Week 10 Central Nervous System The Brain Sheep HumanHuman BrainBrain Brain Expanded Studies

OBJECTIVES Identify the components of the human brain using models and diagrams Identify the cranial nerves Identify the structures of the sheep brain

Objective 1: Anatomy of the Human Brain & Cranial Nerves

Cerebrum (gold area) Diencephalon (Violet area) Brain stem (green area) Cerebellum (pink area) 4 Major Regions of the Brain

Cerebrum 1

Fissure Sulcus Gyrus Ventricles Structures of the Cerebrum Cerebral Hemispheres Left HemisphereRight Hemisphere Gray Matter – Cerebral cortex & Basal nuclei White Matter – Myelinated axons (fiber tracts) Frontal cut

Recap: Pyramidal Cells of Cerebral Cortex Cerebral Cortex Histology - Recap

Structures of the Cerebrum Surface Lateral View Frontal lobe Parietal lobe Temporal lobe Occipital lobe Central sulcus Lateral sulcus Parieto-occipital sulcus Transversefissure Postcentral gyrusPrecentral gyrus

Structures of the Cerebrum Midsagittal Section Parietal lobe Frontal lobe Occipital lobe Temporal lobe Corpus callosum Septum pellucidum Fornix

The Real Thing: Human Brain, Lateral ViewOccipital lobe lobe Frontal Temporal lobe Parietal lobe Gyrus Lateral sulcus Central sulcus Transverse Fissure

The Real Thing: Human Brain, Superior View Longitudinal fissure Central sulcus Post central gyrus Pre central gyrus Frontal pole Occipital pole

Midsagittal Section MRI Fornix Corpus callosum Septum pellucidum

Internal Structures of the Cerebrum Frontal Section Corpus callosum Fornix Lateral Ventricles Septum pellucidum

Kim Peek, the inspiration for the 1988 Oscar-winning movie Rain Man Among other things, his MRI scan shows an absent corpus callosum Read more about Kim, mega savant: kimpeek.cfm

Functional areas of the Cerebral Cortex

Functional Mapping of Pre and Post Central Gyri

Functional areas of the cerebrum Cerebral (Basal) Nuclei Initiate, regulate, monitor intensity of & stop movements Maybe help in regulating attention and in cognition Coordination

Diencephalon 2

Structures of the Diencephalon Midsagittal Section Corpus callosum Intermediate mass Hypothalamus Mammillary body Thalamus Pineal body/gland Optic chiasma Pituitary gland Infundibulum

Functions of the Diencephalon Endocrine System Relay Stations Thalamus

Pineal = “pine cone” Pineal Gland Extends from Epithalamus Secretes melatonin

Internal composition - Function Thalamus Fiber tracts connecting the thalami Relay station of the brain Sensation, Motor activities, Cortical arousal, Learning, Memory

Internal composition - Functions Endocrine System Master gland of the body “The brain of the brain” The power behind the pituitary gland Homeostasis regulation (ANS) Hypothalamus Pituitary Gland Anterior Neurohormones (Hormone storage) Hormones released by pituitary gland control other glands 6 Adeno- hypo- physeal hormones

Mammillary Bodies Limbic System olfaction, emotion, motivation, behavior, and various autonomic functions Fornix Mammillary Body Thalamus Infundibulum Olfaction relay station

Brainstem 3

Structures of the Brainstem Midsagittal Section Pons Medulla oblongata Midbrain: Corpora quadrigemina Superior colliculi Inferior colliculi Cerebral peduncle

Midbrain Corpora quadrigemina Pons Medulla Oblongata Structures of the Brainstem Posterolateral View Cerebral peduncle Superior colliculus Inferior colliculus Pineal gland Thalamus

Structures of the Brainstem Inferior View Midbrain (Cerebral peduncle) Pons Medulla oblongata Spinal cord Optic chiasma Infundibulum Mammilary Bodies

Functions of the Brainstem Visual & Auditory Reflexes

Cerebellum “Little Brain” 4

Structures of the Cerebellum Posterior Connects the two lobes

Arbor Vitae Cerebellar Peduncles Fourth ventricle Structures of the Cerebellum Midsagittal Section

