Unit 1: Neuroanatomy pgs 1-16 Flashcards
a collection of neuron cell bodies
Grey matter
a cluster of neuron cell bodies that are morphologically distinct from other neurons (grey matter)
Nucleus
“layer” or “band” of gray matter= nuclei
Lamina
nuclei, collection of neuronal cell bodies (grey matter)
Bodies
gray matter located on the outer surface
Cortex
an aggregation of neuronal processes/axons/ fibers
White matter
a collection of neuronal fibers/axons that are anatomically or functionally distinct (white matter)
Tract
“bundle” of axons (white matter)
fasciculus
“ribbon” or “band” of axons (grey matter)
lemniscus
“column” or “cord” of white matter
Funiculars
fibers/axons that are traveling rostrally
ascending
fibers/axons that are traveling causally
Descending
The part of the brain that connects the spinal cord to the cerebrum and cerebellum.
Brain stem
Three divisions of the brain stem
Medulla
Pons
Midbrain
gray matter areas of the medulla
Inferior Olivary Nuclei
cranial nerve nuclei
paired nuclear complex (L, R) that forms landmarks on ventrolateral surface
Inferior Olivary Nuclei aka olives
clusters of neurons that contribute fibers to or receive fibers from a cranial nerve.
Cranial nerve nuclei
Cranial nerve nuclei found in the grey matter of the medulla
XII - hypoglossal XI - spinal accessory X - vagus IX - glossopharyngeal VIII - vetibulocochlear (part of complex) V - trigeminal (part of complex)
white matter areas of the medulla
- ascending and descending fiber tracts (ex: pyramids)
- inferior cerebellar peduncles
paired (L, R) landmark structures on ventral surface of medulla comprised of descending corticospinal fibers/axons
Pyramids
paired structures on the dorsal surface of the medulla that help attach the cerebellum to the medulla and consists mostly of axons going to and from the cerebellum
Inferior cerebellar peduncles
Grey areas of dorsal pons include which cranial nerve nuclei
VIII - vestibulocochlear (part of complex)
VII - facial
VI - abducens
V - trigeminal (part of complex)
White matter areas of the dorsal pons
Middle cerebellar peduncles (MCPs)
paired structures (R + L) of the dorsal pons that contain fibers mainly traveling to cerebellum
Middle cerebellar peduncles (MCPs)
What part of the pons includes white and gray matter areas
Ventral pons
collection of neuron cell bodies in the ventral pons that receive input from neurons of the (ipsilateral) cerebral cortex and project axons to the contralateral side of the cerebellum to form the middle cerebellar peduncle that connects the pons to the cerebellum
Pontine nuclei
What part of the brain stem includes part of the brain ventricular system? Which part of the ventricular system?
Midbrain: the cerebral aqueduct (of Sylvius) divides the midbrain into two portions: ventral & dorsal midbrain
What part of the midbrain is formed by a pair of cerebral peduncles - which include white and gray matter?
ventral midbrain or base of the midbrain
gray matter of the ventral midbrain includes which cranial nerve nuclei:
CN III - oculomotor nerve
CN IV - trochlear nerve
CN V - trigeminal nerve (part of complex)
What part of the midbrain is also known as the tectum?
Dorsal midbrain
The dorsal midbrain includes:
- 2 pairs of nuclei, the superior and inferior colliculi
The midbrain is divided into:
Ventral midbrain
Dorsal midbrain
Superior cerebellar peduncles
Neurons of the superior colliculi are concerned with what kind of reflexes?
coordinating certain reflexes in response to visual and auditory information
neurons of the inferior colliculi are involved in?
conscious auditory pathway
What white matter structures connect cerebellum to the midbrain and cerebrum?
superior cerebellar peduncles
Where is most of the grey matter distributed in the cerebellum? Where is some grey matter also found?
- on the outer surface forming the cerebellar cortex
- embedded in the medullary center as grey matter nuclei
The leaf-like folds of the cortical surface of the cerebellum are called what?
folia
The white matter that forms the center of the cerebellum is called what?
medullary center
Functional features of the cerebellum include:
- receives input from most sensory systems and cerebral cortex
- influences activity (posture, equilibrium, coordination) of the skeletal muscle
Is cerebellar control of motor activity conscious or unconscious?
largely unconscious
What 3 paired structures connect the cerebellum to the brainstem?
inferior cerebellar peduncles
middle cerebellar peduncles
superior cerebellar peduncles
What are the two major parts of the cerebrum?
diencephalon
telencephalon
The two halves of the diencephalon are separated by what structure?
3rd ventricle
What forms the core of the cerebrum?
diencephalon
The diencephalon is mostly white or grey matter?
mostly grey with some white
What are the parts of the diencephalon?
thalamus
epithalamus
subthalamus
hypothalamus
What is the structure that is composed of a collection of neurons/nuclei that relay most sensory information to the cerebral cortex? What is another function of this structure?
