Chapt27and28TheReproductiveSystem.ppt

7/25/2019 Chapt27and28TheReproductiveSystem.ppt

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The reticular formationThe reticular formation


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THE RETICULAR FORMATION (cont.)THE RETICULAR FORMATION (cont.)

RF is formed of large number of neuronsRF is formed of large number of neurons

present through the entire brainstem, itpresent through the entire brainstem, it

extends upward to the level of the thalamusextends upward to the level of the thalamusand downward to be continuous with theand downward to be continuous with the

interneurons of the spinal cord.interneurons of the spinal cord.


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Locations of the reticular and

vestibular nuclei in the brain stem


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THE RETICULAR FORMATION (cont.)THE RETICULAR FORMATION (cont.)

Afferent projectionAfferent projection

..All sensory pathwaysAll sensory pathways !general or special!general or specialsensations"sensations"

#.#. $erebral cortex$erebral cortex

%.%. cerebellumcerebellum

&.&. 'asal ganglia!corpus striatum"'asal ganglia!corpus striatum"

(.(.

)estibular nuclei, visual pathway)estibular nuclei, visual pathway'&'&(#alamus *ubt#alamus and(#alamus *ubt#alamus and

+ypot#alamic nuclei+ypot#alamic nuclei


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THE RETICULAR FORMATIONTHE RETICULAR FORMATION

(cont.)(cont.) ,erent pro-ection:,erent pro-ection:

1&1&Reticulobulbar and reticulospinal tractsReticulobulbar and reticulospinal tracts

2&2&descendin! pat#$ay to sympat#eticdescendin! pat#$ay to sympat#eticand parasympat#etic out.o$ of /N*and parasympat#etic out.o$ of /N*

%.%. cerebellumcerebellum

&.&. 'asal ganglia!corpus striatum"'asal ganglia!corpus striatum"0&0&(#alamus *ubt#alamus and(#alamus *ubt#alamus and

+ypot#alamic nuclei+ypot#alamic nuclei


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onnections of Reticularonnections of Reticular

FormationFormation

Fi!& 1 "/erent connections ofreticular formation

Fi!& 2 ,erentconnections of reticularformation


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/scendin! Reticular /ctivatin! *ystem "/scendin! Reticular /ctivatin! *ystem " ARASARAS

t#et#e reticular activatingreticular activatingsystem (RAS)system (RAS)is an area ofis an area oft#e brain 4includin! t#et#e brain 4includin! t#ereticular formation and itsreticular formation and itsconnections) responsibleconnections) responsiblefor re!ulatin! arousalfor re!ulatin! arousaland sleep"$a%e transitions&and sleep"$a%e transitions&

Receives bers from t#eReceives bers from t#esensory pat#$ays via lon!sensory pat#$ays via lon!ascendin! spinal tracts&ascendin! spinal tracts&

/lertness maintenance of/lertness maintenance ofattention and $a%efulnessattention and $a%efulness&&

,motional reactions,motional reactionsimportant in learnin!important in learnin!processes&processes&

(umor or lesion(umor or lesion sleepin! sleepin!sic%ness or coma&sic%ness or coma&

Functional divisions of ReticularFormation

Fi!&3 5rain section&


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FunctionsFunctions

1&1& ontrol of s%eletal musclesontrol of s%eletal muscles

2&2& ontrol of somatic and visceralontrol of somatic and visceral

sensationssensations

3&3& ontrol of /N*ontrol of /N*

6&6& 7n.uence t#e biolo!ic cloc%7n.uence t#e biolo!ic cloc%

0&0& (#e reticular activatin! system(#e reticular activatin! system'&'& ontrol of endocrine nervous systemontrol of endocrine nervous system


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)estibulospinal and reticulospinal tracts

descending in the spinal cord to excite

(solid lines) or inhibit (dashed lines) theanterior motor neurons that control the

body*s axial musculature


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Dama!e to RF persistentDama!e to RF persistent

unconsciousness and even comaunconsciousness and even coma


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Slee

SleeSleeis defined as changed state ofis defined as changed state ofconsciousness from which the person canconsciousness from which the person can

be aroused by sensory or other stimuli, it isbe aroused by sensory or other stimuli, it isfacilitated by reducing sensory input andfacilitated by reducing sensory input and

by fatigue.by fatigue.

ComaComais unconsciousness from whichis unconsciousness from whichthe person cannot be aroused.the person cannot be aroused.

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Chapt27and28TheReproductiveSystem.ppt