The Central Nervous System

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The Central Nervous System
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CNS
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Meninges of the Brain

• Dura Mater (HARD MOTHER) - outer layer, strong
  white fibrous tissue.
• Arachnoid membrane (SPIDER WEB) - middle layer,
  cobweb like layer.
• Pia Mater (SOFT MOTHER)-inner layer, adheres to
  the brain, translucent.

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Divisions of Meninges

• Falx cerebri- parts right and left cerebral
  hemispheres
• Sinuses within the dura function as venus
  reservoirs
• Pia mater contains blood vessels that surround
  brain

Falx cerebri
Falx cerebri
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Did you know?

• Menigitis- inflammation of the meniges caused by
  bacteria, viral or fungal infections.
• Subdural Hematoma- large blood clot found in
  under the dura mater. Usually sign of trauma.

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Cerebral Spinal fluid

• CSF- provides a cushion of protection around
  brain spinal cord.
• Ventricles- 4 fluid filled spaces in the brain.
• 1st 2nd (2 lateral), 3rd and 4th (very tiny)
• CSF is formed in the choroid plexuses then
  circulated via the ventricles

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Ventricles in the Brain
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The Brain Stem

• Brain Stem(vital centers)
• Medulla Oblongata- controls heart rate, blood
  pressure, breathing
• Landmarks- olives pyramids
• Pons- helps control vital functions

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The MidBrain

• Midbrain- connects brain stem and cerebrum via
  the cerebral peduncles
• Corpora quadrigemina (body of four twins) is
  the inferior and superior colliculi.
• Inferior colliculi functions as auditory
  processing center.
• Superior colliculi function as visual processing
  center.
• Red nucleus and substantia nigri(black matter)
  function in motor control., secretes dopamine.

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The Brain

• Cerebellum
• Controls skilled muscle movements, posture and
  balance.
• Is connected to thalamus and motor cortex areas
  of the cerebrum.

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Diencephalon between-brain

• Hypothalamus
• Connects info from nervous and endocrine to
  maintain homeostatsis.
• Regulates appetite and feelings of satisfaction.
• Mind-body link (psychosomatic affect).
• Temperature control site

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Diencephalon

• Thalamus
• detects mild pain and temperature sensation
• determines whether something is pleasant
• Relays sensory info to cerebrum
• Optic chiasma- where optic nerve cross before
  entering the brain
• Pineal gland- secretes melatonin to regulate
  sleep.

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The Cerebrum
Gyrus (bulge)
Sulcus (crevice)
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The Cerebrum
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The Cerebrum

• Cerebrum
• Cerebral cortex- gray matter on the outside of
  the cerebrum
• Responsible for conscious thought
• Memory
• Awareness
• language
• reasoning.

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Cerebral plasticity- regions can vary in their
functions between different individuals.
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Regions of the Cerebrum
Corpus callosum
Cingulate gyrus

• Corpus Callosum-connects the right and left
  hemispheres
• Limbic system- controls emotions, anger, sorrow
  and pleasure.
• Hippocampus- found in the limbic system and
  associated with short term memory
• Amygdala- helps decode

Anterior thalamic nuclei
Hypothalamic nuceli
Fornix
Olfactory tract
Mammillary bodies
Amygdala
Parahippocampal gyrus
Hippocampus
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Regions of the Cerebrum

• Reticular Activating system-when stimulated
  causes consciousness
• REM- rapid eye movement sleep, dreaming
• SWS- slow wave sleep, no dreaming

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Image of Brain Homunculus

• little man represented in each hemisphere of
  the brain, depicts amount of sensory receptors in
  certain areas

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Disorders of the Brain

• Stroke (Cerebrovascular accident CVA)
• Usually because of a clot there is a cessation of
  blood to the brain and the region is starved of
  oxygen.
• Hemiplegia- paralysis on one side of the body.
• Huntington disease
• Involuntary movements, dementia and death
• Creutzfeldt-Jakob
• Human mad cow disease. A prion causes protein
  denaturization in the brain.
• Seizures
• sudden burst of neuron activity. Epilepsy is
  chronic seizure, normally idiopathic.

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The Spinal Cord

• Located within the spinal cavity along with the
  meninges, cerebrospinal fluid, adipose tissue and
  blood vessels

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The Spinal Column

• Dorsal nerve root
• Carry sensory information to the spinal cord,
  afferent pathways
• Cell bodies of these unipolar neurons make up a
  small area of gray matter called the dorsal root
  ganglion
• Ventral nerve root
• Carries motor information out of spinal cord,
  efferent pathways
• Cell bodies of these mulitpolar neurons compose
  the inner core of gray matter
• Spinal Nerve
• Dorsal and Ventral join together to form this
  single nerve

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The Spinal Cord
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The Spinal Cord

• Ascending Tracts
• Conduct sensory impulses up to the brain
• Descending tracts
• Conduct motor impulses down from the brain

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Nerve Repair
PNS

• Nerve damage caused by trauma can sometime be
  repaired by regrowth of the axon
• Neurons can never replicate themselves
• There is evidence that shows new neurons can grow
  out of adult stem cells in the spinal cord

CNS
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Spinal Cord Injuries