Nervous System 2

Question 1

Afferent corresponds to what type of information going in which root? efferent?

Answer 1

sensory/dorsal or posterior

motor/ventral or anterior

Question 2

motor neurons are located ONLY where?

Answer 2

anterior horn

Question 3

interneurons are located where?

Answer 3

both anterior and posterior horn.

Question 4

dura mater is made up of what?

Answer 4

connective tissue

Question 5

what is the layer that surrounds one axon? multiple axons (fassicle)? bunch of fassicles?

Answer 5

endoneurium, perinerium and epineurium.

Question 6

central canal in spinal cord is lined with what?

Answer 6

ependymal cells.

Question 7

grey matter is made up of? white matter? which one would have fewer cell nuclei?

Answer 7

cell bodies
axons/dendrites
white matter because the axons are mylenated therefore would appear white.

Question 8

what is neuropil?

Answer 8

axon + dendrite

Question 9

central canal is lined with what type of cells?

Answer 9

simple cuboidal ependymal cells (or tanocytes)

Question 10

unipolar neurons are what type of neuron? how do they appear?

Answer 10

sensory

round or acinar because they only have one process dont look like neurons.

Question 11

what are the three meninge layers? they are made of what kind of tissue?

Answer 11

all made up of connective tissue.

1. dura mater: firboelastic, subdural space underneath very small
2. arachnoid space: fibrous, lined by squamous cells, subarachnoid space underneath large space containing BV and CSF
3. pia mater: collagen, elastin and fibroblasts, delicate layer

Question 12

BBB contains which junctions? fenestrated or non? what is allowed to pass?

Answer 12

tight junctions, non fenestrated, glucose can freely pass (brains E).

Question 13

once CSF makes it to subarachnoid space from 4th ventricle (choroid plexus) where does it go?

Answer 13

to venous blood at superior saggital sinus.

Question 14

nerves are made up of many what? endoneurium surrounds what? perineurium? epineurium?

Answer 14

axons
axons (around myelin)
fassicles of axons
various fassicles (surrounds nerves)

Question 15

how would you tell difference between muscle and nerves in picture?

Answer 15

the way the cells appear. in muscle, profile of cells. in nerves, axons appear as many tiny dots NOT cell like.

Question 16

ganglion cell axons exit at optic disc and pass through what before going to LGN?

Answer 16

lamina cribosa.

Question 17

approximately how many photoreceptors? ganglion cells?

Answer 17

125 million rods and cones
1 million ganglion cells
therefore many photoreceptors for every 1 ganglion cell

Question 18

the inner nuclear layer contains nuclei of what 5 types of cells?

Answer 18

amacrine, bipolar, ganglion, horizontal, photoreceptors, mueller (more recently interplexiform cells added)

Question 19

which are larger rods or cones? we have more of which?

Answer 19

cones are larger

rods

Question 20

in cones we have two invaginations for synaptic contact (this area is called what?) which are?

Answer 20

synaptic area= pedicle

one bipolar and one horizontal invagination

Question 21

in rods, the synaptic area is called? how many extensions (as opposed to invaginations) and what are they?

Answer 21

spherule

3. 1 bipolar and 2 horizontal

Question 22

RPE is responsible for digesting what? if it cant do this what happens?

Answer 22

old photopigment (old rods and cones). if it cant do this, it partially digests the material and buts it beneath RPE cells into or on bruchs membrane= drusen.

Question 23

what is located at 0 degrees? does the blind spot have rods or cones? where does the retina end? where is the blindspot located?

Answer 23

the fovea (high acuity, highest number of cones).
NO
ora serratta
12 degrees nasal (this is where ganglion cells leave, central retinal artery enters and central retinal vein enters, also where lamina cribosa is located).

Question 24

optic disk is located to where to the fovea? what appears darker, your optic disk or macula?

Answer 24

optic disk is nasal to the fovea

macula due to pigmentation

Question 25

what two pigments are located in the macula (darkened region)? the macula is how big in diameter?

Answer 25

lutein and zeaxanthin (both are xanthophylls)
there is also taller and darker RPE cells
5mm

Question 26

what are the layers of the fovea? what is unique about the first layer?

Answer 26

central smallest layer= foveola, fovea, parafovea, perifovea (outer most)
foveola is avascular and ONLY has cones

Question 27

what is the distance between the macula and the optic disk?

Answer 27

3-4mm

Question 28

what is the fovea? and how large is it?

Answer 28

depression in center of retina (pushes ganglion cells out of the way), 1.5mm.

Question 29

Which layer is thicker, parafovea or peripfovea?

Answer 29

parafovea (thickest ganglion and INL layer, 7-12 cell layers)
perifovea (4 cell layers, ends when it reaches 1 cell layer)

Question 30

in the far peripheral retina what happens to the rods?

Answer 30

they disappear (nuclear and plexiform layers merge) (cones disappear much faster than rods)

Question 31

ora serratta is located how far in front of equator?

Answer 31

5mm.

Question 32

nasal fibres entering the optic disk, do they create arculate patterns? if not what do?

Answer 32

NO (they go through macula)
temporal fibres, these do NOT go through macula they go around, they form superior and inferior archs around macula which make arcuate patterns.

Question 33

what is the papillomacular bundle (PM)?

Answer 33

direct line of deep fibres from the fovea to the temporal edge of optic disk.

Question 34

the further the fibres are in the periphery what does this mean? the closer they are to the fovea?

Answer 34

further out means more superficial, closer to vitreous

closer in means more deep, closer to ganglion cells.

Question 35

optic nerve is surrounded by what?

Answer 35

3 meninges (dura, arachnoid and pia, part of CNS).

Question 36

at the optic disk (blind spot), are there cells present?

Answer 36

NO and NO plexiform layers. millions of axons from ganglion cells present going through lamina cribosa.

Question 37

what is the physiological cup?

Answer 37

indentation region at very center of optic disk.

Question 38

the optic nerve head (disk) is elongated vertically, what are the dimensions? disk lacks all layers except for? what color is it?

Answer 38

vertical 1.9mm x 1.7mm horizontally
fibres and ILM
pale due to no RPE, lamina cribosa also has holes giving it a lighter color, capillaries give it a pinkish color

Question 39

outer layers of retina supplied by? inner? once central retinal artery enters the optic nerve what happens?

Answer 39

choroidal capillaries
central retinal artery
it branches into superior and inferior branches and gives rise to two sets of capillaries 1. superficial (ganglion cell layer) 2. deep (at junction between INL and OPL).

Question 40

the plexiform and photoreceptors are nourished by what circulation?

Answer 40

outer supply (choroidal) NOT inner.

Question 41

blood supply to the optic nerve comes from what four sources?

Answer 41

1. branches from central retinal artery
2. branches from circle of zinn (anastomoses between short ciliary arteries and pial arteries)
3. choroidal branches
4. pial branches (go directly to pia).

Question 42

meinigitis, infection of the meninges normally occurs at what level?

Answer 42

arachnoid