Class 2 Nervous System, cont. Spinal Cord Brain

Development of the Brain and Spinal Cord

Repair of Neurons PNS Slow and/or non-existent Cell body can’t be damaged Axon must be able to find Schwann cells CNS Rare Non-ideal environment Some evidence in laboratories

Protective Coverings of the Central Nervous System Bone: hard, fibrous tissue Skull and Spinal Column

Meninges of the brain Subdural space Skull Pia mater Dura mater Arachnoid mater Cerebrum: Gray matter White matter Subarachnoid space

Cerebrospinal spinal fluid Protective Coverings of the Central Nervous System Meninges

Cerebrospinal Fluid Clear fluid found in and around the brain and spinal cord Formed by choroid plexus in ventricles Absorbed into bloodstream by arachnoid villi CSF provides these functions: – Buoyancy – Protection – Chemical stability

Spinal Cord

Gray Matter and White Matter

The Brain

Cerebrum (The “Higher” Brain) Left and Right Hemispheres separated by the Corpus Callosum bridge of neurons that allow hemispheres to communicate. Surface Convolutions: Gyrus a ridge, ie. Central Gyrus Sulcus a shallow groove Fissures a deep groove, ie. Longitudinal Fissure and Transverse Fissure

Cerebrum 4 Lobes: Frontal Reasoning, Long-Term Memory, Analysis, Movement, Temporal Speech, Memory, Hearing Parietal Integration of Sensation Occipital Visual processing center

Note: Corpus callosum Cerebrum

Cross Section (Gross) Coronal Section (MRI Study)

White matter tracts Cerebrum

Basal Nuclei (aka. Basal Ganglia)

Functions: Conscious Awareness Reasoning Memory Interpretation of Senses Initiates Voluntary Motor Responses Functionally Divided: Sensory Areas Cortex of Parietal Lobe Motor Areas Cortex of Frontal Lobe Association Areas Cortex of all Lobes Cerebrum

Hemisphere Communication and Lateralization

Basal Nuclei (aka. Basal ganglia)

Basal Nuclei (aka. Basal Ganglia)

Diencephalon Thalamus Relay station of sensory input except for sense of smell Hypothalamus regulates autonomic function and major link between the nervous and endocrine systems Epithalamus CSF is made here. The Pineal gland Creates hormone melatonin.

Limbic System

Includes centers for both gratification and aversion – gratification – sensations of pleasure or reward – aversion – sensations of fear or sorrow Corpus callosum Olfactory bulb Hypothalamus Cingulate gyrus Amygdala Hippocampus Thalamic Nuclei

Brain Stem

Midbrain – The midbrain connects the diencephalon to the pons – CN’s III and IV Pons – Connects cerebrum to the cerebellum – Connects midbrain to medulla – CN’s V, VI, VII Medulla – Connects brain to spinal cord – Regulates basic body functions – CN’s VIII, IX, X, XI, XII

Cerebellum Function: Involved with vestibular and eye movement functions Controls proprioception related to muscle tone Fine tunes and coordinates movements

Thank goodness!!!