The Central Nervous The Central Nervous SystemSystem

The BrainThe Brain

The Brain looks pinkish grey, is The Brain looks pinkish grey, is wrinkly like a walnut, and has the wrinkly like a walnut, and has the consistency of oatmeal.consistency of oatmeal.

It weighs on average 3.5 lbs for men It weighs on average 3.5 lbs for men and 3.2 pounds for women.and 3.2 pounds for women.

Embryonic DevelopmentEmbryonic Development

At three weeks old, the outer layer of At three weeks old, the outer layer of the “brain” thickens and forms a line the “brain” thickens and forms a line that runs down the center called a that runs down the center called a neural plate. neural plate.

That plate invaginates to form a That plate invaginates to form a neural fold. (That big line that runs neural fold. (That big line that runs down the center of the brain).down the center of the brain).

As the Neural groove As the Neural groove deepens…deepens…

The superior edges The superior edges of the neural grooves of the neural grooves fuse and drop fuse and drop forming a neural forming a neural tube.tube.

This neural tube This neural tube deepens and extends deepens and extends forming the caudal forming the caudal (tail) end of the brain (tail) end of the brain forming what will forming what will later be defined as later be defined as the spinal cord.the spinal cord.

In week five of In week five of development, the development, the Primary vesicles of Primary vesicles of the brain give rise the brain give rise to secondary to secondary vesicles, which will vesicles, which will later form the later form the major regions of major regions of the brain.the brain.

Secondary structureSecondary structure Telencephalon Telencephalon

Diencephalon Diencephalon

Mesencephalon, Mesencephalon, metencephalon, metencephalon, Myencephalon. Myencephalon.

Forms:Forms: Two cerebral Two cerebral

hemispheres of brainhemispheres of brain Hypothalamus, Hypothalamus,

thalamus, thalamus, epithalamus, and epithalamus, and retina of the eyeretina of the eye

Midbrain, pons and Midbrain, pons and cerebellum, and cerebellum, and medulla oblongatamedulla oblongata

Cerebral HemispheresCerebral Hemispheres

Cerebral HemispheresCerebral Hemispheres

The most superior part of the brain, The most superior part of the brain, makes up 83% of the brains body makes up 83% of the brains body weight. weight.

The elevated ridges of the cerebral The elevated ridges of the cerebral hemispheres are called gyri. They hemispheres are called gyri. They are separated by grooves called are separated by grooves called sulci. sulci.

The deeper grooves are called The deeper grooves are called fissures.fissures.

Regions of the brainRegions of the brain Lobes:Lobes:

FrontalFrontal ParietalParietal OccipitalOccipital TemporalTemporal

CerebellumCerebellum PonsPons Medulla oblongataMedulla oblongata Brain stemBrain stem Olfactoral stemOlfactoral stem Olfactoral tractOlfactoral tract HypocampusHypocampus hypothallumushypothallumus

Gyri and sulciGyri and sulci

Precentral gyrusPrecentral gyrusPostcentral gyrusPostcentral gyrusCentral sulcusCentral sulcusParieto-occipital sulcusParieto-occipital sulcusGyri of insula (medial to temporal Gyri of insula (medial to temporal

lobe)lobe)

FissuresFissures

Longitudinal fissureLongitudinal fissureTransverse cerebral fissureTransverse cerebral fissure

Thing to keep in “mind” about Thing to keep in “mind” about the cerebral cortex.the cerebral cortex.

No one area of the cerebral cortex No one area of the cerebral cortex acts alone, and all conscious acts alone, and all conscious behavior involves every area of the behavior involves every area of the cerebral cortex in some way.cerebral cortex in some way.

The cerebral cortexThe cerebral cortex

Contains three function areas, motor Contains three function areas, motor areas, sensory areas, and association areas, sensory areas, and association areas.areas.

Each hemisphere of the cerebral Each hemisphere of the cerebral cortex is contralaterally concerned cortex is contralaterally concerned with the senses of the opposite side with the senses of the opposite side of the body.of the body.

The cerebral cortex: motor The cerebral cortex: motor areasareas

Primary motor cortex: contains a type of Primary motor cortex: contains a type of nerve cell called pyramidal cells that allow nerve cell called pyramidal cells that allow us to consciously control precise voluntary us to consciously control precise voluntary movement. movement.

