CMD 377 cumulative quiz 1

Neural Tube development

-Endoderm thickens to form the neural plate

-The neural folds create the neural groove. The sides of neural groove are the neural folds

-The folds fuse

-the ectoderm separates from tube

Sensory neuron

-dorsal

-back

-alar plate

Motor neurons

-Ventral

-front

-basal plate

Fourth week vesicles

-prosencephalon

-mesencephalon

-rhombencephalon

Flexures:

-cephalic flexure

-cervical flexure

Fifth week vesicles

-telencephalon

-diencephalon

-mesencephalon

-metencephalon

-myelencephalon

Flexure

-pontine flexure

Congenital malformation of the nervous system

-Craniorachischisis

-Spinal Bifida

-Myelomeningocele

-Arnold-Chiari malformation

-Anencephaly

-Holoprosencephaly

Craniorachischisis

complete failure of the neural tube to close

Spinal Bifida

failure of the caudal neuropore to close

Myelomeningocele

a severe form of spinal bifida, in which the spinal cord and/or nerve roots protrude through the posterior defects

            -often accompanied by an Arnold-Chiari defects

Arnold-Chiari Malformation

the cerebellum and caudal brainstem are elongated and pushed down into the foramen magnum

Anencephaly

failure of the rostral neuropore to close

Holoprosencephaly

partial or complete failure of the prosencephalon to separate into the diencephalon and the paired telencephalon vesicles

Hydrocephalus

-enlarge ventricles of the brain

            -increased production of cerebrospinal fluid

            -decreased absorption of CSF

            -blockage of CSF flow

Shunt procedure reverse the symptoms

CNS (central nervous system)

-nuceli and tracts

-brain and spinal cord

PNS (Peripheral nervous system)

-Ganglia and tracts

-Cranial nerves and spinal nerves

Somatic nerves

enables us to perceive sensory stimuli and carry on volitational motor activity

Autonomic nerves

regulation of internal body function

sympathetic Nervous system

to initiate different responses in a stressful situation

Parasympathetic nervous system

to reinstate the normal internal environment

CN I olfactory

smell

CN II optic

visual

CN III oculomotor

eye movement

CN IV Trochlear

eye movement

CN V Trigeminal

sensory input to the face

CN VI abducens

eye movement

CN VII facial

muscles of facial expression

CN VIII Auditory-vestibular

hearing/ balance

CN IX glossopharyngeal

tongue, pharynx

CN X Vagus

Respiration, heart rate, voice

CN XI Accessory

neck muscle

CN XII Hypoglossal

motor to tongue

Spinal Cord

-consists of ascending and descending tracts

-gray matter in the center

            -dorsal horns: sensory fibers come in

            -ventral horn: motor fibers go out

-white matter outside

Major sulci

-central sulcus

-lateral sulcus

-parietooccipital sulcus

-cingulate sulcus

Major Gyri

-Precentral gyrus

-superior frontal gyri

-middle frontal gyri

-Inferior frontal gyri

major sturctures of the basal ganglia

-caudate nucleus

-lenticular nucleus:

            -globus pallidus

            -putamen

Diencephalon

-Thalamus

-Hypothalamus

-Epithalamus

-subthalamus

Thalamus

acts as a major relay station

Hypothalamus

regulation of emotions

-regulates autonomic nervous system

-vital functions

Epithalamus

Regulating circadian rhythms

Subthalamus

involved in the motor loops

Structures in the midbrain

superior calliculus

• concerned with vision

Inferior colliculus

• concerned with hearing

Pons

-links the brainstem with the cerebellum

-cranial nerves V, VI, VII & VIII emerge from

Medulla

-made up of ascending and descending tracts

-Cranial nerves IX, X, XI, & XII emerge from

Cerebellum

-vermis

-flocculonodular lobe

-anterior lobe

-posterior lobe

Meningeal layers

Dura mater

Arachnoid

Pia mater

Dura mater

-most thick, substantial layer

-outer layer

-inner layer

-attached to inner surface of the skull

Arachnoid

-thin, delicate membrane

-adheres to the innermost layer of the dura but does not follow the contours  subarachnoid space

Pia mater

-thin, delicate, innermost layer

-closely follows the contour of the brain

Dural reflection

Falx cerebri

Tentorium cereblli

Falx cerebelli

Falx cerebri

-intervenes between the two cerebral hemispheres

Tentorium cerebella

-separates the cerebrum and the cerebellum

Falx cerebelli

-partially separates the two cerebellar hemispheres

Dural venous sinuses

Superior sagittal sinus

Transverse sinuse

Straight sinus

Superior sagittal sinus

-along the attached edge of the flax cerebri

Transverse sinuses

along the posterior line of attachment of the tentorium

Straight sinus

-along the line of attachment of the flax cerebri & tentorium cerebrelli

Venous blood flows in the brain

Flows posteriorly in the superior sagittal sinus & straight sinuses

 confluence of the sinuses

 transverse sinuses

 continues as the sigmoid sinus

 empties into the internal jugular vein

Reabsorption of CSF into the venous system

CSF enters the Dural sinuses at many locations through arachnoid villi

The major sites of reabsorption of CSF into the venous system

functions as one-way valves

       The arachnoid has a barrier function, blocking the entry of foreign materials into the brain

Bleeding in the meninges

Epidural hematoma

Subdural hematoma

Subarachnoid hemorrhage

Epidural hematoma

-between the dural periosteum and the skull

Subdural hematoma

-between the meningeal dura and the arachnoid

Subarachnoid hemorrhage

-in the subarachnoid space

Lesion in the major arteries

PICA

-ataxia

AICA

- Ataxia

PCA

-Hemianopsia

-Alexia without agraphia

-amnesia

MCA

-Aphasia

-Hemiplegia/ hemiparesis/ hemianesthesia

ACA

-Hemiplegia and hemianesthesia

Blood flow control mechanisms

Autoregulation

Metabolic mechanism

Autoregulation

  - Allows blood vessels to constrict in response to increased blood pressure & relax in response to decreased pressure

