Neuro Block Flashcards
Which part of neurons are in the white matter? the grey matter? In the Brain
Grey = Myelinatd axons + glia White = Cell bodies aka somata + Glia cells
Where are the antomocial directions?
Brain axis vs Body Axis?
Which parts of the brain make up the diencepalon
What functional areas are either side of Central sulcus and what lobes of cerebrum are divided by it?
Divides the Front and Parietal Lobes
Anterior = Primary motor
Posterior = Primary Somatosensory
Main genral functions of Cerebrum?
Emotions, self, language, memory, movement
Route and what infor they normally carry?
Primary Afferent neuron?
Primary Efferent neuron?
Primary efferent neurons run CNS to PNS = Motor info
Primary afferent neuron (PNS to CNS) = Sensory info
Layers of the Menegines?
Where are the spaces and potential spaces?
Outermost: Skull, Dura mater, Arachnoid mater, Sub-Arachnoid Space Pia Mater (very closely assoc with Brain).
Potential spaces:
Extra dural: between skull and dura
Sub Dural: between Dura and Arachnoid.
What Level does the Spinal Chord end?
What are the nerves called after this point?
L1/L2
Spinal Roots / Cauda Equina
Dorsal Root Has what kind of fibres?
Come from smaller are larger horn of spinal chord?
Sensory Fibers
Small part of Horn
Ventral root has what kind of fibres?
Which horn do they come from?
Comes from ventral horn (Larger ones) and is motor fibers.
Are peripheral nerves mixed or signal type of fibres?
Mixed, why damage will present in motor and sensory loss?
Where is CSF formed and by what kind of cells?
Generated within ventricles - epithelium that is vascular and generates fluid = choroid plexus - fluid is CSF = unique brain fluid that is different to plasma (eg lower in K)
How does CSF get out of the ventricles?
Through the fourth ventricle -> goes into subarchnoid space
Three main cell types in cortex?
Neurons, Astrocytes and Oligodendrocytes
What cells line the Central canal of spinal cord and ventricles? Basic characteristics?
Ependymal cells
No basal lamina
Have interdigitation into undersurfaces
Finger like projections into central canal help the flow of the CSF fluid.
Basic Characteristics of Neurons?
6 things
Morphologically distinct
Electrically active
Rapid Communication over long distance
High level of protein synthesis (purple in H&E)
Metaboligcally Limited
Terminally Differentiated
Neurons can change their morphology through cytoskeletal changes?
Three ways. Dynamic or fixed?
Can change in response to neural stimulation
Actin: allows assembly and disassembly of spines and cones
Fine tuning of each dendrite is possible thorugh cytoskeletal changes
Intermediate filaments: would generally be permanent
Only change during stress etc
Microtubules: Dynamic = tubulin : important in transport along axons
Four major parts of a neuron and their basic roles?
Dendrites: recieve information
Cell Body: Maintanence
Axon: Propagation of signal
Axon Terminals: Output/transfer of signal
Why do neurons produce a lot of proteins? How does appear in H&E staining?
Many proteins required to maintian electrical activity: ion channels, transporters, receptors and cytoskelal components (transport along axon)
Purple in a H&E stain = Nissl bodies - rough EPR, Mitochonria, ribosomes etc. But with pale nucleus.
Key support cells in CNS?
What are they called in PNS?
Astrocytes: CNS
Sattelite cells: PNS
5 Passive support functions of astrocytes?
2 Active support funtions?
Active: Modulation of neuronal function and blood flow through Ca2+ waves.
Passive:
neurotransmitter uptake and degradation
K+ Homeostasis through removal
Neuronal energy supply
Maintenance of BBB
Injury response and recovery
Astrocytes are invovled in the uptake of what neurotransmitters?
What do these neurotransmitters do to neurons?
Glutamate: Depolarisation of neurons –> excitable and GABA: stops the firing of neurons.
Waves of Ca2+ from glia cells have what effect on neurons and blood vessels in the CNS
inhibit neurons through hyperpolarisation
Constrict blood vessels
What cells are invovled in mylination of CNS axons or PNS axons?
