Author: Ivo Klepáček

Obor: general medicine, dentistry

Univerzita Karlova v Praze – 1. lékařská fakulta

Brainstem

truncus encephali

εγκεφαλικού στελέχους truncus encephalicus

Anatomický ústav

CNS hierarchy

III.

II.

I.

IV.

Williams P.L. (ed): Grays Anatomy, Churchill

Livingstone, New York, 1995

CNS phylogenesis

and structure

brain from

below

ventroanterior

view

ventral lateral dorsal

How the brainstem is formed :

dorsal view

Viscero –

motor (parasympaticus)

visceral - sensory

general (nc. solitarius n.

X.) visceral epithelium

visceral -

sensory special (nc. gustatorius n.

VII.,IX.,X.) taste buds

somatic - sensory

general (nc. V.)

Branchio –

motor (special)

VII,VII,IX,X

Nc.gustatorius

VII,IX,X V

Nc.X

solitarius

Somatic -

motor (general)

V,VII,IX,X

III,IV,VI,XII

somatic –sensory

special (n. VIII.,

vestibular + auditory) Characterization of nerve fibers-fuctional aspect

A) Somatomotor General somatic efferent – inervate skeletal muscles

B) Visceromotor General visceral efferent – innervate smooth visceral

muscles, intraocular muscles, heart, salivatory glands…

C) branchial motor Special visceral efferent – innervate skeletal

muscles derived from branchial (pharyngeal) arches (CN V, VII, IX, X)

D) viscerosensitive General somatic afferent – conduct impulses from

skin, skeletal muscles spindles

E) sensory Special somatic afferent – conduct impulses from retina,

auditory and vestibular apparatus

F) somatosensitive General visceral afferent – conduct impulses from

viscera, blood vessels

G) sensory Special visceral afferent – conduct impulses from taste

buds, olfactory mucosa

viscero - motor (parasympaticus)

visceral - sensory

general (nc. solitarius n.

X.) visceral epithelium

visceral - sensory

special (nc.

gustatorius n.

VII.,IX.,X.) taste buds

somatic - sensory

general (nc. V.)

somatic –sensory

special (n. VIII.,

vestibular + auditory)

branchio – motor (special)

somatic motor (general) III,IV,VI,XII

V,VII,IX,X

VII,VII,IX,X

Nc.gustatorius

VII,IX,X

V

Nc.X

solitarius

S G

B S

V m V G V S

S G

S S

Mesencephalon differentiation

Pons differentiation Some levels are unified together

Arteria basilaris

2 aa. vertebrales → a. basilaris

• a. inferior anterior cerebelli (→ a. labyrinthi)

• aa. pontis

• aa.

mesencephalicae

• a.

superior cerebelli

→ aa. cerebri

posteriores

circulus arteriosus

cerebri Willisi

Thomas Willis

(1621-1675), An English

physician

CN nerves

branches and

arteries of the

Willis circle

posterior cerebellar aa.

superior cerebellar aa

basillar a.

pontine aa.

posterior anterior cerebellar aa.

posterior inferior cerebellar aa.

veins draining brainstem

WHAT is INSIDE ?

• Tectum + tegmentum nuclei

• nuclei of CN nerves !!!

• Substantia grisea

• Reticular formation (complexes of nuclei with

different size)

• Precerebellar nuclei (arcuati, Oliva, some of RF)

• Tracts (pathways passing through the

brainstem up and down (ascending and

descending)

Chemical systems in the CNS

Internal structure of the brainstem

Tectal, geniculate medial (caudal end of Dienc.) nuclei

CN nerves nuclei

Two rows of somatomotor

Three visceromotor ncc.

Viscerosensitive nucleus: nucleus tractus solitarii NTS with solitarius

+ interstitial ncc.)

Two rows of somatomotor

Somatosensitive + special ncc.

Three rows of ncc.: medial lateral rapheal + cerebellar + chemical

Precerebellar ncc.:

Nc. ruber, interpeduncular, substantia grisea centralis (+Cajal,

Darkschewitch) + chemical ncc.

Pontine + arcuate ncc.

Oliva

Cerebellar RF ncc.

anteroposterior

section

Brainstem layers Tectum

Tegmentum

Pars ventralis

Tegmentum - huge region passing through

full brainstem. the well

known is a part inside

mesencephalon.

Tegmentum contains:

nuclei of CN nerves NC,

Reticular formation RF,

substantia nigra SN,

nc. ruber NR.

