ICL 2.3: Overview of the Human Brain Flashcards

Question

what are commissures? what are the two commissures of the brain?

Answer 1

1. corpus callosum 2. anterior commissure commissures are points of connection between the right and left hemispheres so that they can communicate

Answer 2

a commissure of the brain that's a large bundle of axons connecting left and right cerebral hemispheres when tumors metastasize from one side of the brain to the other it's because they use the corpus callosum to get there a thin corpus callosum indicates white matter atrophy or degeneration of myelin side note: on a coronal section you will only see the corpus callosum once but in the sagittal section you'll see the whole curve

Answer 3

a small bundle of axons that passes between the two cerebral hemispheres joining the grey matter of the anterior poles of the temporal lobes

Answer 4

a collection of myelinated fibers it has 3 subdivisions and unique fibers travel through each division each with their own function it is bordered by the caudate nucleus, globus pallidus, thalamus, and putamen go look at the picture

Answer 5

caudate nucleus + putamen + globus pallidus it helps you execute smooth rhythmic movement ex. Huntington's is a disease of the basal ganglia and so they have lots of movement problems

Answer 6

1. anterior limb 2. genu 3. posterior limb only in an axial image would you be able to see all 3 of these

Answer 7

corticobulbar fibers these are involved in motor function

Answer 8

corticospinal fibers involved in motor supply

Answer 9

fancy word for the thalamus + hypothalamus

Answer 10

diaphragma sellae

Answer 11

the hypothalamus so the hypothalamus is super close to the pituitary gland, it's only seperated by the pituitary streak this means the hypothalamus is in close proximity to the sellea turcica

Answer 12

the thalamus ALL information that comes from the outside world has to stop at the thalamus and then the thalamus sends it out to the right area of the brain to be processed so basically the thalamus is a relay station and it has specific nuclei that will route information to specific areas of the brain

Answer 13

hypothalamic sulcus

Answer 14

1. midbrain 2. pons 3. medula

Answer 15

2 lateral ventricles 3rd ventricle 4th ventricle note: the lateral ventricle is found in every aspect of the brain; the frontal, temporal and occipital horn!

Answer 16

CSF flows through the ventricles! it flows from the ventricles of the brain to the subarachnoid space in the spinal cord lateral ventricle --> 3rd ventricle --> 4th ventricle --> subarachnoid space CSF leaves 4th ventricle via foramen of magendie (caudal end) & foramina of Luschka (lateral angles of ventricle) to enter subarachnoid space

Answer 17

interventricular formamen

Answer 18

cerebral aqueduct

Answer 19

the choroid plexus this produces CSF

Answer 20

septum pellucidum

Answer 21

the tentorium cerebelli is the dura matter that separates the cerebellum from the occipital lobe if there's an infratutorial tumor below the tentorium cerebelli it's putting pressure on the ventricles; specifically the cerebral aqueduct --> most pediatric brain tumors are infratutorial while most adult ones are supratutorial the problem is that just because there's a tumor doesn't mean that the brain will stop making CSF so the 3rd ventricle will probably get huge since the tumor is compressing on the cerebral aqueduct and not allowing it to drain so what happens is the brain tissue starts to compressed against the skull and get damaged... the take-home message is that if you have a block at either connection between the ventricles you will end up with serious problems

Answer 22

the cerebral cortex is the grey matter of the brain and it's organized into 6 layers all the layers communicate with each other layer 3 and 5 are the important ones

Answer 23

cortical-cortical connections aka commissural and association fibers so layer 3 is important for developing connections so that different parts of the brain can communicate with each other

Answer 24

it sends output to subcortical structures like the pons, brainstem, basal ganglia, and spinal cord so it's what helps form pathway like the corticospinal pathway and corticobulbar pathway it's composed of long projection fibers out of the cerebral cortex the neurons in the cortex of the brain are considered UPPER motor neurons

Answer 25

1. motor cortex (M1) | 2. premotor cortex (M2)

Answer 26

part of the frontal lobe that evokes movement of individual muscles, and is arranged in a somatotopic fashion (homunculus) most axons of the Pyramidal tract originate here.

Answer 27

part of the frontal lobe that evokes mass movements involving postural adjustments both ipsilaterally and contralaterally most extrapyramidal pathways originate in the premotor cortex lesions in this area result in spasticity of contralateral antigravity muscles due to the loss of inhibition provided by upper motor neurons in this area

Answer 28

M1 in the frontal lobe --> posterior limb of the internal capsule --> midbrain --> pons --> mid medulla --> caudal medulla once the signal reaches the caudal medulla, the fibers cross over before ending the spinal cord so if you had an upper motor neuron lesion in the cortex of the brain, your symptoms and muscle weakness would be on the contralateral side of the body!! if in turn, you had a lower motor neuron lesion in the ventral horn of the spinal cord, your deficits would be ipsilateral

Answer 29

1. projection 2. association 3. commissural the white matter in the brain consists of large numbers of myelinated axons (fibers) carrying electrical signals between areas of within the brain and between the brain and the rest of the body --> functionally, there are three major types of white matter fibers in the CNS: Projection Fibers, Association Fibers, and Commissural Fibers

Answer 30

project OUTSIDE of cortex – to the thalamus or basal ganglia or brainstem or spinal cord

Answer 31

send axons to another cortical region in the SAME hemisphere

Answer 32

send axons to cortical regions in the OPPOSITE hemisphere

Answer 33

association fibers connect different parts of the same cerebral hemisphere for example, Broca's area and Wernicke's area connected by the arcuate fasciculus which is a type of association fiber because of this connection patients with lesions in either Broca's or Wernicke's area will have impaired repetition = conduction aphasia damage to the arcuate fasciculus impairs the transmission of information between Wernicke’s area and Broca’s area; this injury leads to impaired repetition thus, the patient can comprehend the speech but cannot transmit the information the speech production centers in Broca's area to allow repetition to occur

Answer 34

NO glial cells are supporting cells

Answer 35

part of the CNS 1. structural support 2. transport of substances from blood to neurons 3. react to injury most brain tumors are astrocytomas

Answer 36

part of the CNS 1. they form the myelin sheaths around axons in the CNS -- multiple axons per oligodendrocyte this means that the loss of just one oligodendrocyte is a big deal because that means no myelin for 50-100 axons 2. provide nutritive functions in gray matter

Answer 37

1. immune function; basically a macrophage -- have lots of lysosomes, inclusions and vesicles that release damaging and neuroprotective chemicals 3. react to injury they're small, elongated nuclei with twisted processes

Answer 38

part of the CNS they line ventricles they're a single layer of cuboidal-to-short columnar epithelium that line the ventricles of the brain and the central canal of the spinal cord they're bound by junctional complexes on the apical side they also have cilia and microvilli that facilitate the movement and absorption of the CSF

Answer 39

part of the PNS they have support functions similar to astrocytes

Answer 40

the cells in the PNS that form myelin around the axons on the pNS

Answer 41

you could end up with severe astrogliosis normally the astrocyte cell body is flat which means there's nothing going on but when they're activated by injury they start to plump up if there's a ton of damage to axons like with a patient who has MS and there's a lot of myelin degeneration around the axon, the astrocytes will occupy the empty space left behind by the myelin and this is how you end up with a glial scar in the brain tissue

Answer 42

the tissue will be composed of round cells with blue nuclei and a rim of clear cytoplasm so the oligodendrocytes look like they're surrounded by cytoplasm and they usually aren't...