CNS

Brain Structure and Function

• The brain is divided into Cerebral Hemispheres, comprising 5 cortical lobes (Frontal, Parietal, Temporal, Occipital, and Insula) and Basal Nuclei (groups of neurons involved in movement and cognition)
• The Diencephalon consists of Thalamus (relays sensory information), Hypothalamus (regulates body temperature, hunger, and thirst), and Epithalamus (involved in emotional response and arousal)
• The Brain Stem, connecting the brain to the spinal cord, is composed of Midbrain, Pons, and Medulla Oblongata, which regulate various involuntary functions (e.g., breathing, heart rate)

Protective Mechanisms for the CNS

• The Blood-Brain Barrier (BBB) is a selective barrier between the bloodstream and the CNS, restricting the passage of substances to maintain a stable environment
• Meningeal Layers (Dura Mater, Arachnoid Mater, and Pia Mater) protect the CNS from mechanical injury and infection
• Cerebrospinal Fluid (CSF) cushions the CNS, removes waste, and maintains chemical balance

Spinal Cord Structure and Function

• The Spinal Cord is divided into Sensory Tracts ( transmit sensory information) and Motor Tracts (transmit motor signals)
• Ventrolateral Horns contain motor neurons that control voluntary movements
• Dorsal Horns receive and process sensory information from the periphery

Transmission of Signals

• Ascending Sensory Signals: fine touch and proprioception (position and movement) are transmitted through the Dorsal Column, while temperature and pain are transmitted through the Anterolateral System
• Descending Motor Pathways: motor signals from the CNS are transmitted to the periphery through the Corticospinal Tract (voluntary movements) and Rubrospinal Tract (-coordinate movements)