The BrainThe Brain

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Learning TargetsLearning TargetsBy the end of this lecture, you should be By the end of this lecture, you should be able toable to::

Identify the four major lobes of the Identify the four major lobes of the brain.brain.

Identify and explain the significance of Identify and explain the significance of several other parts of the human brain.several other parts of the human brain.

Describe how the brain is protected.Describe how the brain is protected.

Explain several brain dysfunctions/ brain Explain several brain dysfunctions/ brain conditionsconditions..

The BrainThe Brain

Largest part of brain= Largest part of brain= cerebral hemispheres cerebral hemispheres (85% brain)(85% brain)

2 other 2 other mainmain divisions divisions of the brain are brain of the brain are brain stem and cerebellumstem and cerebellum

Cavities in brain are Cavities in brain are called ventricles and called ventricles and contain cerebrospinal contain cerebrospinal fluid (CSF)fluid (CSF)

Brain continued..Brain continued..

Ridges on brain= Ridges on brain= gyragyra

Valleys on brain= Valleys on brain= sulcisulci

Gyra and sulci Gyra and sulci increase surface increase surface area of brainarea of brain

Brain continued..Brain continued..

Grey matter (40% of brain)= Grey matter (40% of brain)= unmyelinated neurons; where unmyelinated neurons; where processing is concludedprocessing is concluded

White matter (60% of brain)= White matter (60% of brain)= myelinated neurons; allows myelinated neurons; allows communication to and from grey communication to and from grey mattermatter

Using a computer network as an Using a computer network as an analogy, the grey matter can be analogy, the grey matter can be thought of as the actual computers thought of as the actual computers themselves, whereas the white themselves, whereas the white matter represents the network cables matter represents the network cables connecting the computers togetherconnecting the computers together

CerebrumCerebrumCerebrumCerebrum

Controls speech, thought, Controls speech, thought, language comprehension, language comprehension, memory, feelings, & voluntary memory, feelings, & voluntary actionsactions

About 85% of brain About 85% of brain

Left & right cerebral Left & right cerebral hemispheres connected by hemispheres connected by corpus callosumcorpus callosum

Bundle of nerve fibers Bundle of nerve fibers (millions of axons from (millions of axons from cerebral cortex) that allows cerebral cortex) that allows the two hemispheres to the two hemispheres to communicatecommunicate

Lobes of the CerebrumLobes of the Cerebrum

FrontalFrontal

TemporTemporalal

Parietal Parietal

OccipitalOccipital

Brain Lobe FunctionsBrain Lobe FunctionsFrontal LobeFrontal Lobe

Responsible for Responsible for voluntary movement voluntary movement of skeletal muscles of skeletal muscles and attention and attention

Coordinates muscles Coordinates muscles that create speech that create speech (Broca’s area)(Broca’s area)

““Goal-directed Goal-directed behavior”: behavior”: Creativity, judgment, Creativity, judgment, problem solving, and problem solving, and planningplanning

Brain Lobe FunctionsBrain Lobe FunctionsTemporal LobeTemporal Lobe

Sense of smellSense of smell

HearingHearing

Helps us perform Helps us perform complex visual complex visual tasks like tasks like recognizing facesrecognizing faces

Helps us Helps us comprehend comprehend language (with language (with parietal lobe)parietal lobe)

Brain Lobe FunctionsBrain Lobe FunctionsParietal LobeParietal Lobe

Connected with the Connected with the processing of nerve processing of nerve impulses related to impulses related to the the sensessenses

Location for touch Location for touch perceptionperception

Helps us Helps us comprehend comprehend language (with language (with temporal lobe)temporal lobe)

Brain Lobe FunctionsBrain Lobe Functions

Occipital Occipital LobeLobe

Vision (visual Vision (visual cortex)cortex)

Brain surgery while awake…why? Click brain to see video

Hemispheric SpecializationHemispheric Specialization

The two hemispheres of the cerebral The two hemispheres of the cerebral cortex appear to have some separate cortex appear to have some separate functions. The right hemisphere of the functions. The right hemisphere of the cortex excels at nonverbal and spatial cortex excels at nonverbal and spatial tasks, whereas the left hemisphere is tasks, whereas the left hemisphere is usually more dominant in verbal tasks usually more dominant in verbal tasks such as speaking and writing.such as speaking and writing.

