Gross Brain, Brainstem and Spinal Cord

Question 1

Gray matter

Answer 1

Areas containing neuronal/glial cell bodies and dendrites

Question 2

White matter

Answer 2

Areas where there is a collection of axons, many covered with myelin
Fasciculus, funiculus, lemniscus, peduncle and tract are all terms for white matter

Question 3

Frontal lobe areas

Answer 3

Precentral gyrus, and superior, middle and inferior frontal gyri make up the lateral surface of frontal lobe

Question 4

Precentral gyrus houses what and what is their function

Answer 4

Primary motor cortex
Premotor and supplementary motor areas occupy the remainder of the precentral gyrus and portions of frontal gyri
- planning and initiating voluntary movements

Question 5

Brocas area location/brief description of function

Answer 5

Opercular and triangular parts of inferior frontal gyrus (only in one hemisphere, usually left)
-important in motor aspects of written/spoken language

Question 6

Prefrontal cortex location and brief description of function

Answer 6

Occupies the rest of frontal lobe

-Involved with executive functions, personality, decision making, insight and foresight

Question 7

Parietal lobe areas/functions

Answer 7

Postcentral gyrus- corresponds to primary somatosensory cortex; contrals w/processing of tactile and proprioceptive information, sensory localization
Inferior parietal lobule (one hemisphere, usually left)- involved in language comprehension
Remainder of parietal cortex has aspects in spatial orientation and directing attention

Question 8

Homonculus

Answer 8

A somatotopic map reflecting where somatosensory information enters the brain

Question 9

Temporal lobe areas/functions

Answer 9

Superior, middle and inferior temporal gyri
Inferior surface is made up of broad occipitotemporal (fusiform) gyrus
Superior surface, continuing as a small area of the superior gyrus, is the primary auditory cortex
Wernicke’s area is located on the posterior portion of the superior temporal gyrus (one hemisphere, usually left) is important in comprehension of language
Inferior surface is involved in higher-order processing of visual information
Most medial part is involved in learning and memory
Also includes supramarginal & angular gyri

Question 10

Limbic structures

Answer 10

Mostly composed of the cingulate and parahippocampal gyri
Anterior end of parahippocampal gyrus hooks back on itself forming a medial bump, the uncus
Folded into the temporal lobe at the hippocampal sulcus is the hippocampus
Amygdala lies beneath the uncus of the temporal lobe
Limbic lobe is important in emotional responses, drive related behavior and memory

Question 11

Insula

Answer 11

Additional area of cerebral cortex not included in the five lobes
Lies buried in lateral sulcus
Concealed by portions of frontal, parietal and temporal lobes
Can be seen by prying opening lateral sulcus or by removing opercula of frontal, parietal or temporal lobes
Circular sulcus outlines the insula and marks its borders with the opercular areas of cortex

Question 12

Occipital lobe areas/functions

Answer 12

Lateral surface contains lateral occipital gyri
Cuneus, a wedge shaped area b/w parietooccipital and calcarine sulci
Primary visual cortex is contained in the walls of the calcarine sulcus
Remainder of lobe is the visual association cortex which is involved in higher order processing of visual information

Question 13

Diencephalon

Answer 13

Accounts for only 2% of brain mass but is very important
Includes hypothalamus, epithalamus and subthalamus
Inferior surface of hypothalamus is visible on an intact brain, including the infundibular stalk- two rounded protuberances, mamillary bodies are also visable

Question 14

Basal nuclei

Answer 14

Group of nuclei that lie deep to the cerebral cortex in each hemisphere
Caudate & lenticular nucleus (subdivided into putamen and globus pallidus)
Lenticular nuclei are physically separated from the thalamus and caudate by a thick sheet of fibers, the internal capsule
Internal capsule contains most of the fibers interconnecting the cerebral cortex & thalamus, basal nuclei and brainstem

Question 15

Arcuate fibers

Answer 15

Connect cortical areas within the same sulci/gyri

Question 16

Longitudinal/association fasciculi

Answer 16

Connect cortical areas within the same hemisphere

Question 17

Projection tracts

Answer 17

Connect cortical areas within other body regions

Question 18

Corpus callosum

Answer 18

Interconnects the two cerebral hemispheres, contains somewhere around 250 million axons

Question 19

Anterior commissure

Answer 19

Commissural fibers to/from temporal lobe (especially inferior parts)

Question 20

Brainstem role/areas

Answer 20

Plays major role in cranial nerve function, conveys info to/from forebrain
Midbrain
Pons
Medulla

Question 21

Midbrain

Answer 21

Houses the tectum (latin for roof) of the midbrain
Superior and inferior colliculi, paired bumps posterior to cerebral aqueduct
Paired cerebral peduncles make up most of midbrain

Question 22

Pons

Answer 22

Protruding basal pons & pontine tegmentum forms part of floor of 4th ventricle

Question 23

Medulla

Answer 23

Rostral open portion containing part of 4th ventricle

Caudal closed portion, continuous with SC

Question 24

Cerebellum

Answer 24

Functions in sensory information processing & influences motor neurons
Cerebellar damage results in abnormalities of equilibrium, postural control, and coordination of voluntary movements
Surface is made up of transverse ridges- folia
Prominent fissure divide it into lobes and lobules
White matter in the medullary center, composed of afferent and/or efferent fibers

