Exam 4 challenges

Q: Christopher has Multiple Sclerosis (MS), an autoimmune disease that damages neuronal myelin. What are the two types of action potential conduction, listed alphabetically?

A: Continuous and saltatory conduction.

Q: Christopher has MS, which damages the myelin sheaths of neurons. What is the first type of action potential conduction alphabetically?

A: Continuous conduction.

Q: Christopher has MS, which damages the myelin sheaths of neurons. What is the second type of action potential conduction alphabetically?

A: Saltatory conduction.

Q: Christopher has Multiple Sclerosis (MS), which destroys neuronal myelin. Which type of action potential conduction is primarily affected?

A: Saltatory conduction.

Q: Christopher has MS, a disease that disrupts saltatory conduction by destroying an insulating structure around axons. What structure is destroyed?

A: Myelin sheath.

Q: Christopher has MS, which involves the destruction of neuronal myelin. According to the original question, which cells produce the myelin sheath?

A: Schwann cells.

Q: Christopher has MS, an autoimmune demyelinating disease. Which immune cells are responsible for attacking and destroying myelin?

A: White blood cells.

Q: Christopher has MS, which progressively destroys the insulating material surrounding nerve fibers. What is this structure called?

A: Myelin sheath.

Q: Christopher has MS, resulting in destruction of the myelin sheath. What is the main function of the myelin sheath in relation to action potential conduction?

A: To protect and speed up the action potential.

Q: Christopher has MS, causing loss of myelin around neurons. What happens to the speed of action potential conduction as myelin is destroyed?

A: It slows down.

Q: Christopher has MS, which progressively damages myelin and interferes with neuronal signaling. What may eventually happen to action potential conduction?

A: It may stop completely.

Q: Christopher has MS, which damages myelin and disrupts conduction between exposed regions of the axon. What are the gaps between myelin segments called?

A: Nodes of Ranvier.

Q: Christopher has MS, which destroys the myelin that normally allows impulses to travel rapidly between nodes of Ranvier. What is this type of conduction called?

A: Saltatory conduction.

Q: Christopher has MS, which damages myelin and interferes with saltatory conduction. According to the original question, what type of conduction may replace saltatory conduction?

A: Continuous conduction.

Q: Christopher has MS, which can disrupt sensory signals traveling from receptors toward the central nervous system. What are sensory neurons generally called?

A: Afferent neurons.

Q: Christopher has MS, which can affect myelinated sensory nerve fibers. According to the original question, which group of sensory fibers is affected?

A: Type 1.

Q: Christopher has MS, which can affect nerve signals traveling from the central nervous system to muscles. What are motor neurons generally called?

A: Efferent neurons.

Q: Christopher has MS, which can cause visual impairment due to demyelination of a cranial nerve. Which cranial nerve is at risk?

A: Optic nerve (cranial nerve II).

Q: Christopher has MS, which may damage the optic nerve (cranial nerve II). What sensory function may become impaired or lost?

A: Vision.

Q: Christopher has MS, which may disrupt nerve pathways involved in sensation and movement of the thigh. Which spinal nerve is named in the original case?

A: Femoral nerve.

Q: Christopher has MS and experiences impaired sensory signaling involving the femoral nerve. What sensory ability may be lost?

A: Sensation.

Q: Christopher has MS and develops impaired motor signaling involving the femoral nerve. What physical ability may he become unable to perform?

A: Movement.

Q: Christopher has MS, which can disrupt motor pathways and prevent voluntary movement of affected muscles. What is the resulting loss of movement called?

A: Paralysis.

Q: Christopher has MS, causing disrupted nerve signals to muscles and potentially resulting in paralysis. What muscular process is slowed or prevented?

A: Muscle contraction.

Q: Christopher has MS, and the case discusses the femoral nerve, which carries both sensory and motor signals. What is the first neuron category alphabetically?

A: Afferent neurons.

Q: Christopher has MS, and the case discusses the femoral nerve, which carries both sensory and motor signals. What is the second neuron category alphabetically?

A: Efferent neurons.

Q: Mr. Weitz was hospitalized for cardiac problems and accidentally received an IV infusion containing excessive potassium (K+). Before the infusion, his plasma potassium levels were normal. What is the medical term for normal potassium levels in the blood?

A: Normokalemia.

Q: Mr. Weitz was hospitalized for cardiac problems and accidentally received an IV infusion containing excessive potassium (K+), even though his original potassium levels were normal. What condition would this infusion cause?

A: Hyperkalemia.

Q: Mr. Weitz accidentally received a potassium-rich IV infusion despite having normal plasma potassium levels. What would the excessive potassium cause across cell membranes?

A: Imbalance of ions.

Q: Mr. Weitz received an excessive potassium (K+) infusion, disrupting normal electrolyte distribution. Under normal physiological conditions, where is most potassium located?

A: Intracellular fluid (ICF).

Q: Mr. Weitz received an excessive potassium (K+) infusion, disrupting normal electrolyte distribution. Under normal physiological conditions, where is most sodium (Na+) located?