There are ascending

sensory tracts.

Ventral part of

the brainstem (pyramidal part) is mostly enlarged in

pontine and medulla

oblongata levels. It contais

descending motor tracts.

Tectum - four collicles

(corpora quadrigemina) - decodes

information from senses (eye, ear).

Optic ´visual´ tectum - superior

collicles - collect signals from the

optic tract and somatosesory organs.

´Hearing´´ auditory part - inferior

collicles (torus semicircularis) - collects signals from the audory

apparatus.

Tectum asists in head movements to the

sound source or helps to turn the head to

the moving object.

Inside tectum are fibers from the smell

organ and cerebellum…

• Colliculus superior –

3 layers of gray and 4 layers of white

matter, are incorporated to optic

tract - brachium colliculi – corpus

geniculatum laterale - cortex

• superficial layers react on visual

impulses, deep layers even on

other sensitive impulses

• Te-Spi, Te-RF –orientation

movement, conjugate movements

• Saccadic movements

• Colliculus inferior –

involved to auditory pathway -

brachium colliculi – corpus

geniculatum mediale – cortex

• Central nucleus (tonotopic

organisation) and dorsal and lateral

cortex

• Aferents for dorsal cortex is from

the auditory cortex area

• for lateral from spinal cord, ncl.

gracilis a cuneatus

Tegmentum mesencephali • Substantia grisea

centralis –

surrounds

aquaeductus –

interconnecting

station between

vegetative pathways

and stem (Eferents to MS

• HK flexors are influenced

• part of control cerebellum circuit)

Ncl. ruber – a part of

cerebellar and motor

pathways

Substantia nigra –

dopamin source for

striatum –

(if missed – Parkinsonism

develops)

Ncl. intersticialis (Cajali)

Ncl. intersticialis rostralis (Vertical eyeball movements)

T

Ncl. intersticialis (Cajali), Ncl.

intersticialis rostralis

Division from side to side

Rhomboid fossa

Somatomotoric

Medial line (row) XII, VI, IV, III (+EW)

Lateral line (row) IX, X (ambiguus),

VII, V (motorius)

Visceromotoric (parasympathetic)

X (dorsal), IX (salivatory inferior), VII

(salivatory superior), III (accessory EW)

Viscerosensory

Solitarius (gustatorius, IX, X, tractus

solitarius V,VII,IX,X)

Somatosensory + special

V (spinalis RI-IV)

tractus spinalis – pain, warm, Kunc

tractus VII,IX,X)

V (pontinus – touch, vibratory)

V (mesencephalic)

VIII vestibular, cochlear

Following position

Division from up to down

Rhomboid fossa

Nuclei

of CN

nerves

Reticular

formation

Specific structures

in brainstem parts

Pontine RF

Medulla

oblongata RF

Midbrain RF

Following function and structure

Somatic - motor

nucl. (+ disturbances)

Medial line (column): XII (hemiplegia alternans

inferior),

VI (hemiplegia alternans

media),

IV, III (hemiplegia alternans

superior)

Lateral line (column): Nucl ambiquus (IX, X, XI)

(nucl spinalis XI),

VII, V

brainstem lesion when

nerve and pyramidal tract is

attacked

what seen: palsy of nerves on

ipsilateral side and muscles on the

contralateral side

media et superior

Superior alternating

hemiplegia (Weber's

Syndrome)

has a few distinct

symptoms: contralateral

hemiparesis of limb and

facial muscle accompanied

by weakness in one or more

muscles that control eye

movement on the same side.

Another symptom that

appears is the loss of eye

movement due to damage to

the oculomotor nerve fibers.

The upper and lower

extremities have increase

weakness.

Middle Alternating

Hemiplegia

- typically constitutes

weakness of the

extremities

accompanied by

paralysis of the orbit in

the eye muscle on the

opposite side of the

affected extremities.

There is a lesion in the caudal

and medial pons involving the

abducens nerve root (controls

movement of the eye) and

corticospinal fibers (carries

motor commands from the

brain to the spinal cord).

Inferior Alternating

Hemiplegia

(also known as medial

medullary syndrome) -

involves a “weakness of

the extremities

accompanied by

paralysis of muscles on

the ipsilateral side of the

tongue (seen as a

deviation of the tongue

on that side on

protrusion).

These symptoms indicate a

lesion in the medulla

involving the corticospinal

fibers in the pyramid and

the exiting hypoglossal

nerve roots).

