Topic 2-brain

• Glia: Neurons that support and nourish neurons and provide a framework for the brain
• Glial functions:

  • support neurons physically
  • supply neurons with nutrients and oxygen
  • insulate neurons
  • protect neurons from pathogens
  • modulate/regulate neural activity
• Astrocytes(CNS) and satellite cells(PNS):

  • structural support for neurons
  • helps create the blood-brain barrier
  • provide nutrients to neurons
• Oligodendrocytes and Schwann cells:

  • wrap axons in myelin to insulate them
• Ependymal cells (CNS):

  • help produce and circulate cerebrospinal fluid
• Microglia (CNS):

  • macrophages that devour and digest cellular debris (phagocytosis)
• Peripheral nervous system divisions:

  1. somatic
  2. voluntary control of action
  3. somatosensory: from skin to brain
  4. motor: from brain to muscles
  5. autonomic
  6. sympathetic and parasympathetic: regulation of involuntary functions
• Somatosensory neurons: primary sensory receptor cells of somatosensory system

  Motor neurons: axons from motor neurons in motor nuclei
• 1. Sympathetic nervous system:
  2. fight or flight
  3. increases blood flow and heart rate
  4. Parasympathetic nervous system:
  5. rest and digest
  6. facilitates digestion
• Protection of the CNS:

  • meninges, cerebrospinal fluid, ventricles
• Meninges:

  1. Dura mater
  2. thick, tough membrane
  3. Arachnoid mater
  4. thin membrane with trabeculae extending through subarachnoid space
  5. Subarachnoid space
  6. filled with CSF
  7. Pia mater
  8. membrane that covers the cortical surface
• Ventricles: fluid-filled spaces in the brain

  • left lateral, right lateral, third, fourth
• Cerebrospinal fluid:

  • produced in choroid plexuses
  • circulates in ventricular system
  • buoyancy and protection
  • chemical stability
  • clearing of waste
• Spinal cord:

  1. White matter
  2. myelinated axons
  3. Grey matter
  4. cell bodies of neurons
• Spinal cord:

  1. Dorsal side = sensory neurons
  2. enter through dorsal route (afferents)
  3. Ventral side = motor neurons
  4. exit ventral side (efferents)
• Major divisions of the brain:

  1. Forebrain
  2. Telencephalon
  3. Diencephalon
  4. Midbrain
  5. Mesencephalon
  6. Hindbrain
  7. Metencephalon
  8. Myelencephalon
• Components of the brain stem:

  • Superior colliculus
  • Inferior colliculus
  • Motor nuclei
  • Pons
  • Medulla
• Cranial nerves:

  • brain stem organized similarly to the spinal cord
  • cranial nerves containing afferent and efferent signals
• Medulla: The part of the brain that controls the heart rate and breathing rate.

  Pons: responsible for balance, taste, swallowing
• Midbrain functions:

  1. Inferior colliculi
  2. hearing
  3. Superior colliculi
  4. vision
  5. Substantia nigra
  6. dopamine and addiction
• Subcortical structures:

  • hippocampus
  • basal ganglia
  • hypothalamus
  • thalamus
  • cerebellum
• Subcortical structure functions:

  1. Cerebellum
  2. motor control, coordination
  3. Hypothalamus
  4. hormone release, temperature, hunger
  5. Thalamus
  6. sensory-motor hub and relay
• Lateral geniculate nucleus: visual relay

  Medial geniculate nucleus: auditory relay
• Basal ganglia structures:

  1. Striatum
  2. Caudate: voluntary movement
  3. Putamen: motor skills
  4. Globus pallidus
  5. regulation of voluntary movement
  6. Nucleus accumbens
  7. aversion, motivation, pleasure
• • Amygdala
  • emotion including fear, episodic long term memory
  • Hippocampus
  • episodic long term memory, spatial navigation
• Lobes: The parts of the brain that are responsible for specific functions.

  1. Frontal
  2. Parietal
  3. Temporal
  4. Occipital
• Sulci: grooves in the brain that are the result of the folding of the brain during development

  1. Central sulcus
  2. Lateral fissure
  3. Longitudinal fissure
  4. Calcarine sulcus
  5. Cingulate sulcus
• Gyri: Small, rounded areas of the cerebral cortex that are associated with specific functions

  1. precentral gyrus
  2. postcentral gyrus
  3. cingulate gyrus
  4. cuneus
• Commissures: connections between hemispheres

  1. Corpus callosum
  2. Fornix
  3. Anterior commissure
• Cytoarchitecture:

  • layered organization
  • 6 different layers
  • Layer 4
  • primary receiving layer
  • thicker in sensory cortex
  • Layers 2,3,5,6
  • sending layers
  • thicker in motor cortex
• Brodmann areas:

  • classified regions based on cytoarchitecture (thickness of cell layers)
  • 52 areas
  • structural classification based on functional differences
• Circle of Willis: provides blood flow to the brain
• Connectomics: the study of the 'wiring diagram' of the brain
• Diffusion tensor/spectrum imaging: uses MRI to measure diffusion of molecules in brain

  Tractography: uses DTI data to trace out connections in brain