Nervous System P2

layers of connective tissue

including dural partitions

• meninges

• dura

• pia

• arachnoid

most superficial

thick and strong brain protection

• meninges

• dura

• pia

• arachnoid

avascular network of collagen and elastic fibers

• meninges

• dura

• pia

• arachnoid

thin, vascular

close contact with brain and spinal cord

• meninges

• dura

• pia

• arachnoid

about 80-150 ml

forms a liquid cushion & holds CNS structure

minor exchange of nutrients and waste

• meninges

• cerebrospinal fluid (CSF)

• Blood brain barrier

secreted from choroid plexuses in walls of ventricles

• meninges

• cerebrospinal fluid (CSF)

• Blood brain barrier

consists of brain capillary endothelial cells joined by tight junctions

processes of astrocytes

continuous basement membrane

• meninges

• cerebrospinal fluid (CSF)

• Blood brain barrier

more stringent permeability to restrict passage of many toxins & pathogens

• meninges

• cerebrospinal fluid (CSF)

• Blood brain barrier

100 million neurons

extends from foramen magnum to L1

protected by CSF and meninges

• spinal cord

• posterior dorsal root

• dorsal root ganglion

• anterior ventral root

axons of sensory neurons that enter the spinal cord

sending information UPWARDS

• spinal cord

• (posterior) dorsal root

• dorsal root ganglion

• (anterior) ventral root