- thalamus
- involved in motor pathways
What is the principle autonomic center of the brain that helps control the sympathetic and parasympathetic nervous system?
hypothalamus
What structure of the diencephalon helps control the activity of the pituitary gland?
hypothalamus
What structure of the diencephalon includes the pineal gland?
epithalamus
Where is the epithalamus located relative to the thalamus?
dorsal medially
Where is the sub thalamus located relative to the thalamus and hypothalamus?
inferior to the thalamus and posterior to the hypothalamus
What is the sub thalamic nucleus involved in?
motor pathways
What divides the left and right hemispheres of the telencephalon?
longitudinal cerebral fissure
The grey matter of the telencephalon is organized into which areas?
- cerebral cortex
- corpus striatum
The nuclei (grey matter) located deep within the cerebral hemispheres that are important in motor control function are called what?
corpus striatum
White matter of the cerebrum is organized how?
as the medullary center
What are the three types of fibers that comprise the medullary center?
- association fibers
- commissural fibers
- projection fibers
Fibers/axons that connect a cortical area of one cerebral hemisphere to a similar cortical area of the opposite hemisphere?
commissural fibers
When commissural fibers cross from one hemisphere to another, they ______.
decussate
Fibers/axons that connect different cortical areas within a single cerebral hemisphere?
association fibers
Fibers/axons that connect an area of the cerebral cortex to a subcortical area or subcortical area to a cerebral cortical area?
projection fibers
Corpus callosum is an example of what type of fibers found in the cerebrum?
commissural fibers
The fibers that connect the thalamus to the cerebral cortex (thalamo-cortico fibers) are an example of what type of fibers found in the cerebrum?
projection fibers
Many of the projection fibers converge to form a compact zone of axons called______ that is positioned deep in each cerebral hemisphere
the internal capsule
The surface of the cerebral hemispheres is highly convoluted forming a series of folds called ______
gyri (gyrus = ring or circle)
The grooves or furrows that intervene between adjacent gyri are called ______.
sulci
The five anatomical lobes of each cerebral hemisphere?
(1) frontal lobe
(2) parietal lobe
(3) temporal lobe
(4) occipital lobe
(5) insula or Island of Reil
What is the series of fluid-filled spaces within the brain? What is it derived from?
- ventricular system
- derived from the neural canal of the embryonic neural tube
What lines the ventricular system?
Ependymal cells
The structure in the ventricular system that secretes cerebrospinal fluid (CSF) that fills the ventricular spaces
Choroid plexus
CSF circulates out of the ventricles into what space?
Arachnoid space around the brain and spinal cord
What is the total volume of CSF?
80-150 mL
CSF is constantly produced (and resorbed) at a rate up to ________.
450 mL per day
Most CSF is resorbed at the arachnoid villi into what structure?
the superior sagittal venous sinus
Functions of CSF include:
- cushioning the brain against traumatic impact
- circulation of nutrients
- waste removal
Paired chambers of the ventricular system within each cerebral hemisphere?
Lateral ventricles
Unpaired space of the ventricular system that is located between the two halves of the diencephalon?
3rd ventricle
Paired structures that connect anterior horn of each lateral to the III ventricle?
interventricular foramina (of Monro)
Ventricular canal that resides within the midbrain, dividing it into two parts, and connects the III ventricle to the IV ventricle?
cerebral aqueduct (of Sylvius)
unpaired chamber of the ventricular system that the cerebellum forms the ‘roof’, the pons and medulla form the ‘floor’?
4th ventricle
The floor of the IV ventricle is also called?
Rhomboid fossa
What are the paired structure of the ventricular system that connect the 4th ventricle to the subarachnoid space?
lateral apertures = foramina of Luschka
What is the unpaired structure of the ventricular system that connects the 4th ventricle to the subarachnoid space via the cisterna magna?
median aperture = foramen of Magendie
What is another name for the cisterna magna?
Cerebellomedullary cistern (named for its location at the junction fo the cerebellum and the medulla)
What is the circulation of CSF
(Produced by choroid plexus) lateral ventricles → interventricular foramina of Monro→III ventricle→ cerebral aqueduct of Sylvius→ IV ventricle→ foramina of Luschka/lateral apertures and foramen of Magendie/median aperture → cisterna magna → subarachnoid space → resorption by arachnoid villi →superior sagittal venous sinus
Excess CSF resulting in increased CSF pressure is called?
Hydrocephalus
What are some potential causes of hydrocephalus?
Excess secretion
Blockage
Poor resorption
(Can be congenital or acquired)
Blockage of CSF out of the ventricles is called what? What would occur in the other ventricles if there was a blockage?
