Ectodermal tissue (embryonic) folds creating neural tube. This neural fold tissue creates the brain (anterior fold) and the spinal cord (posterior.

Ectodermal tissue (embryonic) folds Ectodermal tissue (embryonic) folds creating neural tube.creating neural tube.

This neural fold tissue creates the This neural fold tissue creates the brain (anterior fold) and the spinal brain (anterior fold) and the spinal cord (posterior fold)cord (posterior fold)

Anterior fold grows quicker than Anterior fold grows quicker than posterior producing:posterior producing:

Prosencephalon (forebrain)Prosencephalon (forebrain)

Mesencephalon (midbrain) Mesencephalon (midbrain) Rhombencephalon (hind brain) Rhombencephalon (hind brain)

ProsencephalonProsencephalon

1- Telencephalon 1- Telencephalon

- Cerebrum (cerebral cortex, - Cerebrum (cerebral cortex, white matter and basal nuclei)white matter and basal nuclei)

2- Diencephalon 2- Diencephalon 

- (thalamus and hypothalamus)- (thalamus and hypothalamus)

MesencephalonMesencephalon- Brain stem (midbrain)- Brain stem (midbrain)

RhombencephalonRhombencephalon1- Metencephalon 1- Metencephalon

-Brain stem (pons) and -Brain stem (pons) and Cerebellum Cerebellum

2- Myelencephalon2- Myelencephalon- Brain stem (- Brain stem (medulla oblongata)

Hollow spaces in the brain termed Hollow spaces in the brain termed ventricles.ventricles.

CSF is produced and circulated (lined CSF is produced and circulated (lined with ependymal cells)with ependymal cells)

Lateral ventricles (2) separated by a Lateral ventricles (2) separated by a thin membrane called the septum thin membrane called the septum pellucidum. (CSF produced in the pellucidum. (CSF produced in the choroid plexus)choroid plexus)

Each lateral ventricle communicates Each lateral ventricle communicates with the third ventricle via a channel with the third ventricle via a channel called an interventricular foramen called an interventricular foramen ((foramen of Monroforamen of Monro))

Third ventricle is continuous with the Third ventricle is continuous with the fourth ventricle via the cerebral fourth ventricle via the cerebral aquaduct of Sylviusaquaduct of Sylvius

Fourth ventricle drains CSF into spinal Fourth ventricle drains CSF into spinal cord through the foramen of cord through the foramen of Magendie.Magendie.

Cerebral Hemispheres Cerebral Hemispheres Superior part of the brain Superior part of the brain Covered entirely by ridges (gyri), Covered entirely by ridges (gyri),

separated by shallow grooves (sulci) and separated by shallow grooves (sulci) and deeper called grooves (fissures) deeper called grooves (fissures)

Anatomical landmarks: Anatomical landmarks: – Longitudinal fissure Longitudinal fissure – Frontal, parietal, occipital, and temporal lobes Frontal, parietal, occipital, and temporal lobes

Deep to temporal, parietal, and frontal lobes is a fifth Deep to temporal, parietal, and frontal lobes is a fifth lobe called the insula lobe called the insula

– Central sulcus of RolandoCentral sulcus of Rolando– Pre/post central gyri Pre/post central gyri – Lateral sulcus of SylviusLateral sulcus of Sylvius– Calcarine sulcusCalcarine sulcus– Parito-occipital sulcusParito-occipital sulcus– Transverse cerebral fissureTransverse cerebral fissure

Cerebral Cortex:Cerebral Cortex:Seat of consciousness.Seat of consciousness. Cerebral cortex contains three functional Cerebral cortex contains three functional

areas: areas: 1- Motor areas - control voluntary motor 1- Motor areas - control voluntary motor

function function 2- Sensory areas - provide for conscious 2- Sensory areas - provide for conscious

awareness of sensation awareness of sensation 3- Association areas - integrate all other 3- Association areas - integrate all other

information information Each hemisphere is concerned with the Each hemisphere is concerned with the

sensory and motor functions of the sensory and motor functions of the opposite side of the body opposite side of the body

Motor regions are located in the posterior Motor regions are located in the posterior frontal lobe.frontal lobe.