Structures of the Cerebellum Peduncles 3 major input and output fiber bundles Midbrain

Cerebellum Histology - Recap Purkinje Cells

Functions of the Cerebellum Cognition roles: Attention, word association, puzzle solving, processing language and music

Ventricles & Meninges

Meninges of the Brain

A mnemonic PAD from deep to superficial the layers of the meninges are pia, arachnoid, dura (they pad the brain) Pia mater Arachnoid mater Dura mater Meninges = “Membrane” Subarachnoid space

Superior sagittal sinus Arachnoid villus Dural Sinuses Periosteal layer Meningeal layer Well, one of them anyway

Superior Sagittal Sinus

Human Meninges Dura Mater Inner layer of Dura Mater External layer of Dura Mater (Inner Periosteum) SkullSkull Superior Sagittal Sinuses (Outer Periosteum) Pia Mater

Arachnoid Mater

Arachnoid villi Dura Mater

Ventricles of the Brain

Corpus callosum Lateral ventricles Third ventricle Ventricles Coronal Section of Brain Dien- ceph- alon

Cerebrospinal fluid is continually produced by the choroid plexus found in the ventricles Die-cast model

Ventricles Midsagittal Section of Brain Lateral Ventricle Interventricular Foramen Fourth Ventricle Choroid Plexus Third Ventricle Cerebral Aqueduct

Third Ventricle Cerebral Aqueduct Fourth Ventricle Identify these spaces:

Cerebrospinal Fluid Circulation Choriod plexus Superior sagittal sinus Subarachnoid space Arachnoid villus Lateral ventricles ventricle ventricle ventricle ? Vein Interventricular foramen ? 3rd ? Cerebral aqueduct ? 4th

Cerebellum Brainstem Cerebrum Diencephalon Dura mater Corpus callosum Review of the Brain Regions & Structures Ventricles (Meninges) Pons Regions Structures Coverings Spaces Fornix Corpora quadrigemina ? ? ? ?

Cerebrum Cerebral cortex (Meninges) Dura mater Corpus callosum Ventricles Diencephalon Review of the Brain Regions & Structures Thalamus

12 Pairs of Cranial Nerves On Occasion Our Trusty Truck Acts Funny - Very Good Vehicle AnyHow Oh, Oh, Oh - To Touch And Feel Very Good Velvet - AH! Filaments of Olfactory nerve (I) Olfactory bulb Olfactory tract Optic nerve (II) Optic chiasma Optic tractOculomotor nerve (III) Trochlear nerve (IV) Trigeminal nerve (V) Abducens nerve (VI) Hypoglossal nerve (XII) Accessory nerve (XI) Vagus nerve (X) Glossopharyngeal nerve (IX) Vestibulocochlear nerve (VIII) Facial nerve (VII)

The Real Thing Olfactory Bulb (I) Optic Nerve (II) Oculomotor Nerve (III) Trigeminal Nerve (V) Abducens Nerve (VI) Vestibulo- cochlear Nerve (VIII) Facial Nerve (VII) Hypoglossal Nerve (XII) Glosso- Pharyngeal (IX) Accessory Nerves (XI) Vagus (X) Trochlear Nerve (IV)

Human Cranial Nerves - close up Olfactory Bulbs (I) Optic Nerves (II) Oculomotor Nerves (III) Optic Chiasm Trochlear Nerves (IV) Abducens Nerves (VI) OlfactoryTracts Trigeminal Nerves (V)

FUNCTIONSFUNCTIONSFUNCTIONSFUNCTIONS

Hemorrhagic Stroke Tumor Brain Pathologies Ischemic Stroke

Objective 2: Sheep Brain Dissection

1 Identify the external structures Inferior Sheep brain structures are the same as the human brain, only slightly different sizes

Remove Dura mater (w/ pituitary gland) Remove Dura mater (w/ pituitary gland) Identify the external structures Superior Same structures as human brain, only slightly different size2 1 2

Identify the external structures Inferior

Pull back the cerebellum to reveal Corpora Quadrigemina & Pineal Gland3 ?

Brainstem Diencephalon4

Identify the internal structures Midsagittal

Identify the Cavities Lateral Ventricle Third VentricleCerebral AqueductFourth Ventricle