Neuroanatomia e Sistema Nervoso

Overview of Neuroanatomy

• Neuroanatomy is the study of the nervous system's structure.
• It includes the macroscopic and microscopic anatomy of the brain, spinal cord, and peripheral nerves.
• Neuroanatomy is essential for understanding nervous system function and related disorders.

Key Structures and Divisions of the Nervous System

• Central Nervous System (CNS): Contains the brain and spinal cord.
  • The brain is divided into the cerebrum, cerebellum, and brainstem.
  • The spinal cord relays sensory and motor signals between the brain and body.
• Peripheral Nervous System (PNS): Nerves extending from the CNS.
  • Divided into the somatic nervous system (voluntary movements) and the autonomic nervous system (involuntary functions, further subdivided into sympathetic and parasympathetic).
• Neurons: Basic units transmitting information.
  • Key parts include the cell body, dendrites, and axon.
  • The myelin sheath is a fatty layer increasing axon signal speed.
• Neuroglia (glial cells): Supporting cells aiding neurons.
  • Different glial cell types have specialized roles, including structural support and blood-brain barrier contribution.

Brain Regions and Their Functions

• Cerebrum: Largest brain part, responsible for higher-level cognition.
  • Divided into two hemispheres joined by the corpus callosum.
  • Each hemisphere has four lobes: frontal, parietal, temporal, and occipital.
  • Specific areas within lobes handle particular functions (e.g., motor cortex, sensory cortex, Broca's area, Wernicke's area).
• Cerebellum: Below the cerebrum, crucial for movement coordination and balance.
• Brainstem: Connects the brain to the spinal cord.
  • Houses vital centers controlling breathing, heart rate, and consciousness.

Spinal Cord

• Extends from the brainstem down the vertebral column.
• Carries sensory information to the brain and motor commands from the brain to muscles.
• Organized into segments corresponding to body regions.
• Contains ascending and descending tracts for information transfer.

Peripheral Nervous System (PNS) Subdivisions

• Somatic Nervous System: Controls voluntary skeletal muscle movements.
• Autonomic Nervous System: Regulates involuntary functions.
  • Sympathetic: "Fight-or-flight" response, preparing the body for stress.
  • Parasympathetic: "Rest-and-digest" response, restoring energy and relaxation.

Neuroanatomical Techniques

• Histology: Microscopic study of tissue.
• Neuroimaging: Non-invasive brain structure/function visualization.
  • Examples: MRI, CT, fMRI, and PET.
• Electrophysiology: Recording nervous system electrical activity.
  • Electroencephalography (EEG) measures brain electrical activity via scalp electrodes.
• Tracing methods: Analyzing and mapping neuronal connections.

Neuroanatomical Terminology Related to Brain Sections

• Sagittal: Dividing the brain into left and right halves.
• Coronal: Dividing front (anterior) from back (posterior).
• Horizontal (axial): Dividing top (superior) from bottom (inferior).
• Anterior (rostral): Toward the front of the body.
• Posterior (caudal): Toward the back of the body.
• Superior (dorsal): Toward the top of the body.
• Inferior (ventral): Toward the bottom of the body.