 Basics of the Neuron/glia  Overview of the NS

1. neurons – 10 to 100 billion neurons ◦ Role: - can vary tremendously in size and shape but all have 3 components  cell body or soma  contains genetic material, provides nutrients,

1. neurons – 10 to 100 billion neurons can vary tremendously in size and shape but all have 3 components  cell body or soma  contains genetic material, provides nutrients,  Dendrites  Primarily responsible for receiving info from adjacent neurons

neurons – 10 to 100 billion neurons ◦ cell body or soma  dendrites  axons –  Primarily important for conveying info from one neuron to the next

Information flow

 motor neurons ◦ efferent – carry info from CNS  sensory neurons ◦ afferent – carry info toward CNS  interneurons ◦ carry info within regions

 Glial cells provide imp supportive role: ◦ providing nutrients to neurons  neurotrophic factors ◦ provide support for neurons  myelin sheaths ◦ play a role in response to neuronal injury  astrocytes ◦ play a role in brain development  radial glia

 CNS – Central Nervous System ◦ brain, spinal cord  PNS – Peripheral Nervous System

PNS - peripheral nervous system 2 components 1. autonomic nervous system -“involuntary” -role in emotion and stress  controls smooth muscles, cardiac muscles and glands  two anatomically separate components

 “fight or flight” ◦ activated during emergencies, stress and/or arousal  ex.

 Maintain homeostasis, energy restoration ◦ physiological changes:

 Somatic nervous system ◦ conveys sensory info to the CNS and motor commands from the CNS to the muscles  31 pairs of spinal nerves ◦ ** NERVE – BUNDLE OF AXONS OUTSIDE THE CNS

Copyright © 2006 by Allyn and Bacon CNSPNS Clusters of cell bodies Nuclei (singular nucleus) Ganglia (singular ganglion) Bundles of axons TractsNerves

 voluntary nervous system  31 pairs of spinal nerves ◦ ** NERVE – BUNDLE OF AXONS OUTSIDE THE CNS ◦ sensory nerves

 voluntary nervous system  31 pairs of spinal nerves ◦ ** NERVE – BUNDLE OF AXONS OUTSIDE THE CNS ◦ sensory nerves  afferent;  dorsal roots  dorsal root ganglion

Section of Spinal Cord AND Spinal Nerves

◦ motor nerves  ventral  cell bodies in ventral horn  efferents

Section of Spinal Cord AND Spinal Nerves

Importance of the location of injury in spinal cord in understanding the type and extent of damage that a person with spinal cord injury will have

Importance of the location of injury in spinal cord in understanding the type and extent of damage that a person with spinal cord injury will have dermatome map

Cervical – green Thoracic- blue Lumbar- purple Sacral- red

Importance of the location of injury in spinal cord in understanding the type and extent of damage that a person with spinal cord injury will have A high cervical injury vs a low thoracic injury will result in very different outcome!!!!

Christopher Reeve’s damage was between C1 and C2

-brought to the attention of many the need for research in spinal cord injury - strong advocates of stem cell research -changed our beliefs about spinal cord injury

Cranial nerves primarily serve head and face

 Cranial nerves  Differences between cranial nerves and motor/sensory nerves ◦ Cranial go directly into brain (rather than spinal cord) ◦ Cranial can be sensory, motor or both

sphenopalatine ganglioneuralgia

Cranial nerves primarily serve head and face

 Touch tongue to your soft palate.tongue ◦ Underside of tongue may be warmer than the top (which probably cooled by the Slurpee you just chugged.  Drink something warm Drink  Make a mask with your hands to cover your mouth and nose. Breathe quickly, raising the temperature inside your mouth.Breathe quickly  Press a warm thumb against your palate.  Wait it out.

 Swelling or compression of the 7th cranial nerve ◦ causes: ◦ treatment: ◦ recovery:

 How is it protected? ◦ Skull  obvious - advantages of skull  less obvious - disadvantage- closed head injury  coup - site of injury  contre coup

 How is it protected? ◦ Skull ◦ CSF - cerebrospinal fluid  CSF production

How is it protected? –Skull –CSF - cerebrospinal fluid CSF production –role of ventricles ADV: DISADV: »hydrocephaly

 How is it protected? ◦ Skull ◦ CSF - cerebrospinal fluid ◦ meninges

meninges- infections within the meninges – bacteria – bacterial meningitis viral – viral meningitis

 How is it protected? ◦ Skull ◦ CSF - cerebrospinal fluid ◦ meninges ◦ blood brain barrier

 Gray matter- ◦ Butterfly shaped ◦ Contains cell bodies

Gray matter

 Gray matter-  white matter- axons

Section of Spinal Cord AND Spinal Nerves

 Gray matter-  white matter  spinal tracts – bundle of axons inside the CNS

 3 main divisions of brain ◦ hindbrain; midbrain; forebrain Metencephalon myelencephalon Mesencephalon Telencephalon diencephalon

 medulla

medulla pons hindbrain

 medulla ◦ basic reflexes  heart rate, blood pressure, respiration, vomiting  many cranial nerves enter through the medulla

Copyright © 2006 by Allyn and Bacon

 medulla  pons

medulla pons hindbrain

 medulla  pons  cerebellum-

medulla pons hindbrain

 medulla  pons  cerebellum- ◦ balance and coordination ◦ motor memory

 Sensory information  movement ◦ substantia nigra -

 Cerebral cortex ◦ role of convolutions

 Frontal ◦ Motor function

frontal

 Frontal ◦ Motor function ◦ Prefrontal – higher “executive function”

Prefrontal cortex

 Frontal ◦ Motor function  Prefrontal – higher “executive function”  Parietal ◦ Somatosensory function

frontal parietal

 Frontal ◦ Motor function  Prefrontal – higher “executive function”  Parietal ◦ Somatosensory function  Temporal ◦ Audition ◦ Emotion

frontal parietal temporal

 Frontal ◦ Motor function  Prefrontal – higher “executive function”  Parietal ◦ Somatosensory function  Temporal ◦ Audition ◦ emotion  Occipital ◦ vision

frontal parietal temporal occipital

 Different roles for primary and association ◦ Start with primary motor since it is different than the others!

 Primary motor ◦ Sends commands to muscles (via motor neurons)

primary motor strip

 Primary motor ◦ Sends commands to muscles  Association cortex ◦ Sends coordinated commands to primary motor cortex

Motor association cortex

 Primary sensory cortex – ◦ Receives sensory input from that sensory system  Association cortex- ◦ Interprets the input (info) that comes in from the sensory neurons

Association cortex

Visual association cortex

Auditory association cortex

 thalamus – important relay for sensory and motor information  has tremendous projections of neurons across many regions of the cerebral cortex

The thalamus communicates with much of the cerebral cortex - serving as a sensory and motor information relay.

 hypothalamus ◦ 4 F’s – feeding, fleeing, fighting and copulating ◦ hypothalamus contains many nuclei (collections of cell bodies in CNS)  also…. controls maternal behaviors (at least in rodents)  thirst and drinking

Two brothers – same exact age. One with a lesion (damage) to a nucleus in the hypothalamus

 limbic system – number of structures important in emotion ◦ limbic system also includes the hippocampus – important for learning and memory!

 basal ganglia ◦ important in Parkinsons Disease

 corpus callosum – sole purpose of the corpus callosum is to serve as a “bridge” between left and right hemispheres ◦ contains millions and millions of axons ◦ allows left and right side of brain to know what each other is doing!

Corpus callosum