Primary motor cortexPrimary motor cortex - precentral - precentral gyrus in the frontal lobe gyrus in the frontal lobe

- Large neurons (pyramidal cells) allow - Large neurons (pyramidal cells) allow conscious control of movement of conscious control of movement of skeletal muscles skeletal muscles

-The pyramidal cells' long axons from -The pyramidal cells' long axons from voluntary motor tracts called pyramidal voluntary motor tracts called pyramidal (corticospinal) tracts (corticospinal) tracts

-Motor areas have been spatially mapped -Motor areas have been spatially mapped = = somatotropysomatotropy. (Homunculis). (Homunculis)

Premotor cortexPremotor cortex - anterior to the - anterior to the precentral gyrus in the frontal lobe. precentral gyrus in the frontal lobe.

Regions controls learned motor skills Regions controls learned motor skills that are repeated or patterned. that are repeated or patterned.

Also coordinates the movements of Also coordinates the movements of muscles simultaneously and\or muscles simultaneously and\or sequentially by sending activating sequentially by sending activating impulses to the primary motor impulses to the primary motor cortex. cortex.

Broca's areaBroca's area - anterior to the premotor - anterior to the premotor area area

- Involved in directing motor speech. - Involved in directing motor speech.

Frontal eye fieldFrontal eye field - anterior to the - anterior to the premotor cortex and superior to Broca's premotor cortex and superior to Broca's area   area  

Controls voluntary movement of eyes. Controls voluntary movement of eyes.

Sensory Areas (parietal, temporal, and Sensory Areas (parietal, temporal, and occipital lobes) occipital lobes)

Primary somatosensory cortex - Primary somatosensory cortex - postcentral gyrus of parietal lobe postcentral gyrus of parietal lobe (immediately behind primary motor (immediately behind primary motor cortex) cortex) – Neurons receive info (from sensory receptors, Neurons receive info (from sensory receptors,

skin, and muscles) and identifies body region skin, and muscles) and identifies body region being stimulated being stimulated

Somatosensory association area - lies Somatosensory association area - lies posterior to the primary somatosensory posterior to the primary somatosensory cortex cortex – Integrate and analyze somatic sensory inputs Integrate and analyze somatic sensory inputs

(e.g. temperature and pressure) into (e.g. temperature and pressure) into comprehensive evaluation. comprehensive evaluation.

Visual areas Visual areas - occipital lobes - occipital lobes contain primary visual cortex contain primary visual cortex (receive information from retina) and (receive information from retina) and visual association area (interprets visual association area (interprets information from retina). information from retina).

Auditory areasAuditory areas - temporal lobes - temporal lobes contain primary auditory cortex contain primary auditory cortex (receives impulses from inner ear) (receives impulses from inner ear) and auditory association area and auditory association area (interprets sound). (interprets sound).

Olfactory cortexOlfactory cortex - temporal lobe in - temporal lobe in region called the uncus; enables region called the uncus; enables conscious awareness of odors. conscious awareness of odors.

““Skunkus in my uncus”Skunkus in my uncus”

Gustatory cortexGustatory cortex - parietal lobe - parietal lobe deep to temporal lobe; involved in deep to temporal lobe; involved in perception of taste. perception of taste.

Cerebral CortexCerebral Cortex

Association AreasAssociation Areas Somatosensory cortex - posterior to Somatosensory cortex - posterior to

the primary somatosensory cortex the primary somatosensory cortex – The association areas, in turn, The association areas, in turn,

communicate with the motor cortex and communicate with the motor cortex and with other sensory association areas to with other sensory association areas to analyze, recognize, and act on sensory analyze, recognize, and act on sensory inputs. inputs.

Prefrontal cortex - anterior portions Prefrontal cortex - anterior portions of frontal lobe of frontal lobe

- Involved with intellect and complex - Involved with intellect and complex learning (cognition) and personality learning (cognition) and personality

- Tumors may lead to personality - Tumors may lead to personality disorders - prefrontal lobotomy are disorders - prefrontal lobotomy are performed in severe cases of mental performed in severe cases of mental illness. illness.

Alzheimer’s Disease Alzheimer’s Disease

Language areas - found in Wernicke's Language areas - found in Wernicke's area of temporal lobe of one area of temporal lobe of one hemisphere (usually left) hemisphere (usually left)

- Involved in interpretation of - Involved in interpretation of language.language.

Cerebral White Matter:Cerebral White Matter:- Responsible for communication Responsible for communication

within the brain between each within the brain between each hemisphere, cerebral cortex and hemisphere, cerebral cortex and lower CNS centers.lower CNS centers.

- White matter bundled into large White matter bundled into large tractstracts

- Fibers and tracts are classified Fibers and tracts are classified according to the direction in which according to the direction in which they run.they run.