Palsy

tongue is sticken out

to side where lesion

is (peripheral palsy)

tongue is sticken out

to opposite side

(central palsy)

contralaterally

palsy of limbs

intra-

and extra-

glossal

muscles

peripheral

central

(voluntary actions)

Nc. n. V. – lesion – from it portio minor

(motor fibres for all of the masticatory muscles)

Nc. n. VII. – innervates mimic muscles, the

platysma muscle, the posterior belly of the

digastric muscle, the stylohyoid muscle, the

stapedius muscle

Nc. n. IX., X. (ambigus) – contacted with RF

and olivary nuclei, innervates muscles of

tonsillar pillars, pharynx, larynx, oesophagus

lateral motor

column

motor ___

touch -----

pain warm ________

Nc V

Visceral - motor nuclei – (involved with visceral spinal reflexes,

gland actions)

Nc. parasympaticus (dorsalis) n. III.

(Edinger - Westphal) – innervates the

ciliary ganglion, sphincter pupillae,

ciliary muscle – lesion - mydriasis

Nc. dorsalis n. VII. (nc. salivatorius

superior) – innervates glandula

submandibularis, sublingualis, minute

glands of the oral cavity)

Nc. dorsalis n. X. (nc. salivatorius

inferior) – innervates the pneumogastric

system, the heart, parotid gland

mixed nerves

Position of the CN VII. nuclei SoMo – ncl. n. VII, ViMo – ncl. salivatorius sup

ViSe – ncl. solitarius (resp. gustatorius),

SoSe – ncl. spinalis et pontinus n. trigemini

Division of the sensory nerve

nuclei

Somatic sensory and special

sensory nuclei (somatic: transmit pain,

pull, temperature, pressure, vibrations,

proprioception; special: involved in sensory

pathways – auditory, vestibular, cerebellar)

Somatic

Nc. spinalis n. V. – continued to the Rexed I-IV.,

collaterals of centripetal fibres with ganglion

trigeminale Gasseri

Nc. pontinus (principalis) n. V. (connected with

ganglion trigeminale)

Nc. mesencephalicus n. V.) - conducts

proprioception from the gingiva, masticatory

system

motor ___

touch -----

pain warm ________

Somatic sensory

Section through

that tract can stop deep

and cruel pain from the

nV. regions

Nc. tractus nervi trigemini

Trigeminal tract nuclei

Position of the CN V. SM – ncl. n. V – portio minor

VM – no, spread to peripheral branches of other nerves

SoSe – ncl. spinalis. n. V. – pain and termic signals

Ncl. pontinus n. V. - mechanoreception

Ncl. mesencephalicus n. V. – proprioception from masticatory and

oculomotory muscles

mechanoreception from periodontium

Division of the sensory nerve

nuclei Somatic sensory and

special sensory nuclei (somatic: transmit pain, pull, temperature,

pressure, vibrations, proprioception;

special: involved in sensory pathways –

auditory, vestibular, cerebellar)

Special

Nc. vestibulares (medial- Schwalbe;

lateral-Deiters, cranial-Bechterew, caudal-

Roller) – connection with the cerebellar

nuclei

Nc. cochleares (caudal; cranial) –

involved in the auditory pathway,

connections with the corpora trapezoidea

and lemniscus

Division of the sensory nerve

nuclei

Visceral sensory nuclei (transmit visceral

sensations, involved in taste

reflex and in visceral reflex

arches)

Nc. n. V., VII., IX., X.) – nc.

solitarius surrounded by tractus

solitarius:

- rostral part – nc. gustatorius

- caudal part – nc. commisuralis

Ncl. cochleares

(ventralis et dorsalis)

Lemniscus lateralis

Ncl. vestibulares

(medialis,lateralis

cranialis, caudalis)

from semicircular canals – M+Cr

utriculus + sacculus M+L+Cau

Position of the CN VIII.

nuclei

Central connections with

vestibular system

How vestibular

nuclei assist

in balance control

Fasciculus

longitudinalis

medialis

Afferent: Taste !