These pyramidal cells serve for function of These pyramidal cells serve for function of only one area. only one area.

For example, there are pyramidal cells For example, there are pyramidal cells that are specifically for foot movement, that are specifically for foot movement, while there are other pyramidal cells that while there are other pyramidal cells that are designed for hand movement.are designed for hand movement.

StrokeStroke

Stroke is a very serious problem that Stroke is a very serious problem that develops when there is an interruption develops when there is an interruption in the flow of blood to the brain. Also in the flow of blood to the brain. Also known as cerebrovascular accidents or known as cerebrovascular accidents or "brain attacks." "brain attacks."

There are two main types of strokes. There are two main types of strokes. If a blood vessel is blocked by clots or If a blood vessel is blocked by clots or

other particles, it is called an ischemic other particles, it is called an ischemic stroke. stroke.

If a blood vessel breaks and bleeds, it is If a blood vessel breaks and bleeds, it is called a hemorrhagic stroke. called a hemorrhagic stroke.

Signs of a strokeSigns of a stroke

Symptoms of stroke:Symptoms of stroke: Sudden weakness or numbness in your face, Sudden weakness or numbness in your face,

body, arms or legs, especially if only one side body, arms or legs, especially if only one side is affected is affected

Sudden loss of vision or problems seeing in one Sudden loss of vision or problems seeing in one or both eyes or both eyes

Sudden confusion, inability to speak or Sudden confusion, inability to speak or understand what others are saying understand what others are saying

Sudden dizziness, instability or inability to Sudden dizziness, instability or inability to stand, walk or coordinate movement stand, walk or coordinate movement

Sudden severe, unexplained headache Sudden severe, unexplained headache

Commonality of strokeCommonality of stroke

Stroke is the third leading cause of Stroke is the third leading cause of death, after coronary heart disease death, after coronary heart disease and cancer. and cancer.

Each year there are about 600,000 Each year there are about 600,000 strokes in the US, and strokes kill strokes in the US, and strokes kill over 150,000 Americans each year.over 150,000 Americans each year.

Over 15% of people who have had a Over 15% of people who have had a stroke die within 30 days, and 15-stroke die within 30 days, and 15-30% of people who survive a stroke 30% of people who survive a stroke are permanently disabled. are permanently disabled.

Who’s at riskWho’s at risk

Anyone can have a stroke but most Anyone can have a stroke but most people who have strokes are over people who have strokes are over the age of 55. Strokes affect both the age of 55. Strokes affect both men and women. men and women.

African Americans tend to be at African Americans tend to be at highest risk, but people of all races highest risk, but people of all races and ethnicities suffer from strokes. and ethnicities suffer from strokes.

How to prevent strokeHow to prevent stroke

There are many things you can do to There are many things you can do to reduce your risk of stroke: reduce your risk of stroke: don't smoke don't smoke keep your blood pressure under control keep your blood pressure under control stay physically active stay physically active if you have diabetes, treat it if you have diabetes, treat it eat a healthy diet that focuses on fruits, eat a healthy diet that focuses on fruits,

vegetables, and whole grains vegetables, and whole grains maintain a healthy weight maintain a healthy weight keep your blood cholesterol under control keep your blood cholesterol under control avoid illegal drug use avoid illegal drug use

Who should be screened?Who should be screened?

People of all ages should be People of all ages should be periodically screened for risk factors periodically screened for risk factors of stroke: of stroke: diabetes diabetes high blood pressure high blood pressure poor blood cholesterol levelspoor blood cholesterol levelsoverweight/obesityoverweight/obesity

motor areas continuedmotor areas continued

Premotor cortex- In the frontal lobe Premotor cortex- In the frontal lobe of the brain, just anterior of the of the brain, just anterior of the precentral gyrus. Responsible for precentral gyrus. Responsible for learned motor skills and repetitious learned motor skills and repetitious and patterned nature.and patterned nature.

motor areas continuedmotor areas continued

Broca’s area- inferior to the anterior Broca’s area- inferior to the anterior region of the premotor area. Present region of the premotor area. Present only on left side of the brain, directs only on left side of the brain, directs muscles involved in speech muscles involved in speech production.production.

motor areas continuedmotor areas continued

Frontal eye field- superior to Broca’s Frontal eye field- superior to Broca’s area. Controls voluntary movements area. Controls voluntary movements of the eyes.of the eyes.