Left side of brain controls the right side of Left side of brain controls the right side of the bodythe body

Click image for right brain left brain quiz

Right brain/ Left brain conflictRight brain/ Left brain conflict

CerebellumCerebellumCerebellumCerebellum

Coordinates muscle Coordinates muscle activity, balance, activity, balance, equilibrium, & postureequilibrium, & posture

10% of brain by volume, 10% of brain by volume, 50% of brain’s neurons50% of brain’s neurons

Brain StemBrain StemBrain StemBrain StemMade up of midbrain, pons & Made up of midbrain, pons & medulla oblongotamedulla oblongota

Midbrain helps to relay info Midbrain helps to relay info for vision and hearingfor vision and hearing

Pons helps relay messages Pons helps relay messages from cerebrum to cerebellumfrom cerebrum to cerebellum Also plays significant role Also plays significant role

in REM sleepin REM sleep

Medulla oblongata controls Medulla oblongata controls breathing rate, blood breathing rate, blood pressure, respiration, pressure, respiration, coughing, sneezingcoughing, sneezing

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Limbic SystemLimbic System

Consists of a set of Consists of a set of structures lying on both structures lying on both sides and underneath sides and underneath the thalamus, including the thalamus, including the hypothalamus, the hypothalamus, hippocampus, and hippocampus, and amygdala.amygdala.

Limbic system Limbic system the the center of emotion – center of emotion – anger, fear (amygdala), anger, fear (amygdala), sexual arousal, pleasure, sexual arousal, pleasure, and sadnessand sadness

Also has a lot to do w/ Also has a lot to do w/ long-term memory long-term memory (hippocampus)(hippocampus)

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The BrainThe Brain

ThalamusThalamus

Receives and relays Receives and relays messages from sense organs messages from sense organs (the “relay station” to the (the “relay station” to the cerebral cortex)cerebral cortex)

The BrainThe Brain

HypothalamusHypothalamus

Controls hunger, thirst, fatigue, Controls hunger, thirst, fatigue, anger, body temp, regulates anger, body temp, regulates pituitary glandpituitary gland

What brain structures can you see?

Click picture to play video about effects of alcohol on brain parts (8 min)

Protection of CNSProtection of CNS3 layers of protective connective 3 layers of protective connective tissue cover brain & spinal cord tissue cover brain & spinal cord = MENINGES= MENINGES Dura materDura mater Arachnoid (mater)Arachnoid (mater) Pia mater (connected to brain)Pia mater (connected to brain)

Also surrounded by Also surrounded by CSF CSF to help to help cushioncushion

Cerebrospinal fluid (CSF) Cerebrospinal fluid (CSF) secreted by choroid plexuses secreted by choroid plexuses (extensions of pia mater) *500 (extensions of pia mater) *500 mL/ daymL/ day

CSF Functions:Shock absorptionSupport Nourishment

Brain DysfunctionsBrain Dysfunctions

(1)Concussion(1)Concussion Slight brain injury, Slight brain injury,

no permanent no permanent damage (unless damage (unless they are too they are too frequent)frequent)

(2)Contusion(2)Contusion Traumatic brain Traumatic brain

injury causing injury causing permanent damage permanent damage

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Click picture for 5 min video

Brain DysfunctionsBrain Dysfunctions

(3)Coma(3)Coma Brain Brain

doesn’t doesn’t respond to respond to stimulistimuli

Can last for Can last for 6 hours6 hours yearsyears

2 min video

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Brain DysfunctionsBrain Dysfunctions(4) Epilepsy(4) EpilepsyDisorder in which a Disorder in which a person has repeated person has repeated seizures (convulsions) seizures (convulsions) over time. over time.

Seizures are episodes of Seizures are episodes of disturbed brain activity disturbed brain activity that cause changes in that cause changes in attention or behavior.attention or behavior.

Cause is unknown; most Cause is unknown; most controlled with controlled with medication medication

Affects 65 million people Affects 65 million people worldwideworldwide Short clip

Brain DysfunctionsBrain Dysfunctions(5)Cerebrovascula(5)Cerebrovascular Accident (CVA) r Accident (CVA) or Strokeor Stroke Area of the brain Area of the brain

does not get does not get enough oxygen enough oxygen because because deprived of deprived of bloodblood

RECOGNIZING A STROKE Click image for 4 min video

Brain DysfunctionsBrain Dysfunctions

(6)Alzheimer’s (6)Alzheimer’s DiseaseDisease Degeneration of Degeneration of brain from protein brain from protein depositsdeposits

(7)Multiple Sclerosis (7)Multiple Sclerosis (MS)(MS) Autoimmune Autoimmune disorder where disorder where body attacks and body attacks and destroys its own destroys its own myelinmyelin

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Click image for 5 min video