Anatomy & Physiology: Nervous System and Reflexes Study Guide

Q1. The "input" side of the PNS is also known as...

Background

Topic: Peripheral Nervous System (PNS) Organization

This question tests your understanding of the functional divisions of the PNS, specifically the difference between sensory (afferent) and motor (efferent) pathways.

Key Terms:

• Afferent (Sensory) Division: Carries sensory information from receptors to the CNS.

• Efferent (Motor) Division: Carries motor commands from the CNS to effectors (muscles/glands).

Step-by-Step Guidance

1. Recall that the PNS is divided into sensory (afferent) and motor (efferent) divisions.

2. The "input" side refers to the direction information travels toward the CNS.

3. Think about which division is responsible for bringing information from the body to the brain and spinal cord.

4. Match the correct term (afferent or efferent) to the "input" function.

Try solving on your own before revealing the answer!

Final Answer: Sensory or afferent

The "input" side of the PNS is the sensory (afferent) division, which carries information from sensory receptors to the CNS.

Q2. The cell bodies of motor neurons reside in...

Background

Topic: Spinal Cord Anatomy

This question tests your knowledge of where motor neuron cell bodies are located within the spinal cord.

Key Terms:

• Ventral Horn: The anterior (front) section of the spinal gray matter, containing motor neuron cell bodies.

• Dorsal Horn: The posterior (back) section, containing sensory neuron cell bodies.

• Ganglion: A cluster of neuron cell bodies outside the CNS.

Step-by-Step Guidance

1. Recall the structure of the spinal cord gray matter (dorsal and ventral horns).

2. Identify which horn contains the cell bodies of motor neurons.

3. Remember that sensory neuron cell bodies are found in the dorsal root ganglion, not within the spinal cord itself.

4. Choose the correct location for motor neuron cell bodies.

Try solving on your own before revealing the answer!

Final Answer: The ventral horn of the spinal gray matter

Motor neuron cell bodies are located in the ventral (anterior) horn of the spinal cord's gray matter.

Q3. The unconscious outputs of the nervous system are called the...

Background

Topic: Autonomic Nervous System (ANS)

This question is about the division of the nervous system responsible for involuntary (unconscious) control of body functions.

Key Terms:

• Autonomic Nervous System (ANS): Controls involuntary functions like heart rate, digestion, and respiratory rate.

• Somatic Nervous System: Controls voluntary movements of skeletal muscles.

Step-by-Step Guidance

1. Recall the two main divisions of the PNS: somatic (voluntary) and autonomic (involuntary).

2. Think about which division controls unconscious activities such as heart rate and digestion.

3. Identify the correct term for the system responsible for these outputs.

Try solving on your own before revealing the answer!

Final Answer: Autonomic nervous system

The ANS is responsible for unconscious (involuntary) outputs of the nervous system.

Q4. Signals from the brain are carried to the lungs by...

Background

Topic: Cranial Nerves and Autonomic Control

This question tests your knowledge of which nerve carries motor signals from the brain to the lungs (and other thoracic/abdominal organs).

Key Terms:

• Vagus Nerve (Cranial Nerve X): Major parasympathetic nerve to thoracic and abdominal organs.

• Phrenic Nerve: Innervates the diaphragm, not the lungs directly.

Step-by-Step Guidance

1. Recall which cranial nerve is the main parasympathetic supply to the lungs and other organs.

2. Differentiate between the vagus nerve and the phrenic nerve in terms of their targets.

3. Choose the nerve that carries signals from the brain to the lungs.

Try solving on your own before revealing the answer!

Final Answer: Vagus nerve

The vagus nerve (cranial nerve X) carries parasympathetic signals from the brain to the lungs.

Q5. The two output divisions of the ANS are...

Background

Topic: Autonomic Nervous System Divisions

This question is about the two main branches of the autonomic nervous system and their functions.

Key Terms:

• Sympathetic Division: Prepares the body for "fight or flight" responses.

• Parasympathetic Division: Promotes "rest and digest" activities.

Step-by-Step Guidance

1. Recall the two main output divisions of the ANS.

2. Think about their general functions (arousal vs. relaxation).

3. Identify the correct pair of divisions.

Try solving on your own before revealing the answer!

Final Answer: Sympathetic and parasympathetic

The ANS has two output divisions: sympathetic (fight or flight) and parasympathetic (rest and digest).

Q6. The cell bodies of sensory neurons reside in...

Background

Topic: Sensory Pathways and Spinal Cord Anatomy

This question tests your knowledge of where the cell bodies of sensory neurons are located.

Key Terms:

• Dorsal Root Ganglion: Cluster of sensory neuron cell bodies located just outside the spinal cord.