Sensory areasSensory areas

Sensory areas Sensory areas allow for the allow for the conscious conscious awareness of awareness of sensation. Mostly sensation. Mostly in the parietal in the parietal temporal and temporal and occipital lobes.occipital lobes.

Sensory areas continuedSensory areas continued

Primary somatosensory cortex- posterior Primary somatosensory cortex- posterior to the postcentral gyrus. Receives to the postcentral gyrus. Receives information from skin, muscles and information from skin, muscles and tendons when stimulus is applied. tendons when stimulus is applied.

It is not the size of the body part, but the It is not the size of the body part, but the number of sensors in that region that number of sensors in that region that determines sensitivity. The face and determines sensitivity. The face and fingertips are the most sensitive areas.fingertips are the most sensitive areas.

Sensory areas continuedSensory areas continued

Somatosensory association cortex- Somatosensory association cortex- posterior to primary somatosensory posterior to primary somatosensory cortex. Integrates sensory inputs cortex. Integrates sensory inputs like temperature, pressure, etc. from like temperature, pressure, etc. from past experience to judge a stimulus past experience to judge a stimulus without the use of another sense like without the use of another sense like sight. sight.

Sensory areas continuedSensory areas continued

Visual area- extreme posterior of Visual area- extreme posterior of occipital lobe. It creates a occipital lobe. It creates a contralateral map of visual space. contralateral map of visual space.

Auditory areasAuditory areas

Primary auditory cortex: located in Primary auditory cortex: located in superior portion of the temporal lobe. superior portion of the temporal lobe. Involved in interpreting pitch, Involved in interpreting pitch, loudness, and sound.loudness, and sound.

Auditory association area: Posterior Auditory association area: Posterior to the primary motor cortex. It to the primary motor cortex. It interprets and perceives a sound interprets and perceives a sound stimulus.stimulus.

Olfactory cortex:Olfactory cortex:

Medial area of temporal lobe. Used Medial area of temporal lobe. Used to interpret impulses from smell to interpret impulses from smell receptors in the nasal cavity.receptors in the nasal cavity.

Gustatory cortexGustatory cortex

Gustatory (taste) cortex: Located Gustatory (taste) cortex: Located deep in the temporal lobe. It’s deep in the temporal lobe. It’s involved in the perception of tastes.involved in the perception of tastes.

EWW That tastes disEWW That tastes disgustgusting!ing!

Visceral Sensory areasVisceral Sensory areas

Just posterior to the gustatory Just posterior to the gustatory complex, the visceral sensory area is complex, the visceral sensory area is responsible for the perception of responsible for the perception of visceral sensation.visceral sensation.

(i.e. full bladder, upset stomach, (i.e. full bladder, upset stomach, feeling like your lungs will explode if feeling like your lungs will explode if you hold your breath too long.)you hold your breath too long.)

Vestibular cortexVestibular cortex

Responsible for the conscious Responsible for the conscious awareness of balance.awareness of balance.

Multimodal association areasMultimodal association areas

Multimodal association areasMultimodal association areas

• Multimodal association areas are Multimodal association areas are responsible for collecting a large responsible for collecting a large amount of information and amount of information and processing it on multiple levels.processing it on multiple levels.

Multimodal association areas: Multimodal association areas: prefrontal cortexprefrontal cortex

Encompasses most of the cerebrum.Encompasses most of the cerebrum. Is involved in the process of memory Is involved in the process of memory

formation, intellect, complex learning formation, intellect, complex learning abilities, recall, and personality.abilities, recall, and personality.

The ability of the prefrontal cortex The ability of the prefrontal cortex varies greatly from the use of varies greatly from the use of positive and negative feedback.positive and negative feedback.

Multimodal association areas: Multimodal association areas: Posterior association areasPosterior association areas

Encompasses the parietal, temporal Encompasses the parietal, temporal and occipital lobes.and occipital lobes.

Allows one to pay attention to the Allows one to pay attention to the space around them, also plays a role space around them, also plays a role in written and spoken language.in written and spoken language.

Multimodal association areas: Multimodal association areas: Limbic association areasLimbic association areas

Cingulate gyrus, parahippocampal Cingulate gyrus, parahippocampal gyrus, and the hippocampus.gyrus, and the hippocampus.