Metabolic Mechanism

-Vessels dilate with increased CO₂ levels & constrict with decreased CO₂ levels

Perfusion pressure

-Normal blood pressure in the brain

-Difference between arterial, intracranial (CSF) & venous pressure allows blood to circulate

Hypoperfusion pressure

-No pressure difference between the 3 systems

-Causes decrease in the circulation of blood

- distal branches of the 3 cerebral arteries are affected

-Water shed lesions occur

-Causes diffuse sign behaviorally

CVAs

Thrombosis

Embolism

Transient Ischemic attack (TIA)

Aneurysm

Arterial venous malformation

Thrombosis

-occlusion of blood vessels

-typically caused by atherosclerosis (plaque build-up)

Embolism

-the lodging of an embolus inside a blood stream

-typically caused by heart disease

-the embolus is moved and gets lodged

Transient Ischemic attack (TIA)

-temporary occlusion of blood vessel

-followed by complete recovery

-often caused by minuet emboli which becomes broken down

Aneurysm

-balloon-like swelling of arterial walls

-causes neurological deficits

            -by compressing brain structures

            -by rupturing and causing a subarachnoid hemorrhage

Arterial venous malformation

-abnormal coupling of the arterial and venous system

            -hemorrhage may occur

The posterior columns and medial lemniscus pathway

When entering the Spinal cord, dorsal rootlet segregates into a medial and lateral division

-the medial division fibers enter the posterior column

-caudal to T6, forms fasciculus gracilis

-Rostral to T6, forms fasciculus cuneatus

 somatotopic organization

Spinothalamic tract pathway

Begins in the dorsal root ganglion

-enters the Spinal cord and sends axons to synapse at substantia gelatinosa

-the second or third order cells send axons across the midline

-travels up the anterior part of the lateral funiculus

-synapses on nuclei of the thalamus

-travels up to the postcentral gyrus

The posterior column and medial lemniscus function

Carries information of touch, pressure, vibration, & joint position & movement

• Tactile and proprioceptive information

The spinothalamic tract function

-Pain and temperature from the body

-  Itch sensation

- Pressure sensation from bladder & bowel

- Sexual sensation

Brainstem structures

pyramid, sulcus limitans, superior & inferior colliculi, substantia nigra, the reticular formation

Pyramid

-between anterior median fissure and anterolateral sulcus

-Motor pathway

Sulcus limitans

-separates motor and sensory nuclei

Superior colliculi

-part of the visual pathway

Inferior Colliculi

-part of the auditory pathway

Substantia nigra

-synthesize the neurotransmitter dopamine

Reticular formation

-control of movement

-modulates the transmission of information in pain pathways

-controlling heart rate and blood pressure

-control of arousal and consciousness

Frontal lobe

·Extends from the anterior tip of the brain to the central sulcus posteriorly

·Extends to the lateral sulcus inferiorly

·Extends to the cingulate sulcus medially

Parietal lobe

Starts posterior to the central sulcus and runs to lateral sulcus inferiorly

·Runs to the parietooccipital sulcus posteriorly 

Temporal lobe

·Superiorly bordered by the lateral sulcus and inferiorly runs to the base of the brain

Occipital Lobe

·Occupies the posterior part of the brain

Frontal lobe important functional area

·Precentral gyrus → considered as the primary motor cortex

·     Responsible for initiation of voluntary movement

· Premotor and supplementary motor cortex

·   Involved in the initiation of voluntary movements (including planning)

· Broca’s area

·   The opercular and triangular parts of the inferior frontal gyrus of one hemisphere (usually left)

·    Important in the production of written and spoken language

·Prefrontal cortex

·  The remainder of the frontal lobe

·    Responsible for personality, insight, and foresight

Parietal lobe important function area

· Postcentral gyrus → primary somatosensory cortex

·       Responsible for initial cortical processing of tactile and proprioceptive information

·Inferior parietal lobule

·       Important for comprehension of language

· Remainder of the parietal lobe

·       Involved in spatial orientation and perception

Temporal lobe important functional areas

·Primary auditory cortex

·       Small area in the superior temporal gyrus (in Heschl’s gyrus)

· Wernicke’s area

·       The posterior portion of the of the superior temporal gyrus of one hemisphere (usually the left)

·       Comprehensive of language

Occipital Lobe important functional areas

· Primary visual cortex

·       Contained in the walls of the calcimine sulcus

·Visual association cortex

·       The remainder of the lobe

·       Involved in higher order processing of visual information

Frontal lobe language processing

· Broca’s area

·       Important in the production of written and spoken language

·       Location: The opercular and triangular parts of the inferior frontal gyrus of one hemisphere (usually left)

·Inferior frontal gyrus

·       Opercular part + triangular part (important for speech and language)

·       Location: roughly perpendicular to the precentral gyrus

Parietal lobe language processing

· Inferior parietal lobule

·       Important for comprehension of language

·       Location: composed of supramarginal gyrus and angular gyrus

Temporal lobe

· Wernicke’s area

·       Important for the comprehension of language

·       Location: the posterior portion of the superior temporal gyrus of one hemisphere (usually the left)

Aortic arch bifurcates into:

· Common carotid arteries

· Subclavian arteries

Common carotid arteries bifurcates into:

Internal carotid arteries

External carotid arteries

Internal carotid arteries bifurcate into:

·Anterior cerebral arteries (ACA)

·Middle cerebral arteries (MCA)

At the junction between the medulla and pons, the vertebral arteries fuse to form the

basilar artery