Question 25

Spinal cord

Answer 25

Anterior vs posterior horns Posterior rootlets enter SC via posterolateral sulcus, a shallow longitudinal groove Anterior rootlets leave SC via anterolateral sulcus Posterior and anterior rootlets--> spinal nerves

Question 26

Posterior horn

Answer 26

Substantia gelatinosa- region of gray matter that caps the posterior horn Body- interneurons and projection neurons that transmit somatic and visceral sensory information Lissauer's tract- white matter located b/w substantia gelatinosa and surface of SC

Question 27

Clarks nucleus (posterior thoracic nucleus)

Answer 27

Cells located on the medial surface of the base of the posterior horn Has a prominent role in sensory processing and typically treated as part of posterior horn

Question 28

Anterior horn

Answer 28

Cell bodies of lower MNs supplying skeletal muscles Cells provide CNS control over body movements (voluntary or involuntary) Influenced by different pathways to modulate movements

Question 29

Intermediate gray matter

Answer 29

Collection of various projection neurons, sensory interneurons and interneurons Preganglionic sympathetic neurons, in the intermediolateral cell column, form the lateral horn (axons leave via ventral roots) Sacral parasympathetic nucleus spans S2-S4 but does not form a distinct lateral horn

Question 30

Lamina I

Answer 30

Marginal zone- is a thin layer of gray matter covering the substantia gelatinosa

Question 31

Lamina II

Answer 31

Is the substantia gelatinosa

Question 32

Lamina III-VI

Answer 32

Are the body of the posterior horn

Question 33

Lamina VII

Answer 33

Corresponds to the intermediate gray matter (including Clarke's nucleus) but also includes extensions into anterior horn

Question 34

Lamina VIII

Answer 34

Comprises some of the interneuron zones of the anterior horn

Question 35

Lamina IX

Answer 35

Consists of the clusters of motor neurons embedded in the anterior horn

Question 36

Lamina X

Answer 36

Is the zone of gray matter surrounding the central canal

Question 37

Marginal zone

Answer 37

All levels Lamina I Some spinothalamic tract cells

Question 38

Substantia gelatinosa

Answer 38

All levels Lamina II Modulate transmission of pain and temperature info

Question 39

Body of posterior horn

Answer 39

All levels Lamina III-VI Sensory processing

Question 40

Clarke's nucleus

Answer 40

T1-L2 Lamina VII Posterior spinocerebellar tract cells

Question 41

Intermediolateral column

Answer 41

T1-L3 Lamina VII Preganglionic sympathetic neurons

Question 42

Sacral promontory nucleus

Answer 42

S2-S4 Lamina VII Preganglionic parasympathetic neurons--> pelvic viscera

Question 43

Accessory nucleus

Answer 43

Medulla-C5 Lamina IX Motor neurons-->sternocleidomastoid and trapezius

Question 44

Phrenic nucleus

Answer 44

C3-C5 Lamina IX Motor neurons-->diaphragm

Question 45

Primary afferents and lower motor neurons

Answer 45

Convey info to/from the CNS Primary afferents terminate in the CNS on second order neurons (with a few exceptions, sensory primary afferents are ipsilateral) Lower motor neurons convey info from CNS to skeletal muscle

Question 46

Second order neurons

Answer 46

Relay a signal from primary afferents in the periphery to a target in the CNS Can cross the midline of the body

Question 47

Third order neurons

Answer 47

Relay the message to final target in a specific cortical area(s) Cortex decides on given output

Question 48

Ascending tracts

Answer 48

Posterior columns- convey ipsilateral proprioceptive, tactile and vibratory information from the body (not face) Spinocerebellar tracts- information relays to cerebellum, thalamus and motor cortex to influence efficiency of motor activity Anterolateral system- relays pain, temperature and nondiscriminative touch from body (not face)

Question 49

Descending tracts

Answer 49

Corticospinal tract- controls voluntary, fine movements of the musculature Vestibulospinal tract- influence motor neurons innervating primarily axial and neck musculature Rubrospinal fibers- excite flexor motor neurons and inhibit extensor motor neurons

Question 50

Retrolenticular limb of internal capsule fed by what artery

Answer 50

Anterior choroidal arteries

Question 51

Posterior limb of internal capsule fed by what artery

Answer 51

Anterior choroidal arteries

Question 52

Anterior limb of internal capsule has what tracts

Answer 52

Frontopontine Anterior thalamic radiations Frontal eye field

Question 53

Genu of internal capsule has what tracts

Answer 53

Corticonuclear

Question 54

Posterior limb of internal capsule has what tracts

Answer 54

``` Corticorubral, cor. reticular, cor. nigral, cor. subthalamic Superior thalamic radiations Corticospinal Parietopontine Pallidothalamic ```

Question 55

Retrorenticular limb of internal capsule has what tracts

Answer 55

Optic radiations Corticotectal Corticorubral Corticotegmental