Human nervous system

Brain Fun Facts• SIZE OF THE HUMAN BRAIN

The average human brain weighs about 3 pounds (1300-1400 g). • At birth, the human brain weighs less than a pound (0.78-0.88

pounds or 350-400 g). As a child grows, the number of cell remains relatively stable, but the cells grow in size and the number of connections increases. The human brain reaches its full size at about 6 years of age.

• COMPOSITION OF THE BRAIN

The brain consists of gray matter (40%) and white matter (60%) contained within the skull. Brain cells include neurons and glial cells.

• NOURISHMENT OF THE BRAIN Although the brain is only 2% of the body's weight, it uses 20% of the oxygen supply and gets 20% of the blood flow. Blood vessels (arteries, capillaries, and veins) supply the brain with oxygen and nourishment, and take away wastes. • If brain cells do not get oxygen for 3 to 5 minutes, they begin

to die.

CENTRAL NERVOUS SYSTEM

(CNS)

PERIPHERAL NERVOUS SYSTEM

(PNS)

NERVOUS SYSTEM

SOMATIC NERVOUS SYSTEM

(voluntary)

AUTONOMIC NERVOUS SYSTEM

(involuntary)SENSORY AND MOTOR NEURONES TO / FROM

SKELETAL MUSCLE

MOTOR NEURONES TO INTERNAL ORGANS

SYMPATHETIC NERVOUS SYSTEM

(involuntary)

PARASYMPATHETIC NERVOUS SYSTEM

(involuntary)

CONTROLS ORGANS IN TIMES OR STRESS

CONTROLS ORGANS WHEN BODY IS AT REST

The Organisation of the Nervous System

BRAIN AND SPINAL CORD

PERIPHERAL NS

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The Organisation of the Nervous System

The spinal cord (SC) runs through the neural arches of

the vertebrae and in its centre is a canal containing

cerebrospinal fluid.

The brain is a highly specialised area of the SC.

See later

The spinal cord

The brain and spinal cord are surrounded by 3 membranes

called the meninges

The meninges secrete cerebrospinal fluid. The fluid

supplies oxygen and nutrients and acts as a shock absorber

The meninges

Butterfly shaped area of unmyelinated neurones (grey)

Myelinated neurones (white)

Canal

Lobes may vary from person to Simpson

The Brain’s 4 Major Regions• Cerebrum, the diencephalon, the

brainstem, and the cerebellum. • The cerebrum is divided into two halves,

called the left and right cerebral hemispheres.

• Each hemisphere is subdivided into five functional areas called lobes.

• Outer surface of an adult brain exhibits folds called gyri (gyrus) and shallow depressions between those folds called sulci (sulcus).

• The brain is associated with 12 pairs of cranial nerves.

Dezvoltarea encefalului

• Prosencephalon (forebrain)• Telencephalon: cerebrum• Diencephalon:epithalamus• thalamus,hypothalamus

• Mesencephalon (midbrain)• Mesencephalon: cerebral peduncles,

colliculi • Rhombencephalon (hindbrain)

• Metencephalon: pons, cerebellum • Myelencephalon: medulla oblongata

Organizarea țesutului nervos

• Gray matter:• motor neuron and interneuron cell bodies, dendrites, axon terminals• unmyelinated axons.

• White matter:• composed primarily of myelinated axons. • lies deep to the gray matter of the cortex. • Within the masses of white matter:

• discrete innermost clusters of gray matter called cerebral nuclei

(or basal nuclei).

• are oval, spherical, or sometimes irregularly shaped clusters of

neuron cell bodies. • During brain development, an outer, superficial region of gray matter

forms from migrating peripheral neurons. • External sheets of gray matter, called the cortex, cover the surface of

most of the adult brain (the cerebrum and the cerebellum).

Support and Protection of the Brain

• The brain is protected and isolated by multiple structures:• bony cranium • Meninges:

• Protective connective tissue membranes• surround and partition portions of the brain.

• Cerebrospinal fluid (CSF)• acts as a cushioning fluid.

• Blood-brain barrier:• prevents entry of harmful materials from the bloodstream.

