Neuroanatomy Flashcards
What is the brain stem composed of?
The combination of midbrain, pons and medulla oblongata
What is a neuron?
The “Communicators”. They receive information, chiefly via synapses, integrate the information, and then transmit electrical impulses to another neuron or effector cell.
What is a neuron made up of?
A neuron has three main parts: dendrites, an axon, and a cell body or soma, which can be represented as the branches, roots and trunk of a tree, respectively.
What is the role of astrocytes?
Roles in support, maintaining the blood-brain barrier, environmental homeostasis. Astrocytes are the most numerous cell type within the CNS
What are oligodendrocytes?
Produce myelin in the CNS (NOT IN THE PNS). Myelination of axons allows rapid saltatory conduction of nerve impulses and contributes to axonal integrity.
What are microglia?
Cells of similar lineage to macrophages (i.e., hemopoietic origin). Immune monitoring and antigen presentation.
What are ependymal cells?
Ciliated cuboidal/columnar epithelium that lines the ventricles.
Type of neuronal support cell (neuroglia) that forms the epithelial lining of the ventricles (cavities) in the brain and the central canal of the spinal cord.
What is the grey matter of the brain?
Home to neural cell bodies, axon terminals, dendrites, and nerve synapses. This brain tissue is abundant in the cerebellum, cerebrum, and brain stem. It also forms a butterfly-shaped portion of the central spinal cord.
What is the white matter of the brain?
White matter is found in the deeper tissues of the brain (subcortical). It contains nerve fibres (axons), which are extensions of nerve cells (neurons).
What are the fissures of the brain?
A fissure is a deeper grove and is often used interchangeably with sulcus. Each cerebral hemisphere divides into four separate lobes by a central sulcus, parieto-occipital sulcus, and lateral fissure.
What are the gyrus of the brain?
A gyrus (plural: gyri) is the name given to the bump’s ridges on the cerebral cortex (the outermost layer of the brain).
What are the sulcus of the brain?
A sulcus (plural: sulci) is another name for a groove in the cerebral cortex.
What are the roles of the gyri and sulci?
Each gyrus is surrounded by sulci and together, the gyri and sulci help to increase the surface area of the cerebral cortex and form brain divisions.
Difference between sulcus and fissure?
A fissure separates one lobe from another, while a sulcus is within a lobe and determines the boundaries of the gyri.
What is the lateral ventricle?
The two largest ventricles of the brain and contain cerebrospinal fluid (CSF).
Each cerebral hemisphere contains a lateral ventricle, known as the left or right ventricle, respectively.
What is the thalamus and its role?
The thalamus is composed of different nuclei that each serve a unique role, ranging from relaying sensory and motor signals, as well as regulation of consciousness and alertness.
What is the lentiform nucleus?
The lentiform nucleus is a collective name given to the putamen and globus pallidus, both of which are nuclei in the basal ganglia - As part of the basal ganglia, it carries out complex functions related to movement, cognition, and emotion.
What is the basal ganglia?
A group of subcortical nuclei responsible primarily for motor control, motor learning, executive functions, behaviours, and emotions. Disruption of the basal ganglia network forms the basis for several movement disorders.
Corpus callosum
The primary commissural (joining/junction) region of the brain consisting of white matter tracts that connect the left and right cerebral hemispheres.
Internal capsule
A white matter structure composed of bundles of myelinated fibres that course past the basal ganglia.
It separates the caudate nucleus and thalamus from the lentiform nucleus.
What is the midbrain?
The midbrain serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing.
What are the pons?
Connect the medulla with the cerebellum.
Works together with the medulla oblongata to serve an especially critical role in generating the respiratory rhythm of breathing.
Medulla?
It plays an essential role in passing messages between your spinal cord and brain. It’s also essential for regulating your cardiovascular and respiratory systems.
What is the pineal gland?
the “Seat of the Soul”, and it is located in the center of the brain. Receives information about the state of the light-dark cycle from the environment and convey this information to produce and secrete the hormone melatonin.