A: Extracellular fluid (ECF).

Q: Mr. Weitz accidentally received an excessive potassium (K+) infusion, which can disrupt the electrical signaling of neurons. What is the electrical nerve impulse generated by a neuron called?

A: Action potential.

Q: Mr. Weitz received an excessive potassium (K+) infusion that can alter the electrical properties of neurons. What is the normal resting membrane potential of a typical neuron?

A: -70 mV.

Q: Mr. Weitz received a potassium-rich IV infusion that can disrupt the normal resting membrane potential of neurons. Where are sodium ions (Na+) normally most concentrated?

A: Extracellular fluid (ECF).

Q: Mr. Weitz received a potassium-rich IV infusion that can disrupt the normal resting membrane potential of neurons. Where are potassium ions (K+) normally most concentrated?

A: Intracellular fluid (ICF).

Q: Mr. Weitz received an excessive potassium infusion that can disrupt neuronal membrane potential. What negatively charged macromolecules inside cells contribute to the negative resting membrane potential?

A: Proteins.

Q: Mr. Weitz received an excessive potassium infusion that can disrupt neuronal membrane potential. Besides negatively charged proteins, which negatively charged ions inside cells contribute to the resting membrane potential?

A: Phosphate ions.

Q: Mr. Weitz accidentally received an excessive potassium (K+) infusion, resulting in hyperkalemia and altered neuronal electrical activity. According to the case's answer key, would his resting membrane potential become higher or lower than normal?

A: Lower.

Q: Mr. Weitz received an excessive potassium (K+) infusion, disrupting his normal neuronal resting membrane potential of -70 mV. According to the case's answer key, what new resting membrane potential might occur?

A: -80 mV.

Q: Mr. Weitz received an excessive potassium infusion, and the case describes his neuronal resting membrane potential changing from -70 mV to -80 mV. What is this change called?

A: Hyperpolarization.

Q: Mr. Weitz accidentally received an excessive potassium infusion, which the case associates with membrane hyperpolarization and disrupted action potential generation. What is the phase of an action potential in which the membrane potential becomes less negative?

A: Depolarization.

Q: Mr. Weitz received an excessive potassium infusion, affecting action potential generation. During a normal action potential, which phase follows depolarization and restores the membrane potential toward its resting value?

A: Repolarization.

Q: Mr. Weitz received an excessive potassium infusion that the case associates with disrupted action potential generation. What is the period during which a neuron cannot generate another action potential, or requires a stronger stimulus?

A: Refractory period.

Q: Mr. Weitz accidentally received an excessive potassium infusion, disrupting nerve impulses. What is the electrical event that a neuron may become unable to generate?

A: Action potential.

Q: A neuron receives signals from hundreds of presynaptic axonal knobs simultaneously. Although many presynaptic neurons release neurotransmitters, the receiving neuron does not generate an action potential. What neural integration process is occurring?

A: Summation.

Q: Hundreds of axonal knobs release neurotransmitters onto a single neuron at the same time, but the receiving neuron does not fire an action potential. What is the receiving neuron called?

A: Postsynaptic neuron.

Q: A postsynaptic neuron receives simultaneous signals from hundreds of other neurons but does not generate an action potential. What are the neurons sending these signals called?

A: Presynaptic neurons.

Q: Hundreds of presynaptic neurons simultaneously communicate with one postsynaptic neuron. These neurons may release different chemical messengers. What are these chemical messengers called?

A: Neurotransmitters.

Q: Hundreds of presynaptic neurons release neurotransmitters onto a single postsynaptic neuron, which remains inhibited. Into what gap between the communicating neurons are neurotransmitters released?

A: Synaptic cleft.

Q: A postsynaptic neuron receives signals from hundreds of presynaptic neurons, but the combined signals do not produce an action potential. What is the first type of neural summation alphabetically?

A: Spatial summation.

Q: A postsynaptic neuron receives signals from hundreds of presynaptic neurons, but the combined signals do not produce an action potential. What is the second type of neural summation alphabetically?

A: Temporal summation.

Q: Hundreds of axonal knobs communicate simultaneously with one postsynaptic neuron, which does not generate an action potential. What are the neurons sending these incoming signals called?

A: Presynaptic neurons.

Q: Hundreds of presynaptic neurons communicate with one postsynaptic neuron at the same time by forming functional connections and releasing neurotransmitters. What is this process of neuronal communication called?

A: Synapsing.

Q: Hundreds of different presynaptic neurons release neurotransmitters onto one postsynaptic neuron simultaneously. The postsynaptic neuron remains inhibited and does not generate an action potential. What type of summation is occurring?

A: Spatial summation.

Q: Hundreds of presynaptic neurons release neurotransmitters onto one receiving neuron, but it does not transmit an action potential. What is the receiving neuron called?

A: Postsynaptic neuron.

Q: Hundreds of presynaptic neurons release neurotransmitters simultaneously onto a postsynaptic neuron, but the neuron does not fire. What type of neurotransmitter must have the greater inhibitory influence?