• Three dense regular connective tissue layers:• separate the soft tissue of the brain from the bones of the cranium.• Enclose and protect blood vessels that supply the brain.• Contain and circulate cerebrospinal fluid.• Parts of the cranial meninges form some of the veins that drain

blood from the brain. • From superficial to deep, the cranial meninges are the dura mater, the

arachnoid, and the pia mater

Dura Mater• Tough membrane composed of two fibrous layers. • Strongest of the meninges. • Dura mater is composed of two layers.

• periosteal layer, the more superficial layer, attaches to the periosteum of the cranial bones

• meningeal layer lies deep to the periosteal layer • The meningeal layer is usually fused to the periosteal layer

• Exception: in specific areas where the two layers separate to form large, blood-filled spaces called dural venous sinuses.

Arachnoid • Also called the arachnoid mater or the arachnoid membrane. • Lies immediately internal to the dura mater.• Partially composed of a delicate web of collagen and elastic

fibers, termed the arachnoid trabeculae.• Between the arachnoid and the overlying dura mater is the

subdural space.• Immediately deep to the arachnoid is the subarachnoid space.

• The innermost of the cranial meninges. • Thin layer of delicate connective tissue that tightly

adheres to the brain and follows every contour of the brain surface.

Pia Mater

Cranial Dural Septa

• The meningeal layer of the dura mater extends as flat partitions (septa) deep into the cranial cavity;• at four locations• called cranial dural septa.

• Membranous partitions separate specific parts of the brain and provide additional stabilization and support to the entire brain.• falx cerebri• tentorium cerebelli • falx cerebelli• diaphragma sellae

The Spinal Cord

• The spinal cord is the major nerve pathway to and from the brain.

• It is protected by the vertebral column and the meninges.

• 31 pairs of spinal nerves branch out from the spinal cord, connecting the brain to the body.

• Certain kinds of information, such as reflexes, are processed directly in the spinal cord.

• A reflex is a quick, automatic response to a stimulus. It allows the body to respond to danger immediately.

Brain Ventricles

• Cavities or expansions within the brain that are derived from the lumen (opening) of the embryonic neural tube.

• Continuous with one another as well as with the central canal of the spinal cord.

• Four ventricles in the brain. • two lateral ventricles are in the cerebrum, separated by a thin

medial partition called the septum pellucidum • within the diencephalon is a smaller ventricle called the third

ventricle • each lateral ventricle communicates with the third ventricle

through an opening called the interventricular foramen

• The fourth ventricle is located within the pons and cerebellum.

Cerebrospinal Fluid

• A clear, colorless liquid that circulates in the ventricles and subarachnoid space.

• Bathes the exposed surfaces of the central nervous system and completely surrounds it.

• Performs several important functions. • buoyancy • protection • environmental stability

• Formed by the choroid plexus in each ventricle. • Produced by secretion of a fluid from the ependymal

cells that originate from the blood plasma. • Is similar to blood plasma.

Cerebrum

• Account for 83% of brain mass• Fissures – deep grooves – separate major regions of the brain

• Transverse fissure – separates cerebrum and cerebellum• Longitudinal fissure – separates cerebral hemispheres

• Sulci – grooves on the surface of the cerebral hemispheres • Gyri – twisted ridges between sulci • Prominent gyri and sulci are similar in all people• Deeper sulci divide cerebrum into lobes• Lobes are named for the skull bones overlying them• Central sulcus separates frontal and parietal lobes

• Bordered by two gyri• Precentral gyrus • Postcentral gyrus

• Parieto-occipital sulcus • Separates the occipital from the parietal lobe

• Lateral sulcus • Separates temporal lobe from parietal and frontal lobes

• Insula – deep within the lateral sulcus

Cerebral cortex • Composed of gray matter

• Neuronal cell bodies, dendrites, and short axons• Folds in cortex – triples its size • Approximately 40% of brain’s mass• Brodmann areas – 52 structurally distinct areas

Cerebrum: functional areas

• Home of our conscious mind • Enables us to:

• Be aware of ourselves and our sensations• Initiate and control voluntary movements• Communicate, remember, and understand

• Three kinds of functional areas• Motor areas• Sensory areas• Association areas

Motor areas

• Controls motor functions• Primary motor cortex (somatic motor area)• Located in precentral gyrus (Brodmann area 4)

• Pyramidal cells – large neurons of primary motor cortex• Corticospinal tracts descend through brainstem and spinal cord

• Axons signal motor neurons to control skilled movements • Contralateral – pyramidal axons cross over to opposite

side of the brain• Specific pyramidal cells control specific areas of the body• Face and hand muscles – controlled by many pyramidal cells• Motor homunculus – body map of the motor cortex

Sensory cortex

• Cortical areas involved in conscious awareness of sensation

• Located in parietal, temporal, and occipital lobes

• Distinct area for each of the major senses

Sensory Areas – Visual Areas

• Primary visual cortex • Corresponds to Brodmann area 17• Located deep within the calcarine sulcus

• On the posterior and medial part of the occipital lobe• Receives visual information that originates on the retina• First of a series of areas that interprets visual input

• Visual association area• Surrounds the primary visual area• Coincides with Brodmann areas 18 and 19• Continues the processing of visual information• Complex visual processing extends into:

• Temporal and parietal lobes

Sensory Areas – Auditory Areas

• Primary auditory cortex• Function – conscious awareness of sound• Location – superior edge of the temporal lobe• Corresponds to Brodmann areas 41 and 42

• Auditory association area• Lies posterior to the primary auditory cortex• Located within Brodmann area 22• Permits evaluation of different sounds• Lies in the center of Wernicke’s area • Involved in recognizing and understanding

speech

Sensory Areas – Gustatory Cortex

• Involved in the conscious awareness of taste stimuli

• Corresponds to Brodmann area 43• Located on the “roof” of the lateral sulcus

Sensory Areas – Vestibular Cortex

• Located in the posterior part of the insula• Deep to the lateral sulcus

Sensory Areas – Olfactory Cortex• Lies on the medial aspect of the cerebrum• Located in a region called the piriform lobe• Olfactory nerves transmit impulses to the olfactory cortex

• Provides conscious awareness of smells• Part of the rhinencephalon – “nose brain”• Includes – the piriform lobe, olfactory tract, and olfactory

bulb• Connects the brain to the limbic system

• Explains why smells trigger emotions• Orbitofrontal cortex

• Involved with consciously identifying and recalling specific smells

Association areas

• Make associations between different types of sensory information

• Associate new sensory input with memories of past experiences

• New name for association areas – higher order processing areas

Association Areas – Prefrontal Cortex

• Large region of the frontal lobe anterior to motor areas• Performs cognitive functions

• All aspects of thinking and perceiving • Remembering and recalling information • Also related to mood• Has close links to the limbic part of the forebrain

• Functional neuroimaging techniques • Reveal functions of specific parts of the prefrontal cortex

• Anterior pole of frontal cortex • Active in solving the most complex problems

• The farther rostrally one goes in the CNS, the more complex the neural functions

• Functional areas located on the medial side of the frontal lobe• Regions anterior to the corpus callosum

• Involved in complex personal and social interactions• Regions superior to the corpus callosum

• Involved in “mentalization

Association Areas – General Interpretation Area

• Function is currently under investigation• Located at the interface of:

• The visual, auditory, and somatosensory association areas

• Newer studies show most of this region is involved in the visual processing of spatial relationships

Association Areas – Language Area• Surrounds the lateral sulcus in the left cerebral

hemisphere• Five parts have been identified

• Broca’s area – speech production• Wernicke’s area – speech comprehension• Lateral prefrontal cortex – conceptual analysis of

spoken words• Five parts have been identified (continued)

• Most of the lateral and inferior temporal lobe• Coordination of auditory and visual aspects of

language• Parts of the insula

• Initiation of word articulation • Recognition of rhymes and sound sequences

Association Areas – Insula

• Functions of its cortex – not well understood• Some parts function in language and the sense of balance• Other parts – visceral function