Function of the frontal lobe?
The frontal lobes are considered our behaviour and emotional control centre and home to our personality.
Function of the temporal lobe?
The second largest lobe. They are most commonly associated with processing auditory information and with the encoding of memory. Language as well.
o Recognition deficits (agnosias)
Function of the occipital lobe?
Smallest of the four lobes. The occipital lobe is primarily responsible for visual processing. It contains the primary and association visual cortex.
o Visual field defects
Function of the parietal lobe?
Process somatosensory information from the body; this includes touch, pain, temperature, and the sense of limb position. Like the temporal lobes, the parietal lobes are also involved in integrating information from different modalities.
What are the three meninges layers from superficial to deep
Dura mater - outermost layer
Arachnoid mater - middle layer
Pia mater - is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord.
What is the cerebellum?
The cerebellum is important for making postural adjustments in order to maintain balance.
What does the anterior cerebral artery supply?
The anterior cerebral artery (ACA) is one of a pair of cerebral arteries that supplies oxygenated blood to most midline portions of the frontal lobes and superior medial parietal lobes of the brain.
What does the middle cerebral artery supply?
It supplies blood to lateral (side) areas of the frontal, temporal, and parietal lobes.
What does the posterior cerebral artery supply?
Supply the posterior medial parietal lobe, inferior and medial part of the temporal lobe including the hippocampal formation, and the medial and inferior surfaces of the occipital lobe.
What is the spinal cord?
The spinal cord is the caudal continuation of the brainstem. It commences at the foramen magnum and traverses the vertebral foramen to the lower border of the first lumbar vertebra (L1) in an adult
What are the two tracts of the spinal cord called?
the ascending (towards brain) and descending tracts (away from brain) of the spinal cord
What is the end of the spinal cord called and where is it?
As the spinal cord approaches its most inferior limit, it tapers off to form the conus medullaris. At the inferior border of L1, a filamentous extension of the spinal cord known as the filum terminale is continuous caudally, to the point of insertion at the coccyx.
What is present at the lumbar enlargement?
The spinal nerves arborize to form the cauda equina
The spinal cord is divided into a white and grey matter like the brain, what is the grey matter of the spinal cord?
Butterfly-shaped collection of neuronal cell bodies.
It is subdivided into the dorsal (posterior), intermediate (lateral), and ventral (anterior) grey columns (horns).
What is the white matter of the spinal cord and how is it arranged?
Collection of myelinated nerve fibres that travel to and from the brain. Like the grey matter, it can be subdivided into anterior (ventral), posterior (dorsal), and lateral segments called funiculi (s. funiculus).
The dorsal funiculus is unique as it can be divided into two fasiculi; what are they called?
The gracile fasciculus (fasciculus gracilis) and the cuneate fasciculus (fasciculus cuneatus)
How many pairs of spinal nerves are there?
31 pairs
What are the two enlargements of the spinal cord?
Cervical, which is related to the upper limb, and lumbar, which is related to the lower limb.
What is the conus medullaris?
The distal tapering end of the spinal cord at L1 - This structure serves to stabilize the spinal cord by connecting the conus to the coccyx via the coccygeal ligament.
What is the Filum terminale?
The fibrous extension of the cord, the filum terminale, is a nonneural element that extends down to the coccyx.
What are cisterns?
Enlarged pockets of CSF created due to the separation of the arachnoid mater from the pia mater based on the anatomy of the brain and spinal cord surface.
The butterfly shaped grey matter of the spinal cord is divided into 4 sections; what are they?
Left and right posterior (dorsal) horn - sensory
Left and right anterior (ventral) horns - motor
Where is the somatosensory cortex located and what is its role?
Area of the cerebral cortex that receives sensory information from the somatic senses, plus proprioceptive senses, and some visceral senses.
It is located on the postcentral gyrus of the parietal lobe
What is the sensory humunculus?
Topographic representation of the body parts along the postcentral gyrus of the parietal lobe.
What are the ascending tracts?
