Chapter 3: Structure of the Nervous System
Lecture Overview
Overview of Brain
Anatomy Terms
Blood supply and CSF
Central Nervous System
Five divisions
Peripheral Nervous System
Somatic Nervous System
Autonomic Nervous System
The Two Nervous Systems
CNS: Brain and Spinal Cord
Conduit for info to and from brain
PNS: Cranial and spinal nerves
Run to target organs and muscles (efferent)
Carry sensory info (afferent)
Neuroanatomy Terms
Directional
Anterior (rostral)
Posterior (caudal)
Ventral (inferior)
Dorsal (superior)
Location in brain:
Ipsilateral: same side of brain
Contralateral: opposite side of brain
Anatomical Planes
Three anatomy planes
Sagittal:
(mid- vs para-sagittal)
Coronal (transverse)
Horizontal
The Meninges
Dura mater-outer (thick) layer
Arachnoid-middle layer
Overlies the arachnoid space (CSF)
Blood vessels run through arachnoid layer
Pia mater- inner layer
Overlies every detail of the outer brain
Cerebrospinal Fluid (CSF)
Brain floats in CSF (1400 g--> 80 g)
CSF produced by choroid plexus of the ventricles
Lateral
Third
Fourth
Ventricles are an access point for drug studies
Loss of CSF produces headaches
e.g. spinal cord punctures
Hydroencephalus
Overview of the CNS
Cerebral Cortex
Grooves in cortex:
Sulci (small)
Fissures (large)
Bulges in cortex are termed gyri
6 layers of cortical cells
Mapping of the Cortex
Fritsch and Hitzig (1870)
Penfield (1950’s) at Montreal
Sensory cortex
Motor cortex
"Homunculus": Map of external body region that serve various areas of cortex
"Brodman" maps based on architectural features
Cortical Lobes
Limbic System
Hippocampus (learning and memory)
Amygdala (emotion)
Septum (rage after lesions)
Fornix
Mammillary Bodies
Basal Ganglia
"Ganglia" is a misnomer (term refers to collections of cell bodies in periphery.
Basal ganglia consists of:
Globus pallidus
Caudate nucleus
Putamen
Basal ganglia are involved in the control of movement.
Midline View of Subcortical Structures
The Peripheral Nervous System
Somatic
Controls muscle action, gland secretion
Some afferent info back to CNS
Autonomic NS
Parasympathetic: "Digestion"
Sympathetic: "Fight or Flight"
Definitions
Nerve: collection of axons outside CNS
Tract: collection of axons inside CNS
Nucleus: collection of cell bodies inside CNS
Ganglion: collection of cell bodies outside CNS
Somatic Nervous System
Spinal Nerves (31 pair)
Afferents and efferents
8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
Cranial Nerves
Three types: Motor only, sensory only, mixed function
"On old olympus towering tops, a french-speaking German viewed some hops"
The Autonomic Nervous System