Lec 5 Intro to Organization of the Nervous System Flashcards
What is afferent vs efferent?
afferent = input efferent = output
What are the 4 planes of section/imaging?
- horizontal/axial
- coronal/frontal
- sagittal
- all others are “oblique”
What are the 8 bones of the cranium?
- frontal
- parietal (2)
- occipital
- temporal (2)
- sphenoid
- ethmoid
What are the 4 unpaired cranial bones?
- frontal
- occipital
- shepnoid
- ethmoid
What are the 2 paired cranial bones?
- parietal
- temporal
What are sutures?
- tight joints between bones, fized by fibrous membranes
What are the 4 most prominent sutures?
- coronal
- lambdoid
- sagittal
- parieto-temporal (squamosal)
Where does the coronal suture join?
the two parietal bones with the frontal bone
What does the lambdoid suture join?
the two parietal bones with the occipital bone
What does the sagittal suture join?
the two parietal bones along the midline
What does the parieto-temporal (squamosal) suture join?
- joins the parietal and temporal bones
What are the three compartments of the base of the cranium?
- the anterior, middle, and posterior fossae
Where does the spinal cord merge with the brainstem? [which foramen, bone, area of cranial base]
- via the foramen magnum
- in the posterior fossa of the cranial base
- the foramen magnum is in the occipital bone
What are the 5 sections of the vertebral column? How many segments in each?
30 total vertebrae segments
- cervical (7)
- thoracic (12)
- lumbar (5)
- sacral (5)
- coccygeal (1 fused)
Where does the end of the audlt spinal cord end?
- caudal border of the L1 vertebrae where it forms the conus medullaris
How many spinal nerves are there? What are they?
31
- 8C
- 12T
- 5L
- 5S
- 1 Coccygeal
Where does the C1 spinal nerve emerge?
between C1 vertebral segment and the occipital bone
Where does the cauda equina start?
caudal to L2
What is the order from outside to inside of the 3 meninges?
- dura mater
- arachnoid
- pia mater
What is the dura mater?
- tougher outer layer of meninges
What are the 4 dural folds/reflections?
- falx cerebri
- tentorium cerebelli
- falx cerebelli
- diaphragma sellae
Where is the falx cerebri?
between the two cerebral hemispheres
Where is the tentorium cerebelli?
overlying the cerebellum
Where is the falx cerebelli?
between the two cerebellar hemispheres
Where is the diaphragma sellae?
- forms a roof over the pituitary fossae, perforated by the pituitary stalk
How many layers of dura surround the cerebrum?
- 2 layers
What is the function of the inner and outer laters of dura mater surrounding the cerebrum
- outer layer lines skull = periosteum for the cranium, rich in blood vessels and nerves
- inner layer = adherent to arachnoid in many places
What are dural sinuses?
- channels between the two dural layers
- critical for venous blood and CSF circulation and drainage
Where is the superior longitudinal sinus?
- mid-sagitally (at midline) at junction of dural cap and falx cerebri
What is the arachnoid?
- middle meningeal layer
What is the subarachnoid space (SAS)? What is in it?
- the space between arachnoid and pia mater
- filled with CSF
What are subarachnoid cisterns?
- areas where the pia and arachnoid are more separated from each other –> contain larger pools of CSF
What are the 4 most notable cisterns in the brainstem area?
- cisterna magna
- pontine cistern
- superior [quardigeminal] cistern
- basal [interpeduncular] cistern
Where is the lumbar cistern? important?
- below the L1 vertebral segment
- area of lumbar puncture
- lower risk target for harvesting CSF because conus medullaris already terminated above it
What are arachnoid villi?
- finger-like extensions of the arachnoid into the dural sinuses
What are arachnoid granulation?
- calcified arachnoid villi
- can become sites of neoplastic tumors
- increase in frequency with age
WHat is the pia mater?
- innermost meningeal layer
- adheres to almost all the underlying nervous tissue
- actually composed of 2 membranes
What is difference between inner and outer pia?
inner pia = pia intima – adheres to nerovus tissue, avascular
outer pia = epipia – continuous with arachnoid trabeculae, contains blood vessels of spinal cord
What are dentate ligaments?
- bands of epipia [outer pia] tissue that anchor the spinal cord in the dura laterally
Where do blood vessels lie in spinal cord vs brain?
- in spinal cord: blood vessels lie in the epipia [outer pia]
- in brain: cerebral blood vessels on surface of pia intima [inner pia] within subarachnoid space
What are the leptomeninges?
pia + arachnoid together
What are the 4 main differences between meninges of spinal cord and cerebrum?
- in cerebrum: 2 layers of dura; in spinal : 1 dura layer
- cerebrum: single pial layer; in spinal: 2 distint layers
- cerebrum: blood vessels on surface of intima pia within subarachnoid space; in spinal: blood vessels in epipial layer
- arachnoid villi way more common in cerebrum
What is the filum terminale? Coccygeal ligament? their function?
they tether the meninges to the base of the coccyx
- filum terminale = continuation of epipia
- cocygeal ligament = continuation of dura mater