The neural pathways by which sensory information from the peripheral nerves is transmitted to the cerebral cortex.
Functionally, the ascending tracts can be divided into the type of information they transmit – conscious or unconscious: what are the conscious tracts called?
Conscious tracts – comprised of the dorsal column-medial lemniscal pathway and the anterolateral system.
What is the DCML pathway?
Accending pathway
Conveys sensations of fine touch, vibration, two-point discrimination, and proprioception (position) from the skin and joints - Part of the somatosensory system
The conscious ascending anterolateral tract can be divided into two different spinothalamic tracts; what are they called?
Anterior spinothalamic tract – carries the sensory modalities of crude touch and pressure.
Lateral spinothalamic tract – carries the sensory modalities of pain and temperature.
Functionally, the ascending tracts can be divided into the type of information they transmit – conscious or unconscious: what is the unconscious tract called?
Unconscious tracts – comprised of the spinocerebellar tracts.
What are the 4 spinocerebellar tracts called
Posterior spinocerebellar tract – Carries proprioceptive information from the lower limbs to the ipsilateral cerebellum.
Cuneocerebellar tract – Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.
Anterior spinocerebellar tract – Carries proprioceptive information from the lower limbs. The fibres decussate twice – and so terminate in the ipsilateral cerebellum.
Rostral spinocerebellar tract – Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.
Describe the route of the descending pathway from the brain to the muscles for movement?
Goes from cerebral cortex pyramidal cells to medulla (pyramidal decussation) to form lateral corticospinal and ventral corticospinal tracts, both tracts synapse in the anterior grey horn of spinal cord.
What are the 4 other extrapyramidal systems outside the pyramidal tract?
Vestibulospinal tract - maintain balance
Rubrospinal tract - inhibit extensor and promote flexor, muscle activity.
Reticulospinal tracts - provide regulatory impulses to the spinal reflex centres and voluntary movement.
Tectospinal tract - integrate with the reflex centres to produce the postural movements in response to visual stimuli.
There are 31 pairs of spinal nerves; what are they called?
8 cervical: C1 - C8 12 thoracic: T1-T12 5 lumbar: L1 - L5 5 sacral: S1 - S5 1 coccygeal: Co1
What is segmental innervation?
Each spinal nerve supplies innervation to a unilateral area of the body - results in body wall being ‘segmented’
Dermatome
area of skin supplied with sensory innervation from a single spinal nerve
Myotome
the skeletal muscles supplied with motor innervation from a single spinal nerve
What are the dermatome landmarks of the trunk?
Nipple = T4 segment Umbilicus = T10 segment
Cervical plexus
C1-C4
Posterior scalp, neck, and diaphragm
Brachial plexus
C5-T1
Upper limb
Lumbar plexus
Lumbar plexus : L1-L4
Lower limb
Sacral plexus
L5-S4
Lower limb, gluteal region, and perineum
What is the corticospinal tract?
Remember the corticospinal tract is part of the descending tracts involved in motor movements (4 types of extrapyramidal tracts: vestibulospinal, tectospinal, rubrospinal and reticulospinal tracts).
Describe the structure of the cerebellum?
Consists of two hemispheres which are connected by the vermis, Like other structures in the CNS, the cerebellum consists of grey matter and white matter:
What is the grey matter of the cerebellum and what are the three layers?
The cerebellar cortex is divided into 3 layers:
Molecular layer (outer)
Purkinje cell layer (middle)
Granule cell layer (inner)
What is the tentorium cerebelli?
Tough layer of dura mater that separates cerebellum from occipital and temporal lobes
What are the three lobes of the cerebellum?
the anterior lobe, the posterior lobe and the flocculonodular lobe.
What are the three functional divisions of the cerebellum called?
the cerebrocerebellum, the spinocerebellum and the vestibulocerebellum.
What are the functions of the basal ganglia?
To facilitate purposeful movement
Inhibit unwanted movements.
Role in posture and muscle tone.
What is the basal ganglia?
a group of subcortical nuclei responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviours, and emotions
What are the input nuclei of the basal ganglia?