• Conscious perception of: • Upset stomach• Full bladder• Some aspects of the sense of smell

Cerebral White Matter

• Different areas of the cerebral cortex communicate:• With each other • With the brainstem and spinal cord

• Fibers are usually myelinated and bundled into tracts• Types of tracts

• Commissures – composed of commissural fibers• Allows communication between cerebral

hemispheres• Corpus callosum – the largest commissure

• Association fibers - Connect different parts of the same hemisphere

• Projection fibers – run vertically • Descend from the cerebral cortex • Ascend to the cortex from lower regions

Basal nuclei

• A group of nuclei deep within the cerebral white matter• Caudate nucleus – arches over the thalamus• Lentiform nucleus – “lens shaped”• Amygdala – sits on top of the caudate nucleus

• Functionally belongs with the limbic system• Lentiform nucleus - Divided into two parts

• Globus pallidus• Putamen

• Cooperate with the cerebral cortex in controlling movements• Receive input from many cortical areas• Evidence shows that they:

• Start, stop, and regulate intensity of voluntary movements• In some way estimate the passage of time

The Diencephalon

• Forms the center core of the forebrain• Surrounded by the cerebral hemispheres• Composed of three paired structures:

• Thalamus, hypothalamus, and epithalamus• Border the third ventricle• Primarily composed of gray matter

The Thalamus

• Makes up 80% of the diencephalon• Contains approximately a dozen major nuclei• Send axons to regions of the cerebral cortex• Nuclei act as relay stations for incoming

sensory messages• Afferent impulses converge on the thalamus

• Synapse in at least one of its nuclei• Is the “gateway” to the cerebral cortex• Nuclei organize and amplify or tone down

signals

The Hypothalamus• Lies between the optic chiasm and the

mammillary bodies • Pituitary gland projects inferiorly • Contains approximately a dozen nuclei• Main visceral control center of the body• Functions include the following:

• Control of the autonomic nervous system

• Control of emotional responses• Regulation of body temperature• Regulation of hunger and thirst

sensations• Control of behavior• Regulation of sleep-wake cycles• Control of the endocrine system• Formation of memory

The Epithalamus• Forms part of the “roof” of

the third ventricle• Consists of a tiny group of

nuclei• Includes the pineal gland

(pineal body)• Secretes the hormone

melatonin • Under influence of the

hypothalamus

The Brain Stem

• Includes the midbrain, pons, and medulla oblongata

• Several general functions• Produces automatic behaviors

necessary for survival• Passageway for all fiber tracts running

between the cerebrum and spinal cord• Heavily involved with the innervation of

the face and head• 10 of the 12 pairs of cranial nerves attach to

it

The Midbrain• Lies between the diencephalon and the pons• Central cavity – the cerebral aqueduct• Cerebral peduncles located on the ventral surface of the brain

• Contain pyramidal (corticospinal) tracts• Superior cerebellar peduncles- Connect midbrain to the cerebellum• Periaqueductal gray matter surrounds the cerebral aqueduct

• Involved in two related functions • Fright-and-flight reaction• Mediates response to visceral pain• Corpora quadrigemina – the largest nuclei, divided into• Superior colliculi – nuclei that act in visual reflexes• Inferior colliculi – nuclei that act in reflexive response to sound

• Imbedded in the white matter of the midbrain, presents two pigmented nuclei

• Substantia nigra – neuronal cell bodies contain melanin, Functionally linked to the basal nuclei

• Red nucleus – lies deep to the substantia nigra, Largest nucleus of the reticular formation

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The Pons

• Located between the midbrain and medulla oblongata

• Contains the nuclei of cranial nerves V, VI, and VII

• Two general groups of cranial nerve nuclei• Motor nuclei• Sensory nuclei

The Medulla Oblongata• Most caudal level of the brain stem

• Continuous with the spinal cord• Choroid plexus lies in the roof of the fourth

ventricle• Pyramids of the medulla – lie on its ventral

surface • Decussation of the pyramids – crossing

over of motor tracts• Cranial nerves VIII–XII attach to the medulla

• The core of the medulla contains:• Much of the reticular formation

• Nuclei influence autonomic functions• Visceral centers of the reticular formation

include:• Cardiac center• Vasomotor center• The medullary respiratory center• Centers for hiccupping, sneezing,

swallowing, and coughing

The Cerebellum • Located dorsal to the pons and medulla• Smoothes and coordinates body movements • Helps maintain equilibrium