- Non-communicating (obstructive) hydrocephalus
- excess CSF would accumulated upstream of the blockage
What is excess CSF throughout entire ventricular system called?
Communicating hydrocephalus
What is an abnormal increase in CSF that causes the ventricles to enlarge called? What is the cause?
- normal pressure hydrocephalus (NPH):
- often idiopathic
What sort of clinical symptoms might occur with hydrocephalus?
-mechanical damage to tissues, resulting in
neurological deficits
-HAs
-papilledema
What is papilledema?
edema of the optic disc where the optic nerve
connects
What is the nucleus involved in motor control that lies along the lateral ventricle?
Caudate nucleus
Where, relative to the lateral ventricle, is the head of the caudate nucleus found?
in the lateral wall of the anterior horn of the lateral ventricle
Where, relative to the lateral ventricle, is the body of the caudate nucleus found?
in lateral wall of the body of the lateral ventricle?
Where, relative to the lateral ventricle, is the tailed of the caudate nucleus found?
in the ‘roof’ of the inferior horn of the lateral ventricle
Nuclear complex of the limbic system that is positioned just beyond the tip of the inferior horn of lateral ventricle and anterior to hippocampus?
Amygdala
What is the gray matter structure of the limbic system that is involved in processing memory and emotions?
Hippocampus
Where is the hippocampus located relative to the ventricular system?
lies along the ‘floor’ of the inferior horn of the lateral ventricle
What is the major tract of fibers that originates from the hippocampus and projects largely to the diencephalon (hypothalamus)?
Fornix
What are the series of nuclei (gray matter) positioned deep in each hemisphere that are involved in motor control?
Corpus striatum
What is the medial portion of the lentiform/lenticular nucleus called?
Globus pallidus (pallidum)
What is the lateral portion of the lentiform/lenticular nucleus called?
Putamen
The anterior limb of the internal capsule separates what two structures?
Head of the caudate nucleus from the lenticular nucleus
The posterior limb of the internal capsule separates what structures?
lenticular nucleus and the thalamus
The internal capsule is comprised of what kind of fibers?
Projection fibers
Damage to the internal capsule would result in what?
Sensory and/or motor deficits
What is the thin structure that separates the anterior horns of the left and right lateral ventricles?
Septum pellucidum
What is the gray matter structure that physically connects the left and right halves of the thalamus but is not always present?
interthalamic adhesion = aka “massa intermedia”
What is the bulge of the spinal cord that accommodates for innervation of the upper extremities via the brachial plexus? What vertebral level is it located between?
Cervical enlargement between C4-T1
What is the bulge of the spinal cord that accommodates for innervation of the lower extremities? What vertebral level is it located between?
Lumbosacral enlargement between L2-S3
What happens to the diameter of the spinal cord through the thoracic region?
It narrows
The collection of lumbosacral roots in the lower part of the subarachnoid space?
Cauda equine
The part of the spinal cord that is at vertebral level: L1-L2 and tapers into filum terminale
Conus medullary
Is the ventral median (V-M) fissure continuous or discontinuous along the spinal cord?
Continuous
Is the dorsal median (D-M) sulcus continuous or discontinuous along the spinal cord?
Continuous
Are the ventral lateral (V-L) sulci continuous or discontinuous along the spinal cord?
Continuous
The zone of ventral rootlets of spinal nerves is located along what spinal cord landmark?
Ventral lateral sulci
Are the dorsal lateral (D-L) sulci continuous or discontinuous along the spinal cord?
Continuous
The zone of dorsal rootlets of spinal nerves is located along what spinal cord landmark?
Dorsal lateral sulci
Are the dorsal intermediate (D-I) sulci continuous or discontinuous along the spinal cord?
Discontinuous, present at T6 and above only
How is the white matter of the spinal cord distributed relative to the grey matter?
It is distributed peripherally, surrounding the gray matter
What are the three divisions of white matter areas in the spinal cord?
- Posterior/dorsal funiculi
- Lateral funiculi
- Anterior/ventral funiculi
What paired anatomical divisions of the spinal cord are bordered by the dorsal median sulcus and dorsal lateral sulcus and composed mainly of ascending fibers?
Posterior/dorsal funiculi
The lateral funiculi are composed of ascending fibers, descending fibers or both?
Both
The anterior/ventral funiculi are composed of ascending fibers, descending fibers or both?
Both
The posterior/dorsal funiculi are composed of ascending fibers, descending fibers or both?
Primary ascending fibers
A ‘bundle’ of fibers that have a similar origin, course, termination or function is called?
Fasciculus
What is the function of ascending or sensory pathways of fasciculi?
To carry information to the higher centers of the CNS
What is the function of descending or motor pathways in fasciculi?