Respiratory digestive systems

Chemo+baroreceptors of vessels

Efferent: Thalamus – 43 taste area

Reticular formation – hypothalamus amygdala

To motor ncc. V.,VII.,XII. Phrenicus,

Control

of emotional

behavior

Autonomic

functions

Position of the CN IX + X nuclei SoMo – ncl. ambiguus

ViMo – ncl. salivatorius inf. (IX) + ncl. dorsalis n. vagi

ViSe – ncl. solitarius (resp. gustatorius)

SoSe – ncl. spinalis et pontinus n. trigemini

Ncl. spinalis n.

accessorii in C1-C6 Innervation of STCM and trapezius

muscles using rad. spinalis a r.

externus

Neurons for branchial muscles are in

ncl. ambiguus; using radix cranialis

and ramus internus are added to n.

vagus

Ncl. n. hypoglossi

Intraglossal and extraglossal

muscles

macroscopic sections

Ncl. gracilis et cuneatus (Ncl. cuneatus lateralis)

Lemniscus medialis et deccusatio

Lower section Medulla oblongata

Medulla spinalis

Ncl. olivaris – p.crbl. inf.

climbing fibers

Rytmic dyskinesis

Medulla

oblongata

Upper section

The ventral portion of the medulla oblongata contains

medullary pyramids. These two ridge-like structures travel along the length of the medulla oblongata and are

bordered medially by the anterior median fissure. They each have an anterolateral

sulcus along their lateral borders.

Also located laterally from each pyramid is a pronounced bulge known as an olive.

The medullary pyramids contain motor fibers that are known

as the corticobulbar and corticospinal tracts.

The corticospinal tracts are on the anterior surface of the

pyramids.

These tracts condust motor signals that originated in the precentral gyrus

and travelled through the internal capsule to the medulla oblongata and

pyramids. Extrapyramidal tracts are those motor tracts that do not

traverse the medullary pyramids.

Lateral medulla oblongata syndrome

Ipsilaterally

Loose of

thermal

and pain

feelings in

face

Contralaterally

loose of thermic

ang pain

feelings in

remaning body

parts of thermal

and pain feelings

in face

Pons Varoli

Petrovický P. a spol. Anatomie, Centrální

nervový systém. Karolinum, Praha, 1995

Williams P.L. (ed): Grays Anatomy,

Churchill Livingstone, New York, 1995

Pyramidal tract

Lower

section

Distribution

of white matter

fasciculi inside

brainstem

Ncl. pontis

Fibrae pontis longitudinales Co-po, CO –

Spi

Fibrae pontis transversae – brachia pontis

Ponto-

mesencephalic

border

ponto-mesencephalic border

IV. ventricle

mesencephalon lower

section through inferior collicles

mesencephalon upper

Tectum

Tegmentum

Crura cerebri

Midbrain

section through

superior

colliculus

cortico-pontine

pathways

corticospinal

pathways

Mesencephalon

Williams P.L. (ed): Grays

Anatomy, Churchill

Livingstone, New York,

1995 Petrovický P. a spol. Anatomie, Centrální nervový systém.

Karolinum, Praha, 1995 (English mutation)

Substantia grisea

centralis SGG

• Afferent connection from spinal cord,

nc. solitarius, limbic system, amygdala

• Efferent connection to spinal cord,

RF(magnocellular part), thalamus,

hypothalamus Stimulation causes analgesia, increases pressure tachycardia,

support protection reractions

Probably helps to increase serotonin concentration in dorsal spinal

cord horn; pain to thalamus is decreased

Substantia nigra SN • Compact part - dopaminergic (Tsai group)

• Reticular part – GABA

• Afferent connection from striatum (basal

nuclei) smaller part from pallidum

• Efferent connection to striatum, amygdala +

neocortex

Loose of dopamin – Parkinsonism (hypokinesis, hypertonism, tremor)

Nucleus ruber NR • magnocellular part - dopaminergic (Tsai

group)

• parvicellular part – GABA

• Afferent connection from cingular cortex

(noncrossed)

• Efferent connection to lateral spina fasciculus

(rubrospinal tract)

to oliva inferior

to RF

Reticular formation

www.macalester.edu http://img132.imageshack.us

Mostly produce serotonin (B1-B6)

Reticular

formation nuclear system and

system of nervous

tracts through all

brainstem parts

arrangement in three

perpendicular strips -

rapheal, medial and

lateral

Rapheal – middle, unpaired

nuclear strip; many

connections with medial row

and with limbic system

Medial – paired, massive,

long connections

Lateral – only in medulla

oblongata and pons, small

cells, connections with

rapheal system,

+ nuclei showing

characteristic nervous

conections or typical mediator (cerebellar cholinergic adrenergic)

raphe nccl.:

linear ncc. L

dorsal rapheal Rod

superior central CS

magnus rapheal Romg

parvus rapheal Ropo

medial nccl.:

cuneiform Cu

pedunculopontinus pePO

oral pontis OPO

oral caudal PC

gigantocellular GC

ventral and oblongatae RV

superior central CS

magnus rapheal Romg

parvus rapheal Ropo

lateral nccl.:

subcuneiform Scu

parvocellular p.c.