CommissuralCommissural- Connects the gray areas of both Connects the gray areas of both

hemispheres so the brain functions as one hemispheres so the brain functions as one unitunit

- Corpus callosum: superior to the lateral Corpus callosum: superior to the lateral ventriclesventricles

- Fibers run horizontalFibers run horizontal

Association fibers:Association fibers:

- Connect within the same hemisphere.- Connect within the same hemisphere.

- Connects adjacent gyri and different lobes.- Connects adjacent gyri and different lobes.

- Fibers run horizontal- Fibers run horizontal

Projection fibers:Projection fibers:- Connects cortex to lower brain Connects cortex to lower brain

centers (spinal cord and brain stem).centers (spinal cord and brain stem).- Fibers run verticalFibers run vertical- Internal capsule and corona radiataInternal capsule and corona radiata

Basal nuclei: (cell bodies) ganglia:Basal nuclei: (cell bodies) ganglia:

Receive extensive input from the entire Receive extensive input from the entire cerebral cortex and project messages cerebral cortex and project messages (via relays) to the premotor and (via relays) to the premotor and prefrontal cortices prefrontal cortices

Amygdala: hangs off of the tail of the Amygdala: hangs off of the tail of the caudate nucleus. Center for fear.caudate nucleus. Center for fear.

DiencephalonDiencephalon (thalamus, (thalamus, hypothalamus)hypothalamus)

Thalamus:Thalamus:- Gray matter areas enclose the third Gray matter areas enclose the third

ventricle.ventricle.- Receive and projects fibers from the Receive and projects fibers from the

cerebral cortex.cerebral cortex.- All senses (afferent) from the body All senses (afferent) from the body

will pass through the thalamus (relay will pass through the thalamus (relay center). Senses are then sorted outcenter). Senses are then sorted out

- Gateway to the cerebral cortexGateway to the cerebral cortex

Hypothalamus:Hypothalamus:- Walls of hypothalamus (tissue) meet and Walls of hypothalamus (tissue) meet and

extend, forming infundibulum (stalk), extend, forming infundibulum (stalk), connecting the pituitary to base of connecting the pituitary to base of hypothalamus. hypothalamus.

- The hypothalamus is the main visceral The hypothalamus is the main visceral control center of the body.control center of the body.

Homeostatic roles: Homeostatic roles: 1- Autonomic control center - regulates 1- Autonomic control center - regulates

involuntary nervous system activity involuntary nervous system activity (influences BP, HR, GI motility, Respiration (influences BP, HR, GI motility, Respiration rate and depth, and pupil size). rate and depth, and pupil size).

2- Center for emotional response and 2- Center for emotional response and behavior - numerous connections behavior - numerous connections with cortical association areas with cortical association areas (initiates physical expressions of (initiates physical expressions of emotion). emotion).

3- Body temperature regulation - 3- Body temperature regulation - hypothalamus neurons monitor blood hypothalamus neurons monitor blood temperature flowing through temperature flowing through hypothalamus (initiates sweating, hypothalamus (initiates sweating, shivering, etc.). shivering, etc.).

4- Regulation of food intake - responds 4- Regulation of food intake - responds to hormones and blood levels of to hormones and blood levels of nutrients. (hunger; satiation)nutrients. (hunger; satiation)

5- Regulation of water balance and 5- Regulation of water balance and thirst - triggers ADH release, causing thirst - triggers ADH release, causing kidneys to retain water; thirst kidneys to retain water; thirst centers stimulated, cause us to drink.centers stimulated, cause us to drink.

6- Sleep-wake cycle regulation - set 6- Sleep-wake cycle regulation - set timing of our sleep cycle in response timing of our sleep cycle in response to daylight-darkness cues. to daylight-darkness cues.

7- Control of endocrine system - 7- Control of endocrine system - hypothalamus produces releasing hypothalamus produces releasing hormones that control the secretion hormones that control the secretion of anterior pituitary hormonesof anterior pituitary hormones

Brainstem:Brainstem:- Gray matter surrounded by white Gray matter surrounded by white

mattermatter- Controls automatic functions Controls automatic functions

necessary for survival (cardiac, necessary for survival (cardiac, breathing, digestion, head and eye breathing, digestion, head and eye movement)movement)

- Composed of theComposed of the- midbrain- midbrain- pons- pons- medulla oblongata- medulla oblongata