• Consists of two cerebellar hemispheres• Surface folded into ridges called folia

• Separated by fissures• Hemispheres each subdivided into:

• Anterior lobe• Posterior lobe

• Composed of three regions• Cortex – gray matter• Internal white matter• Deep cerebellar nuclei – deeply situated gray

matter • Cerebellum must receive information

• On equilibrium • On current movements of limbs, neck, and

trunk• From the cerebral cortex

Cerebellar Peduncles

• Fibers to and from the cerebellum are ipsilateral• Run to and from the same side of

the body • Thick tracts connecting the

cerebellum to the brain stem• Superior cerebellar peduncles• Middle cerebellar peduncles• Inferior cerebellar peduncles

Functional Brain Systems

• Networks of neurons functioning together• The limbic system – spread widely in the forebrain • The reticular formation – spans the brain stem

The Limbic System• Location

• Medial aspect of cerebral hemispheres• Also within the diencephalon

• Composed of:• Septal nuclei, cingulate gyrus, and hippocampal

formation• Part of the amygdala

• The fornix and other tracts link the limbic system together• The “emotional brain”

• Cingulate gyrus • Allows us to shift between thoughts• Interprets pain as unpleasant

• Hippocampal formation • Hippocampus and the parahippocampal gyrus

The Reticular Formation

The Reticular Formation• Widespread connections - Ideal for arousal of the brain as

a whole• Reticular activating system (RAS)

• Maintains consciousness and alertness• Functions in sleep and arousal from sleep

Brain Functions

• Vision• Taste• Cognition• Emotion• Speech• Language• Hearing• Motor Cortex• Sensory Cortex• Autonomic Functions

Vision

The visual cortex resides in the occipital lobe of the brain.

Sensory impulses travel from the eyes via the optic nerve to the visual cortex.

Damage to the visual cortex can result in blindness.

Taste

The gustatory complex (green circle) is the part of the sensory cortex (purple area) that is responsible for taste.

Cognition

The prefrontal cortex is involved with intellect, complex learning, and personality.

Injuries to the front lobe can cause mental and personality changes.

Emotion

Emotions are an extremely complex brain function. The emotional core of the brain is the limbic system. This is where senses and awareness are first processed in the brain.

Mood and personality are mediated through the prefrontal cortex. This part of the brain is the center of higher cognitive and emotional functions.

Prefrontal cortex

Limbic system

Speech

Broca’s area is where we formulate speech and the area of the brain that sends motor instructions to the motor cortex.

Injury to Broca’s area can cause difficulty in speaking. The individual may know what words he or she wishes to speak, but will be unable to do so.

Broca’s Area

Language

Wernicke’s area is a specialized portion of the parietal lobe that recognizes and understands written and spoken language.

Wernicke’s area surrounds the auditory association area.

Damage to this part of the brain can result in someone hearing speech, but not understanding it.

Wernicke’s Area

Auditory Association Area

HearingThere are two auditory areas of the brain:

• The primary auditory area (brown circle) is what detects sounds that are transmitted from the ear. It is located in the sensory cortex.

• The auditory association area (purple circle) is the part of the brain that is used to recognize the sounds as speech, music, or noise.

Motivational systems

• HUNGER

• THIRST

• SEXUAL BEHAVIOR

Hunger

LACK OF

FOOD

REDUCEDAVAILABILITYOF GLUCOSE

CONTRACTIONS OF EMPTYSTOMACH

LOWTRIGLYCERIDELEVELSIN FAT CELLS

GLUCOSE RECEPTORSIN HYPOTHALAMUS

MECHANO-RECEPTORSIN STOMACH

PANCREAS

HUNGER

Thirst

WATERDEFICIENCY

OSMORECEPTORSIN SUPRAOPTICAND SUPRA-VENTRICULARNUCLEI OFHYPOTHALAMUS

THIRST

ADHSERETIONBY PITUITARY

WATERRETENTION BY KIDNEY

Sexual behavior

• Anterior hypothalamus receives input from de receptors stimulated by feromones

• Androgens determine release of luteinizing hormones, cyclic or constant

Brain Plasticity

• The ability of the brain to change as a result of experience, drugs, or injury.