dorsal and oblongatae

RF connections

RF

Spinal cord Thalamus

Hypothalamus

Cerebellum

RF connections

RF

Spinal cord Thalamus

Hypothalamus

Cerebellum

Pallidum SN

RF connections

efferent connections with other CNS

structures, in all cases there are

collateral fibers branching to

surrounding nuclei

nervous impuls can be conducted to many

cells and becames stronger

afferent fibers coming from medulla,

sensory tracts, cranial nerves, CRBL,

hypothalamus, cortex, limbic system

efferent fibers - MS, CRBL, Th, HypoTh

reticular

formation functional centers

pneumotactic

vasomotoric

inspiration expiration

Eye movement

coordination

Vestibular

acoustic

Functio-structural centers: Center for breathing – RF nuclei under surface

of the fossa rhomboidea (rhomboid fossa), parts

of expiration and inspiration + tr. RF – Spi

+ feedback to n. X.

centrum is under control of the s.c.

pneumotaxic center - pO2, pH, pCO2

vasomotoric center under tr. n X., responsible

for regulation of blood press,

center for heart control (acceleration or

retardation of the heart beating),

vomiting center

Reflexes of “resuscitation“:

swalloving reflex,

sucking reflex,

reflexes of salivary glands,

visceromotoric reflexes

Protecting reflexes:

ef + af: fibers NC, under RF control

twinking, blinking, corneal, tearing, coughing,

vomiting (suffocating), iridial

Frédéric Bremer

neurophysiologist

1892–1982

« encéphale isolé »

« cerveau isolé »

Encéphale isolé medulla is cut at level C1-C2,

sleep and vigilance changes each other,

animal reacts on sound, head skin and visual

impulses.

Eyes are open, tongue and ears are

moveable.

EEG is typical for awaken events

Cerveau isolé the brainstem is cut between colliculi

superiores and colliculi inferiores.

There is lost relation between telencephalon

and other brain parts.

animal has closed eyes, miosis, noreaction

for irritation, deep sleep.

EEG is typical for sleep (EEG waves are

changed by high spindles)

respiration is spontaneous, tonus of muscles

is increased (decerebration rigidity)

Activation of CNS by RF

http://www.ott.zynet.co.uk branching of neurons in RF (rat braistem)

RF -

Activation role increases intensity of impulses for

cortex and medullar motoneurons and

vice versa

Inhibitory role inhibites activity of spinal cord

motoneurons

cerveau isole, encephale isole

Pathways inside

brainstem

• pedunculi cerebellares

• lemniscus medialis

• tr. spino - thalamicus

• crura cerebri – tr. cortico – spinalis, cortico-pontinus

• Corpus trapezoideum et lemniscus lateralis

• FLM, FLD (fasciculus medialis fasciculus dorsalis (Schutz)

Precerebellar nuclei

nuclei inside brainstem projecting to

cerebellum:

• Ncl. pontis – synapses of cortex fibers for

cerebellum

• Ncl. olivares – synaptic nccl. for spinal cord

fibers for cerebellum

Chemical systems in the CNS

Main mediators:

acetylcholin, catecholamins (adrenalin,

noradrenalin, dopamin), indolamins (serotonin,

histamin).

Peptids - substance P, enkefalin, endorfin

derivatives

Gas - CO, NO

Modulators - peptids, located in synaptic

connections commonly with other mediators.

Cholinergic system (Ch 1-6) acetylcholin – many functions,

mediator for motor and vegetative (autonomic)

functions, memory and training,

exciting mediator, due to receptor type exerts

nervous activation as well as inhibition.

Incidence: targeting neurons and interneurons

located in archicortex, neocortex and RF,

Damage: loose of memory, Alzheimer disease

Monoamines catecholamines (adrenalin, noradrenalin, dopamin)

(A 1 – 16)

caudorostral arrangement, predominantly exciting

influence

containing pigment instead of adrenergic cells,

indolamines (serotonin, histamin) (B1 - 9)

predominantly exerting inhibition

Adrenergic system (C1 - 3)

located in RF

Noradrenergic system (A 1 - 7, )

localized in RF (A1-5) and under locus

coeruleus (A 6,7),

throung nervous conections conveys to all

CNS: significantly increases attention - cortical

arousal reaction

impulses for breathing and cardiovascular

systems

Degeneration in locus coeruleus - demention

Dopaminergic system (A 8 - 10)

dopamin is necessary for extrapyramidal motor

effects,

(A9) - subst. nigra compacta – through nigrostriatic

tracts to striatum,

Disturbance in striatum – Parkinson syndrome

(akinesis, tremor, rigor) due to degeneration of

nigrostriatic system.