Midbrain:Midbrain:Structures: Structures: Cerebral peduncles - pyramidal motor tracts Cerebral peduncles - pyramidal motor tracts

descending toward spinal cord. descending toward spinal cord. Cerebral aqueduct - connect 3rd and 4th Cerebral aqueduct - connect 3rd and 4th

ventricle, enclosed by nuclei ventricle, enclosed by nuclei Nuclei - corpora quadragemina (two pair) Nuclei - corpora quadragemina (two pair)

– Superior colliculi (visual reflex, head/eye Superior colliculi (visual reflex, head/eye movement) movement)

– Inferior colliculi (auditory relay, startle reflex) Inferior colliculi (auditory relay, startle reflex) Also embedded in white matter of midbrain Also embedded in white matter of midbrain

are two pigmented nuclei Substantia nigra are two pigmented nuclei Substantia nigra (site of dopamine production)(site of dopamine production)

and red nucleus (contains iron & and red nucleus (contains iron & hemoglobin and coordinates muscular hemoglobin and coordinates muscular movements: limb flexion).movements: limb flexion).

Classes of Neurotransmitters:Classes of Neurotransmitters: Acetylcholine: excitatory (skeletal muscle) Acetylcholine: excitatory (skeletal muscle) Biogenic amines Biogenic amines

– Dopamine, Norepinephrine, and epinephrine Dopamine, Norepinephrine, and epinephrine (feel good catecholamines)(feel good catecholamines)

– Serotonin: inhibitorySerotonin: inhibitory– Histamine Histamine

Amino acids Amino acids – GABA (gamma-aminobutyric acid) (inhibitory)GABA (gamma-aminobutyric acid) (inhibitory)– Glutamate: excitatoryGlutamate: excitatory

Peptides Peptides – Endorphins and enkephalins: inhibitory Endorphins and enkephalins: inhibitory

(opioids)(opioids)

Pons:Pons: - between midbrain and medulla - between midbrain and medulla

oblongata oblongata - Conduction pathway between higher - Conduction pathway between higher

and lower brain centers and lower brain centers - Middle cerebellar peduncles connect - Middle cerebellar peduncles connect

pons with the cerebellum pons with the cerebellum - Some pons nuclei (pneumotaxic) are - Some pons nuclei (pneumotaxic) are

respiratory centers that help respiratory centers that help maintain normal rhythm of maintain normal rhythm of breathing. breathing.

Medulla Oblongata:Medulla Oblongata:- most inferior part of brain stem, blends most inferior part of brain stem, blends

into spinal cord at the level of the foramen into spinal cord at the level of the foramen magnum.magnum.

Structures: Structures: - Pyramids - pyramidal tracts descending - Pyramids - pyramidal tracts descending from motor cortex from motor cortex - Decussation of pyramids - fibers of - Decussation of pyramids - fibers of pyramids cross over at one point; pyramids cross over at one point; supporting that each hemisphere controls supporting that each hemisphere controls voluntary muscles voluntary muscles - Olives - lateral to pyramids, relay sensory - Olives - lateral to pyramids, relay sensory information on the state of stretch of our information on the state of stretch of our muscles and joints to the cerebellummuscles and joints to the cerebellum

Medulla oblongata contains visceral Medulla oblongata contains visceral motor nuclei that control: motor nuclei that control:

1- Force and rate of heart contraction 1- Force and rate of heart contraction

2- Regulate BP (by regulating smooth 2- Regulate BP (by regulating smooth muscle respiratory contraction) muscle respiratory contraction)

3- Rate and depth of breathing, 3- Rate and depth of breathing, therefore maintain respiratory therefore maintain respiratory rhythm rhythm

4- Vomiting, hiccupping, swallowing, 4- Vomiting, hiccupping, swallowing, coughing, and sneezing coughing, and sneezing

Cerebellum: “little brain”.Cerebellum: “little brain”.Processes inputs from the cerebral Processes inputs from the cerebral motor cortex, brainstem nuclei, and motor cortex, brainstem nuclei, and sensory receptors to provide precise sensory receptors to provide precise timing and patterns of skeletal timing and patterns of skeletal muscle contraction. Coordinated muscle contraction. Coordinated movements such as driving and movements such as driving and playing the piano. Controls playing the piano. Controls equilibrium. equilibrium.

- Composed of two cerebellar - Composed of two cerebellar hemispheres connected by the hemispheres connected by the vermisvermis

- Transverse gyri (pleated) called folia.Transverse gyri (pleated) called folia.- Pattern of white matter inside resembles a Pattern of white matter inside resembles a

branching tree; arbor vitae.branching tree; arbor vitae.- ContainsContains posterior and anterior lobes that posterior and anterior lobes that

regulate subconscious skeletal.regulate subconscious skeletal.

