Chapter 7: Major Brain Regions (CNS)

Major Brain Regions (x4)

Functions of these major regions: 1. Cerebrum (Cerebral Hemispheres) 2. Diencephalon 3. Brain Stem 4. Cerebellum

Cerebellum

Projects dorsally from under the occipital lobe of the cerebrum and also has a convoluted surface Main Functions: - Provides information from the cerebral motor cortex, proprioceptors, visual, and equilibrium pathways - Provides instruction to cerebral motor cortex and subcortical motor centers, resulting in smooth, coordinated skeletal muscle movements - Responsible for proper balance and posture

Brain Stem

Attaches to the spinal cord, and provides the pathways for ascending and descending tracts 1. Mid Brain 2. Pons 3. Medulla Oblongata 4. Reticular Formation (a functional system)

Diencephalon (x4)

Commonly referred to as the interbrain, sits atop of the brain stem, and is enclosed by the cerebral hemispheres (cerebrum) 1. Thalamus 2. Hypothalamus 3. Epithalamus 4. Limbic System (a functional system)

Hypothalamus

Main Functions: - Chief integration center of autonomic (involuntary) nervous system - Regulates body temperature, food intake, water balance, and thirst - Regulates hormonal output of anterior pituitary gland and acts as an endocrine organ (producing ADH & Oxytocin)

Mid Brain

Main Functions: - Contains auditory and visual reflex centers - Contains subcortical motor functions - Contains nuclei of cranial nerves (III-3) and (IV-4); contains protections fibers- e.g., fibers of the pyramidal tracts

Epithalamus

Main Functions: - Forms the roof of the 3rd ventricle - Houses the pineal gland

Limbic System

Main Functions: - Includes cerebral and diencephalon structures --> Hypothalamus and anterior thalamic nuclei - Mediates emotional response; involved in memory processing

Cortex (Gray Matter)

Main Functions: - Localizes and interprets "see" sensory inputs - Controls voluntary and skilled skeletal muscle activity - Acts in intellectual and emotional processing

Reticular Formation

Main Functions: - Maintains cerebral cortical alertness; filters out repetitive stimuli - Helps regulate skeletal and visceral muscle activity

Medulla Oblongata

Main Functions: - Relays ascending sensory pathway impulses from skin and proprioceptors - Contains nuclei controlling heart rate, blood vessel diameter, respiratory rate, vomiting, etc. - Relays sensory information to the cerebellum - Site of decussation (crossover) of pyramids - Contains nuclei for cranial nerves (VIII-XII: 8-12); contains projection fibers

Pons

Main Functions: - Relays information from the cerebrum to the cerebellum - Cooperates with the medullary centers to control respiratory and rate of depth - Contains nuclei of cranial nerves (V-VII: 4-6); contains projection fibers

Thalamus

Main Functions: - Relays sensory impulses to the cerebral cortex - Relays impulses between the cerebral motor cortex and lower motor centers - Involved in memory

Basal Nuclei (Ganglia)

Main Functions: - Subcortical motor centers help control skeletal muscle movements

Cerebrum (x2)

The cerebral hemispheres separated by the longitudinal fissure 1. Cortex (Gray Matter) 2. Basal Nuclei (Ganglia)