Nervous System Overview

Nervous System Overview

• The nervous system is comprised of the central nervous system and the peripheral nervous system.
• The central nervous system consists of the brain and spinal cord.
• The brain is located inside the skull.
• The spinal cord runs inside the vertebral column.

Central Nervous System

• Brain: The brain is composed of the forebrain, midbrain, and hindbrain.
  • Forebrain: Includes cerebrum and diencephalon.
  • Midbrain: Located below the diencephalon.
  • Hindbrain: Includes pons, medulla oblongata, and cerebellum.
• Brain Stem: Connects the cerebrum with the spinal cord. Includes the midbrain, pons, and medulla oblongata.
• Spinal Cord: A continuation of the medulla oblongata, descending through the vertebral column. It's surrounded by protective meninges (dura mater, arachnoid matter, pia mater).
• Cerebrospinal Fluid (CSF): Clear fluid found in the subarachnoid space between the arachnoid and pia mater, cushioning the brain and spinal cord. CSF originates from the lateral ventricles, traveling through the 3rd and 4th ventricles to the subarachnoid space.

Cerebrum

• The cerebrum is the largest portion of the brain.
• Separated into two cerebral hemispheres by the medial longitudinal fissure.
• Each hemisphere has three surfaces: superolateral, medial, and inferior.
• The cerebral surface has sulci and gyri to increase surface area.
• Key areas within the cerebrum include: Central, lateral and parieto-occipital sulci which divide the hemisphere into four lobes; frontal, parietal, temporal, and occipital, these contain specialized areas for body functions each lobe.

Brain Stem

• Location: Connects the cerebrum and spinal cord.
• Parts: Midbrain, Pons, Medulla Oblongata
• Function: Carries signals between the brain and spinal cord, involved in autonomic functions and cranial nerve nuclei.

Meningeal Layers

• Dura mater; arachnoid matter, pia mater.
• They surround and protect the brain and spinal cord.

Cerebellum

• Part of the brain located behind the pons and medulla oblongata; separated from them by the 4th ventricle.
• It's involved in coordinating movement, balance, and muscle tone.

Spinal Cord

• Column of nerve tissue extending from the medulla oblongata.
• Protected by vertebral column and meninges (dura mater, arachnoid mater, pia mater).
• Divided into segments (cervical, thoracic, lumbar, sacral, coccygeal).
• Contains gray matter (cell bodies) and white matter (axons).
• Contains dorsal and ventral roots

Spinal Nerves

• 31 pairs of nerves branching from the spinal cord.
• Connected to the spinal cord by ventral (motor) and dorsal (sensory) roots.
• Carries motor and sensory information.

Peripheral Nervous System

• Composed of 12 pairs of cranial nerves (arising from the brain) and 31 pairs of spinal nerves (arising from the spinal cord).
• Connects the central nervous system with sensory receptors, muscles, and glands.
• Somatic nervous system: innervates skeletal muscles; autonomic nervous system: regulates processes like heart rate, digestion, and glandular activity (sympathetic and parasympathetic).

Autonomic Nervous System

• Part of the peripheral nervous system.
• Regulates involuntary functions like heart rate, breathing, and digestion.
• Includes sympathetic and parasympathetic branches, which often have opposing effects.