Guided Study: Brain Structure, Function, and Nervous System (ANP 109 Topic 7)

Q1a. Which parts of the brain (and on which side) initiate voluntary, learned movement of the right leg’s skeletal muscle when kicking a football? Explain.

Background

Topic: Motor control and brain lateralization

This question tests your understanding of which brain regions are responsible for initiating voluntary, learned movements, and how the brain's hemispheres control the body.

Key Terms and Concepts:

• Primary motor cortex: The region of the brain that initiates voluntary muscle movements.

• Contralateral control: Each hemisphere of the brain controls the opposite side of the body.

• Learned movement: Movements that are practiced and refined, often involving the premotor cortex.

Step-by-Step Guidance

1. Recall that voluntary movements are initiated in the primary motor cortex, located in the precentral gyrus of the frontal lobe.

2. Consider the concept of contralateral control: the left hemisphere of the brain controls the right side of the body, and vice versa.

3. Think about the role of the premotor cortex and supplementary motor areas in planning and coordinating learned movements.

4. Identify which hemisphere and which specific cortical areas would be active when kicking with the right leg.

Try solving on your own before revealing the answer!

Q1b. Which part of the brain causes the kicker’s head to instinctively jerk toward a sudden, bright light? Explain.

Background

Topic: Reflexive responses and sensory processing in the brain

This question examines your knowledge of brain regions involved in automatic, reflex-like responses to sensory stimuli.

Key Terms and Concepts:

• Reflexive movement: An automatic, rapid response to a stimulus.

• Midbrain (tectum): Contains structures involved in visual and auditory reflexes.

• Superior colliculus: A midbrain structure involved in orienting the head and eyes toward visual stimuli.

Step-by-Step Guidance

1. Identify which brain region is responsible for processing sudden visual stimuli.

2. Recall the function of the superior colliculus in the midbrain.

3. Consider how this structure coordinates head and eye movements in response to bright lights.

Try solving on your own before revealing the answer!

Q2. Why can damage to the medulla oblongata cause death, while similar damage in the cerebrum might go unnoticed?

Background

Topic: Brainstem function vs. cerebral cortex function

This question tests your understanding of the vital functions controlled by different brain regions.

Key Terms and Concepts:

• Medulla oblongata: Part of the brainstem that controls vital autonomic functions (e.g., breathing, heart rate).

• Cerebrum: Responsible for higher-order functions (e.g., thought, voluntary movement).

• Vital centers: Areas that regulate life-sustaining processes.

Step-by-Step Guidance

1. List the main functions of the medulla oblongata and why they are essential for survival.

2. Compare these to the functions of the cerebrum and consider which cerebral areas might be non-vital.

3. Think about what happens if each area is damaged—what processes are affected?

Try solving on your own before revealing the answer!

Q3. How do walking a straight line and touching the nose with a finger indicate sobriety? Which part of the brain is being tested? Explain.

Background

Topic: Cerebellar function and coordination

This question assesses your understanding of how the brain controls balance and coordination, and how impairment affects these abilities.

Key Terms and Concepts:

• Cerebellum: Coordinates voluntary movements, balance, and posture.

• Ataxia: Lack of muscle coordination, often due to cerebellar dysfunction.

• Field sobriety tests: Assess motor coordination and balance.

Step-by-Step Guidance

1. Recall the main functions of the cerebellum in movement and balance.

2. Consider how alcohol affects the cerebellum and what symptoms might appear.

3. Explain why tasks like walking a straight line or touching the nose require cerebellar coordination.

4. Think about what signs of impairment would indicate cerebellar dysfunction.

Try solving on your own before revealing the answer!

Q4. Which lobes of the cerebrum are likely injured with trauma to the posterior head (behind the ears)? What symptoms might result?

Background

Topic: Cerebral lobe anatomy and function

This question tests your knowledge of the locations and functions of the cerebral lobes, and how injury affects neurological function.