Step-by-Step Guidance

1. Recall the structure of a typical spinal nerve and its roots.

2. Identify which root (dorsal or ventral) carries sensory information.

3. Remember where the cell bodies of these sensory neurons are found.

4. Choose the correct anatomical structure.

Try solving on your own before revealing the answer!

Final Answer: Dorsal root ganglion

Sensory neuron cell bodies are located in the dorsal root ganglion, just outside the spinal cord.

Q7. The sympathetic and parasympathetic nervous systems...

Background

Topic: Autonomic Nervous System Function

This question is about how the two branches of the ANS interact in the body.

Key Terms:

• Sympathetic and Parasympathetic: These systems often have opposing effects but can be active simultaneously to varying degrees.

Step-by-Step Guidance

1. Recall that both divisions can be active at the same time, but their activity levels vary depending on the body's needs.

2. Think about whether only one can be active at a time, or if both can be active together.

3. Choose the statement that best describes their relationship.

Try solving on your own before revealing the answer!

Final Answer: Are always both active to a greater or lesser extent

Both sympathetic and parasympathetic systems are active simultaneously, but their relative activity changes depending on the situation.

Q8. The dorsal roots of the spinal cord contain...

Background

Topic: Spinal Cord Anatomy

This question tests your knowledge of the types of fibers found in the dorsal roots of the spinal cord.

Key Terms:

• Dorsal Root: Contains only sensory (afferent) fibers entering the spinal cord.

• Ventral Root: Contains only motor (efferent) fibers leaving the spinal cord.

Step-by-Step Guidance

1. Recall the function of the dorsal root (sensory input to the CNS).

2. Identify which type of neuron (sensory or motor) is present in the dorsal root.

3. Choose the correct structure (axon or dendrite) for these neurons.

Try solving on your own before revealing the answer!

Final Answer: Axons of sensory neurons

The dorsal roots contain the axons of sensory neurons entering the spinal cord.

Q9. Match the cranial nerve to its function.

Background

Topic: Cranial Nerves and Their Functions

This question tests your ability to match each cranial nerve with its primary function.

Key Terms:

• Cranial Nerves: Twelve pairs of nerves that emerge directly from the brain.

• Examples: Olfactory (I) - smell, Optic (II) - vision, Facial (VII) - facial expression, etc.

Step-by-Step Guidance

1. Recall the Roman numeral and name for each cranial nerve.

2. Match each nerve to its main function (e.g., II - vision, VII - facial expression).

3. Use mnemonic devices if needed to remember the order and function.

4. Fill in the correct matches for each function listed.

Try solving on your own before revealing the answer!

Final Answer:

• VII - facial expression

• II - vision

• VIII - hearing

• III - eye movements

• I - smell

• XII - tongue movements

• XI - shrugging shoulders

• X - slow down heart

Each cranial nerve has a specific function, and matching them helps reinforce your understanding of neuroanatomy.

Q10. Which nerve connects the brain to the enteric (gut) nervous system?

Background

Topic: Autonomic Nervous System and Cranial Nerves

This question is about which cranial nerve provides parasympathetic innervation to the gut.

Key Terms:

• Vagus Nerve (X): The main nerve connecting the brain to the gut (enteric nervous system).

Step-by-Step Guidance

1. Recall which cranial nerve is responsible for parasympathetic control of the digestive tract.

2. Differentiate between the vagus nerve and other cranial nerves in terms of their targets.

3. Choose the nerve that connects the brain to the enteric nervous system.

Try solving on your own before revealing the answer!

Final Answer: Vagus nerve

The vagus nerve (cranial nerve X) connects the brain to the enteric (gut) nervous system.

Q11. The phrenic nerve...

Background

Topic: Peripheral Nerves and Their Functions

This question tests your knowledge of the function of the phrenic nerve.

Key Terms:

• Phrenic Nerve: Innervates the diaphragm, essential for breathing.

Step-by-Step Guidance

1. Recall the main muscle involved in breathing (the diaphragm).

2. Identify which nerve stimulates the diaphragm to contract.

3. Choose the correct function of the phrenic nerve from the options.

Try solving on your own before revealing the answer!

Final Answer: Stimulates the diaphragm

The phrenic nerve is responsible for stimulating the diaphragm, which is crucial for breathing.

Q12. Which of the following cranial nerves are both sensory and motor? [Select all that apply.]

Background

Topic: Cranial Nerve Classification

This question asks you to identify which cranial nerves have both sensory and motor functions (mixed nerves).

Key Terms:

• Mixed Nerves: Cranial nerves that carry both sensory and motor fibers.

• Examples: Trigeminal (V), Facial (VII), Glossopharyngeal (IX), Vagus (X).

