Comparative Anatomy Nervous System Note Set 12 Chapter 16

Primary Brain Vesicles Prosencephalon (Forebrain) Smell Mesoncephalon (Midbrain) Vision Rhombencephalon (Hindbrain) Hearing Figure 15.1: Primary brain vessicles (book figure 16.13).

Primary Brain Vesicles (con’t) Figure 15.2: Basic brain plan. Figure 15.3: Brain divisions.

Hindbrain Myelencephalon Metencephalon Medulla oblongata Vagal lobe Involuntary reflexes Vagal lobe Metencephalon Cerebellum Roof of metencephalon Reflex control of skel. muscle Pons Figure 15.4: Neural tube development.

Hindbrain (con’t) Lateral ventricles Posterior choroid plexus Two cerebral hemispheres Posterior choroid plexus Roof in hindbrain 4th ventricle tissue Cerebral spinal fluid Tela choroidea Roof of medulla Thin membrane Figure 15.5: Choroid plexus shown of larval anuran (book figure 16.18).

Divisions and Vesicles Figure 15.6: Divisions of the brain and ventricles numbered.

Midbrain No subdivisions Optic lobes Auditory lobes Optic reflex centers Well developed in birds Auditory lobes Caudal to optic lobes Superior (optic) and inferior (auditory) colliculi- when lobes occur together Corpora quadrigemina collectively Figure 15.7: Mesoncephalon and tectum region.

Midbrain (con’t) 3rd ventricle Optic ventricles- extension to optic lobe Ventricles disappear in higher phylogeny Cerebral aqueduct Restricted passageways Conducts 3rd and 4th ventricle Aqueduct of Sylvius when restricted further Figure 15.8: Cerebral aqueduct and ventricles of brain.

Forebrain- Diencephalon Optic chiasma Two optic nerves cross Pituitary gland Caudal to optic chiasma Saccus vasculosus Posterior to pituitary in some fish Depth receptor Figure 15.9: Regions of the diencephalon of a shark with third ventricle in red (book figure 16.19).

Forebrain- Diencephalon (con’t) Hypothalamus Floor of diencephalon Autonomic nervous system Thalamus Walls of diencephalon 3rd ventricle cavity Communicates with lateral ventricles Foramen of Monro Figure 15.10: Medial view of the brain showing thalamus and hypothalamus of the diencephalon.

Forebrain- Diencephalon (con’t) Epithalamus Several evaginations Roof of diencephalon Paraphysis anteriorly Epiphyseal complex Pineal Photoreceptors Parapineal Pineal eye (3rd eye) Figure 15.11: Epithalamus; gross mid-sagittal section of the human brain. Figure 15.12: Pineal in detail (book figure 16.24).

Forebrain- Telencephalon Cerebral hemispheres posterior Rhinencephalon anterior Olfaction Lower vertebrates Rhinencephalon prominent Hemispheres smaller Higher vertebrates Hemispheres increase in size Olfactory get smaller Figure 15.13: Front section of cerebral hemisphere formation (book figure 16.13).

Craniate Brains Figure 15.14: Craniate brains.

Craniate Brains (con’t) Figure 15.15: Dorsal view of craniate brains (book figure 16.14).

Fish Cerebrum Primitive sensory Motor area Pallium- dorsal area Subpallium- ventral area Globus pallidus (Striatum) Figure 15.16: Globus pallidus of fish; left cerebral hemisphere (book figure 16.25).

Amphibian Cerebrum Similar pallium and globus pallidus Split left and right hemispheres Figure 15.17: Globus pallidus of amphibian; left cerebral hemisphere (book figure 16.25).

Reptile Cerebrum Cerebrum is huge compared to amphibians Increase of lateral walls Pushes into lateral ventricle Dorsal ventricular ridge forms Receives visual, auditory, and sensory stimuli Figure 15.18: Globus pallidus of reptile and bird; left cerebral hemisphere (book figure 16.25).

Bird Cerebrum Similar to reptiles Avian ridge (hyperstiatum) Stratum of neurons that capped ridge Processes visual information Important to instinctive stereotypic behavior Migration and courtship

Mammal Cerebrum Lateral ventricles extremely expanded Neocortex Higher mental facilities Grooves (sulci) Folds (gyrae) Figure 15.19: Neocortex of mammalian brain.

Mammal Cerebrum (con’t) Figure 15.20: Ventral view of human brain (book figure 16.17).

Mammal Cerebrum (con’t) Portion of primitive brain retained Ventral medially Hippocampus- ancient olfactory pallium Memory storage? Globus pallidum pushed interiorly Basal ganglia Changes in basal ganglia  motor dysfunction Parkinson’s Disease Figure 15.21: Globus pallidus of human; left cerebral hemisphere (book figure 16.25).

Mammal Cerebrum (con’t) Figure 15.22: Sagittal section of the human brain (book figure 16.24).

Cranial Nerves Amniotes have 12 Anamniotes have 10 Terminal nerve (Nerve 0)- uncommon in humans Associated 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 (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 (con’t)

Cranial Nerves (con’t)

Literature Cited 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. Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001. Figure 15.2- http://people.eku.edu/ritchisong/342notes11.html Figure 15.3- http://web.lemoyne.edu/~hevern/psy340/lectures/psy340.04.2.ns.structure.html Figure 15.4- http://people.eku.edu/ritchisong/342notes11.html Figure 15.6- http://brain.exp.univie.ac.at/08_vorlesung_ss04/bilder.htm Figure 15.7- http://songweaver.com/brain/index.html Figure 15.8- http://www.medfriendly.com/multiplesclerosis.html Figure 15.10- http://www.csuchico.edu/~pmccaff/syllabi/CMSD%20320/362unit5.html Figure 15.11- http://www.sci.uidaho.edu/med532/epithala.htm Figure 15.14- http://people.eku.edu/ritchisong/342notes11.html Figure 15.19- http://www.aishamusic.com/prayer.htm Figure 15.23-http://www.besthealth.com/besthealth/bodyguide/reftext/html/nerv_sys_fin.html Figure 15.24- http://www.neurophys.com/EMG/Cranial_Nerves/ Figure 15.25- http://www1.appstate.edu/~clarkhm/swallow_distance/page2.htm Figure 15.27- http://isc.temple.edu/neuroanatomy/lab/embryo_new/nerves/