To help mediate motor activity
What is another name for the dorsolateral tract of the spinal cord?
Lissauer’s tract
Is Lissauer’s tract continuous or discontinuous through the spinal cord?
Continuous
Where is Lissauer’s tract located?
At the dorsal lateral sulcus
What kind of fibers are found in Lissauer’s tract?
ascending and descending fibers that travel short distances along the cord
Is fasciculus gracilis continuous or discontinuous in the spinal cord?
Continuous
What kind of fibers are found in fasciculus gracilis?
Primarily ascending
What kind of fibers are found in fasciculus cuneatus?
Mainly ascending
What kind of fibers are found in spinothalamic tract?
Mainly ascending
Is the fasciculus cuneatus continuous or discontinuous in the spinal cord?
Discontinuous, only presentation T6 or above when the dorsal intermediate sulcus appears
Is the spinothalamic tract continuous or discontinuous in the spinal cord?
Continuous
Where is the spinothalamic tract located?
located in the anterolateral part of the white matter
What kind of fibers are found in the anterior white commissure of the spinal cord?
mostly decussating (crossing) fibers that contribute to the spinothalamic tract
What portion of the spinal cord grey matter contains primarily sensory neurons?
Posterior/dorsal horns
What portion of the spinal cord grey matter contains primarily motor neurons?
Anterior/ventral horns
What portion of the spinal cord gray matter extends from one side, across midline, to the opposite side and includes sensory neurons and inter neurons?
Intermediate zone
What portion of the spinal cord grey matter is comprised of preganglionic sympathetic neurons?
Lateral horns
Where are the lateral horns of the spinal cord grey matter located?
In the lateral part of the intermediate zone, primarily within T1 to L2-3 cord segments
What are the features of lumbar/sacral cord segments?
Volume of grey matter is high
Volume of white matter is low
What are the features of the thoracic cord levels?
Volume of grey matter is low
Volume of white matter is intermediate
What are the features of the cervical cord segments?
Volume of grey matter is high
Volume of white matter is very high
The small neurons that make local synaptic connections and communicate over short distances?
Interneurons
What are the longitudinal columns of neurons along the spinal cord?
Laminae of Rexed
Thin layer of grey matter located at tip of dorsal horn that receives dorsal root fibers and projects some axons to contralateral spinothalamic tract?
Lamina I
What is another name for lamina II?
substantia gelatinosa
Layer of grey matter in the dorsal horn that receives dorsal root fibers and descending fibers and contains interneurons for modification of nociception pathways?
Lamina II
The layer of grey matter found in the dorsal horn that contains the majority of interneurons?
Lamina III
Layer of grey matter in the dorsal horns that receives input from dorsal root fibers and contains tract cells (neurons) that contribute fibers to the contralateral spinothalamic tract?
Lamina IV
Layers of grey matter at the base of the dorsal horn that receives dorsal root fibers, input from descending fibers and includes tract cells that contribute to the contralateral spinothalamic tract?
Laminae V and VI
Layer of grey matter in the intermediate zone and part of the ventral horn that is composed of 4 nuclear columns?
Lamina VII
What are the 4 nuclear cell columns included in lamina VII?
- intermediolateral nucleus
- nucleus dorsalis
- sacral autonomic nucleus
- intermediomedial nucleus
The nuclear cell column of lamina VII that is located in the lateral horn of cord segments T1-L2/3 and contains pre ganglionic sympathetic neurons?
Intermediolateral nucleus (IML)
The nuclear cell column of lamina VII that is found at cord segments C8-L3 and whose axons form the dorsal spinocerebellar tract?
Nucleus dorsalis aka Clarke’s nucleus
The nuclear cell column of lamina VII that is present at cord segments S2-S4 and contains preganglionic parasympathic neurons?
Sacral autonomic nucleus
Layer of grey matter located medially in the ventral horn that receives input from descending fibers and projects axons to laminae VII and IX?
Lamina VIII
Layer of grey matter with multiple neuron columns embedded in laminae VII or VIII in the ventral horn, some of which function as interneurons but most are motor neurons?
Lamina IX
Axons of the neurons of lamina IX exit the cord via what? What do they innervates?
Exit via the ventral roots of spinal nerves and innervate skeletal muscle cells
In general, lamina IX cell columns positioned more
medially innervate what?
Muscles of the trunk
In general, lamina IX cell columns positioned more laterally innervate what?
Extremity muscles
What special motor nuclei of lamina IX are in cord segments C3,4,5 and function to innervate the diaphragm?
Phrenic nucleus
What special motor nuclei of lamina IX is found in cord segment C1-5, have axons that form spinal root of CN XI and function to provide motor innervation to SCM and trapezius?
(spinal) accessory nucleus
The area of gray commissure in the spinal cord that is composed mostly interneurons?
Lamina X