Nervous System Overview Quiz

Nervous System Functions

• Monitors internal and external changes through sensory receptors
• Processes and interprets sensory input, generating responses
• Activates effector organs to execute responses

Nervous System Structures

• Divided into the Central Nervous System (CNS) and Peripheral Nervous System (PNS)
• CNS: Brain and spinal cord, responsible for integrating and commanding the nervous system
• PNS: Nerves extending from the CNS, divided into cranial nerves (brain) and spinal nerves (spinal cord)
• Ganglia: Clustered neuronal cell bodies in PNS

Neuron Structure & Function

• Billions of neurons form the basic unit of the nervous system
• Responsible for conducting electrical signals
• Exhibit extreme longevity, do not divide, have high metabolic rate
• Components: Cell body (nucleus and cytoplasm) and Processes (dendrites and axons)
• Dendrites: Branching processes receiving signals, increasing surface area for interaction, conduct signals towards the cell body
• Axons: Single, uniform diameter, transmit nerve impulses away from the cell body
• Myelin sheaths: Insulating layers around axons, produced by oligodendrocytes (CNS) and Schwann cells (PNS)
  • Prevent electrical current leakage
  • Increase signal conduction speed
• Synapses: Communication sites between neurons, using chemical messengers
  • Presynaptic neuron: Transmits signals towards the synapse
  • Postsynaptic neuron: Transmits signals away from the synapse

Neuron Functional Classification

• Sensory neurons: Transmit impulses towards the CNS from sensory receptors
• Motor neurons: Carry impulses away from the CNS to effector organs
• Interneurons: Connect motor and sensory neurons, forming complex neuronal pathways

The Brain

• Composed of gray matter (neuronal cell bodies) and white matter (axons)
• Gray matter: Outer layer of the brain, center of the spinal cord
• White matter: Deep parts of the brain, superficial parts of the spinal cord
• Functions:
  • Maintain internal environment through autonomic and endocrine systems control
  • Perform high-level tasks like intelligence, consciousness, memory, sensory-motor integration, emotions, behavior, and socialization

Brain Structures

• Brain stem: Medulla oblongata, pons, midbrain, responsible for passage of fiber tracts, face and head innervation, autonomic behaviors, and sensory reflexes
• Cerebellum: Coordinates body movements, maintains posture and equilibrium
• Diencephalon: Thalamus, hypothalamus, epithalamus, controls visceral functions and emotions
• Cerebrum: Two cerebral hemispheres (83% brain mass), divided into five lobes: frontal, parietal, temporal, occipital, insula

Cerebral Lobes

• Frontal: Planning, initiating, and enacting motor movements, higher-level cognitive functions
• Parietal: Conscious awareness of somatic sensation, spatial awareness, speech understanding
• Temporal: Hearing, smell, object, word, face recognition, language comprehension, emotional response, memory
• Occipital: Vision
• Insula: Taste

Brain Stem Structures

• Medulla oblongata: Lowest part, continuous with spinal cord, transmits signals, contains cardiac, respiratory, and vasomotor centers
  • Cardiac: Force and rate of heartbeat
  • Respiratory: Rhythm and rate of breathing
  • Vasomotor: Regulates blood pressure through blood vessel contraction
• Pons: Bulge connecting midbrain and medulla oblongata, serves as a bridge, origin of important nerves, involved in autonomic functions and sleep cycles
• Midbrain: Connection between brain and spinal cord, motor movement control (eye movements) and auditory/visual processing

Cerebellum

• 11% of brain mass, dorsal to pons and medulla oblongata
• Smooths and coordinates body movements, maintains posture and equilibrium

Diencephalon

• Central core of the forebrain, controls visceral functions and emotions
• Thalamus: Relay center for information to cerebral cortex, organizes and modifies signals
• Hypothalamus: Visceral control center, regulates autonomic nervous system, body temperature, hunger, thirst, sleep, endocrine system, emotions, motivation, and memory
• Epithalamus: Dorsal part, contains pineal gland, secretes melatonin (sleep-wake cycle)

Meninges

• Three connective tissue layers surrounding the brain and spinal cord: Dura mater, arachnoid mater, pia mater
• Functions: Protect CNS, enclose blood vessels, contain cerebrospinal fluid

Cerebrospinal Fluid

• Clear watery fluid in subarachnoid space and CNS cavities
• Functions: Buoyancy and cushioning for CNS, protects from compression and blows, nourishes brain, removes waste, carries chemical signals

Spinal Cord

• Extends from foramen magnum to L1 or L2 vertebrae
• 31 pairs of spinal nerves, named by vertebral location (cervical 8, thoracic 12, lumbar 5, sacral 5, coccygeal 1)
• Cervical and lumbar enlargements: Areas with larger diameters
• Cauda equina: Collection of nerve roots at the end, resembling a horse's tail
• Functions: Sensory and motor innervation for the body (except head), two-way conduction between body and brain, reflex center

Test your knowledge on the functions and structures of the nervous system. This quiz covers the Central and Peripheral Nervous Systems, neuron structure, and signal conduction. Get ready to delve into the complexities of how our nervous system operates!