Brain And Spinal Chord Flashcards
Cranial Dura mater (Dura mater encephalli)
In adittion to lining the cavity, the dura mater makes partitions(skillevegger) thatprojects inwards.
Whatare the partitions/borders?
- Falx Cerebri - extends from CRISTA GALLI —> Int. Occipital protuberance —>projects into FISSURA LONGTUDINALIS between the two hemispheres.
- Transverse tentorium cerebelli —> the falx cerebre meets the TTC caudally —> Separates the CEREBRUM from CEREBELUM.
Membranous tentorium cerebelli —> borders the tentorial notch, through which the brainstem passes through
- Diaphragma Sellae —> forms the ROOF of the. HYPOPHYSEAL FOSSA in which the HYPOPHYSIS is situated. Forming a diaphragm around the infundibular stalk.
Cranial Dura mater VS Spinal Dura mater
Connection to the PERIOSTEUM
Cranial: Fused with the inner periosteum of the skullbones
Spinal: Separated from the perosteum lining the vertebral canal by epidural space.
Where do you find the epidural space, and why is it importaint?
The Epidural space is filled with FAT and contain a large Venus plexus.
When Spinal roots runs thorugh the Spinal canal they are enclosed by MENINGEAL sheets.
Regional ANAESTHESIA can be performed:
- Between last lumbar and first sacral vertebra (Spatium lumbosacrale)
- Between last sacral and first caudal verteba
What does the caudal END of the dura matter form? And where does it continue?
A blind sac —> and UNITES with other meiningeal layers to form a fibrous chord (FILUM TERMINALE DURA MATRIS). Fuseswith DORSAL surface of CAUDAL VERTEBRAE.
It continues with the cranial dura mater at the FOR.MAGNUM
Spinal dura mater is vascularized by?
SPINAL ARTERIES
Cranial Dura Mater is vascularized by?
MENINGEAL ARTERIES
Like the Spinal nerves the Cranial nerves are surounded by?
Dural Sheats untill they leave the cranial cavity. Together with the LEPTOMENINGES they form CUFFS thatare surounded by CEREBROSPINAL fluid.
- CEREBROSPINAL fluid can reach Perineural lymph vessels = Cause diseases to spread from lymph —> meninges —> Neural tissue
The arachinoid membrane in contact with DURA and Pia Mater
Outer part: Continous membrane, moulded to the Dura Mater
- space between ARACH and DURA = SUBDural SPACE= cappillary space
- not clear, space or not
Inner part: Continous celllayer of arach.membr moulded against the PIA mater.
Between the two membranes:
- Trabecula and filaments exceed = network of communicating chambers. = SUBARACHINOID SPACE (Cavum subarachinoidale). Filled with CEREBROSPINAL fluid.
Debth of the subarachinoid space?
Variable since the arachinoid membrane stays in contact with DURA MATER, while PIA MATTER follows the surface ofte brain.
What is a CISTERNA?
Sertain sites of the ARACHINOID membrane is enlarged to form CISTERNAE.
Usedfor EXTRACTION of CSF! Or Injection
CEREBROMEDULLARY CISTERN!!
Location and usage of the CEREBROMEDULLARY CISTERN?
Located: Where the caudal surface of the CEREBELLUM meets the dorsal surface of the modulla oblungata (MO).
Common site for obtaining CSF
Can be reached by passing a needle BTW the ATLAS and the SKULL.
Alternate site to the CSF (not CEREBROMEDULLARY CISTERN)
LUMBOSACRAL SPACE or
the space between the last sacral and first caudal vert.
Large mushroom-shaped projections extending from the arachinoidmembrane.
GRANULATIONES ARACHINOIDALES(Pacchioni granulationes) into dural Venus sinuses. Hypothese: From herre CSF can enter the general circulation. This arachinoid villis are not pressent in sheeps.
Types of meninges
- Pachymeninges= Dura Mater
2. LEPTOMENINGES = Arachinoid membrane and Pia Mater
Pia Mater Encephali et Spinalis
In contact with?
Direct contact with Glial Limiting Membrane ofte neural tissue
Pia mater innervated ?
Richly
Recieves a generous bloodsupply (several bloodvessels extend into the neural tissue)
Ligament of the Pia Mater
Lig. Denticulate
Pia M is bilaterally thickened along the lateral surface of the Spinal Chord!!
Extentions of the ligament crosses the SUBARACHINOID space. —> Attaced to the Pia Mater.
= Suspends the Spinal chord in CSF within the SUB.A. Space
Pia mater surrounds?
Cranial vessels for a short distance after entering the brain.
CSF is thought to be able to enter the veins at these Pial sleeves.
What is the Diaphragma Sellae?
