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Nervous Tissue
Brain
Spinal Cord
ANS
100

If a neuron is hyperpolarized, what is the most likely explanation?

  • Potassium ions exited the cell or chloride ions entered, making it more negative.
  • Sodium ions entered the cell, making it more positive.
  • Calcium ions accumulated inside the cell.
  • Voltage-gated channels became inactivated.

Potassium ions exited the cell or chloride ions entered, making it more negative.

100

How might a blockage in the cerebral aqueduct affect the brain's functionality?

  • It would impair motor coordination by disrupting cerebellar communication.
  • It would block blood supply to the thalamus, impairing sensory relay.
  • It could lead to hydrocephalus due to disrupted cerebrospinal fluid flow.
  • It would decrease melatonin production by the pineal gland.

It could lead to hydrocephalus due to disrupted cerebrospinal fluid flow.

100

Why does damage to the ventral root of a spinal nerve result in a loss of motor function but not sensation?

  • The ventral root carries sensory axons, not motor axons.
  • The ventral root contains only motor neuron axons, while sensory axons travel in the dorsal root.
  • The dorsal root ganglion compensates for the loss of motor function.
  • The ventral root carries both sensory and motor axons

The ventral root contains only motor neuron axons, while sensory axons travel in the dorsal root.

100

How does the balance between parasympathetic and sympathetic tone affect heart rate at rest versus during exercise?

  • Sympathetic tone decreases during exercise to conserve energy.
  • Parasympathetic tone increases heart rate during exercise, while sympathetic tone decreases.
  • Parasympathetic tone dominates at rest, while sympathetic tone increases during exercise.
  • Both systems are inactive at rest, and sympathetic tone exclusively regulates exercise.

Parasympathetic tone dominates at rest, while sympathetic tone increases during exercise.

200

How does the blood-brain barrier, maintained by astrocytes, protect the central nervous system?

  • By allowing all substances to freely enter the brain for rapid signaling
  • By filtering out harmful pathogens and regulating the chemical environment
  • By increasing the speed of action potential propagation through the brain
  • By promoting rapid diffusion of ions across neuron membranes

By filtering out harmful pathogens and regulating the chemical environment

200

A patient experiences impaired motor coordination and balance after a traumatic brain injury. Which brain region is most likely affected, and why?

  • Cerebrum
  • Cerebellum
  • Hypothalamus
  • Thalamus

Cerebellum

200

What is the clinical significance of testing dermatomes in a patient with a suspected spinal cord injury?

  • It determines motor deficits in affected limbs.
  • It assesses the function of cranial nerves.
  • It identifies the specific spinal nerve or segment affected.
  • It tests the integrity of autonomic nervous system pathways.

It identifies the specific spinal nerve or segment affected.

200

Which of the following is a function of the sympathetic division of the autonomic nervous system?

  • Stimulating digestion
  • Reducing heart rate
  • Increasing metabolic rate
  • Promoting salivation

Increasing metabolic rate

300

A patient has a demyelinating disorder that impacts motor functions. Which cell type in the nervous system is likely affected, and why?

  • Astrocytes; they maintain blood-brain barrier integrity
  • Schwann cells; they form myelin sheaths in the peripheral nervous system
  • Microglia; they perform phagocytosis in the CNS
  • Ependymal cells; they assist in cerebrospinal fluid circulation

Schwann cells; they form myelin sheaths in the peripheral nervous system

300

A stroke patient has difficulty speaking but understands language. Damage to which area of the brain would most likely explain this deficit?

  • Broca’s area
  • Prefrontal cortex
  • Primary motor cortex
  • Wernicke’s area

Broca's area

300

How does reciprocal inhibition enhance coordinated body movements during reflex actions?

  • It increases the speed of nerve impulse transmission.
  • It prevents simultaneous contraction of agonist and antagonist muscles.
  • It strengthens the flexor reflex response.
  • It amplifies sensory input to the spinal cord.

It prevents simultaneous contraction of agonist and antagonist muscles.

300

Why might a patient with damage to the hypothalamus exhibit difficulties regulating autonomic functions such as heart rate or digestion?

  • The hypothalamus regulates autonomic tone and directs the activities of visceral motor neurons.
  • The hypothalamus directly controls skeletal muscle.
  • Damage to the hypothalamus impacts voluntary motor control.
  • It produces neurotransmitters like norepinephrine and acetylcholine.

The hypothalamus regulates autonomic tone and directs the activities of visceral motor neurons.

400

What might happen if ligand-gated ion channels on a neuron’s dendrites are blocked?

  • Action potentials could not propagate along the axon.
  • The neuron could not generate graded potentials in response to neurotransmitters.
  • Synaptic vesicles would release neurotransmitters uncontrollably.
  • Resting membrane potential would reach zero.

The neuron could not generate graded potentials in response to neurotransmitters.

400

A patient with chronic emotional stress develops high blood pressure and frequent heartburn. Which brain region could be responsible for these psychosomatic symptoms, and how?

  • Hypothalamus
  • Cerebrum
  • Pons
  • Medulla oblongata

Hypothalamus

400

If the phrenic nerve is damaged, what immediate consequence might you expect, and why?

  • Paralysis of the diaphragm, leading to breathing difficulties
  • Loss of sensation in the lower limbs due to interruption of lumbar plexus function
  • Impaired swallowing due to pharyngeal muscle weakness
  • Loss of reflexes in the abdominal muscles

Paralysis of the diaphragm, leading to breathing difficulties

400

A patient has difficulty controlling their urinary bladder. Which sacral parasympathetic nerves might be involved?

  • Pelvic splanchnic nerves
  • Lumbar splanchnic nerves
  • Thoracic splanchnic nerves
  • Hypogastric nerves

Pelvic splanchnic nerves

500

During a synaptic transmission, which event is directly responsible for neurotransmitter release from the presynaptic neuron?

  • Depolarization reaching the trigger zone
  • Binding of neurotransmitters to postsynaptic receptors
  • Exocytosis of vesicles containing neurotransmitters due to sodium influx
  • Influx of calcium ions through voltage-gated channels

Influx of calcium ions through voltage-gated channels

500

Why would damage to the basal nuclei likely result in difficulty initiating voluntary movements?

  • It disrupts sensory feedback required for motion planning.
  • It impairs the thalamic relay of sensory information.
  • It inhibits the coordination of antagonist muscle groups.
  • It prevents the cerebellum from issuing movement instructions.

It inhibits the coordination of antagonist muscle groups.

500

During a reflex test, a patient's patellar reflex is absent. Which of the following could explain this finding?

  • Damage to the primary motor cortex
  • Lesion in the L2-L4 spinal cord segments
  • Overactive gamma motor neurons in the muscle spindle
  • Dysfunction in the cerebellum

Lesion in the L2-L4 spinal cord segments

500

A patient is unable to salivate properly. Which parasympathetic cranial nerves and ganglia might be affected?

  • Vagus nerve (X) and submandibular ganglion
  • Facial nerve (VII) and submandibular ganglion
  • Glossopharyngeal nerve (IX) and otic ganglion
  • Both b and c

Both b and c