A: Inhibitory neurotransmitter.

Q: A postsynaptic neuron receives hundreds of simultaneous inputs but remains inhibited because inhibitory signals dominate. What type of neurotransmitter has the lesser overall influence in this situation?

A: Excitatory neurotransmitter.

Q: Hundreds of presynaptic neurons simultaneously release neurotransmitters onto a postsynaptic neuron. The neuron does not generate an action potential because inhibitory signals dominate. Which postsynaptic potentials have the greater overall influence?

A: IPSPs (inhibitory postsynaptic potentials).

Q: A postsynaptic neuron receives hundreds of simultaneous presynaptic inputs but does not fire an action potential because IPSPs dominate. Which postsynaptic potentials are outweighed by the IPSPs?

A: EPSPs (excitatory postsynaptic potentials).

Q: Gabriel develops a high fever and difficulty moving his left arm. Blood tests reveal a major infection that has damaged the motor neurons in the anterior horn of his spinal cord. What condition does Gabriel most likely have?

A: Poliomyelitis.

Q: Gabriel develops a high fever and difficulty moving his left arm. He is diagnosed with poliomyelitis, which damages motor neurons in the spinal cord. What type of infection is poliomyelitis?

A: Viral.

Q: Gabriel develops poliomyelitis, a viral infection that damages lower motor neurons in the anterior horn of the spinal cord and causes difficulty moving his left arm. What specific part of these neurons is primarily affected?

A: Cell bodies.

Q: Gabriel develops poliomyelitis, which damages the cell bodies of motor neurons in the anterior horn of the spinal cord, resulting in difficulty moving his left arm. What type of motor neurons are primarily affected?

A: Lower motor neurons.

Q: Gabriel develops poliomyelitis, which damages the cell bodies of lower motor neurons and causes difficulty moving his left arm. In which horn of the spinal cord are these motor neuron cell bodies located?

A: Anterior horn.

Q: Gabriel has poliomyelitis that damages lower motor neurons in the anterior horn of his spinal cord, producing difficulty moving his left arm. According to the case, which specific spinal cord levels are affected?

A: C6–T1.

Q: Gabriel has poliomyelitis affecting spinal cord levels C6–T1 and experiences difficulty moving his left arm. Which side of his spinal cord is specifically affected?

A: Left.

Q: Gabriel develops poliomyelitis and has difficulty moving his left arm because of damage to lower motor neurons in the anterior horn of his spinal cord. According to the professor's answer key, which specific muscle is identified in the case?

A: Biceps brachii.

Q: Gabriel develops poliomyelitis that affects lower motor neurons involved in moving his left arm. According to the case, which other spinal cord region remains unaffected?

A: Lumbar region.

Q: Gabriel develops poliomyelitis, affecting lower motor neurons associated with movement of his left upper extremity. Which network of spinal nerves supplies the affected upper limb?

A: Brachial plexus.

Q: Gabriel develops poliomyelitis affecting the brachial plexus, a network of spinal nerves associated with the upper limb. What type of nerves make up this network, carrying both sensory and motor fibers?

A: Mixed spinal nerves.

Q: Gabriel develops poliomyelitis that damages lower motor neurons associated with movement of his left arm. Which specific nerve of the brachial plexus supplies the biceps brachii muscle and may be affected?

A: Musculocutaneous nerve.

Q: Gabriel develops poliomyelitis affecting the musculocutaneous nerve's motor pathways, resulting in difficulty moving his left arm. Which muscle controlled by this nerve is specifically identified in the case?

A: Biceps brachii.

Q: Gabriel develops poliomyelitis affecting motor function involving the musculocutaneous nerve, which supplies the biceps brachii. What type of nerve is the musculocutaneous nerve, since it contains both sensory and motor fibers?

A: Mixed nerve.

Q: Gabriel develops poliomyelitis that affects motor function involving the musculocutaneous nerve and biceps brachii muscle. What type of motor neurons are included in this nerve and responsible for controlling skeletal muscle movement?

A: Lower motor neurons.

Q: Gabriel develops poliomyelitis, damaging lower motor neurons and causing difficulty moving his left arm. However, he can still feel pain because which type of neurons in the spinal nerves remain unaffected?

A: Sensory neurons.

Q: Gabriel has poliomyelitis affecting lower motor neurons in the anterior horn of his spinal cord, but his sensory neurons remain intact, allowing him to feel pain. Which portion of the spinal cord is associated with sensory input?

A: Dorsal portion.

Q: Gabriel has poliomyelitis affecting lower motor neurons but preserving sensory function. What part of the sensory neurons is found in the dorsal root ganglion?

A: Cell bodies.

Q: Gabriel develops poliomyelitis that damages lower motor neurons in the anterior horn of his spinal cord. His sensory neurons remain intact. Where are the cell bodies of these sensory neurons located?

A: Dorsal root ganglion.

LEFT OFF ON CHALLENGE 5