ROOF of the hypophyseal fossa where the HYPOPHYSIS is situated
What is the name of the caudal END/continuation of the DURA MATER
FILUM TERMINALE
Which ARTERIES supply the brain?
In horse and dog: A.Carotis interna (paired)
Cat/ru: a.carotis interna closes closely after birth. = Bloodsupply to brain provided by branches of A.Maxillaris
Which ARTERIES supply the Spinal chord
Cervical Spinal Chord is vascularized by: segmental ARTERIES from the A.VERTEBRALIS - a branch of A.Subclavia
Rest of the Spinal chord recieves blood from segmental ARTERIES from the cervical, intercostal and lumbar ARTERIES.
Segmental ARTERIES enters the vertebral canal through Foramina intervertebralia —> Thea devide into DORSAL and VENTRAL branch. That reaches the Spinal chord together with the Spinal nerves.
VENTRAL SPINAL ARTERY
DORSOLATERAL SPINAL ARTERY (Paired)
Which veins supply the brain?
A.Carotis interna(EQ,ca)
Cat/ru: Branches of the A.Maxillaris
Which veins drain the Spinal chord?
Spinal VEINS form a network similar to Arterial plexuses.
Drainingvens follow the Spinal nerves before they open into the EPIDURAL VENOUS PLEXUS
Composed of 2channels connected by transverse branches.
Veins composing the plexus= no valves= blood can travel in either direction.
What is the Sinus System?
Is a arrrangement that cools Arterial bloodsupply to the brain.
- Sinus Dura Matis
DORSAL system
- Dorsal saggital Sinus
- Straight Sinus
- Transverse Sinus
- Temporal Sinus
VENTRAL or BASILLAR SYSTEM
6. Cavernosal Sinus (surrounds the HYPOPHYSIS)
Formation of the circle of willis(Cerebral Arterial circle)
A.Carotis interna (EQ,Ca)/ Carotid cerebral artery(ru+ other) penetrate the DURA MATER at the DIAPHRAGMA SELLAE forming a ring around the infundibular stalk ventral to the hypothalamus.
Only compleete in dog. Rostrally open in other.
Circle of Willis is joined caudally by
BASILLAR and VERTEBRAL ARTERIES.
In OX, the vertebral artery contributes a considerbly portion to the circle of Willis.
The circle of Willis and A.Basillaris given rise to?
A.Cerebri rostralis
A. Cerebri media
A. Cerebri caudalis
A. Cerebelli rostralis
A.Cerebelli caudalis
Arterial network at the base of the brain.
Consist of:
Rostral & Caudal EPIDURAL RETE MIRABILA
Reunite in: CEREBRAL CAROTID ARTERY
A+V close to each other = Temperature regulations
The veins of the brain grouped into
Grouped into
- DORSAL
- Basal
- Inner veins
Valveless and independent of the ARTERIES.
Open into also valveless: DURAL VENOUS SINUSES (Sinus dura matis)
Sinuses enclosed within the Dura Mater = Devided into DORSAL and ventral systems.
DORSAL Sinus system
- DORSAL SAGGITAL SINUS collects blood from dorsal part of the brain. Passes within the FALX CEREBRI. Joined toward itscaudal END by:
- Straight Sinus, before it devides into:
- TRANSVERSE Sinus, which extend to boths sides in MEMBRANA TENTORIUM CEREBELLI
- recieves blood from CEREBELLAR VEINS
- Unite with the: - TEMPORAL SINUS
- open into FOR.Retroarticulare
- connects. With. The. Ventral system.
VENTRAL Sinus system
Ventral or BASILLAR System: -drains ventral part of the brain and parts of the FACE! - consists of: 1. SINUS CAVERNOSUS - surrounds the HYPOPHYSIS - closely connected to the: Distal Sigmoid end of the A.CAROTIS INT. EPIDURAL RETE MIRABILE
VENTRAL SYSTEM recieves from: - face - Orbit - nasal cavity By the: V.FACIALIS PROFUNDA
How does the arrangement of the VENTRAL Sinus system cool down the bloodsupply to the brain?
Because A. Carotis INT is «Bathed» in colder VENOUS BLOOD when it passes through the SINUS. CAVERNOSUS
What does grey mater consist of?
Substantia Grisea
- composed of cell bodies and processes of NEURONS and GLIAL Cells.
- Butterfly shape
1- COLUMNA DORSALE - Cornu DORSALE (in transverse sections)
Consist of somatisk and afferent visceral neurons.
2- COLUMNA VENTRALE - Cornu ventrale (in transverse sections)
Mainly composed by motorneurons.
3- COLUMNA LATERALE - Cornu laterale(in transverse sections)
Of the THORACOLUMBAR spine contain visceromotor neurons. Sympathetic neurons.
What does white mater consist of?