Step-by-Step Guidance

1. Recall which cranial nerves are classified as mixed (both sensory and motor).

2. Review the list of cranial nerves and their primary functions.

3. Select all that apply from the options provided.

Try solving on your own before revealing the answer!

Final Answer: Trigeminal, facial, glossopharyngeal, vagus

These cranial nerves have both sensory and motor components.

Q13. Match the body areas with the nerve plexus that innervates them.

Background

Topic: Nerve Plexuses and Body Regions

This question tests your knowledge of which nerve plexus supplies which body region.

Key Terms:

• Cervical Plexus: Neck, diaphragm

• Brachial Plexus: Upper limb

• Lumbar Plexus: Anterior thigh

• Sacral Plexus: Posterior thigh, lower leg, foot

Step-by-Step Guidance

1. Recall the main body regions each plexus innervates.

2. Match each body area (e.g., fingers, upper arm, diaphragm) to the correct plexus.

3. Use anatomical landmarks to help with matching.

Try solving on your own before revealing the answer!

Final Answer:

• Fingers - brachial plexus

• Lower face and neck - cervical plexus

• Feet - sacral plexus

• Upper leg - lumbar plexus

• Diaphragm - cervical plexus

• Upper arm - brachial plexus

Each plexus supplies specific regions of the body.

Q14. Which of the following are examples of sensory transduction? [Select all that apply.]

Background

Topic: Sensory Receptors and Transduction

This question tests your understanding of how sensory stimuli are converted into neural signals.

Key Terms:

• Sensory Transduction: The process by which sensory receptors convert external stimuli into electrical signals.

Step-by-Step Guidance

1. Review the definition of sensory transduction.

2. Identify which examples involve the conversion of a physical or chemical stimulus into an action potential.

3. Select all correct examples from the list.

Try solving on your own before revealing the answer!

Final Answer:

• Pressure on the skin causes action potentials in a sensory neuron

• Chemicals binding to olfactory receptors causes cranial nerve I to fire

• Sound waves bend cells in the cochlea and trigger the vestibulocochlear nerve to fire

• Light striking rods and cones in the retina causes action potentials in retinal neurons

These are all examples of sensory transduction.

Q15. Match the receptors with the perception they would lead to.

Background

Topic: Sensory Receptors and Perception

This question tests your knowledge of different types of sensory receptors and the sensations they produce.

Key Terms:

• Nociceptors: Pain

• Thermoreceptors: Temperature (e.g., cold)

• Photoreceptors: Vision

• Chemoceptors: Smell, taste

• Proprioceptors: Sense of body position

• Pacinian corpuscles: Vibration

Step-by-Step Guidance

1. Recall the function of each type of receptor.

2. Match each receptor to the correct perception (e.g., nociceptor - pain).

3. Fill in the correct matches for each pair.

Try solving on your own before revealing the answer!

Final Answer:

• Nociceptors - pain

• Thermoreceptors - sensation of cold

• Photoreceptors - vision

• Chemoceptors - smell

• Proprioceptors - sense of where your hand is

• Pacinian corpuscles - vibration

Each receptor is specialized for a specific type of stimulus.

Q16. If the receptive fields of the neurons that innervate an area are very small, then...

Background

Topic: Sensory Discrimination and Receptive Fields

This question tests your understanding of how receptive field size affects sensory discrimination.

Key Terms:

• Receptive Field: The area monitored by a single sensory neuron.

• Sensory Discrimination: The ability to distinguish between different stimuli.

Step-by-Step Guidance

1. Recall that smaller receptive fields allow for more precise localization of stimuli.

2. Think about how this affects the ability to distinguish between two points of contact.

3. Choose the statement that best describes the effect of small receptive fields.

Try solving on your own before revealing the answer!

Final Answer: Sensory discrimination in that area would be very fine.

Small receptive fields allow for fine sensory discrimination.

Q17. Which of the following are examples of referred pain? [Select all that apply.]

Background

Topic: Pain Pathways and Referred Pain

This question tests your understanding of referred pain, where pain is perceived at a location other than its source.

Key Terms:

• Referred Pain: Pain perceived at a site different from the origin, often due to shared neural pathways.

Step-by-Step Guidance

1. Recall common examples of referred pain (e.g., heart pain felt in the left arm).

2. Identify which options describe pain felt in a location different from the source.

3. Select all correct examples from the list.

Try solving on your own before revealing the answer!

Final Answer:

• Pain from heart dysfunction is felt in the left arm.

• Pain signals from the liver are experienced in the right shoulder.

These are classic examples of referred pain.

Q18. During conscious movements, lower motor neurons receive signals from...

Background

Topic: Motor Pathways

This question tests your knowledge of the pathway for voluntary (conscious) movement.

