Forebrain, third ventricle & related structures & cortex

Question 1

what are the major functional regions in the cerebral cortex?

Answer 1

-frontal lobe
-parietal lobe
-temporal lobe
-occipital lobe

Question 2

what does the frontal lobe contain?

Answer 2

-motor cortex - controls voluntary mvt of the skeletal muscles
-prefrontal cortex - responsible for higher cognitive functions eg planning, decision making etc

Question 3

what does the parietal lobe contain?

Answer 3

-somatosensory cortex - receives and processes sensory info from the skin, muscles and joints enabling the perception of touch, temp & pain

Question 4

what does the temporal lobe contain?

Answer 4

-auditory cortex - processes auditory information
-wernickes area - language comprehension & understanding

Question 5

what important functions does the occipital lobe have?

Answer 5

-contains the visual cortex - processes visual info from the eyes
-contains visual association areas

Question 6

what are the 3 different types of fibres in the brain?

Answer 6

-association
-projection
-commisural

Question 7

what are association fibres?

Answer 7

fibres which connect different areas within the same cerebral hemispheres
-eg the cingulum (white matter tract)

Question 8

what are commissural fibres & give an example?

Answer 8

fibres that connect corresponding areas of the cerebral cortex in different hemispheres
eg the corpus callosum

Question 9

what is a a projection fibre & give an example?

Answer 9

-fibres that connect the connect the cerebral cortex with lower brain regions such as the brain stem and spinal cord
eg the corticospinal tract

Question 10

where is brocas area located & what is its function?

Answer 10

-located in the frontal lobe in the dominant hemisphere (which is typically the left hemisphere in RH individuals)
-associated with language production & speech articulation

Question 11

what can happen as a result of damage to brocas area?

Answer 11

-brocas aphasia - difficulty in forming grammatically correct sentences
-patient is aware of the problem
-comprehension/ understanding of words is still intact

Question 12

what wernicke’s area - where is it located, function?

Answer 12

-located in the temporal lobe
-situated in the dominant hemisphere
-interpret & comprehend spoken and written language
-processes incoming auditory info and assigns meaning to words & sentences

Question 13

what can happen as a result of damage to wernickes area?

Answer 13

wernickes aphasia - fluent speech but impaired comprehension of language and difficulty in selecting appropriate words
-patient is not aware of the problem

Question 14

what is the ventricular system in the brain?

Answer 14

• a set of communicating cavities within the brain
  -these structures are responsible for production & removal of CSF

Question 15

what are the ventricles of the brain?

Answer 15

-lateral ventricles
-third ventricle
-4th ventricle

Question 16

describe the anatomy of the lateral ventricles

Answer 16

-right & left lateral ventricles
-they have horns - anterior and posterior horns
-body

Question 17

how are the lateral ventricles connected to the third ventricle?

Answer 17

interventricular foramen (of Monro)

Question 18

how is the third ventricle connected to the 4th ventricle?

Answer 18

via the cerebral aqueduct

Question 19

what cells line the lateral ventricles?

Answer 19

ependymal cells which form a structure called the choroid plexus in the lateral ventricles which produces CSF

Question 20

what structures allow the fluid to drain the CSF into the dural venous sinuses?

Answer 20

the arachnoid granulations

Question 21

describe the flow of cerebral spinal fluid CSF through the ventricular system of the brain

Answer 21

-CSF is produced by the choroid plexus within the lateral ventricles
-from the lateral ventricles, CSF flows through the intraventricular foramen into the 3rd ventricle
-from the 3rd ventricle, CSF flows through the cerebral aqueduct into the 4th ventricle
-CSF flows from the 4th ventricle into the median aperture or the lateral apertures into the subarachnoid space

Question 22

once the CSF goes into the subarachnoid space, where does it flow to next?

Answer 22

-CSF circulates within the subarachnoid space and is eventually reabsorbed into the blood stream via specialised arachnoid granulations which are located in the dural venous sinuses

Question 23

what is hydrocephalus?

Answer 23

abnormal condition caused by build up/ accumulation of CSF in the ventricles of the brain

Question 24

where is the 3rd ventricle located?

Answer 24

-midline of the brain, situated between the 2 halves of the thalamus

Question 25

what structures are closely related to the 3rd ventricle?

Answer 25

-thalamus
-hypothalamus
-pineal gland / epithalamus
-optic chiasm
-infundibulum (stalk of pituitary gland)

Question 26

what important hormone does the pineal gland secrete?

Answer 26

melatonin

Question 27

what is the important function of the thalamus?

Answer 27

-it serves as a relay station for sensory signals travelling to the cerebral cortex

Question 28

what are important parts of the thalamus located posteriorly?

Answer 28

-lateral geniculate body - visual info
-medial geniculate body - auditory relay

Question 29

what are the major somatosensory pathways in the brain?

Answer 29

-dorsal column and spinothalamic tract

Question 30

briefly describe the DCML pathway (dorsal column medial lemniscal pathway)

Answer 30

-sensations eg tactile, fine touch, vibration transmitted through this pathway
-3 orders of neurons
-1 neuron located in dorsal root ganglia
-2 order neurons located in the medulla
-3rd order neurons located in the thalamus

Question 31

briefly describe the spinothalamic tract

Answer 31

-pathway carries sensations of pain, temp, pressure
-3 order neurons
-1 order - dorsal root ganglia
-2 order - dorsal horn of cord
-3rd order in thalamus

Question 32

in terms of decussication, what is the difference between the DCML pathway vs spinothalamic tract?

Answer 32

-DCML - decussates in the medulla
-spinothalamic tract - decussates immediately