Neuro 3 Flashcards
3 layers of the meninges
dura mater
arachnoid mater
pia mater
3 spaces of the meninges
epidural space
subdural space
subarachnoid space
What are the pachymeninges?
Dura mater
- tough = protection
-outer later
- encompasses venous sinuses
- Infoldings separate parts of the brain
• Faux cerenri between cerebral hemispheres
• Tentorium cerebelli between cerebrum and cerebellum
What are the leptomeninges
arachnoid mater and pia mater
Arachnoid mater overview
spider web like
- Function: cushioning and absorption of CSF
- holds small arteries
-has granulations to absorb CSF back to the bloodstream
Pia mater overview
delicate
- follows the gyri and sulci
-function: barrier, blood vessel penetration
What is the circle of Willis and what leads up to it
anatomical circle of blood flow to the brain
comes from internal carotid arteries, and basilar artery (from 2 vertebral arteries)
2 arteries that supply blood to the spinal cord
dorsal and ventral spinal artery
(1 supplies dorsal white/gray matter, the other ventral AND lateral white/gray matter)
2 major veins of the spinal cord
dorsal spinal vein and ventral spinal vein
What is the function of the blood brain barrier
protect the neural tissue from pathogens and toxins in the bloodstream
What are the components of the blood brain barrier
• Endothelial cells with tight junctions
• Basement membrane
• Pericytes – contractile cells
• Astrocyte foot processes
How did they discover the blood brain barrier
Intravenous dye injection stained all tissue except the brain and CSF
choroid plexus and meninges were stained
Ventricle of the telencephalon
lateral ventricles
what are the ventricles of the diencephalon
third ventricle
what part of the ventricular system is in the mesencephalon
mesencephalic aqueduct
What ventricle is in the rhombencephalon (met and myel)
fourth ventricle
what part of the ventricular system is in the spinal cord?
central canal
Lateral ventricles
ventricles 1 and 2
-in the cerebral hemispheres
left and right divided by septum pellucidum
(has choroid plexus)
Third ventricle
donut shape around the intrathalamic adhesion
(has choroid plexus)
mesencephalic aqueduct
connects 3rd and 4th ventricle
common site of obstruction bc it is small
Fourth ventricle
connects aqueduct to central canal
has lateral and medial openings into subarachnoid space
- prion diseases attack here
(has choroid plexus)
Cerebrospinal fluid overview
• Clear, colorless fluid
• Fills the ventricular system and subarachnoid space
• Produced by choroid plexus from blood
• Functions
• Protection/shock absorption
• Homeostasis
• Clearance of waste products
What is the choroid plexus?
• Specialized ependymal cells forms CSF from blood
• Form papillary structures containing many blood vessels
• Located in lateral, third and fourth ventricles
Flow of cerebrospinal fluid (8)
• Lateral ventricle
• Interventricular foramen
• Third ventricle
• Mesencephalic aqueduct
• Fourth ventricle
• Medial and lateral foramens
• Subarachnoid space
• Reabsorbed by arachnoid granulations
Where are the low and high spinal taps located?
High: cerebellomedullary cistern (cisternal)
Low: Lumbar
axons can be
myelinated or unmyelinated
Connective tissue of peripheral nerves (3)
• Endoneurium – around individual axons
• Perineurium – around bundles of axons
• Epineurium – around nerves
What myelinates peripheral nerve axons?
schwann cells
Peripheral nerves
White
• Solid and do not stretch
• Typically run in the fascia between muscle bodies
• May parallel the blood vessels (neurovascular bundle)
Divisions of the peripheral nervous system
splits into somatic and autonomic
autonomic splits into parasympathetic, sympathetic, and enteric
Somatic = skeletal voluntary
Somatic nervous system
voluntary movement, skeletal muscle, 1 neuron with the cell body in CNS
Autonomic nervous system
Visceral, cardiac and smooth muscle contraction and gland secretion
2 neurons that synapse outside of the CNS
Parasympathetic Nervous system
maintain homeostasis
slow
ganglia in/near target organ
origin in brainstem/sacral
long preganglionic and short post ganlionic motor neurons
presynaptic and postsynaptic neurotransmitter =
ACETYLCHOLINE
Sympathetic chart overview
response to stress
fast!
ganglia in parallel chain next to spinal cord
origin in lateral horns of thoracic and lumbar spine
short preganglionic and long postganglionic motor neurons
presynaptic neurotransmitter= acetylcholine
postsynaptic neurotransmitter = norepinephrine
Actions of sympathetic nervous system
• Fight, flight, fright response (stress)
• Increased heart and respiratory rate
• Increased blood flow to muscles
• Decreased digestive processes
• Innervates nearly every tissue in the body
motor pathways vs sensory pathways in sympathetic nervous system
Motor= preganglionic neuron and postganglionic neuron
Sensory = similar to somatic (skeletal) system
cell bodies in dorsal root ganglion
Adrenal gland overview
• Located cranial and medial to kidney (on top)
• Endocrine gland – releases chemical messengers into blood
• Parts
• Cortex
• Controlled by the pituitary gland
• Medulla
• Controlled by sympathetic nerves (stress)
• Releases catecholamines (epinephrine and norepinephrine)
Parasympathetic actions
• Rest and digest
• Decreased heart and respiratory rate
• Increased digestion
Parasympathetic motor vs sensory pathway
motor = pre/post ganglionic neurons
sensory = similar to cranial and spinal nerves
Enteric nervous system
Web-like series of neurons located in the wall of the intestine
“second brain” more neurons than the brain
uses vagus nerve
