meninges in brain complete anatomy and physiology

What is Meninges? 

  • The Meninges are the membrane covering the Brain and Spinal cord.
  • The Meninges consist of three membranes:
  1. The dura mater
  2. The arachnoid mater
  3. The pia mater

. Dura Mater 

  • It is a thick dense inelastic membrane and the outermost layer of the meninges
  • It is bilaminar( consists of two-layer.

 . 1. Endosteal layer( outer layer)

. 2. Meningeal layer( inner layer) 

  • These are closely united except along certain lines, where they separate to form venous sinuses.


  •    Dura mater septa

 . 1. Falx cerebri

. 2. Falx cerebelli

. 3. Tentorium cerebelli

. 4. Diapharagma sellae





Dural Nerve Supply 

  • Branches of the Trigeminal, Vagus and first three Cervical nerves and branches from the sympathetic system pass to the dura 
  • The dura is sensitive to stretching which produces the sensation of headache.


Dural Blood Supply


 Arterial supply

  • Dura mater's arteries supply from the internal carotid, maxillary, ascending pharyngeal, occipital and vertebral arteries.

Venous Drainage 

  • It drains by the Meningeal vein lie in the endosteal layer of the dura.

         

          Arachnoid Mater

  • It is a delicate, impermeable and avascular membrane covering the brain. 
  • It is lying between pia mater and dura mater.
  • It separated from dura mater by a potential space, the subdural space 
  • It is separated from pia mater by the subarachnoid space 
  • The outer and inner surfaces covered with flattened mesothelial cells.



            Pia Mater

  • It extends out over the cranial nerves and fuses with their epineurium.
  • The cerebral arteries entering the substance of the brain, carry a sheath of pia mater with them.
  • The pia mater forms the TELA CHOROIDAE.
  • The tela choroidea fuse with ependyma to form the choroid plexus.
  • Choroid plexus forms CFS.


What is the brain? 


It is one of the largest Organ in the body and coordinates most body activities.


It is the centre for all -thought, memory, judgement and emotion.


Each part of the brain is responsible for controlling different body functions, such as temperature regulation and breathing.




Functions of brain

  • The brain is contained in skull and weight 1300-1400g
  •    It is made up of about 1000 billion neurons 7 each neuron is surrounded by about 10 glial cells ( neuroglia).
  • Neurons cannot multiply and many neurons are lost every day in life but glial cells can multiple throughout life.
  • The brain is also covered by "Meninges" like a spinal cord -outer diameter, middle arachnoid matter and inner pia mater.