Lec 5 Intro to Organization of the Nervous System

Question 1

What is afferent vs efferent?

Answer 1

afferent = input
efferent = output

Question 2

What are the 4 planes of section/imaging?

Answer 2

• horizontal/axial
• coronal/frontal
• sagittal
• all others are “oblique”

Question 3

What are the 8 bones of the cranium?

Answer 3

• frontal
• parietal (2)
• occipital
• temporal (2)
• sphenoid
• ethmoid

Question 4

What are the 4 unpaired cranial bones?

Answer 4

• frontal
• occipital
• shepnoid
• ethmoid

Question 5

What are the 2 paired cranial bones?

Answer 5

• parietal

- temporal

Question 6

What are sutures?

Answer 6

• tight joints between bones, fized by fibrous membranes

Question 7

What are the 4 most prominent sutures?

Answer 7

1. coronal
2. lambdoid
3. sagittal
4. parieto-temporal (squamosal)

Question 8

Where does the coronal suture join?

Answer 8

the two parietal bones with the frontal bone

Question 9

What does the lambdoid suture join?

Answer 9

the two parietal bones with the occipital bone

Question 10

What does the sagittal suture join?

Answer 10

the two parietal bones along the midline

Question 11

What does the parieto-temporal (squamosal) suture join?

Answer 11

• joins the parietal and temporal bones

Question 12

What are the three compartments of the base of the cranium?

Answer 12

• the anterior, middle, and posterior fossae

Question 13

Where does the spinal cord merge with the brainstem? [which foramen, bone, area of cranial base]

Answer 13

• via the foramen magnum
• in the posterior fossa of the cranial base
• the foramen magnum is in the occipital bone

Question 14

What are the 5 sections of the vertebral column? How many segments in each?

Answer 14

30 total vertebrae segments

• cervical (7)
• thoracic (12)
• lumbar (5)
• sacral (5)
• coccygeal (1 fused)

Question 15

Where does the end of the audlt spinal cord end?

Answer 15

• caudal border of the L1 vertebrae where it forms the conus medullaris

Question 16

How many spinal nerves are there? What are they?

Answer 16

31

• 8C
• 12T
• 5L
• 5S
• 1 Coccygeal

Question 17

Where does the C1 spinal nerve emerge?

Answer 17

between C1 vertebral segment and the occipital bone

Question 18

Where does the cauda equina start?

Answer 18

caudal to L2

Question 19

What is the order from outside to inside of the 3 meninges?

Answer 19

• dura mater
• arachnoid
• pia mater

Question 20

What is the dura mater?

Answer 20

• tougher outer layer of meninges

Question 21

What are the 4 dural folds/reflections?

Answer 21

• falx cerebri
• tentorium cerebelli
• falx cerebelli
• diaphragma sellae

Question 22

Where is the falx cerebri?

Answer 22

between the two cerebral hemispheres

Question 23

Where is the tentorium cerebelli?

Answer 23

overlying the cerebellum

Question 24

Where is the falx cerebelli?

Answer 24

between the two cerebellar hemispheres

Question 25

Where is the diaphragma sellae?

Answer 25

- forms a roof over the pituitary fossae, perforated by the pituitary stalk

Question 26

How many layers of dura surround the cerebrum?

Answer 26

- 2 layers

Question 27

What is the function of the inner and outer laters of dura mater surrounding the cerebrum

Answer 27

- outer layer lines skull = periosteum for the cranium, rich in blood vessels and nerves - inner layer = adherent to arachnoid in many places

Question 28

What are dural sinuses?

Answer 28

- channels between the two dural layers | - critical for venous blood and CSF circulation and drainage

Question 29

Where is the superior longitudinal sinus?

Answer 29

- mid-sagitally (at midline) at junction of dural cap and falx cerebri

Question 30

What is the arachnoid?

Answer 30

- middle meningeal layer

Question 31

What is the subarachnoid space (SAS)? What is in it?

Answer 31

- the space between arachnoid and pia mater | - filled with CSF

Question 32

What are subarachnoid cisterns?

Answer 32

- areas where the pia and arachnoid are more separated from each other --> contain larger pools of CSF

Question 33

What are the 4 most notable cisterns in the brainstem area?

Answer 33

- cisterna magna - pontine cistern - superior [quardigeminal] cistern - basal [interpeduncular] cistern

Question 34

Where is the lumbar cistern? important?

Answer 34

- below the L1 vertebral segment - area of lumbar puncture - lower risk target for harvesting CSF because conus medullaris already terminated above it

Question 35

What are arachnoid villi?

Answer 35

- finger-like extensions of the arachnoid into the dural sinuses

Question 36

What are arachnoid granulation?

Answer 36

- calcified arachnoid villi - can become sites of neoplastic tumors - increase in frequency with age

Question 37

WHat is the pia mater?

Answer 37

- innermost meningeal layer - adheres to almost all the underlying nervous tissue - actually composed of 2 membranes

Question 38

What is difference between inner and outer pia?

Answer 38

inner pia = pia intima -- adheres to nerovus tissue, avascular outer pia = epipia -- continuous with arachnoid trabeculae, contains blood vessels of spinal cord

Question 39

What are dentate ligaments?

Answer 39

- bands of epipia [outer pia] tissue that anchor the spinal cord in the dura laterally

Question 40

Where do blood vessels lie in spinal cord vs brain?

Answer 40

- 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

Question 41

What are the leptomeninges?

Answer 41

pia + arachnoid together

Question 42

What are the 4 main differences between meninges of spinal cord and cerebrum?

Answer 42

1. in cerebrum: 2 layers of dura; in spinal : 1 dura layer 2. cerebrum: single pial layer; in spinal: 2 distint layers 3. cerebrum: blood vessels on surface of intima pia within subarachnoid space; in spinal: blood vessels in epipial layer 4. arachnoid villi way more common in cerebrum

Question 43

What is the filum terminale? Coccygeal ligament? their function?

Answer 43

they tether the meninges to the base of the coccyx - filum terminale = continuation of epipia - cocygeal ligament = continuation of dura mater