• Collateral sprouting: growth of new neuron branches

• Substitution of function: other areas of the brain take over for damaged areas

• Neurogenesis: generating new neurons

Learning takes place in the brain.

• However, various parts of the brain function differently and provide localized areas for the retention of diverse types of knowledge.

Human Memory System• 3 memory processes

• Encoding – getting information into memory• Storage – keeping the information in memory• Retrieval – getting the information back outExpert learners have successful strategies for using the first two

processes which makes the last one more probable.Types of Memory

• Sensory Store – how information enters • Gatekeeper of the mind• Much of this is ignored.

• Short-term Memory – “ working” memory• Decay’s after 30 seconds

• Can be renewed through maintenance rehearsal• Limited capacity (5-9 items)

• Can be expanded through chunking (ex.SSN)• Long-term Memory – What you “know”

• Unlimited capacity, unlimited duration• Must be retrieved before used (cues)

Two Basic Memory Processes

• Declarative memory• Facts and events• Occurs primarily in brain systems involving

the hippocampus• Procedural memory

• Skills or cognitive operations that cannot be represented in declarative sentences

• Occurs primarily in the brain systems involving the neostriatum

The brain is divided into two halves or hemispheres identified as right and left.

• The left hemisphereiconsidered analytic in

approach A successive processor (left brain) prefers to learn in a step-by-step sequential format, beginning with details leading to a conceptual understanding of a skill.

This part of the brain controls and makes the final decisions concerning information collected throughout the brain.

• At the same time, the left hemisphere simultaneously inhibits the visual-spatial right brain’s cognitive and decision making processes.

Conversely and concurrently…• The right brain

described as holistic or global. A simultaneous processor ( right brain) prefers to learn beginning with the general concept and then going on to specifics.

a “left brain person” is …1. Verbal2. Responds to word meaning3. Sequential 4. Processes information linearly5. Responds to logic6. Plans ahead7. Recall people's names8. Speak with few gestures9. Punctual10. Prefer formal study design11. Prefer bright lights while

studying

For example…

Let’s meet a week from today to talk about this.

If this is true, then it is logical that we …

Because left-brain thinkers are logical and practical, they are also …

• Ruled by facts• Detail oriented• Users of words and

language• Focused on the present

and past• Perceive order & pattern• Reality based• Strategy Formulators

a “right brain person” is …

1. Visual2. Responds to tone of voice3. Random4. Processes information in varied order5. Responds to emotion6. Impulsive7. Recall people’s faces8. Gesture while speaking9. Less punctual10. Prefer sound/ music background while

studying11. Prefer frequent mobility while studying

Because right-brain thinkers are intuitive and willing to take risks, they are also …

• Imaginative• “Big Picture”

oriented• Users of symbols and

images• Focused on the

present and future• Spatially perceptive• Fantasy based• Presenters of

Possibility

Specific learning skills are associated with right and left brain hemispheric dominance.

LEFT BRAIN • Reading & Language• Symbols• Locating details &

facts• Talking & Recitation• Following Directions• Listening• Auditory Association

RIGHT BRAIN• Computation & Patterns• Spatial Relationships• Singing & Music• Art Expression• Creativity• Visualization• Feelings & Emotions

brain dominance is concerned with ways of perceiving, processing, and

organizing information and experiences.