CerebellarCerebellar ProcessingProcessing: : 1- Initiates voluntary muscle contraction 1- Initiates voluntary muscle contraction 2- Determines body orientation (body 2- Determines body orientation (body parts in space) parts in space) 3- Coordinates forces, direction, extent of 3- Coordinates forces, direction, extent of muscle contraction muscle contraction

CerebellumCerebellum

Limbic system:Limbic system:

Complex group of fiber tracts that form Complex group of fiber tracts that form a ring around the brainstema ring around the brainstem

Part of the brain that is associated with Part of the brain that is associated with emotions, pleasure, pain, fear, emotions, pleasure, pain, fear, memory, anger, rage, sorrow and sex memory, anger, rage, sorrow and sex drive.drive.

Smell is tied in with memorySmell is tied in with memory

Amygdala: fearAmygdala: fear

Hippocampus: memoryHippocampus: memory

Meninges (PAD): connective tissue Meninges (PAD): connective tissue that covers the brain and spinal cordthat covers the brain and spinal cord

1- Pia mater: contacts brain surface 1- Pia mater: contacts brain surface and is found within the fissures and and is found within the fissures and sulcisulci

2- Arachnoid: separated from pia 2- Arachnoid: separated from pia mater by subarachnoid space mater by subarachnoid space

3- Dura mater (tough mother): double 3- Dura mater (tough mother): double membrane surrounding brain. membrane surrounding brain.

A- Periosteal layer - attached to skull A- Periosteal layer - attached to skull B- Meningeal layer - deep to periosteal, B- Meningeal layer - deep to periosteal,

outermost brain covering; extends outermost brain covering; extends inward to form flat septa that anchor inward to form flat septa that anchor brain to skull: brain to skull: – Falx cerebri (in longitudinal fissure) Falx cerebri (in longitudinal fissure) – Falx cerebelli (runs along vermis of Falx cerebelli (runs along vermis of

cerebellum) cerebellum) – Tentorium cerebelli (in transverse Tentorium cerebelli (in transverse

fissure) fissure)

Spinal Cord: runs through the vertebral Spinal Cord: runs through the vertebral foramen.foramen.

Begins at the foramen magnum and ends at Begins at the foramen magnum and ends at the level of L2.the level of L2.

- Cervical and lumbar enlargements - Cervical and lumbar enlargements

- Anterior median fissure and posterior - Anterior median fissure and posterior median sulcus median sulcus

- Conus medullaris (L1-L2), cauda equina, - Conus medullaris (L1-L2), cauda equina, and filum terminale and filum terminale

- 31 pairs of nerves each two points of - 31 pairs of nerves each two points of attachment called roots (dorsal and attachment called roots (dorsal and ventral)ventral)

Spinal Cord AnatomySpinal Cord Anatomy

Lumbar Puncture (LP)

Posterior/dorsal root containing Posterior/dorsal root containing sensory nerve fibers -includes a sensory nerve fibers -includes a swelling (ganglion) containing cell swelling (ganglion) containing cell bodies of sensory neurons (dorsal bodies of sensory neurons (dorsal root ganglion)root ganglion)

Anterior/ventral root containing Anterior/ventral root containing motor nerve fibers motor nerve fibers

- Interior gray matter (cell bodies) - Interior gray matter (cell bodies) surrounded by white matter (myelinated surrounded by white matter (myelinated neurons) neurons)

- Central canal (continuous with the fourth - Central canal (continuous with the fourth canal) canal)

- Gray matter divided into horns: anterior, - Gray matter divided into horns: anterior, posterior, and lateral posterior, and lateral

- White matter divided into columns: - White matter divided into columns: anterior, posterior, and lateral anterior, posterior, and lateral

- Each white column contains bundles of - Each white column contains bundles of nerve axons (called tracts) having a nerve axons (called tracts) having a common origin or destination common origin or destination

- Two types of tracts: ascending (sensory) - Two types of tracts: ascending (sensory) and descending (motor) and descending (motor)

Major spinal cord tracts:Major spinal cord tracts:

Corticospinal: descending motor tract Corticospinal: descending motor tract that transmits motor impulse from that transmits motor impulse from cerebral cortex down spinal cord out cerebral cortex down spinal cord out to skeletal muscleto skeletal muscle

Spinothalamic: ascending sensory Spinothalamic: ascending sensory tract that transmits pain, tract that transmits pain, temperature and deep pressure.temperature and deep pressure.

Spina BifidaSpina Bifida