Comparative Comparative AnatomyAnatomy

Nervous SystemNervous System

Note Set 12Note Set 12

Chapter 16 Chapter 16

Primary Brain VesiclesPrimary Brain Vesicles

Prosencephalon Prosencephalon (Forebrain)(Forebrain) Smell Smell

Mesoncephalon Mesoncephalon (Midbrain)(Midbrain) VisionVision

Rhombencephalon Rhombencephalon (Hindbrain)(Hindbrain) Hearing Hearing Figure 15.1: Primary brain

vessicles (book figure 16.13).

Figure 15.2: Basic brain plan.

Primary Brain Vesicles Primary Brain Vesicles (con’t)(con’t)

Figure 15.3: Brain divisions.

HindbrainHindbrain MyelencephalonMyelencephalon

Medulla oblongataMedulla oblongata Involuntary reflexesInvoluntary reflexes

Vagal lobeVagal lobe Metencephalon Metencephalon

CerebellumCerebellum Roof of metencephalonRoof of metencephalon Reflex control of skel. Reflex control of skel.

musclemuscle Pons Pons

Figure 15.4: Neural tube development.

Hindbrain Hindbrain (con’t)(con’t)

Lateral ventriclesLateral ventricles Two cerebral Two cerebral

hemisphereshemispheres

Posterior choroid Posterior choroid plexusplexus Roof in hindbrainRoof in hindbrain 44thth ventricle tissue ventricle tissue Cerebral spinal fluidCerebral spinal fluid

Tela choroideaTela choroidea Roof of medullaRoof of medulla Thin membraneThin membrane

Figure 15.5: Choroid plexus shown of larval anuran (book figure 16.18).

Divisions and VesiclesDivisions and Vesicles

Figure 15.6: Divisions of the brain and ventricles numbered.

MidbrainMidbrain No subdivisionsNo subdivisions Optic lobesOptic lobes

Optic reflex centersOptic reflex centers Well developed in birdsWell developed in birds

Auditory lobesAuditory lobes Caudal to optic lobesCaudal to optic lobes

Superior (optic) and Superior (optic) and inferior (auditory) inferior (auditory) colliculi- when lobes colliculi- when lobes occur togetheroccur together Corpora quadrigemina Corpora quadrigemina

collectivelycollectively

Figure 15.7: Mesoncephalon and tectum region.

Midbrain Midbrain (con’t)(con’t)

33rdrd ventricle ventricle Optic ventricles- Optic ventricles-

extension to optic lobeextension to optic lobe Ventricles disappear Ventricles disappear

in higher phylogenyin higher phylogeny Cerebral aqueduct Cerebral aqueduct

Restricted Restricted passageways passageways

Conducts 3Conducts 3rdrd and 4 and 4thth ventricleventricle

Aqueduct of Sylvius Aqueduct of Sylvius when restricted when restricted furtherfurther

Figure 15.8: Cerebral aqueduct and ventricles of brain.

Forebrain- DiencephalonForebrain- Diencephalon

Optic chiasmaOptic chiasma Two optic nerves Two optic nerves

crosscross Pituitary glandPituitary gland

Caudal to optic Caudal to optic chiasmachiasma

Saccus vasculosus Saccus vasculosus Posterior to pituitary Posterior to pituitary

in some fishin some fish Depth receptorDepth receptor

Figure 15.9: Regions of the diencephalon of a shark with third ventricle in red (book figure 16.19).

Forebrain- Diencephalon Forebrain- Diencephalon (con’t)(con’t)

HypothalamusHypothalamus Floor of diencephalonFloor of diencephalon Autonomic nervous Autonomic nervous

systemsystem ThalamusThalamus

Walls of diencephalonWalls of diencephalon 33rdrd ventricle cavity ventricle cavity

Communicates with Communicates with lateral ventricleslateral ventricles

Foramen of MonroForamen of Monro

Figure 15.10: Medial view of the brain showing thalamus and hypothalamus of the diencephalon.

Forebrain- Diencephalon Forebrain- Diencephalon (con’t)(con’t)

EpithalamusEpithalamus Several evaginationsSeveral evaginations Roof of diencephalonRoof of diencephalon Paraphysis Paraphysis

anteriorlyanteriorly Epiphyseal complexEpiphyseal complex

PinealPineal PhotoreceptorsPhotoreceptors

ParapinealParapineal Pineal eye (3Pineal eye (3rdrd eye) eye)

Figure 15.11: Epithalamus; gross mid-sagittal section of the human brain.

Figure 15.12: Pineal in detail (book figure 16.24).

Forebrain- Forebrain- TelencephalonTelencephalon

Cerebral hemispheres Cerebral hemispheres posteriorposterior

Rhinencephalon Rhinencephalon anterior anterior OlfactionOlfaction

Lower vertebratesLower vertebrates Rhinencephalon Rhinencephalon

prominentprominent Hemispheres smallerHemispheres smaller

Higher vertebratesHigher vertebrates Hemispheres increase in Hemispheres increase in

sizesize Olfactory get smallerOlfactory get smaller

Figure 15.13: Front section of cerebral hemisphere formation (book figure 16.13).

Craniate BrainsCraniate Brains

Figure 15.14: Craniate brains.

Craniate Brains Craniate Brains (con’t)(con’t)

Figure 15.15: Dorsal view of craniate brains (book figure 16.14).