Provides the emotional impact of a Provides the emotional impact of a scene, which allows for the proper scene, which allows for the proper response to a stimulus.response to a stimulus.

Cerebral White MatterCerebral White Matter

Responsible for communication Responsible for communication between hemispheres of the brain.between hemispheres of the brain.

Commissures (made of commissural Commissures (made of commissural fibers) connect the grey areas of the fibers) connect the grey areas of the hemispheres. The largest fissure is hemispheres. The largest fissure is called the corpus callosum.called the corpus callosum.

Cerebral White Matter Cerebral White Matter continuedcontinued

Association fibers- connects different Association fibers- connects different parts of the same hemisphere.parts of the same hemisphere.

Projection fibers- motor output from Projection fibers- motor output from the cerebral cortex to the rest of the the cerebral cortex to the rest of the body. Projection fibers run vertically body. Projection fibers run vertically in the brain, while association fibers in the brain, while association fibers and commissure fibers run and commissure fibers run horizontally.horizontally.

Basal NucleiBasal Nuclei

Receives input from the entire Receives input from the entire cerebral cortex as well as from other cerebral cortex as well as from other subcortical nuclei and each other.subcortical nuclei and each other.

The true function of the Basal nuclei The true function of the Basal nuclei is unclear due to many parts of the is unclear due to many parts of the cerebral cortex having overlapping cerebral cortex having overlapping functions.functions.

DiencephalonDiencephalon

Contains the: Contains the: ThalamusThalamusHypothalamusHypothalamusepithalamus.epithalamus.

Diencephalon: ThalamusDiencephalon: Thalamus

The thalamus contains a pair of egg The thalamus contains a pair of egg shaped nuclei. The thalamus acts as shaped nuclei. The thalamus acts as the relay station for all information the relay station for all information that enters the cerebral cortex.that enters the cerebral cortex.

Diencephalon: hypothalamusDiencephalon: hypothalamus Hypothalamus (below the thalamus) is the Hypothalamus (below the thalamus) is the

main visceral control center of the brain and main visceral control center of the brain and is in charge of homeostasis in the body. is in charge of homeostasis in the body.

It is responsible for: It is responsible for: autonomic controlautonomic control emotional response emotional response body temperature regulation body temperature regulation Regulation of food intake Regulation of food intake regulation of water balance and thirst regulation of water balance and thirst regulation of sleep/wake cycle regulation of sleep/wake cycle control of endocrine system functions control of endocrine system functions

Diencephalon: epithalamusDiencephalon: epithalamus

Contains the pineal gland, which Contains the pineal gland, which secretes melatonin. This is a major secretes melatonin. This is a major part of the sleep/wake cycle.part of the sleep/wake cycle.

Brain stemBrain stem

Contains the: Contains the: pons pons midbrainmidbrainmedulla oblongatamedulla oblongata

Brain stem: midbrainBrain stem: midbrain

b/w the diencephalon and the pons. b/w the diencephalon and the pons. Contains the: Contains the:

corpora quadragemina: forms four corpora quadragemina: forms four bumps on the mid brain which bumps on the mid brain which themselves hold:themselves hold:superior colliculi-visual reflex centersuperior colliculi-visual reflex centerinferior colliculi-Allows for the reflex inferior colliculi-Allows for the reflex

response to sound.response to sound.

Brain stem: PonsBrain stem: Pons

Wedged between the midbrain and the Wedged between the midbrain and the medulla oblongata. Composed mostly of medulla oblongata. Composed mostly of conduction tracts.conduction tracts.

The pons relays signals from the The pons relays signals from the forebrain to the cerebellum, along with forebrain to the cerebellum, along with nuclei that deal primarily with sleep, nuclei that deal primarily with sleep, respiration, swallowing, bladder control, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye hearing, equilibrium, taste, eye movement, facial expressions, facial movement, facial expressions, facial sensation, and posture.sensation, and posture.

