brain: lobes, SC paths, Aa system

Question 1

visual system and tie to brain

Answer 1

optic nn from each eye carry the info of respective side-input from both used to construct image at the occipital lobe
cross over at optic chiasm
damage to nn ahead of chiasm-deficit in vision on that side
damage after that the chiasm- loss of that part of the world, not just vision= hemineglect

Question 2

hemispheres/lobes

Answer 2

L and R hemispheres- comm via corpus collosum

each with 4 lobes: frontal, parietal, occipital, temporal

Question 3

frontal lobe function

Answer 3

motor homunculus here ant to central sulcus
prefrontal cortex
Broca’s area

Question 4

parietal lobe function

Answer 4

sensory homunculus post to the central sulcus

Question 5

temporal lobe function

Answer 5

auditory cortex and assosiation cortex

weirnicke’s area

Question 6

homunculi

Answer 6

4 total: 2 motor and 2 sensory

1 of each on each hemisphere

Question 7

general layout of the homunculi

Answer 7

like upside down person with legs beginning at midline

Question 8

broca’s and wernickies functions, mostly located where?

Answer 8

Broca’s: in the L frontal lobe, responsible for all motor production of language
Wernickie’s: in the L temporal lobe, responsible for the reception and understanding of written and heard language

Question 9

majority of homunculus devoted to?

Answer 9

both motor and sensory have major devotions to our hands (sensation and fine motor control)
also large contributions to the face

Question 10

spinal paths

Answer 10

dorsal column
spinothalamic
corticospinal

Question 11

Pyramidal or Lateral Corticospinal tract

Answer 11

used for voluntary movement
impulse begins in the primary motor cortex= upper motor nn
moves down to cervical SC, signal crosses over at pryamidal dessucation
axon now in the corticospinal tract and down SC
enter the. grey matter at apporiate level and synapse with the Lower motor nn in ventral horn
Lower project axon to periphery to inn mm

Question 12

Posterior Columns or Dorsal Columns

Answer 12

Vibration, Fine Touch and Position
sensation at peripheral processes>signal to cell body in the dorsal root ganglia
projects axon up to the medulla to synapse with secondary sensory nn
secondary sensory nn then projects axon across sensory decussation
axon then goes to the thalamus to synapse with third sensory nn
3rd will project axon to primary somatosensory cortex

Question 13

Anterolateral or Spinothalamic tract

Answer 13

crude Touch, Pain, Temperature
sensation at periphrey sends signal to the cell body in the doral root ganglia
projects axon to synapse with second order nn in dorsal horn
2nd order will project the axon acress the ant commissure and to the contralteral anterolateral pathway
2nd order continues up to the thalamus to synape with 3rd order nn that then projects axon to the somatosensory cortex

Question 14

Aa supply of the head

Answer 14

Int and ext carotid from the common carotid
int doesnt branch until in the skull
ext supplies mostly the face and scalp

Question 15

vertebral aa

Answer 15

will move up the vertebral column into the foramen magnum and merge in the skull to form the basilar aa

Question 16

what structures hitch a ride on the int carotid aa?

Answer 16

sympathetic nn fibers

Question 17

entrance of the int carotid into the skull

Answer 17

enters through the carotid canal and passes over the foramen lacerum
will enter and twist several times before becoming the cerebral portion that join the circle of willis

Question 18

int carotid gives rise to which aa?

Answer 18

mid and ant cerebral aa

Question 19

label the following

Answer 19

Question 20

label

Answer 20

Question 21

ant cerebral supplies

Answer 21

middle aspects of the cerebral cortices

superior aspect of the midline as well

Question 22

middle cerebral supplies

Answer 22

lateral aspects of the brain aside from the extreme superior, anterior, posterior and inferior portions
supplies a majority of the motor and sensory homunculi

Question 23

post cerebral supplies

Answer 23

supplies the posterior aspect

inside temporal lobe and its inferior aspect

Question 24

redundant flow of the circle of willis

Answer 24

can allow for redundancy in the flow despite blockages within the circle
this can prevent the loss of nn due to lack of blood flow

Question 25

hydrocephalus, adult vs baby?

Answer 25

can be due to blockage or stenosis of a foramen in the ventricular system
continued CSF produced despite the blockage=back up of CSF and increased intracranial pressure
babies heads can expand and compensate for this but adults cannot which can lead to deficits

Question 26

aneurysms, treatment

Answer 26

usually occur where vessels converge with one another
weakened vessel walls allow for the increased pressure to cause a berry to form>further increased pressure can lead to rupture of this berry and loss of blood flow, could be a stroke in the brain
treated with clipping/coiling to reduce possibility of rupture if found early