How does it speed up transmission?
CNS: Oligodendrocytes
PNS: Schwann Cells
Gaps: Nodes of Ranvier - jump between.
Role of Microglia in CNS and how they perform it?
how they look?
Immune cells from bone marrow that are in CNS (immune privilegded), look like macrophages (also phagocytic).
Have cell body with spidery process that monitor the environment. Mobilse and release inflam mediators when “notice” something.
Layers of Peripheral nerve fibres?
Epineurium (covers whole nerve) –> perineurium covers bundles fascicle (bundle of nerves) –> endoneurium (loose vascular tissue in between) –> Schwann cell around axon of individual neurons.
Three sutures seen from Superior view of Skull? What bones are they between?
Coronal: Frontal Bone and 2x Parietal Bones
Sagittal suture: between 2 x Parietal Bones
Lambdoid Suture: Parietal Bones and Occipital Bone.
What four bones meet at he Pterion?
What shaped suture?
What structure does it overlie?
Frontal, Parietal, Squamous temporal and junction of greater wing of sphenoid.
H shaped
Anterior division of middle meningeal artery
Two main parts of frontal bone?
Vertical: forms forehead
Horizontal: forms roof of orbital plate and the anterior part of the cranial floor.
Which part of the cranial floor does the occipital bone form? Name of bump on back of head?
Posterior cranial fossa, External Occipital Protuberance
Two parts of the Temporal Bone?
One has three projections?
Squamous = Flat exterior surface
zygomatic proccess, Mastoid process and Styloid process.
Petrou Part of Temporal Bone: forms part of Middle Cranial Fossa.
Describe the anatomy of the greater and lesser wings of the Sphenoid Bone?
Lesser wings in line with frontal bone –> step down (leaving a gap: Superior orbital fissure) to the greater wings (form part of middle cranial fossa)
What bones make up the Anterior? Middle and Posterior Cranial Fossa?
Anterior: Frontal + Lesser wings of sphenoid
Middle: Greator wings of sphenoid + Petrous part of temporal Bone
Posterior: Occipital Bone
What travels through Foramina of Cribriform Plate?
In what bone?
CN 1 Olfactory Nerve Axons
In Ethmoid Bone
What travels through Optic Canals?
How are they formed?
CN II: Optic Nerves & opthalmic arteries
Canal present in spheniod bone
What passes through Superior Orbital Fissure?
How is it formed?
Ophthalmic Arteries and Nerves (CNV1), Sympathetic fibres, Extraocular muscle nerves: CN III (Oculomotor), CN IV (Trochlear), CN VI (Abducens)
Between lesser and greater wings of spheniod bone
Where does the Maxillary Nerve pass through?
What bone? Branch of what nerve?
Foramen Rotundum, Spheniod Bone, Trochlear Nerve
What foramen does the middle menigeal artery run through?
What aspect of spheniod bone is foramen?
Foramen of Spinsosum
Most lateral foramen of spheniod bone. Near join with temperal bone.
What runs through foramen ovale?
Mandibular nerve.
Foramen inbetween rotundum and spinsoum.
What nerves run through internal acoustic meatus?
What bone?
CN VII: Facial
CN VIII: Vestibulocochlear
Petrous Part of Temporal Bone
What runs through Jugular Foramen?
Which bones form?
IX: glossopharygeal, X: Vagus, XI: Accessory nerves
Internal jugular vein and some small arteries
Formed at join of Petrous part of temporal bone and occipital bone.
What does CN XII run through?
The Hypoglossal nerve runs through the hypoglossal canal of the occipital bone.
Three spaces/potential spaces in meninges?
What fluid would/does fill them?
Potential: Epidural space -> arterial bleed eg middle meningeal artery
Sub-Dural - venous drainage from scalp, skull and neural drains into collection where dura splits to form Falx cerebri etc –> so underneath can fill with a venous bleed
Sub-Arachnoid Space: normally filled with CSF –> drained from 4th ventricle.