Key Terms:

• Lower Motor Neurons: Neurons that directly innervate skeletal muscle.

• Upper Motor Neurons: Neurons in the motor cortex that send signals to lower motor neurons.

Step-by-Step Guidance

1. Recall the hierarchy of motor control: upper motor neurons (in the cortex) send signals to lower motor neurons (in the spinal cord).

2. Identify the source of input to lower motor neurons during voluntary movement.

3. Choose the correct structure from the options.

Try solving on your own before revealing the answer!

Final Answer: Upper motor neurons in the motor cortex

During conscious movement, lower motor neurons receive input from upper motor neurons in the motor cortex.

Q19. Lower motor neurons are located...

Background

Topic: Motor Neuron Anatomy

This question tests your knowledge of the anatomical location of lower motor neurons.

Key Terms:

• Lower Motor Neurons: Located in the ventral horn of the spinal cord and in certain cranial nerve nuclei.

Step-by-Step Guidance

1. Recall the location of lower motor neuron cell bodies in the CNS.

2. Differentiate between upper and lower motor neuron locations.

3. Choose the correct anatomical site from the options.

Try solving on your own before revealing the answer!

Final Answer: Lower motor neurons in the spinal cord

Lower motor neurons are located in the ventral horn of the spinal cord.

Q20. In a reflex movement, lower motor neurons receive signals from...

Background

Topic: Reflex Arcs

This question tests your understanding of the neural pathway involved in reflexes.

Key Terms:

• Reflex Arc: The neural pathway that mediates a reflex action, often involving sensory neurons, interneurons, and motor neurons.

Step-by-Step Guidance

1. Recall that reflexes are often mediated at the level of the spinal cord, not the brain.

2. Identify which neurons provide input to lower motor neurons during a reflex.

3. Choose the correct answer from the options.

Try solving on your own before revealing the answer!

Final Answer: Sensory or interneurons in the spinal cord

In reflexes, lower motor neurons receive input from sensory neurons or interneurons in the spinal cord.

Q21. The main descending pathway for conscious movements is the...

Background

Topic: Motor Pathways

This question tests your knowledge of the major neural tract responsible for voluntary movement.

Key Terms:

• Pyramidal (Corticospinal) Tract: The main pathway for voluntary motor control.

Step-by-Step Guidance

1. Recall the name of the tract that carries signals from the motor cortex to the spinal cord for voluntary movement.

2. Differentiate between pyramidal and extrapyramidal tracts.

3. Choose the correct tract from the options.

Try solving on your own before revealing the answer!

Final Answer: Pyramidal tract

The pyramidal (corticospinal) tract is the main descending pathway for conscious movement.

Q22. Which of the following is a monosynaptic reflex arc?

Background

Topic: Reflex Arcs

This question tests your knowledge of the simplest type of reflex arc, which involves only one synapse.

Key Terms:

• Monosynaptic Reflex: A reflex involving a direct connection between a sensory and a motor neuron (e.g., stretch reflex).

Step-by-Step Guidance

1. Recall the definition of a monosynaptic reflex arc.

2. Identify which reflex involves only one synapse between the sensory and motor neuron.

3. Choose the correct reflex from the options.

Try solving on your own before revealing the answer!

Final Answer: Stretch reflex

The stretch reflex is a classic example of a monosynaptic reflex arc.

Q23. In the flexor reflex, a painful stimulus causes you to...

Background

Topic: Reflexes and Protective Responses

This question tests your understanding of the body's response to painful stimuli via the flexor reflex.

Key Terms:

• Flexor Reflex: A withdrawal reflex that moves a limb away from a painful stimulus.

Step-by-Step Guidance

1. Recall the purpose of the flexor (withdrawal) reflex.

2. Identify the typical response to a painful stimulus (e.g., pulling your hand away from a hot object).

3. Choose the correct action from the options.

Try solving on your own before revealing the answer!

Final Answer: Pull your limb away

The flexor reflex causes you to withdraw the affected limb from a painful stimulus.

Q24. The pathway involved in the withdrawal reflex is...

Background

Topic: Reflex Pathways

This question tests your knowledge of the neural pathway for the withdrawal (flexor) reflex.

Key Terms:

• Withdrawal Reflex: Involves a nociceptor (pain receptor), spinal cord, and motor neurons.

Step-by-Step Guidance

1. Recall the sequence of events in the withdrawal reflex: pain receptor activation, signal to spinal cord, activation of motor neurons.

2. Identify the correct order of structures involved in the pathway.

3. Choose the pathway that matches this sequence.

Try solving on your own before revealing the answer!

Final Answer: Nociceptor - spinal cord - motor neurons

The withdrawal reflex pathway is: nociceptor (pain receptor) → spinal cord → motor neurons.