Úvod do nervové soustavy - Univerzita Karlovaanatomie.lf3.cuni.cz/centralni_prezentace/cns_uvod_eng.pdf · Development of neural tube Nervous tissue develops from neuroectoderm

Intro

to

nervous system

© David Kachlík 30.9.2015

Nervous tissue cells parcellation

Two types of cells:

• neurons – cells transmitting informations

• Glial cells (neuroglia, glia) (neuroglia) –

neuronal support, protection and

participation in their nutrition and work

– astrocytes (astrocytus)

– oligodendrocytes (oligodendrocytus)

– microglia (microgliocytus)

– ependymal cells (ependymocytus)


Nerves• Are formed by clusters of nervous fibers

• Nerve fibers have covering similarly to muscular

tissue:

– endoneurium

• Layer of reticular fibers around individual nerve fibers

– perineurium

• „sleeve“ containing bundles of nerve fibers formed by

layers of epiteloid cells

• Numerous zonulae occludentes – non-passable

barrier shielding nerve fibers

– epineurium

• Fibrous covering of whole nerve© David Kachlík 30.9.2015

Nerves


Ganglias• Nerve ganglias are accumulation of pericaryons

in PNS

• They have ovoid shape and their surface is

covered by capsule from thick non-organized

fibrous tissue

• Typical are satellite cells (gliocyti ganglionici) –

small cuboid cells surrounding perikarya of

neurons

http://en.wikipedia.org/wiki/Dorsal_root_ganglion http://www.pharmainfo.net/introduction-autonomic-nervous-system/classification


Ganglias - dichotomization• Spinal ganglia (ganglion spinale)

– sensory (ganglion sensorium)

– In posteroir roots of spinal nerves and in the course of

cranial nerves (V, IX, X)

– Contain typical pseudounipolar neurons

– Carry sensory impulses from periphery into CNS

• autonomous (vegetative) ganglias (ganglion

autonomicum)

– In the course of autonomic nerves

– Contain multipolar neurons

– Layer of satellite cells is incomplete

– Intramural ganglias

• Parasympatetic ganglias in the wall of hollow organs© David Kachlík 30.9.2015

Development of neural tube

Nervous tissue develops from neuroectoderm

• Neuroectoderm originates from ectoderm

by notochord induction

neural plate in the neurulation process

creates neural tube=foundation of CNS

• Remnant of neuroectoderm separates

neural crest (crista neuralis) = foundation

of PNS and other structures

(ectomezenchyme of the head etc.)© David Kachlík 30.9.2015



• Primary neurulation

– Separates ectoderm into three cell types

• Inside oriented neural tube

• epidermis externally

• Cells of neural crest

• Secondary neurulation

– Cells of neural plate create chorda dorsalis

• In the course of 35th somite formation



Epitelium of neural tube soon changes into multi layer neuroepitelium in which are created 3 layers:

• internal (germinal) zone (zona ventricularis; matrix germinalis)– Until half of intrauterine life fast proliferating (origination of

neuroblasts)

– Then reduction into ependyme

• Middle (shell) zone (zona intermedia; zona pallii)– Formed mostly by migrating neuroblasts

– Grey matter originates from it

• External (marginal) zone (zona marginalis)– Formed by extenstions of neuroblasts

– White matter originates from it




Somite (somitus)

• somitomers around 3rd week

• At the end of 5th week 42-44 somites

http://www.aps.uoguelph.ca/~swatland/HTML10234/LEC5/LEC5.html

http://www.uprightape.net/Image_Pages/UA_Fig7-4_SomiteDevel.html© David Kachlík 30.9.2015

Myotome

• Central part of

primitive segment

• Starting 4th week

during differentiation it

retains lastly epiteloid

organization

• Foundation of skeletal

muscles


Sclerotome

• Dorzomedial part of

primitive segment

• At the 4th week gains

chars of mesenchyme

• Getting thicker around

chorda dorsalis

• Creates foundation of

axial skeleton

(vertebras, costas,

sternum) and base of

skull© David Kachlík 30.9.2015

• Ventrolateral part of primitive segment

• During differentiation from start of 4th week of development gains mesenchyme char

• Migrates into somatopleura

• Give foundation to fibrous part of skin (dermis and tela subcutanea)

• Parts originating from the same dermatome have nerve supply from one spinal root

Dermatome



Composition of brain tissue

• Grey matter (substantia grisea)