What separates the two cerebral hemispheres?
Sickle shaped double layer of dura = Falx cerebri
What does the Falx cerebelli separate?
To cerebellum hemispheres
Name of the double layer of dura that is tent like, is at right angle to falx cerebri and separates cerebral hemispheres and cerebellum?
What type of movement does it prevent?
Tentorium cerebelli
Rotational
How many Cranial, Thorasic, Lumbar and Sacral Dermatomes are there?
C=8
T=12
L=5
S=4
What dermatomes correspond to the upper limbs and are the spinal roots that contribute to the brachial plexus
C4, C5, C6, C7, C8, T1
Which dermatome corresponds to the middle finger? the umbillicus? and the big toe?
Middle finger = C7
umbillicus = T10
Big Toe = L5
Middle Meningeal Artery Branches from what? What kind of injury is it associated with?
Branch of Maxillary Artery, which comes from External Cartoid Artery. Enters skull through foramen spinosum.
Passes under Pterion (branches there): vunerable to injury with a blow to the side of the head. Associated with an epidural bleed.
Describe the pathway of CSF from production to the return to the venous system?
Vascular Choroid Plexus in Ventricles produce the CSF (500 ml/day, low in K+, lower pH, ultrafiltrate of plasma), Epedymal Cells (Cillia, no basal membrane) line ventricles and spinal canal to aid movement of CSF.
Lateral Ventricles > Inter ventricular foramen > 3rd ventricle > Cerebral Aqueduct > 4th ventricle (Anterior to cerebellum, Posterior to BS):
Central Canal to Spinal Cord OR
Median Apeture or 2x lateral apeture to Sub Arachnoid Space > Arachnoid granulations into Superior sagittal sinus > Venous system.
What do the Lenticulostriate Arteries Supply and where do they branch from?
Supply the basal ganglia and the internal capsule. Branch from the Middle Cerebral Artery
Layer of the Scalp? Plane of movement? Infection? When it is cut?
Five Layers:
- Skin
- Dense Connective Tissue, lots of vessles = neurovascular plain : a fibrous septa attched holds vessels open when cut.
- Aponeurosis of anterior frontalis muslce and posterior occipitalis muscle (pulling of two bellies contribute to bleeding when scalp cut).
- Loose Connective tissue layer: allows plane of movemet between aponeurosis and periosteum, also spider-web of LCT is a good medium for spread of infection
- Pericranium that is fixed to the skull.
Layers of the Face?
Skin
Neurovascular Plane/Dense connective tissue
Muscles of Facial Expression (CN 7)
Periosteum
Same as Scalp except no LCT layer and Muscles of Facial exression instead of aponeurosis.
Distribution of sensory supply of trigeminal nerve and rest of neck and face?
Opthalmic nerve (Superior Oribital Fissure, Forehead, supraorbital and superficial nose)
Maxilary ( Foramen rotundum, Upper lip Mucous membrane of nasal cavity and cheeks)
Mandibular (Foramen ovale, Jaw and lower lip, Auriculotemporal nerve too).
Back of head and neck = Dorsal rami or cervical spinal nerve C2 and C3
C4 is shoulder tip.
Course of Facial Artery?
Facial artery branches of ECA and passes on inferior border of mandible (palpable), heads on a non-straight course to medial border of eye (gives branches to check, upper and lower lip and nose): anastomose with brances of internal carotid that supply the for forehead.
One terminal branch of ECA is the facial artery what is the other one and what is its course?
The other is the Superficial temporal artery branches within the partoid duct and exits on superior border to supply the area of the skin/fascia overlying temporal bone
Borders of the Partoid Gland?
Inferior: angle of mandible
Posterior = ear
Superior: Zygomatic Arch
Anterior: Masseter
Deep: Styloid Process.
Course of Partoid Duct?
Emerges from fronto fthe parotid runs across masseter and pieces Buccinator and enters oral cavity near second upper molar.
