Lab 4 The Central Nervous System Sheep Brain

Lab 4 – The Central Nervous System & Sheep Brain Dissection Dr. Siddique Introduction to Human Anatomy East Los Angeles College

DO NOW • Label the anatomic features of the skull • • • Cribriform plate Ethmoid bone Spenoid bone Sella turcica Greater wing Lesser wing Occipital bone Foramen magnum Jugular foramen Carotid canal Internal acoustic meatus

Learning Objectives 1. Compare and contrast structure and function of various glial cells and neurons. 2. Analyze the external and internal structures of the brain by dissecting, inspecting , and identifying external and internal structures on diagrams, models, and a sheep brain specimen. 3. Analyze spinal cord structures (including select peripheral nerves and ganglia) on a model and diagram.

Cells of the CNS Astrocytes Ependymal cells Microglia Oligodendrocytes

Structural Regions of the Brain 1. 2. 3. 4. Cerebrum Diencephalon Brain stem Cerebellum

Lobes of the Cerebral Hemispheres • • Frontal lobe Parietal lobe Occipital lobe Temporal lobe

External Features of the Brain

What tissues comprise the cerebral cortex? • Gray matter – Neuron cell bodies – Dendrites – Neuroglia – Blood vessels – NO AXONS! (fiber tracts) • High surface area – composes 40% of brain mass • All neurons of the cortex are interneurons, not sensory or motor neurons.

Functional Areas of the Cerebral Cortex 1. Motor areas A. Primary Motor cortex B. Pre-motor cortex C. Broca’s area 2. Sensory areas A. Comprised of 8 areas 3. Multimodal association areas A. Anterior association area (prefrontal cortex) B. Posterior association area (posterior association area) C. Limbic area (limbic association area)

1. Motor areas A. Primary Motor cortex Ø Precentral gyrus Ø Pyramidal neurons span entire spinal cord Ø Voluntary skeletal muscle movement B. Pre-motor cortex Ø Plan/coordinate C. Broca’s area Ø Speech

2. Sensory areas

3. Multimodal association areas A. Anterior association area (prefrontal cortex) B. Posterior Working memory for association spatial. Tasktasksmanagment Working memory for object area recall tasks Solving complex (posterior multitask problems association area) C. Limbic area (limbic association area)

Motor cortex Premotor cortex Multimodal association area Somatosensory association cortex Primary somatosensory cortex How does information flow in and out of the cerebral cortex?

What is the function of the white matter in the cerebral hemispheres? • Communication between areas, cortex, and lower CNS centers Association fibers • Basal nuclei – cell bodies of projection fibers

Structural Regions of the Brain 1. 2. 3. 4. Cerebrum Diencephalon Brain stem Cerebellum

What is the function of diencephelon? • Composed of thalamus & hypothalamus • Thalamus – Relay center Thalamus Hypothalamus • Hypothalamus – Regulates body temp, hunger, thirst, biorhythms – Regulates hormonal output of ant pit

Structural Regions of the Brain 1. 2. 3. 4. Cerebrum Diencephalon Brain stem Cerebellum

• Midbrain • Pons • Medulla oblongata

Structural Regions of the Brain 1. 2. 3. 4. Cerebrum Diencephalon Brain stem Cerebellum

Function: receives input from multiple centers and coordinates/fine-tunes responses

Vermis of Cerebellum

Structure of the Spinal Cord • Surrounded by meninges • Meninges surrounded by fat • Extends to L 1/L 2 • Meninges extend to S 2 • Lumbar puncture below L 3 • Conus medularis – tapering of spinal cord • Filum terminale – attachment of spinal cord to coccyx • Cervical & lumbar enlargements where upper/lower limb nerves arise

• Spinal cord gray matter – Cell bodies of multipolar neurons – Dorsal horns – interneurons – Ventral horns – mainly cell bodies of somatic motor neurons axons go to muscles via ventral rootlets – Lateral horns – cell bodies of autonomic motor neurons axons go to visceral organs via ventral rootlets Spinal Cord Structure Ganglion = collection of neuron cell-bodies

Organization of Gray Matter in Spinal Cord

Spinal Cord

Study Guide 1. Identify various types of neuroglia and neurons. 2. Match neuroglial and neuronal structure and function. 3. Identify internal and external structures of the brain. 4. Explain the function of the ventricular system and CSF, and identify the components of the ventricular system. 5. Identify the anatomical features of spinal cord tissue.