Topic 1 – Neuroanatomy Review - York University · Topic 1 – Neuroanatomy Review Spinal Cord...

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1) Organization of the nervous system – axes and planes, CNS vs. PNS

2) Structure of spinal cord 3) Structure of brain4) Neurons and glial cells

Topic 1 – Neuroanatomy Review




CNS Organization - Axes

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

dorsal

ventral

caudalrostral Alignment of quadruped brain and spine

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Alignment of human brain and spine

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

CNS Organization - Axes

Anterior (in front of; toward the front) Posterior

(behind; toward the back)

Inferior (below) Caudal

Superior (above)

Rostral

Caudal

Medial (middle)

Lateral (to the side)

Coronal Sagittal

Horizontal or Axial

CNS Organization - Planes

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

(Parasagittal)

CNS and PNS

• CNS – Central Nervous SystemConsists of the brain and spinal cord.

• PNS – Peripheral Nervous SystemConsists of the peripheral nerves and ganglia.

The CNS & PNS are separated anatomically but functionally interconnected.

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

Afferent – carries info towards the CNSEfferent – carries info away from the CNS


2) Structure of spinal cord3) Structure of brain4) 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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Source: Zigmond et al., Fundamental Neuroscience, Academic Press, 1999

Sensory IN(afferent)

Motor OUT(efferent)

Dorsal Horn

Ventral Horn


Gray matter –

Dorsal horn – groups of afferent sensory neurons from periphery

Ventral horn – groups of efferent motor neurons (cell bodies)

Also contains interneurons which modulate information flowing between the sensory and motor components


White matter –

Bundles of ascending and descending axons for carrying information towards and away from the brain

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Main regions of brainCerebellum – important for balance and coordination of movements

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

Cerebellar

hemisphere

Vermis

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

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

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


Main regions of brainMidbrain – important for coordination of visual and auditory reflexes


Main regions of brainDiencephalon –consists of

-Thalamus

-Hypothalamus

-Epithalamus

-Subthalamus


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Main regions of brainCerebral hemispheres

Source: MacKay, Neuro 101, Sefalotek Ltd., 1999 and Purves et al. Neuroscience, Sinauer Associates Inc: Massachusetts, 2001

Longitudinal fissureDorsal View

Left hemisphere

Right hemisphere

Gyrus

Sulcus

Subdivisions of Cerebral Cortex


Temporal lobe

Frontal lobe

Parietal lobe Occipital

lobe Frontal lobe

Parietal lobe

Occipital lobe

Temporal lobe

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

Functional Divisions of the Cortex (a few examples) -

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Anatomical divisions of the cortex -

e.g. Brodmann areas

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

Brodmann areas are based on microscopic variations in neuronal architecture.

e.g.

A) prefrontal cortex

B) primary visual cortex

A B

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

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Cerebrospinal Fluid System


Ventricle




The nervous system is made up of two main categories of cells –

Neurons (nerve cells)

Glia (supporting cells)

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Neurons –

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


4 main anatomical regions –-Soma (cell body)

-Dendrites

-Axon

-Presynaptic terminals

Axon Hillock

Presynapticterminals

1) Input

2) Integrative

3) Conductile

4) Output

4 common functional regions


Neurons come in many shapes and sizes…

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

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Sensory Motor Interneuron


Synaptic cleft


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

The nervous system is made up of two main categories of cells –

Neurons (nerve cells)

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 blood-brain barrier

-Provide lactate (‘fuel’) for neurons

3 types of macroglia cells –1. Astrocytes

2. Oligodendrocytes

3. Schwann cells

Oligodendrocytes and Schwann Cells

Schwann cells (PNS only)

Oligodendrocytes (CNS only)


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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

Proliferate from other microglia or from macrophages which migrate in from blood

End of Topic 1 – Neuroanatomy Review.

Topic 1 – Neuroanatomy Review - York University · Topic 1 – Neuroanatomy Review Spinal Cord...

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