NB1-3 - General Morphology and Surface Structures of the CNS and DLAs

Question 1

What are the peaks and valleys of the brain called?

Answer 1

The bumps are called gyri and the valleys are called sulci

Question 2

Answer 2

Question 3

Important note about the parietooccipital sulcus

Answer 3

It’s not a real sulcus. Its an imaginary line drawn from the preoccipital notch to form a boundary for the occipital lobe.

Question 4

Label image and say what the radiographs are highlighting.

Answer 4

The insular lobe

Question 5

Answer 5

E

Question 6

Answer 6

Question 7

On a mid-sagital section of the brain, how do you locate the central sulcus?

Answer 7

You follow the cingulate sulcus to the surface of the brain, the next most rostral sulcus is the central sulcus.

Question 8

Answer 8

Question 9

What is the clinical significance of the calcarine sulcus?

Answer 9

Everything you see below your visual focus is represented above the calcarine sulcus and vice versa.

Question 10

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Question 11

Answer 11

Question 12

List the parts of the corpus callosum and their functions

Answer 12

• Splenium - connects occipital lobes
• Genu - connects frontal lobes
• Body - connects parietal lobes and connects frontal lobes
• Rostrum - connects frontal lobes

Question 13

Answer 13

Question 14

What is the purpose of the septum pellucidum?

Answer 14

To separate the lateral ventricles from one another

Question 15

What is a commissure?

Answer 15

A place where two structures are joined

Question 16

What does the anterior commisure do?

Answer 16

It joins the tips of the temporal lobes and the olfactory bulb

Question 17

What does the posterior commissure do?

Answer 17

It is involved with certain aspects of eye movements and pupilary responses

Question 18

Answer 18

Question 19

What is highlighted in this image?

Answer 19

The fornix

Question 20

Answer 20

Question 21

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Question 22

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Question 23

What is the optic chiasm and where is it located?

Answer 23

It is where the CN2 fibers decussate to form an “X” shape. It is located just inferior and anterior to the hypothalamus.

Question 24

What is the clinical significance of the mamillary bodies?

Answer 24

They appear to have a role in the formation of memories which makes sense since they are very closely related to the hippocampus

Question 25

What is the significance of the interventricular foramen?

Answer 25

It is the passageway through which CSF from the lateral ventricles enter the 3rd ventricle

Question 26

Answer 26

Question 27

What is the function of the massa intermedia?

Answer 27

It is the commissure of the thalamus

Question 28

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Question 29

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Question 30

What does the middle cranial fossa cradle? What will the anterior cranial fossa cradle? Why is this clinicaly significant?

Answer 30

The inferior pole of the temporal lobes The orbital gyri If someone hits their head very hard, these two areas of the brain are most likely to be damaged.

Question 31

What is this a zoomed in image of? What is the arrow pointing to? What is this structure a part of? What is the clinical significance of this structure?

Answer 31

This is the inferior surface of the brain zoomed in on the brain stem. The arrow is pointing to the _uncus which is a part of the parahippocampal gyrus_. In the event of a brain herniation, the uncus can compress CN3 which will cause the eyes to be dilated. Therefore, a simple way to check for brain herniation is to check the pupils of the patient.

Question 32

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Question 33

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Question 34

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Question 35

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Question 36

List the sections of the inferior frontal gyrus and their functions.

Answer 36

* Pars opercularis * Pars triangularis Both of these function in formulating fluid speech * Pars orbitalis (don't need to know function)

Question 37

Answer 37

Question 38

Answer 38

Question 39

What does the inferior parietal lobe consist of?

Answer 39

The supramarginal and angular gyri

Question 40

Answer 40

Question 41

List the Brodman areas we need to know, the areas of the brain they correspond to, and their clinical significance.

Answer 41

Brodman 1,2, & 3 - postcentral gyrus - damage to this causes somatosensory loss Brodman 4 - precentral gyrus - damage to this causes muscle weakness Brodman 17 - occipital lobe - damage to this causes blindness Brodman 44 and 45 - pars opercularis and pars triangularis, respectively - damage to this causes speech problems Brodman 22 - Wernicke's area - damage to this causes language comprehension problems

Question 42

Answer 42

E

Question 43

List the important motor and sensory pathways.

Answer 43

* Corticospinal - motor * Corticobulbar - motor * Vestibulospinal (lateral & medial) - motor * Reticulospinal (lateral & medial) - motor * Rubrospinal - motor * Dorsal Column (medial lemniscus) - sensory * Anterolateral System (spinothalamic tract) - sensory

Question 44

In which region of the brain is the motor homunculus?

Answer 44

The primary motor cortex which is layer 5 (pyramidal cell) of the precentral gyrus

Question 45

Answer 45

Question 46

Describe the origin, route, and end of teh corticospinal tract.

Answer 46

Origin - the primary motor cortex Route - corona radiata \> internal capsule \> crus cerebri \> basilar pons \> pyramids of medulla \> decussation at caudal end of medulla \> lateral corticospinal tract in spinal cord End - the ventral motor nuclei of the spinal cord

Question 47

How do you distinguish a lower motor neuron from an upper motor neuron?

Answer 47

If a neuron synapses directly on a muscle then it is always considered to be a lower motor neuron.

Question 48

What are the mnemonics to remember the cranial nerves and whether they are sensory, motor, or both.

Answer 48

Oh, Oh, Oh, to touch and feel very good velvet. Such Heaven! Olfactory (I), Optic (II), Oculomotor (III), Trochlear (IV), Trigeminal (V), Abducens (VI), Facial (VII), Vestibulocochlear (VIII), Glossopharyngeal (IX), Vagus (X), Spinal Accessory (XI), Hypoglossal (XII) Some say marry money but my brother says big brains matter most s = sensory, m = motor, b = both

Question 49

In general, what does each cranial nerve do?

Answer 49

1. CN I - Olfactory - Sense of smell 2. CN II - Optic - Vision 3. CN III - Oculomotor - superior, inferior, and medial rectus and inferior oblique muscles (elevation, depression, adduction, extortion); levator palpebrae (eyelid retraction), and iris constrictors. 4. CN IV - Trochlear - superior oblique muscles (intortion, depression, abduction) 5. CN V - Trigeminal - Chewing muscles and some facial sensation 6. CN VI - Abucens - lateral rectus muscles (abduct) 7. CN VII - Facial - Facial muscles (including eyelid closure), some salivation, and taste from anterior two-thirds of tongue 8. CN VIII - Vestibulocochlear - senses sound, rotation, and gravity 9. CN IX - Glossopharyngeal - motor to stylopharyngeas and parotid gland, taste from posterior one-third of tongue, and sensory from upper pharynx 10. CN X - Vagus - Motor to swallowing muscles (including one tongue muscles) and nearly all thoracoabdominal viscera up to splenic flexure, some sensation from ear 11. CN XI - Spinal Accessory - Motor to SCM and Trapezius 12. CN XII - Hypoglossal - Motor to tongue

Question 50

Label all of the cranial nerves. Include name and number

Answer 50

Question 51

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Question 52

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Question 53

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Question 54

Describe where the anterior and posterior commisures are located

Answer 54

The AC is located about where the septum pellucidum and hypothalmus touch The PC is located near the most superior part of the tectum