Brain stem: medulla Brain stem: medulla oblongataoblongata

Most inferior part of the brain stem. Most inferior part of the brain stem. The medulla oblongata controls autonomic The medulla oblongata controls autonomic

functions, and relays nerve signals between the functions, and relays nerve signals between the brain and spinal cord. It is also responsible for brain and spinal cord. It is also responsible for controlling several major points and autonomic controlling several major points and autonomic functions of the body:functions of the body: respiration– chemoreceptorsrespiration– chemoreceptors cardiac center – sympathetic, parasympathetic cardiac center – sympathetic, parasympathetic

systemsystem vasomotor center – baroreceptorsvasomotor center – baroreceptors reflex centers of vomiting, coughing, sneezing, reflex centers of vomiting, coughing, sneezing,

and swallowingand swallowing

The CerebellumThe Cerebellum

The cerebellumThe cerebellum

Located posteriorly, and is inferior to Located posteriorly, and is inferior to the occipital lobe of the cerebrum. the occipital lobe of the cerebrum. Has two cerebellar hemispheres . Has two cerebellar hemispheres .

Special purkinji cells are located in Special purkinji cells are located in the cerebellum, which send signals the cerebellum, which send signals through the white matter to synapse through the white matter to synapse the central nuclei of the cerebellum.the central nuclei of the cerebellum.

Cerebellar processingCerebellar processing

The cerebellum processes The cerebellum processes information in the following way:information in the following way:1. motor areas of the cerebral cortex 1. motor areas of the cerebral cortex

notify the cerebellum that it will trigger notify the cerebellum that it will trigger a voluntary muscle movement.a voluntary muscle movement.

2. At the same time, the cerebellum receives 2. At the same time, the cerebellum receives information from the body (muscle tension, information from the body (muscle tension, tendons, etc…). This allows the cerebellum tendons, etc…). This allows the cerebellum to evaluate body position and momentum.to evaluate body position and momentum.

3. Cerebellar cortex calculates the best way 3. Cerebellar cortex calculates the best way to handle force, direction, and extent of to handle force, direction, and extent of muscle contraction to prevent overshoot, muscle contraction to prevent overshoot, maintain posture, and ensure smooth maintain posture, and ensure smooth coordinated movements. coordinated movements.

4. Then the cerebellum dispatches it’s 4. Then the cerebellum dispatches it’s information for coordinated movement. information for coordinated movement.

The cerebellum’s role in The cerebellum’s role in cognitioncognition

The cerebellum is responsible for The cerebellum is responsible for recognizes and predicts sequences of recognizes and predicts sequences of events so that it can adjust for the events so that it can adjust for the multiple movements exerted on a multiple movements exerted on a limb involving several joints.limb involving several joints.

Functional Brain SystemsFunctional Brain Systems

A function brain system is a system A function brain system is a system that spans far distances in the brain that spans far distances in the brain but still works closely together.but still works closely together.

Examples:Examples:Limbic systemLimbic systemReticular formationReticular formation

The Limbic systemThe Limbic system

A group of structures located in the A group of structures located in the medial aspect of the cerebral medial aspect of the cerebral hemisphere and diencephalon. hemisphere and diencephalon.

This system is the main emotional, or This system is the main emotional, or affective area of the brain. affective area of the brain.

The Limbic SystemThe Limbic System

The reticular formationThe reticular formation

Extends through the central core of the Extends through the central core of the medulla oblongata, pons, and midbrain.medulla oblongata, pons, and midbrain.

maintains tone, balance, and posture--maintains tone, balance, and posture--especially during body movements.especially during body movements.

Acts as a filter for the massive amounts Acts as a filter for the massive amounts of information from sensory input.of information from sensory input.

Higher Mental FunctionsHigher Mental Functions

Higher mental functionsHigher mental functions

Brain wave patterns and EEG: The Brain wave patterns and EEG: The EEG is a tool that records aspects of EEG is a tool that records aspects of brain activity. brain activity.

These activities are electrically These activities are electrically recorded as brain waves.recorded as brain waves.

Wave TypesWave Types

Alpha Waves: regular, rhythmic and low Alpha Waves: regular, rhythmic and low amplitude. Indicator of calm and awake amplitude. Indicator of calm and awake brain.brain.

Beta waves: rhythmic but not as regular as Beta waves: rhythmic but not as regular as alpha waves. Occurs when focusing on a alpha waves. Occurs when focusing on a problem or stimulus.problem or stimulus.

Theta waves: less common than beta waves. Theta waves: less common than beta waves. Uncommon in awake adults, but may appear Uncommon in awake adults, but may appear when concentrating.when concentrating.

Delta waves: seen during sleep. In an awake Delta waves: seen during sleep. In an awake adult, this indicates brain damage.adult, this indicates brain damage.