Adolescent brain development

• Underdevelopment of the frontal lobe/prefrontal cortex and the limbic system make adolescents more prone to “behave emotionally or with ‘gut’ reactions”

• Adolescents tend to use an alternative part of the brain– the AMYGDALA (emotions) rather than the prefrontal cortex (reasoning) to process information

• Amygdala and nucleus acumbens (limbic system within the prefrontal cortex) tend to dominate the prefrontal cortex functions– this results in a decrease in reasoned thinking and an increase in impulsiveness

• Because of immature brains, adolescents do not handle social pressure, instinctual urges, and other stresses the way adults do

• A major part of adolescence is learning how to assess risk and consequences — adolescents are not yet skilled at these tasks

Hot and cold cognition

• Thoughts and emotions are intertwined – teens need to develop a balance between cognitive and affective systems of the brain

• “COLD” cognition refers to thinking under conditions of low emotions and/or arousal

• “HOT” cognition refers to thinking under conditions of strong feelings or arousal

• Decisions made under conditions of strong affect are difficult to influence by cool rational thought alone

• Decision making in teens cannot be fully understood without considering the role of emotions and the interaction between thinking and feeling

• Teen decisions are unlikely to emerge from a logical evaluation of the risk/benefits of a situation – rather decisions are the result of a complex set of competing feelings – desire to look cool, fear of being rejected, anxiety about being caught, excitement of risk, etc.

Mental Disorders

• Creates problems with feeling, thinking and perception.• Affects a person’s behavior by involuntarily causing bizarre

and/or inappropriate behavior.• Are primarily brain disorders.• Can be short term (acute) or long term (chronic).• Can occur at anytime in a person’s life.• Associated with distress, or• With significant increased risk of suffering death, pain,

disability, or an important loss of freedom.• Not an expected response to a particular event (e.g., death

of a spouse).• Current manifestation of a behavioral, psychological, or

biological dysfunction.

Categorization of Mental Disorders

• Delirium• Psihotic disorders• Dementia• Cognitive disorders• Affective disorders• Anxiety disorders• Personality disorders• Substance abuse/dependence.• Impulse control disorders.• Adjustment disorders.• Sexual disorders

Alcohol & Other Drug Abuse

• Abuse and Dependence Both Defined as Mental Disorder in DSM IV. • Dependence is Pattern of Use Causing Impairment or Distress

Including • Tolerance• Withdrawal• Increasing Amounts Over Longer Time• Unsuccessful Attempts to Control Use• Time Spent Obtaining, Using, Recovering• Activities Given Up Due to Use• Continued Use Despite Problems

Alcohol & Other Drug Abuse:

• Long term use can result in deteriorated functioning.

• Can cause:• Depression.• Dementia.• Anxiety disorders.

• Use and withdrawal can cause acute psychotic symptoms.

• Addiction is chronic, progressive, & terminal.

Mental Retardation

• Below Average Intellectual Functioning.

• Begins Before Age 18, Usually Present at Birth.

• Unrelated to Other Mental Illness.• Impaired Social-living Adaptation &

Functioning:• Personal care & hygiene.• Money management.• Leisure activities.• Social relationships.

The Brain - Function

Shrinkage of brain tissue.Ventricles enlarge. short-term memory begins to decline ability to perform routine tasks also declines.

Emotional outbursts may occur and language is impaired. Progressively more nerve cells die with subsequent behaviour changes, such as wandering and agitation.

The ability to recognize faces and to communicate is completely lost in the final stages. Patients lose bowel and bladder control, and eventually need constant care.

The average length of time from diagnosis to death is 4 to 8 years, but can take 20

Alois Alzheimer

Alzheimer’s disease First recorded by Alzheimer after studying the brain of a woman who had died after suffering dementia in 1906.

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The Brain - Function

Ageing. Less than 1 in 1000 people < 65 have Alzheimer's. 1 in 20 > 65 has!

A small proportion of sufferers have a genetic (familial) form

A varied and active life may help avoid Alzheimer’s.

Severe blows to the head (especially in the over 50s) may increase the chance of developing the disease

Smoking and high cholesterol may also be risk factors for Alzheimer’s

Future therapy?

A vaccine to break down the β amyloid plaques? Trials in mice

An inhibitor of the membrane enzyme that breaks down APP into Aβ?

Risk factors

Alzheimer’s

…..WISH YOU GOOD LUCK IN MANAGING YOU BRAIN…