Damage of the A10 system is followed with

demention.

(A10) - area tegmentalis ventralis – through

telencephalicus medialis tract activating frontal and

limbic core, amygdalar complex and brain septum

Dopamin distribution is basic for reward

mechanism:

gratifying cmfortable feeling following some

body function as “reward“,

some drugs (cannabis derivatives, opium,

cocain, alcohol) support dopamin distribution;

at the some time serotonin distribution is

blocked - this is principle of neurobiological

base for the drug dependence.

Serotoninergic system rapheal nuclei (B1 - 9) distribute its compounds to all

CNS, serotonin there is predominantly inhibiting

factor (due to receptor type)

Great function spectrum:

in medulla: systém inhibits sympathetic neurons and

pain transduction; all motoneurons are activated,

exerts influence temperature regulation, sexual

behavior, digestion, brain blood supply, relax (dream)

regulations, serotonin decreasing is followed with endogenous depressive

reactions

Reflex

irritation – answer cycle in organism; the simpliest event.in

CNS effectors = mostly muscles

Reflexes: uncoditional (congenital) stereotypical, permanent –

(sneezing, coughing, corneal, reflex extenzing limbs, patellar)

Newborn - grasping

Reflexes: conditional (not congenital obtained through life):

Depends on experiences because of selfteaching I.P.Pavlov (dog

bulb and food), develops on uncoditionalreflex if some conditional irritation is added.

Monosynaptický

reflex

Afferent (senzoric centripetal) neuron conducts impuls through

one synapsis only to efferent (motor , centrifugal) neuron

Lingering , grip-like

Polysynaptic

reflex

Afferent (senzoric, centripetal) neuron conducts impuls through

interneuron (two synapses) to efferent (motor, centrifugal)

neuron.

Česky: Korneální reflex, Rohovkový

reflex

English: Corneal reflex, Blink reflex

Corneal reflex arch:

Afferent:

Corneal exteroreceptors, afferent n.ophtalmicus (1. branch of n.V.)

efferent:

n.VII. tom. orbicularis oculi.

Cornea is touched - impuls is conducted through nervi cilliares a nervus ophthalmicus (V1.) to brainstem.

Efferentsugnal is conducted through VII . Nerve to m. orbicularis oculi (m. orbicularis oculi)

Česky: mrkací

reflex

English: blink

reflex

Blink reflex je relativně

relatively simple

Afferent part: (free nervous endings in

cornea, n. trigeminus, ganglion, radix and

tractus spinalis n. V.,

Continues to interneurons of RF, next

bilaterally to motor nucleus CN VII and to

m. orbicularis oculi.

Effect: lower eylid contracts

Rohovkový reflex

Česky: Faryngový reflex, Dávivý reflex

English: Pharyngeal reflex, Gag reflex

Irritation (e.g. Cotton of wool) of dorsal wall of pharynx; patient at the

same time pronounces „a" or „e".

Physiologic answer - elevation and constriction ofpharynx; tongue is

retracted.

Vyšetření zvlášť vlevo a vpravo umožní rozlišit lézi aferentní

(oboustranné snížení nebo vymizení odpovědi při dráždění jedné strany)

a eferentní části (jednostranné snížení nebo vymizení odpovědi při

dráždění obou stran) reflexního oblouku.

Dávivý reflex

Cough is repeated strong expiration – airways

are cleaned Irritation - (chemical, thermal, mechanical)

receptors: Mucous membrane of upper and lower airways (vagal region - pleura, spleen, outer ear,

stomach, pericardium);

afferent: senzitive fibers nervus vagus (nervus laryngeus superior);

Cough center: medulla oblongata (n. ambiguus, n. retroambigularis), brain cortex

(voluntary);

Efferent: motoric fibers nervus vagus;

effectors: respirátory muscles;

Pressure gradient above 10 kPa;

Air flow speed 150–280 m/s (cough)

Some material used from various authors:

Petrovicky: CNS, PNS (paper texts), lectures

Petrovicky et al. Anatomy with topographic remarks

(Czech), Vol. III.

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