Substantia Alba consist of:
Mainly MYELINATED ASCENDING and DESCENDING Nerve fiber
MYELINATED sheets are formed by oligodendrocytes = responsible for the whitecolour.
White mater devided into COLUMS orFUNICULI
= composed of bundles of nervefibers of common origin/dest/funct
1. FUNICULUS DORSALIS
2. FUNICULUS VENTROLATERALIS
Spinal chord can be devided into segments, what are they?
Pars cervicalis
Pars thoracica
Pars Lumbalis
Pars Coccygea
The Spinal chord has two enlargements. What are they, and what do they do?
- Intumescentia cervicalis
- involvescaudal part of cervical spine and initial part of th spine
- gives rise to the Spinal nerves that forms BRACHIAL PLEXUS that innervates the thoracic limb. - Intumescentia lumbalis
- Gives rise to the Spinal nerves which innervates the pelvic cavity and limb.
What is found caudal to the INTUMESCENTIA LUMBALIS
Spinal chord tapers into an elongated cone (CONUS MEDULLARIS)
Which is reduced and bcomes FILUM TERMINALE.
How does the SPINAL NERVE FORM?
The nervefibers of each root are bound together at the FOR.INTERVERTEBRALE.
Developent:
In the fetus the Spinal chord and the vertebral collumn has the same length, and each Spinal nerve leaves the vertebral canal through the For.intervertebrale at the level of ITS origin.
During development, however the vertebral collumn increases more in length than the Spinal chord, and the caudal END of the Spinal chord is cranial to the caudal END of the vertebral collumn.
Therefore in order to leave the vertebral canal the Spinal nerves has to pass caudally within the vertebral canal untilll it reaches the appropriate intervertebral foramina.
Caudal and Sacral Spinal roots stream caudally beyond the CONUS MEDULLARIS to exit their respektive foramina. These roots are DESIGNATED CAUDA EQUINA.
What does the RHOMBENCEPHALON consist of?
= HINDBRAIN
- Myelencephalon = Medulla oblongata (caudal part)
- Metencephalon = Pons and Cerebellum (rostral)
Also includes 4th ventricle
What is MYELENCEPHALON?
MEDULLA OBLUNGATA
BORDER: From 1st pair of nervi cervicales –> Pons
ENCLOSES: Caudal part of the IV Ventricle
+ Velum medullare caudale
Where is the myelencephalon located?
MO is located in FOSSA MEDULLA OBLUNGATA dorsal to Basi occipital bone.
What are the nuclei of Myelencephalon?
Nuclei of cranial nerves:
VI –> XII
+ corresponding PARASYMPH nuclei
+ caudal part og large nucleus of TRIGEMINAL N.
What is the function of the MYELENCEPHALON?
- Controlls respiration & circulation
- Reflex for:
- PROTECTION of eye
= palpebral reflex and lacrimal secretion
- UPPER RESPIRATORY TRACT
= Sneezing and coughing - FOOD INTAKE
= Sucling, swallowing
Defects on Myelencephalon
LESION of MO
= Defect of cranial nerves –> Death
What are the parts of the METENCEPHALON?
Pons
Cerebellum
Tegmentum metencephali
Velum medullare rostrale
What are the pons?
Bridge btw MO and Mesencephalon
The Pons has two parts
Dorsal part = Tegmentum points = roof of 4th ventricle
Ventral part
Function of the PONS
Motorfunctions of the body
- a lot of motor nuclei
What are the main features of the PONS
- Trigeminal nerve (lat)
+ its motor nucleus
+ Other motor nuclei - Nucleii + nervefibers of FORMATIO RETICULARIS = 1/2 pons
- Ascending + Descending tracts –> Cerebellum
Pedunculus cerebellaris medius - FOSSA RHOMBOIDEA –> 4th ventricle
CEREBELLUM location
ABOVE 4th ventricle/ dorsal to fossa rhomboidea
CEREBELLUM composed of
Bulk of GREY MATTER = Cortex cerebelli
+ WHITE MATER (enclosed in cortex) = Corpus Medullare
= forms the TREE of LIFE = ARBOR VITAE
Function of the CEREBELLUM
Balance
Coordination of skeletal muscles// posture and locomotion
Caudal lobe: Motor function
Rostral lobe: Proprioceptive info
Parts of the CEREBELLUM
Medial saggiata ridge = VERMIS
Lateral hemispheres = HEMISPHERA CEREBELLI
The VERMIS (lobes) of CEREBELLI
- Rostral Lobe = AUCHICEREBELLUM
- Caudal Lobe = NEOCEREBELLUM
- Caudoventral Lobe = PALEOCEREBELLUM
+ HEMISPHERA CEREBELLI
Cerebellums connection to the Brainstem
PEDUNCLE
- Rostral cerebellar Peduncle -> Velum medullare rostr
- Caudal cerebellar Peduncle -> Velum medu caud
- Middle Cerebellar Peduncle -> Pons
What does the roof of the 4th ventricle consist of?