Brain WavesBrain Waves

What does it mean to be What does it mean to be clinically conscious?clinically conscious?

These criteria are the suppositions about These criteria are the suppositions about being conscious:being conscious:

Consciousness involves stimulus of large Consciousness involves stimulus of large areas of the brain.areas of the brain.

It is superimposed on other types of neural It is superimposed on other types of neural activity (like cognition and motor control).activity (like cognition and motor control).

It is holistic and totally interconnected. It is holistic and totally interconnected. Information about thought can be Information about thought can be collected by different areas of the brain collected by different areas of the brain simultaneously.simultaneously.

Sleep and Sleep-wake cyclesSleep and Sleep-wake cycles

NREM sleep- The first two stages of NREM sleep- The first two stages of sleep, where we do not dream. (Takes sleep, where we do not dream. (Takes 30-45 minutes) 30-45 minutes)

In the 3In the 3rdrd and 4 and 4thth stages we enter slow stages we enter slow wave sleep where brain wave frequency wave sleep where brain wave frequency slows and wave amplitude increases.slows and wave amplitude increases.

After stages four of NREM sleep After stages four of NREM sleep

is achieved, EEG are changedis achieved, EEG are changed

abruptly. (90 minutes)abruptly. (90 minutes)

Sleep and Sleep-wake cyclesSleep and Sleep-wake cycles

REM sleep-After stage four of NREM, the EEG will REM sleep-After stage four of NREM, the EEG will change back and forth to all various types of change back and forth to all various types of wavelengths.wavelengths.

Increases, heart rate and breathing rate and Increases, heart rate and breathing rate and other sympathetic responses. Oxygen rates other sympathetic responses. Oxygen rates skyrocket higher than when awake. A temporary skyrocket higher than when awake. A temporary paralysis occurs in the skeletal muscles.paralysis occurs in the skeletal muscles.

NOTE that most nightmare occur in NREM sleep NOTE that most nightmare occur in NREM sleep stages three and four.stages three and four.

Also, REM is associated with sexual arousal, thus Also, REM is associated with sexual arousal, thus “morning wood.”“morning wood.”

LanguageLanguage

Broca’s area: the region of the brain Broca’s area: the region of the brain responsible for language and responsible for language and language interpretation.language interpretation.

Wernicke’s area: the area Wernicke’s area: the area responsible for speech production. responsible for speech production. Damaging Wernicke’s area will cause Damaging Wernicke’s area will cause people to speak incoherent people to speak incoherent gibberish.gibberish.

MemoryMemory

Involves the storage and retrieval of Involves the storage and retrieval of information. information.

Short term memory involves the Short term memory involves the immediate retrieval of information immediate retrieval of information and application of that information. and application of that information. Short term memory lasts for only up Short term memory lasts for only up to 15 seconds.to 15 seconds.

memorymemory

Long term memory involves the Long term memory involves the storage of information for any time storage of information for any time after 15 seconds.after 15 seconds.

As sensory information bombards the As sensory information bombards the cerebral cortex, information we do cerebral cortex, information we do not even think of consciously is not even think of consciously is stored in our minds. stored in our minds.

Emotional state: When Emotional state: When norepinephrine is present in the norepinephrine is present in the brain, emotional information we brain, emotional information we receive is almost instantaneous.receive is almost instantaneous.

Rehearsal: repeating a process or Rehearsal: repeating a process or speech over and over again. This is speech over and over again. This is why studying your notes repeatedly why studying your notes repeatedly helps you do well on a test.helps you do well on a test.

Association: Association of new Association: Association of new memories is easier to remember if it memories is easier to remember if it can be associated with old can be associated with old memories.memories.

Automatic memory: Automatic Automatic memory: Automatic memory occurs when you are memory occurs when you are receiving input and store other receiving input and store other information while receiving said information while receiving said input.input.

Categories of memoryCategories of memory

Declarative memory: Learning explicit Declarative memory: Learning explicit information like names and faces.information like names and faces.

Procedural memory: (Skill) Learning a Procedural memory: (Skill) Learning a process like playing the piano.process like playing the piano.

Motor memory: doing a motor function Motor memory: doing a motor function like riding a bike.like riding a bike.

Emotional memory: remembering Emotional memory: remembering something that changing your something that changing your emotional state.emotional state.

