Upload
theodore-wilkins
View
236
Download
6
Embed Size (px)
Citation preview
Chapter 7 : The Nervous System
Central Nervous System,
Anatomy
Regions of the BrainRegions of the Brain
Figure 7.12
Central Nervous System: Central Nervous System: AnatomyAnatomy
Protection of the Central Nervous Protection of the Central Nervous System:System:
Scalp and skin
Skull and vertebral column
Meninges
Cerebrospinal fluid
Blood brain barrier
Figure 7.16a
Central Nervous System: Central Nervous System: AnatomyAnatomy
MeningesMeninges Dura mater
Double-layered external covering
Periosteum – attached to surface of the skull
Meningeal layer – outer covering of the brain
Folds inward in several areas
Central Nervous System: Central Nervous System: AnatomyAnatomy
MeningesMeninges Arachnoid
layer
Middle layer
Web-like
Pia mater
Internal layer
Clings to the surface of the brain
Central Nervous System: Central Nervous System: AnatomyAnatomy
Cerebral AnatomyCerebral Anatomy The surface
is made of ridges (gyri) and grooves (sulci)
Deep sulci are called fissures
Figure 7.13a
Central Nervous System: Central Nervous System: AnatomyAnatomy
Gray matter
Outer layer
Composed mostly of neuron cell bodies
Basal nuclei – internal islands of gray matter
Figure 7.13a
Central Nervous System: Central Nervous System: AnatomyAnatomy
Cerebral AnatomyCerebral Anatomy
White matter
Fiber tracts inside the gray matter
Example: corpus callosum connects hemispheres
Central Nervous System: Central Nervous System: AnatomyAnatomy
Cerebral AnatomyCerebral Anatomy
Cerebral Hemispheres (Cerebrum)Cerebral Hemispheres (Cerebrum) Paired (left
and right) superior parts of the brain
Include more than half of the brain mass
Central Nervous System: Central Nervous System: Cerebral AnatomyCerebral Anatomy
Lobes of the CerebrumLobes of the Cerebrum Fissures (deep grooves) divide the
cerebrum into lobes
Surface lobes of the cerebrum
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Central Nervous System: Central Nervous System: Cerebral AnatomyCerebral Anatomy
CerebellumCerebellum Two hemispheres with convoluted
surfaces
Provides involuntary coordination
of body movements
Central Nervous System: Central Nervous System: Cerebellar AnatomyCerebellar Anatomy
DiencephalonDiencephalon Sits on top of the brain stem
Enclosed by the cerebral hemispheres
Made of three parts Thalamus
Hypothalamus
Epithalamus
Central Nervous System: Central Nervous System: AnatomyAnatomy
Thalamus - Surrounds the third ventricle
Hypothalamus - Under the thalamus
• The pituitary gland is attached to the hypothalamus
Epithalamus – Upon the thalamus
• Forms the roof of the third ventricle
• Houses the pineal body (an endocrine gland)
• Includes the choroid plexus – forms cerebrospinal fluid
Central Nervous System: Central Nervous System: DiencephalonDiencephalon
Brain StemBrain Stem Attaches to the spinal cord
Parts of the brain stem Midbrain
Pons
Medulla oblongata
Central Nervous System: Central Nervous System: AnatomyAnatomy
MidbrainMidbrain Mostly composed of tracts of nerve fibers
Has two bulging fiber tracts – cerebral peduncles
Has four rounded protrusions – corpora quadrigemina
Central Nervous System: Central Nervous System: Brain StemBrain Stem
PonsPons The bulging center part of the brain stem
Mostly composed of fiber tracts
Includes nuclei involved in the control of breathing
Medulla OblongataMedulla Oblongata The lowest part of the brain stem Merges into the spinal cord Includes important fiber tracts
Figure 7.15a
Central Nervous System: Central Nervous System: AnatomyAnatomy
Ventricles and Location of the Ventricles and Location of the Cerebrospinal FluidCerebrospinal Fluid
Central Nervous System: Central Nervous System: AnatomyAnatomy
Figure 7.17b
Central Nervous System: Central Nervous System: Ventricles and Cerebrospinal FluidVentricles and Cerebrospinal Fluid
Cerebrospinal Fluid Similar to blood plasma
composition
Formed by the choroid plexus
Forms a watery cushion to protect the brain
Circulated in arachnoid space, ventricles, and central canal of the spinal cord
Central Nervous System: Central Nervous System: Ventricles and Cerebrospinal FluidVentricles and Cerebrospinal Fluid
Nervous Tissue: Supporting Cells Nervous Tissue: Supporting Cells (Neuroglia, or simply Glia)(Neuroglia, or simply Glia)
Astrocytes Abundant, star-shaped cells
Anchor neurons
Form barrier between capillaries and neurons
Control the chemical environment of the brain Figure 7.3a
Central Nervous System: Central Nervous System: NeurogliaNeuroglia
Microglia Spider-like phagocytes
Dispose of debris
Ependymal cells Line cavities of the
brain and spinal cord
Circulate cerebrospinal fluid with beating cilia
Figure 7.3b, c
Central Nervous System: Central Nervous System: NeurogliaNeuroglia
Oligodendrocytes
• Produce myelin sheath around nerve fibers in the CNS
Figure 7.3d
Central Nervous System: Central Nervous System: NeurogliaNeuroglia
• Function like Schwann cells in the PNS
Spinal CordSpinal Cord Extends from the
medulla oblongata to the region of T12
Below T12 is the cauda equina (a collection of spinal nerves)
Enlargements occur in the cervical and lumbar regions
Figure 7.18
Central Nervous System: Central Nervous System: Spinal CordSpinal Cord
Spinal Cord AnatomySpinal Cord Anatomy Meninges cover the spinal cord
Nerves leave at the level of each vertebrae
• Dorsal root
• Associated with the dorsal root ganglia – collections of cell bodies outside the central nervous system
• Ventral root
Central Nervous System: Central Nervous System: Spinal CordSpinal Cord
Exterior white mater – conduction tracts
Figure 7.19
Central Nervous System: Central Nervous System: Spinal CordSpinal Cord
Central canal filled with cerebrospinal fluid
Internal gray matter - mostly cell bodies
• Dorsal (posterior) horns
• Anterior (ventral) horns
Figure 7.19
Central Nervous System: Central Nervous System: Spinal CordSpinal Cord
Michelangelo’s “The Creation of Adam” from his fresco in the Sistine Chapel.
Does the red cloth look familiar?