– pericarya of neurons, mostly non myelinated nerve fibers

– Protoplazmic astrocytes, oligodendrocytes and microglia

• White matter (substantia alba)

– Mostly myelinated fibers

– Fibrilary astrocytes, oligodendrocytes and microglia

http://library.med.utah.edu/WebPath/HISTHTML/NEURANAT/CNS230A.htmlhttp://fuckyeahnervoussystem.tumblr.com/post/1276369326/spinal-cord-light-micrograph-of-a-cross-section


CNS description- parts

• Spinal cord (Medulla spinalis)

• Brain stem (Truncus encephali)

– Oblongate (Medulla oblongata)

– Pons (Pons) – formerly pons Varoli

– Midbrain (Mesencephalon)

• Small brain (Cerebellum)

• Diencephalon (Diencephalon)

• Forebrain (Telencephalon)

– Basal ganglia (nuclei basales)

– Brain cortex (cortex cerebri)© David Kachlík 30.9.2015

Telencephalon

Diencephalon

Mesencephalon

Pons

Medulla oblongata

Medulla spinalis

Cerebellum


CNS description

• Inside CNS cavities– 4th ventricle, 3rd ventricle and two lateral

ventricles• CNS covered by meninges:

– Hard meninge (pachymeninx= dura mater)

– Soft meninge (leptomeninx)• arachnoid (arachnoidea mater)• pia (pia mater)

• Inside ventricles is cerebrospinal fluid (liquor cerebrospinalis = CSF)

http://faculty.irsc.edu/FACULTY/TFischer/AP1/AP%201%20resources.htm

http://mortdev.blogspot.cz/2008/09/brain-autopsy.html



CNS functions• Spinal cord – reflexes, ascending and

descending tracts

• Brain stem – vitally important reflexes (respiratory, cardiovascular, vomiting, coughing, synchronization of eyeball movement)

• diencephalon – hormonal production, circadian rhytms, termoregulation, food intake, autonomic regulation

• Terminal brain– cortex: functional cortical areas

– Basal ganglia: movement patterns

• limbic system – behavior, emotions, memory© David Kachlík 30.9.2015


Brain stem

• Converting all ascending and descending nerve tracts (tractus)

• Reticular formation (RF; formatio reticularis)

– Vital reflex centers• Cardiac activity, respiration,

vazomotorics, consciousness

• Nuclei of cranial nerves

– n. III - XII


Mesencephalon

Pons

Medulla oblongata

Medulla spinalis


Truncus encephali

• Medulla oblongata = oblongate

• Pons (Varoli) = pons

• Mesencephalon = mid brain

Cavities of brain stem

• ventriculus quartus = 4th ventricle– fossa rhomboidea = bottom of 4th ventricle

• aqueductus mesencephali (Sylvii) = for CSF between 3rd and 4th ventricle

Brain stem - composition





Medulla oblongata

Ventral side:

• pyramis

– Fibers of tractus

corticospinalis

• oliva

dorsal side:

• tuberculum

gracile +

cuneatum © David Kachlík 30.9.2015




Mesencephalon =

Mid brain

• Cranial part of brain stem (2 cm)

Ventral side:

• fossa interpeduncularis (intercruralis)– Exit of n. III

• crura cerebri– Descending motor

systems (tractus pyramidalis)

• fibrae corticospinales

• other© David Kachlík 30.9.2015

Dorzal side:

lamina quadrigemina

= lamina tecti

• colliculi superiores

– vision

• colliculi inferiores

– hearing

• Exit of n. IV

Mesencephalon =

Mid brain


Mesencephalon = mid brain

Internal structure: 3 parts on section

• tectum mesencephali (mesencephalic tectum)

= dorzal thin plate with two pairs of tubers

- aqueductus mesencephali Sylvii

• pedunculus cerebri (brain pedicle)

= ventral most of midbrain

– tegmentum mesencephali

• nucleus ruber – motor nucleus of stem

• substantia nigra – motor nucleus – basal ganglion

• Ascending and descending tracts

– crus cerebri – contains only descending tracts© David Kachlík 30.9.2015


RF


Formatio reticularis

(reticular formation) RF

• Fylogenetically oldest part of brain

• Maintains basic stereotypes (walk, sleep)

• Influences wake, tiredness and motivation

• Morphologically ill defined

• Centrall and dorsally in brain stem, especially in the pons

• Ascending activation systém → talamus, hypotalamus, cortex

• Descending inhibitory systém → cerebellum, sensory nerves© David Kachlík 30.9.2015

