Neuroanatomy Review - York University

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Topic 1 – Neuroanatomy Review. CNS Organization - Axes. Fig. 1-1: Leonard, The Neuroscience of Human Movement, Mosby:Toronto, 1998. dorsal ventral.
Topic 1 – Neuroanatomy Review 1) Organization of the nervous system – axes and planes, CNS vs. PNS 2) Structure of spinal cord 3) Structure of brain 4) Neurons and glial cells

Topic 1 – Neuroanatomy Review 1) Organization of the nervous system – axes and planes, CNS vs. PNS 2) Structure of spinal cord 3) Structure of brain 4) Neurons and glial cells

CNS Organization - Axes dorsal

caudal

rostral

Alignment of quadruped brain and spine

ventral

Fig. 1-1: Leonard, The Neuroscience of Human Movement, Mosby:Toronto, 1998.

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CNS Organization - Axes

Superior (above) Lateral (to the side)

Rostral

Medial (middle)

Anterior (in front of; toward the front)

Alignment of human brain and spine

Caudal Posterior (behind; toward the back)

Inferior (below)

Caudal

Fig. 1-9: Purves et al. Neuroscience, Sinauer Associates Inc: Massachusetts, 2001.

CNS Organization - Planes Coronal

Sagittal (Parasagittal)

Horizontal or Axial

Fig. 1-9: Purves et al. Neuroscience, Sinauer Associates Inc: Massachusetts, 2001.

CNS and PNS • CNS – Central Nervous System Æ Consists of the brain and spinal cord.

• PNS – Peripheral Nervous System Æ Consists of the peripheral nerves and ganglia.

The CNS & PNS are separated anatomically but functionally interconnected.

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Afferent – carries info towards the CNS Efferent – carries info away from the CNS Source: Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

Topic 1 – Neuroanatomy Review 1) Organization of the nervous system – axes and planes, CNS vs. PNS 2) Structure of spinal cord 3) Structure of brain 4) Neurons and glial cells

Spinal Cord • Segmented – each segment has 1 pair of dorsal and ventral roots.

Source: Zigmond et al., Fundamental Neuroscience, Academic Press, 1999

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Dorsal Horn Sensory IN (afferent)

Motor OUT (efferent)

Ventral Horn Source: Zigmond et al., Fundamental Neuroscience, Academic Press, 1999

Gray matter – ÆDorsal horn – groups of afferent sensory neurons from periphery ÆVentral horn – groups of efferent motor neurons (cell bodies) Æ Also contains interneurons which modulate information flowing between the sensory and motor components Source: Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

White matter – Æ Bundles of ascending and descending axons for carrying information towards and away from the brain

Source: Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

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Topic 1 – Neuroanatomy Review 1) Organization of the nervous system – axes and planes, CNS vs. PNS 2) Structure of spinal cord 3) Structure of brain 4) Neurons and glial cells

Main regions of brain Cerebellum – important for balance and coordination of movements

Vermis

Cerebellar hemisphere

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999 And Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

Main regions of brain Medulla – important role in regulation of critical cardiovascular and respiratory functions

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999

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Main regions of brain Pons – conveys information about movement from the cerebral hemispheres to the cerebellum

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999

Main regions of brain Midbrain – important for coordination of visual and auditory reflexes

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999

Main regions of brain Diencephalon – consists of -Thalamus -Hypothalamus -Epithalamus -Subthalamus

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999

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Main regions of brain Cerebral hemispheres

Dorsal View

Longitudinal fissure

Gyrus Sulcus Left hemisphere

Right hemisphere

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999 and

Purves et al. Neuroscience, Sinauer Associates Inc: Massachusetts, 2001

Subdivisions of Cerebral Cortex

Frontal lobe

Parietal lobe

Occipital lobe

Frontal lobe

Parietal lobe Occipital lobe

Temporal lobe

Temporal lobe

Source: Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

Functional Divisions of the Cortex (a few examples) -

Source: Kandel et al., Principles of Neural Science, McGraw Hill, 2000

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Anatomical divisions of the cortex -

e.g. Brodmann areas

Brodmann areas are based on microscopic variations in neuronal architecture. e.g.

A

B

A) prefrontal cortex B) primary visual cortex

Source: Mesulam M.-M., Principles of Behavioral and Cognitive Neurology, 2nd Ed. Oxford University Press, 2000

There can be up to 6 different types of layers in the cortex:

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Cerebrospinal Fluid System Ventricle

Source: Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

Topic 1 – Neuroanatomy Review 1) Organization of the nervous system – axes and planes, CNS vs. PNS 2) Structure of spinal cord 3) Structure of brain 4) Neurons and glial cells

The nervous system is made up of two main categories of cells – Æ Neurons (nerve cells)

Æ Glia (supporting cells)

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Neurons – the excitable cells responsible for transmission of information in the nervous system.

Axon Hillock

4 main anatomical regions – -Soma (cell body) -Dendrites -Axon

Presynaptic terminals

-Presynaptic terminals

Source: Kandel et al., Principles of Neural Science, McGraw Hill, 2000

4 common functional regions 1) Input 2) Integrative 3) Conductile 4) Output

Source: Kandel et al., Principles of Neural Science, McGraw Hill, 2000

Neurons come in many shapes and sizes…

Source: Purves et al. Neuroscience, Sinauer Associates Inc: Massachusetts, 2001.

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Sensory

Motor

Interneuron

Source: Kandel et al., Principles of Neural Science, McGraw Hill, 2000

Synaptic cleft

Neurotransmitters from the presynaptic terminal bind to receptors on a post-synaptic region

Source: Lundy-Ekman, Neuroscience: Fundamentals for Rehabilitation, Saunders, 2002

The nervous system is made up of two main categories of cells – Æ Neurons (nerve cells)

Æ Glia (supporting cells)

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Two main types of glial cells 1. Macroglia – large glial cells 2. Microglia – small glial cells

3 types of macroglia cells – 1. Astrocytes 2. Oligodendrocytes 3. Schwann cells

Astrocytes - only found in the CNS -main function is to maintain an appropriate chemical environment for neuronal signaling - take up extra K+ ions, remove and metabolize chemical transmitters from synaptic cleft, remove debris - important during development of CNS

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Astrocytes -Part of the bloodbrain barrier -Provide lactate (‘fuel’) for neurons

Source: Kandel et al., Principles of Neural Science, McGraw Hill, 2000

3 types of macroglia cells – 1. Astrocytes 2. Oligodendrocytes 3. Schwann cells

Oligodendrocytes and Schwann Cells

Oligodendrocytes (CNS only)

Schwann cells (PNS only)

Source: Kandel et al., Principles of Neural Science, McGraw Hill, 2000

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Two main types of glial cells 1. Macroglia – large glial cells 2. Microglia – small glial cells

Microglia -Scavenger cells that ingest foreign cells (e.g. bacteria) and old or injured cells. -Increase in number after injury or disease ÆProliferate from other microglia or from macrophages which migrate in from blood

End of Topic 1 – Neuroanatomy Review.

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