brain brain

• Ectoderm


  All nervous tissue
• Mesoderm


  All skeletal & cardiac ms, most smooth ms, glands etc
• Endoderm

  linings of our organs
• Primary brain vesicles

  Prosencephalon (forebrain)

  Mesencephalon (midbrain)

  Rhombencephalon (hindbrain)
• Prosencephalon vesicle


  Prosencephalon~telencephalon~cerebrum
• Prosencephalon vesicle


  Prosencephalon~Diencephalon~thalamus, hypothalamus, epithalamus
• Mesencephalon vesicle


  Mesencephalon~mesencephalon~midbrain
• Rhombencephalon ventricle

  Rhombencephalon~metencephalon~Pons & Cerebellum
• Rhombencephalon ventricle


  Rhombencephalon~myelencephalon~medulla oblongata
• Brainstem=


  Cerebrum, diencephalon, cerebellum, brain stem
• 4 Protective coverings of the brain

  1. Cranium

  2. Cranial meninges (3)

  3. CSF

  4. Blood-brain barrier
• Note that cranial meninges is the

  2nd type of protective covering of the brain
• dura mater (1st cranial meninge) contains the

  Periosteal layer & meningeal layer
• periosteal layer of dura mater is next to

  skull
• meningeal layer of dura mater is next to

  arachnoid
• Arachnoid mater (2nd cranial meninge)


  Spiderlike web to pia mater
• Pia mater (3rd cranial meninge)-


  Thin covering on cerebrum, contains vessels
• 3 extensions of the dura mater

  •falx cerebrum

  •falx cerebelli

  •tentorium cerebelli
• Falx cerebrum (1st extension of dura mater)


  -between cerebral hemispheres

  -in longitudinal fissure
• Falx cerebelli (2nd extension of dura mater)


  -b/w cerebellar hemispheres
• Tentorium cerebelli (3 extension of dura mater)

  -b/w cerebrum & cerebellum

  -in transverse fissure
• Dura mater & venous drainage

  1. Falx cerebri

  2. Transverse sinus

  3. Sigmoid sinus
• Falx cerebri includes the

  •superior Sagittal sinus

  •inferior sagittal sinus

  •confluence of sinuses
• Note that CSF is the

  3rd type of protective covering of the brain
• CSF fxns:

  •Protects brain and SC from injury

  •carries molecules & cells in subarachnoid space
• CSF is formed in

  Choroid plexus
• Choroid plexus=

  Modified capillary network in walls of ventricles
• Ventricular system

  •2 lateral ventricles

  •interventricular foramen

  •3rd ventricle-b/n thalami

  •cerebral aqueduct

  •4th ventricle-b/n pons & cerebellum

  •central canal in spinal cord
• Fxns of CSF

  1. Mechanical protection

  2.chemical protection

  3.circulation
• Mechanical protection-

  shock absorption
• Chemical protection-

  Ion balance
• Circulation-

  Exchange of nutrients & metabolic wastes (similar to lymph system)
• CC: hydrocephalus=

  Elevated CSF pressure
• Note that the Blood Brain Barrier is the

  4th protective covering of the brain
• Blood Brain Barrier or "BBB" (4th protective covering of the brain) is

  •tight jxns b/en endothelial cells of blood capillaries

  •protects from harmful substances

  •water, glucose can be sent to brain
• Astrocytes secrete chemicals in BBB to

  Maintain tight jxn's
• The Telencephalon (Cerebrum) consists of the

  •cerebral cortex (grey) and white matter

  •basal nuclei

  •limbic system
• Note that telencephalon=

  Cerebrum
• Cerebrum is responsible for

  -consciousness of all perception, analytical thought, intelligence, personality, decision making etc
• In cerebrum...

  Outer cortex: thin & grey

  Internal white matter: axons