Fish CerebrumFish Cerebrum

Primitive sensoryPrimitive sensory Pallium- dorsal areaPallium- dorsal area

Motor areaMotor area Subpallium- ventral areaSubpallium- ventral area

Globus pallidus (Striatum)Globus pallidus (Striatum)

Figure 15.16: Globus pallidus of fish; left cerebral hemisphere (book figure 16.25).

Amphibian CerebrumAmphibian Cerebrum

Similar pallium and globus Similar pallium and globus pallidus pallidus

Split left and right hemispheresSplit left and right hemispheres

Figure 15.17: Globus pallidus of amphibian; left cerebral hemisphere (book figure 16.25).

Reptile CerebrumReptile Cerebrum

Cerebrum is huge Cerebrum is huge compared to compared to amphibiansamphibians Increase of lateral wallsIncrease of lateral walls Pushes into lateral Pushes into lateral

ventricleventricle Dorsal ventricular ridge Dorsal ventricular ridge

formsforms Receives visual, auditory, Receives visual, auditory,

and sensory stimuliand sensory stimuliFigure 15.18: Globus pallidus of reptile and bird; left cerebral hemisphere (book figure 16.25).

Bird CerebrumBird Cerebrum

Similar to reptilesSimilar to reptiles Avian ridge (hyperstiatum)Avian ridge (hyperstiatum)

Stratum of neurons that capped ridgeStratum of neurons that capped ridge Processes visual informationProcesses visual information Important to instinctive stereotypic Important to instinctive stereotypic

behaviorbehavior Migration and courtshipMigration and courtship

Mammal CerebrumMammal Cerebrum

Lateral ventricles extremely Lateral ventricles extremely expandedexpanded NeocortexNeocortex

Higher mental facilitiesHigher mental facilities Grooves (sulci)Grooves (sulci) Folds (gyrae)Folds (gyrae)

Figure 15.19: Neocortex of mammalian brain.

Mammal Cerebrum Mammal Cerebrum (con’t)(con’t)

Figure 15.20: Ventral view of human brain (book figure 16.17).

Mammal Cerebrum Mammal Cerebrum (con’t)(con’t)

Portion of primitive brain Portion of primitive brain retainedretained Ventral mediallyVentral medially Hippocampus- ancient Hippocampus- ancient

olfactory palliumolfactory pallium Memory storage?Memory storage?

Globus pallidum pushed Globus pallidum pushed interiorlyinteriorly

Basal gangliaBasal ganglia

Changes in basal ganglia Changes in basal ganglia motor dysfunctionmotor dysfunction Parkinson’s DiseaseParkinson’s Disease

Figure 15.21: Globus pallidus of human; left cerebral hemisphere (book figure 16.25).

Mammal Cerebrum Mammal Cerebrum (con’t)(con’t)

Figure 15.22: Sagittal section of the human brain (book figure 16.24).

Cranial NervesCranial Nerves Amniotes have 12Amniotes have 12 Anamniotes have 10Anamniotes have 10 Terminal nerve (Nerve 0)- uncommon in Terminal nerve (Nerve 0)- uncommon in

humanshumans Associated with pheromone receptorsAssociated with pheromone receptors

Figure 15.23: Cranial nerve locations on the brain.

Figure 15.24: Cranial nerve innervation.

Figure 15.25: Cranial nerve innervation.

Cranial Nerves Cranial Nerves (con’t)(con’t)

Figure 15.27: Cranial nerves in 6th week embryo.

Figure 15.26: Head organization in 4th week embryo (book figure 16.39).

Cranial Nerves Cranial Nerves (con’t)(con’t)

Cranial Nerves Cranial Nerves (con’t)(con’t)

Literature CitedLiterature CitedFigure 15.1, 15.5, 15.9, 15.12, 15.13, 15.15, 15.16, 15.17, 15.18, 15.20, Figure 15.1, 15.5, 15.9, 15.12, 15.13, 15.15, 15.16, 15.17, 15.18, 15.20,

15.21 & 15.22, 15.27- Kent, George C. and Robert K. Carr. 15.21 & 15.22, 15.27- Kent, George C. and Robert K. Carr. Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001.Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001.

Figure 15.2- Figure 15.2- http://people.eku.edu/ritchisong/342notes11.htmlFigure 15.3- Figure 15.3-

http://web.lemoyne.edu/~hevern/psy340/lectures/psy340.04.2.ns.structure.html

Figure 15.4- Figure 15.4- http://people.eku.edu/ritchisong/342notes11.htmlFigure 15.6- Figure 15.6- http://brain.exp.univie.ac.at/08_vorlesung_ss04/bilder.htmFigure 15.7- Figure 15.7- http://songweaver.com/brain/index.htmlFigure 15.8- Figure 15.8- http://www.medfriendly.com/multiplesclerosis.htmlFigure 15.10- Figure 15.10- http://www.csuchico.edu/~pmccaff/syllabi/CMSD

%20320/362unit5.htmlFigure 15.11- Figure 15.11- http://www.sci.uidaho.edu/med532/epithala.htmFigure 15.14- Figure 15.14- http://people.eku.edu/ritchisong/342notes11.htmlFigure 15.19- Figure 15.19- http://www.aishamusic.com/prayer.htmFigure Figure

15.23-15.23-http://www.besthealth.com/besthealth/bodyguide/reftext/html/nerv_sys_fin.html

Figure 15.24- Figure 15.24- http://www.neurophys.com/EMG/Cranial_Nerves/Figure 15.25- Figure 15.25-

http://www1.appstate.edu/~clarkhm/swallow_distance/page2.htmFigure 15.27- Figure 15.27-

http://isc.temple.edu/neuroanatomy/lab/embryo_new/nerves/