potential spreads through muscle causing contraction - answer ✔✔-Describe the events that
occur during synaptic transmission at a neuromuscular junction
Rods and cones - answer ✔✔-What are the two major photoreceptors in the retina?
Cones - answer ✔✔-Which of the two types of photoreceptors is responsible for color vision?
Rods: highly sensitive to light, low acuity: not able to resolve fine detail, can't discriminate color
Cones: not as sensitive to light, high acuity: able to resolve fine detail, each cone has a slightly
different photopigment - answer ✔✔-How do the two types of photoreceptors differ with respect to their
sensitivity to light vs. acuity (resolution)?
Photoreceptors release a neurotransmitter that inhibits bipolar cells and ganglion cells. Bipolar and
ganglion cells produce action potentials that travel to visual centers. - answer ✔✔-How is light
converted to electrical impulses in neurons (phototransduction)?
Sensitivity of rods is low due to light "bleaching". Retinal and opsin re-associate and make new
photopigment. Can detect light again, but takes a few minutes. - answer ✔✔-What is meant by dark
adaptation?
In small changes in light intensity, pupillary dilation and constriction are enough to compensate. Larger
changes in light intensity requires changes in photopigment levels in photoreceptors. - answer ✔✔-
What is meant by light adaptation?
Accommodation: increasing curvature of lens to focus light from near objects on retina - answer ✔✔-
How is the amount of light entering the eye regulated?
Dilation - answer ✔✔-How does the sympathetic nervous system affect pupil diameter?
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