RF function

• Seat of reflexes

– nutrition

– self defense

• respiratory

• pneumotactic center

• vazomotor center

• center for heart beat rate regulation

• center for vomiting

• Pain

• Body temperature maintenance© David Kachlík 30.9.2015

Cerebellum© David Kachlík 30.9.2015

Cerebellum = small brain

• vermis (worm) – midline non paired

• hemispheria (cerebellar hemispheres) –

paired

• cortex x corpus medullare

• 3 lobes

– lobus anterior

– lobus posterior

– lobus flocculonodularis

• 4 nuclei cerebelli (small brain nuclei)

– nucleus dentatus

– nucleus emboliformis


Cerebellum – posterior view

VERMIS



Cerebellum – three pedicles

• pedunculus cerebellaris inferior

= corpus restiforme + juxtarestiforme

• pedunculus cerebellaris medius

= brachium pontis

• pedunculus cerebellaris superior= brachium conjunctivum


Cerebellum – ventral view

P.C.MEDIUS

P.C.SUPERIOR

P.C.INFERIOR© David Kachlík 30.9.2015

Diencephalon

• thalamus

• metathalamus

• subthalamus

• hypothalalmus

• epithalamus

• thalamus opticus


Thalamus (thalamus dorsalis)

• „brain secretary“ all except for smell

• Nuclei parcellated according to positionor connection

– nuclei anteriores, dorsales, intralaminares, mediani, mediales, posteriores, ventrales, reticularis

– specific • ncl. ventralis posterolateralis, posteromedialis (VPL,

VPM) – hmat, bolest, proprioception

• ncl. ventralis anterior, lateralis (VA, VL) - motoric

– Non specific nuclei - (? function)

– Association nuclei© David Kachlík 30.9.2015

Parcellation of thalamic nuclei

according to positionnuclei anteriores, dorsales, intralaminares, mediani,

mediales, posteriores, ventrales, reticularis


Metathalamus

• Lateral geniculate body (corpus geniculatum

laterale) – vision center

• Medial geniculate body (corpus geniculatum

mediale) – hearing center


Subthalamus

• zona incerta= unsure region)

– Function similar to ncll. reticulares thalami

– Making difference of other impulses that regularly enter into talamus

• nucleus subthalamicus= corpus Luysi

– Connected with basal ganglia


Hypothalamus

Highest autonomic center

• nuclei x transversal and longitudinal zones

• Crossing of optic nerve (chiasma opticum)

• hypophysis

• Mammillary bodies (corpora mamillaria)


Hypothalamus


Hypothalamus – fyziology

Hormones (blood), nerves, CSF

HYPOTHALAMUS

Endocrine + autonomic system

HOMEOSTASIS emotions (= LIMBIC SYSTEM)


Telencephalon = Cerebrum

• Pallium (pars pallialis; pallium)

cerebrum (= hemispheres)

• Basal part (pars basilaris) nuclei

basales = bazal ganglias

• Septal part (pars septalis) septum


Pallium

• Paired hemispheres (hemishperia)

• 5 lobes (lobi)– frontal (lobus frontalis)

– parietal (lobus parietalis)

– occipital (lobus occipitalis)

– temporal (lobus temporalis)

– insular (lobus insularis) = inzula

• gyr) x sulci– basic description unit


Cortical parcellation

(Areae Brodmanni)

• primary – for one modality

• association

– secondary

– terciary

• example:

– area 4 – primary motoric

– area 17 – primary visual

– area 18,19 – association visual


bazal ganglia; nuclei basales

• Striated body (corpus striatum)

– Caudate nucleus (nucleus caudatus)

– putamen

• globus pallidus

• substantia nigra – in mid brain

• ncl. subthalamicus – in diencephalon

Basic function: motor patterns formation© David Kachlík 30.9.2015


Limbic system

• „visceral brain“

• Around brain stem (= “collar“)

• emotions, memory, smell

• Connected with emotional reactions, sexual

behavior and offspring care, social behavior,

memory and regulation of many autonomic

function

• Cortical and subcortical parts

• hippocampus

• corpus amygdaloideum = amygdala

• other© David Kachlík 30.9.2015


Documents

Úvod do nervové soustavy - Univerzita Karlovaanatomie.lf3.cuni.cz/centralni_prezentace/cns_uvod_eng.pdf · Development of neural tube Nervous tissue develops from neuroectoderm