Velum medullare + Cerebellum = Roof of 4th ventricle
What is the floor of the 4th ventricle?
Fossa Rhomboidea - Walls marked by bilateral eminences = AREA ACCUSTICA - Eminentia Medialis: Btw sulcus medaianus and limitans. Nuclei of cranial nerves IX, X and XII
What is OBEX
Caudal end of sulcus medians
What is MESENCEPHALON
Midbrain
What does the MESENCEPHALON consist of from dorsal to ventral
+TECTUM MESENCEPHALI (=lamina tact, =lamina quadrigemina)
+ TEGMENTUM MESENCEPHALI
+ CEREBRAL PEDUNCLES/ Crura cerebri, Pedunculi Cerebrii
What does DIENCEPHALON comprise?
EPITHALAMUS
THALAMUS
MATATHALAMUS
HYPOTHALAMUS
Functions of the midbrain
Function of the mesencephalon
1- Nuclei of III and IV Cranial nerves
= Coordination of volunteer muscle functions
2- RED NUCLEUS
= Muscle toning, body posture, locomotion
3- SUBSTANTIA NIGRA
= Initial phase of FAST MOVEMENT
What is TECTUM MESENCEPHALLI?
= Roof of midbrain
covers: AQUADUCTUS MESENCEPHALI:
= btw III and IV ventricle.
TECTUM MESENCEPHALL
What is the COLLICULI responsible for?
Colliculi = Reflex centers for Hearing and vision.
- Colliculi ROSTRALE
= VISION PATHWAY
Corpus geniculatum laterale - Colliculi CAUDALE
= AUDITORY PATHWAY
What does the cerebral peduncle Flank?
Interpeduncular fossa
Interpeduncular Fossa contain
Mammillary Body
Hypophyseal Infundibulum
Pituitary Gland
What determines the function of the midbrain?
Nuclei of third and fourth cranial nerves, and reflexcenters of hearing and vision.
It plays an important role in voluntary motorfunction!
controlled by higher centers:
1. RED nucleus -> Muscle tone, body posture and locomotion.
2. Substantia Nigra -> Initiating phase of FAST Movements.
How is the Cerebellum attached to the Brainstem?
By Cerebellar Peduncles (3) on each side and by caudal and rostral cerebral vela
What are the divisions of the RHINENCEPHALON
- Pars Basilaris
- Pars Septalis
- Pars Limbica
What is the caudal Cerebellar peduncle composed of?
Largely composed of afferent fibers! - some running from origins within the Spinal Chord - others from: VESTIBULAR NUCLEI OLIVARY NUCLEUS and RETICULAR FORMATION
What does the middle Peduncle compose of?
AFFERENT fibers
Arising from PONTINE NUCLEI
What is the rostral Peduncle connected to?
Attached to the MIDBRAIN
What is the rostral Peduncle composed of?
Largely composed of EFFERENT fibers dispatched toward: RED NUCLEUS RETICULAR FORMATION THALAMUS But also afferent components that continues the Ventral spinocerebellar tract
What is the function of the CErEbELLUm?
Controll of balance and the coordination of postural and locomotor activities
Balance: Located in FLOCCULONoDULaR node
Caudal Lobe: feedback regulation of motor function. Recieves direct Input from PONTINE and OLIVARY NUCL
Where do you find the Midbrain ?
Exposed on the Ventral surface of the intact Brain
What does the Midbrain cobtribute to?
Crura Cerebri
Fossa i interpeduncularis
Superf origin of
oculomotor Nerves (III)
What is the lumen of the Midbrain?
Aqueduct = simple passage joining 3rd and 4th ventricle
Midbrain Comprises
Tectum (Rostral and caudal Colliculi)
Tegmentum
Cerebral Peduncle
What does the caudal Colliculi controll?
Auditory pathway
What does the rostral Colliculi controll?
Visual pathway
What does the TEGMENTUM Comprises ?
Core of the Midbrain
Mutch of it formed by Reticular formation
What is the Principal mesenphallic Nuclei?
- Mesenphallic Nuclei of TRIGEMINAL nerve (v)
- Trochlear nuclei(IV)
- Principal and parasymph oculomotor nuclei(III)
- Red Nuclei
- periaqueductal grey
- Substantia Nigra
The red Nucleus and the Substantia Nigra Is accossiated with
Basal Nuclei
Controll of voluntary movements
Where does the occulomotor nerve emerge
Interpeduncular fossa, rostral to the Pons
What is the LIMBIC System?
System responsible for emotional behaviour.
