Nervous System Quiz

Nervous System

• Composed of two parts: Central Nervous System (CNS) and Peripheral Nervous System (PNS)
• CNS includes spinal cord and brain
• PNS consists of nerves and fibers extending from the CNS
• 12 pairs of cranial nerves
• 31 pairs of spinal nerves
• Spinal nerves are afferent (sensory receptors) and efferent (motor messengers)

Central Nervous System

• Composed of the brain stem, midbrain, pons, cerebellum, medulla, and spinal cord
• The thalamus is a key relay station for sensory input
• The hypothalamus regulates vital functions like respiration
• The basal ganglia help maintain muscle tone
• The cerebellum coordinates motor activity and balance

Cerebral Cortex

• The outer layer of the cerebrum, composed of nerve cells
• Center of higher functions (thoughts, memory, reasoning, movement)
• Divided into four lobes: frontal, parietal, temporal, and occipital

Lobes of the Cerebral Cortex

• Frontal lobe: personality, behavior, emotions, intellectual functions, motor speech (Broca's area)
• Parietal lobe: sensory functions, postcentral gyrus is the primary sensory center
• Temporal lobe: hearing, taste, smell, primary auditory reception center, language comprehension (Wernicke's area)
• Occipital lobe: primary visual receptor center

Damage to the Nervous System

• Damage to specific cortical areas leads to corresponding function loss
• Motor weakness and paralysis
• Loss of sensation
• Impaired language processing
• Damage occurs when highly specialized neurological cells lack blood supply (like a blocked cerebral artery)

Sensory Pathways

• Sensory information travels via afferent fibers through the dorsal root
• Two routes for sensory information: anterolateral tract and posterior (dorsal) columns
  • Anterolateral tract transmits pain, temperature, and crude touch
  • Posterior (dorsal) columns transmit position, vibration, and finely localized touch

Sensory Pathways and Brain

• Sensory information travels from posterior spinal cord to thalamus
• Thalamus relays information to relevant cortex regions

Reflexes

• Basic defense mechanisms of the nervous system
• Involuntary, below conscious control, enabling quick reaction to potentially harmful situations
• Three types of reflexes:
  • Stretch/deep tendon (e.g., knee-jerk reflex): involves sensory, motor neurons, and a synapse
  • superficial/cutaneous (e.g., plantar reflex): involves skin
  • visceral (e.g., pupillary response to light and accommodation): involves organs

Reflex Arc

• Pathway for reflex actions: receptor → sensory neuron → interneuron → motor neuron → effector

Motor Pathways

• Corticospinal (Pyramidal) tract: responsible for voluntary movements; skilled, discrete, purposeful
• Extrapyramidal tracts: maintain muscle tone, control gross automatic movements (like walking)

Cerebellum

• Coordinates movement
• Maintains equilibrium and posture
• Receives sensory information about body position and movement

Cranial Nerves

• 12 pairs of nerves emerge from the brain
• Designated by Roman numerals (I-XII)
• Some are sensory, some motor, and some mixed
• Mnemonic: On Old Olympus Towering Tops A Finn And German Viewed Some Hops
• Functions vary, affecting sensory perception, motor control, and communication

Cranial Nerve Functions

• Mnemonic: Some Say Marry Money But My Brother Says Big Brains Matter Most
• (S)ensory, (M)otor, (B)oth

Dermatomes

• Circumscribed skin areas supplied by a specific spinal cord segment and a specific nerve
• Dermatomes overlap, so if one nerve is damaged, sensation is often maintained by the adjacent nerves
• Useful for locating spinal cord damage or problems

Subjective Data

• Patient's description of symptoms, including headache, head injury, dizziness/vertigo, seizures, and tremors
• Note: Include onset, duration, location, and other related factors
• Also important to gather information on other associated factors, such as past medical history, and patient-centered care
• Incoordination, numbness, tingling, difficulty swallowing, and difficulty speaking are also important

Test your knowledge about the nervous system, including information about dermatomes, autonomic muscle regulation, and somatic functions. This quiz will help consolidate your understanding of how the nervous system operates.