Key Terms and Concepts:

• Occipital lobe: Located at the back of the brain; processes visual information.

• Temporal lobe: Located on the sides of the brain; involved in hearing and memory.

• Symptoms of lobe injury: Loss of specific sensory or cognitive functions.

Step-by-Step Guidance

1. Identify which lobes are located at the posterior and lateral aspects of the cerebrum.

2. Recall the main functions of the occipital and temporal lobes.

3. Predict what symptoms might occur if these lobes are damaged (e.g., visual or auditory deficits).

Try solving on your own before revealing the answer!

Q5. Why can cerebral meningitis (inflammation of the brain’s meninges) be life threatening?

Background

Topic: Meninges and central nervous system infections

This question examines your understanding of the protective coverings of the brain and the consequences of their inflammation.

Key Terms and Concepts:

• Meninges: Three protective membranes (dura mater, arachnoid mater, pia mater) surrounding the brain and spinal cord.

• Meningitis: Inflammation of the meninges, often due to infection.

• Intracranial pressure: Pressure within the skull, which can increase with inflammation.

Step-by-Step Guidance

1. Describe the role of the meninges in protecting the brain.

2. Explain how inflammation can affect brain function and intracranial pressure.

3. Consider why increased pressure or infection in this area can be life threatening.

Try solving on your own before revealing the answer!

Q6. What would happen if the normal circulation or resorption of cerebrospinal fluid (CSF) were blocked?

Background

Topic: Cerebrospinal fluid dynamics

This question tests your understanding of CSF production, circulation, and its importance in brain health.

Key Terms and Concepts:

• Cerebrospinal fluid (CSF): Fluid that cushions and protects the brain and spinal cord.

• Hydrocephalus: Condition caused by accumulation of CSF due to blockage.

• Intracranial pressure: Can increase if CSF is not properly circulated or absorbed.

Step-by-Step Guidance

1. Recall the normal pathway of CSF circulation and absorption in the brain.

2. Consider what happens if there is a blockage in this pathway.

3. Think about the consequences of increased CSF volume and pressure on brain tissue.

Try solving on your own before revealing the answer!

Q7. How do a nerve and a neuron differ? Which would have a greater effect on motor and sensory function: damage to a neuron or to a nerve? Explain.

Background

Topic: Structure and function of neurons and nerves

This question assesses your understanding of the difference between individual nerve cells and bundles of nerve fibers, and the implications of damage to each.

Key Terms and Concepts:

• Neuron: A single nerve cell that transmits electrical impulses.

• Nerve: A bundle of axons (nerve fibers) in the peripheral nervous system.

• Motor and sensory function: Dependent on intact pathways of neurons and nerves.

Step-by-Step Guidance

1. Define what a neuron is and what a nerve is, noting the difference in structure and function.

2. Consider what happens if a single neuron is damaged versus an entire nerve.

3. Think about which would have a broader impact on motor and sensory function and why.

Try solving on your own before revealing the answer!

Q8. How might you assess the function of the following cranial nerves in a patient?

Background

Topic: Cranial nerve assessment

This question tests your knowledge of the functions of specific cranial nerves and how to evaluate them clinically.

Key Terms and Concepts:

• Cranial nerves III, IV, VI (Oculomotor, Trochlear, Abducens): Control eye movements.

• Cranial nerve XII (Hypoglossal): Controls tongue movement.

• Cranial nerve VIII (Vestibulocochlear): Has two branches: cochlear (hearing) and vestibular (balance).

• Cranial nerve V (Trigeminal): Controls facial sensation and muscles of mastication.

Step-by-Step Guidance

1. For III, IV, VI: Think about how you would test eye movement in different directions and look for double vision or inability to move the eyes properly.

2. For XII: Consider how you would assess tongue movement and strength.

3. For VIII: Recall tests for hearing (cochlear branch) and balance (vestibular branch).

4. For V: Think about how to test facial sensation and the strength of jaw muscles.

Try solving on your own before revealing the answer!