Caudate nucleus and putamen (neostriatum)
What are the intrinsic nuclei of the basal ganglia?
External globus pallidus
Subthalamic nucleus
Pars compacta of the substantia nigra
What are the output nuclei of the basal ganglia?
Internal globus pallidus
Pars reticulata of the substantia nigra
What is the lenticular nucleus of the basal ganglia?
includes the putamen and globus pallidus.
What is the corpus striatum made up of?
the caudate nucleus, putamen AND globus pallidus.
How many vertebrae is there?
33 o 7 cervical (C1-C7) o 12 thoracic (T1-T12) o 5 lumbar (L1-L5) o 5 sacral (fused to form 1 sacrum) o 4 coccygeal (fused to form 1 coccyx)
What are the functions of the vertebrae?
support head and trunk when upright
protect the spinal cord (& spinal nerves)
allow movements of the head on the neck & movements of the trunk
What is the ligamentum flavum
connect adjacent laminae of vertebrae posterior to spinal cord
supraspinous ligament
connects tips of spinous processes
interspinous ligament
connects superior and inferior surfaces of adjacent spinous processes
C2 dermatome
back of scalp and adam’s apple
C3 dermatome
back of neck and jugular notch
C4 dermatome
clavicle and shoulder tip
C5 dermatome
badge area (arm)
C6 dermatome
thumb
C7 dermatome
middle finger
C8 dermatome
little finger
T1 dermatome
medial forearm
T2 dermatome
medial arm and sternal angle
T8 dermatome
Xyphoid process
L1 dermatome
groin
L2 dermatome
anterior thigh
L3 dermatome
anterior knee
L4 dermatome
medial malleolus
L5 dermatome
dorsum of foot
S1 dermatome
heel
S2 dermatome
posterior knee
S3 dermatome
buttocks
S4 dermatome
perineum
What is another name for the midbrain and what is it made up of?
Also called mesencephalon, region of the developing vertebrate brain that is composed of the tectum and tegmentum
What lobe is most commonly injured in traumatic brain injuries?
Frontal - Largest lobes in the human brain, and they are also the most common region of injury in traumatic brain injury.
What is the largest lobes of the brain
The Frontal lobes
What is the anterior spinothalamic pathway
carries the sensory modalities of crude touch and pressure.
What is the function of the posterior and anterior spinocerebellar tracts?
Posterior spinocerebellar tract – Carries proprioceptive information from the lower limbs to the ipsilateral cerebellum
Anterior spinocerebellar tract – Carries proprioceptive information from the lower limbs. The fibres decussate twice – and so terminate in the ipsilateral cerebellum.
What is the role of the rostral spinocerebellar tract?
– Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.
What is the role of the cuneocerebellar tract?
Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.
What is the role of the medial and lateral vestibulospinal tract?
Vestibulospinal tract - maintain balance
- Medial vestibulospinal - synchronize the head movements with the movement of the eyes
- Lateral vestibulospinal - excites antigravity muscles (extensors)
What does the rubrospinal tract do?
inhibit extensor and promote flexor, muscle activity.
What does the Reticulospinal tract do?
provide regulatory impulses to the spinal reflex centres and voluntary movement.
Prepatory and movement-related activities, postural control, and modulation of some sensory and autonomic functions.
What does the tectospinal tract do?
Integrates with the reflex centres to produce the postural movements in response to visual stimuli
What is the role of the upper optic radiation?
Carries fibres from the superior retinal quadrants (corresponding to the inferior visual field quadrants). It travels through the parietal lobe to reach the visual cortex.
Where does the upper optic radiation travel through to reach the visual cortex?
It travels through the parietal lobe to reach the visual cortex.
What is the role of the Lower optic radiation?
Carries fibres from the inferior retinal quadrants (corresponding to the superior visual field quadrants).
Where does the lower optic radiation travel through to reach the visual cortex?
It travels through the temporal lobe, via a pathway known as Meyers’ loop, to reach the visual cortex.