Protecting the BrainProtecting the Brain

The meninges is the covering that The meninges is the covering that protects the brain. It reduces the protects the brain. It reduces the damage from impact and prevents the damage from impact and prevents the brain from rubbing against the skull.brain from rubbing against the skull.

The meninges formed by three layers:The meninges formed by three layers:Dura materDura materArachnoid materArachnoid materPia materPia mater

The meninges formed by The meninges formed by three layersthree layers

● ●Dura mater- Dura mater- Strongest layer; the dura Strongest layer; the dura veinous sinuses are located here, which veinous sinuses are located here, which drain blood back to the neck.drain blood back to the neck.

Arachnoid mater- Arachnoid mater- separated from the separated from the dura mater by a space called subdural dura mater by a space called subdural space. Never enters the sulci of the space. Never enters the sulci of the brain.brain.

Pia mater- Pia mater- Clings tightly to the brain Clings tightly to the brain like a cellophane hat.like a cellophane hat.

Cerebrospinal FluidCerebrospinal Fluid

Cushion that surrounds the brain and Cushion that surrounds the brain and spinal cord. Looks kind of like blood spinal cord. Looks kind of like blood plasma. plasma.

About 500 ml of CSF is produced About 500 ml of CSF is produced daily. About 150 ml of CSF is daily. About 150 ml of CSF is covering the brain and spine at any covering the brain and spine at any one time.one time.

Blood-Brain BarrierBlood-Brain Barrier

The The blood-brain barrier blood-brain barrier is the end-all-is the end-all-be-all of maintaining homeostasis of be-all of maintaining homeostasis of the brain. the brain.

The blood-brain barrier prevents The blood-brain barrier prevents fluxuations in the brain’s balance of fluxuations in the brain’s balance of nutrients and minerals from causing nutrients and minerals from causing the neurons of the brain to fire the neurons of the brain to fire uncontrollably.uncontrollably.

The Spinal CordThe Spinal Cord

The Spinal CordThe Spinal Cord

The spinal cord provides a two way The spinal cord provides a two way conduction path for information to conduction path for information to enter and leave the brain. enter and leave the brain.

The spinal cord is the major reflex The spinal cord is the major reflex center in your body. center in your body.

The spinal dura mater is a meningx The spinal dura mater is a meningx that protects the spine from trauma that protects the spine from trauma with the CSF.with the CSF.

Drawing CSF for testingDrawing CSF for testing

The procedure known as a The procedure known as a Lumbar Lumbar puncturepuncture is the process of drawing is the process of drawing CSF to screen for pathogens and CSF to screen for pathogens and drugs.drugs.

Typically done below the L3 Typically done below the L3 vertebrae, due to there being a low vertebrae, due to there being a low chance of damaging the spinal cord.chance of damaging the spinal cord.

For the majority of the spinal For the majority of the spinal cordcord

It is about the width of your thumb It is about the width of your thumb for the majority of your body with the for the majority of your body with the exception of the cervical exception of the cervical enlargement and the lumbar enlargement and the lumbar enlargement, which are larger bulbs enlargement, which are larger bulbs in the spinal cord that act as nexus’ in the spinal cord that act as nexus’ for spinal nerves.for spinal nerves.

Ascending pathways to the Ascending pathways to the brainbrain

First order neuronsFirst order neurons: cell bodies that lie in a : cell bodies that lie in a ganglion (bundle of related sensory ganglion (bundle of related sensory neurons) which conduct impulses from neurons) which conduct impulses from cutaneous layers of the skin. cutaneous layers of the skin.

Second order neuronsSecond order neurons: Reside in dorsal : Reside in dorsal portion of the spinal cord. They transmit portion of the spinal cord. They transmit impulses to the thalamus or to the impulses to the thalamus or to the cerebellum where they synapse.cerebellum where they synapse.

Third order neuronsThird order neurons: They relay impulses to : They relay impulses to the somatosensory cortex of the cerebrum.the somatosensory cortex of the cerebrum.

Developmental aspects of the Developmental aspects of the CNSCNS

During prenatal development, there During prenatal development, there are certain areas of the brain that are certain areas of the brain that develop specific to each gender. develop specific to each gender.

Exposure to drugs and alcohol during Exposure to drugs and alcohol during pregnancy can cause mental defects pregnancy can cause mental defects in the fetus, if not death.in the fetus, if not death.