Post on 09-Apr-2018
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The HumanThe Human Brain:Brain: FunctionalFunctional
ABDUL HAFIZ ALIAS
H8
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Central Nervous SystemCentral Nervous System
The part of the nervous system that integrates the
information that it receives from, andcoordinates the
activity of, all parts of the bodies of bilateral animals,
It contains themajority of thenervous system andconsists of the brain and the spinal cord.
With the peripheral nervous system, it has a
fundamental role in thecontrol of behavior.
The CNS is contained within the dorsal cavity, withthe brain in the cranial cavity and the spinal cord in
the spinal cavity.
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Cerebrum (Forebrain)Cerebrum (Forebrain)
Parietal Lobe
Temporal Lobe
Frontal Lobe
Limbic Lobe
Occipital Lobe
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Frontal Lobe
Highercognitive functions
Examples : Problem solving, Spontaneity,Memory, Language (Broca), Motivation,Judgment, Impulsecontrol, Social and Sex
Temporal Lobe
Emotions, smelling, tasting, perception,memory,understandingmusic, aggressiveness, sexual behavior,Language
Parietal Lobe sensations of touch, smell, and taste
processes sensory and spatial awarenessa
eye-handco-ordination and armmovement
Wernickes area that is responsible formatching written
words with the sound of spoken speech.
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Occipital Lobe
Controls vision and recognition
Limbic Lobe
Makes up the limbic system
Limbic System
Regulates emotion andmemory.
It directly connects the lower andhigher
brain functions
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ThalamusThalamusThalamus means inner room in Greek,as it sits deep in the brain at the top of
the brainstem.
The thalamus is called thegateway to
thecerebral cortex, as nearly all
sensory inputs pass through it to the
higher levels of the brain.
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HypothalamusHypothalamus
Thehypothalamus sits under the thalamus at
the top of the brainstem. Although the
hypothalamus is small, it controls many critical
bodily functions:
Controls autonomicnervous system
Center foremotional response and behavior
Regulates body temperature
Regulates food intake
Regulates water balance and thirst
Controls sleep-wakecycles
Controls endocrine system
Thehypothalamus isshaded blue.The pituitary
glandextends from the
hypothalamus.
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The VentriclesThe Ventricles
Click image to play or pause video
The ventricles are a complex
series of spaces and tunnels
through thecenter of the brain.
The ventricles secrete
cerebrospinal fluid, which
suspends the brain in the skull.
The ventricles also provide a
route forchemical messengers
that are widely distributed through
thecentral nervous system.
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Cerebellum (Midbrain)Cerebellum (Midbrain)Thecerebellum is connected to the
brainstem, and is thecenter for
body movement and balance.
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The PonsThe Pons
The pons is the rounded
brainstem region between the
midbrain and themedulla
oblongata. In fact, pons means
bridge in Latin.
Themain function of the pons is
to connect thecerebellum to the
rest of the brain and to modify the
respiratory output of themedulla.
The pons is the origin of several
cranial nerves.
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The MedullaThe Medulla OblongataOblongata
(Hindbrain)(Hindbrain)Themedulla oblongata mergesseamlessly with the spinal cord and
creates the base of thebrainstem.
Themedulla is primarily a control
center for vital involuntary reflexes
such as swallowing, vomiting,
sneezing,coughing, and regulation of
cardiovascular and respiratory activity.
Themedulla is also the origin ofmany
cranial nerves.
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CEREBROSPINAL FLUID (CSF)CEREBROSPINAL FLUID (CSF)
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What is CSF ?What is CSF ?
A clear bodily fluid that occupies the subarachnoidspace and the ventricular system around andinside the brain and spinal cord.
Produced in the choroid plexus. The CSF occupies the space between
the arachnoid mater (themiddle layer of the braincover, meninges), and the pia mater (the layer ofthemeninges closest to the brain).
It constitutes thecontent of all intra-cerebral (insidethe brain,cerebrum) ventricles,cisterns,and sulci (singular sulcus), as well as the centralcanal of the spinal cord.
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FunctionsFunctions
Buoyancy: allows the brain to maintainits density without being impaired by itsown weight, which wouldcut off blood supply and
kill neurons in the lower sections without CSF. Protection: CSF protects the brain tissue from
injury when jolted orhit. Incertain situations suchas auto accidents or sports injuries, the CSFcannot protect the brain from forcedcontact with
the skull case,causing hemorrhaging, braindamage, and sometimes death.
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Chemical stability: CSF flows throughoutthe inner ventricular system in the brain and
is absorbed back into the bloodstream,rinsing the metabolic waste from the centralnervous system through the blood-brainbarrier.This allows forhomeostaticregulation of thedistribution of
neuroendocrine factors, to which slightchanges cancause problems ordamage tothenervous system.
Prevention of brain ischemia: The
prevention of brain ischemia is made bydecreasing the amount of CSF in the limitedspace inside the skull.This decreases totalintracranial pressure andfacilitates blood perfusion.
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The BrainstemThe Brainstem
The brainstem is themost
primitive part of the brain and
controls the basic functions of
life: breathing,heart rate,
swallowing, reflexes to sight or
sound, sweating, bloodpressure, sleep, and balance.
Click image to play or pause video
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SPINAL CORDSPINAL CORD
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FunctionsFunctions
Transmission of nerve impulses
Neurons in the whitematter of the spinal cord
transmit sensory signals from peripheral
regions to the brain andmotor signals from thebrain to peripheral regions.
Spinal reflexes
Neurons in thegray matter of the spinal cord
integrate incoming sensory information andrespond withmotor impulses that control
muscles (skeletal, smooth, orcardiac) or
glands.
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TractTract
Ascending (sensory) tracts transmit
sensory information from various parts
of the body to the brain.
Descending (motor) tracts transmit
nerve impulses from the brain to
muscles andglands.
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PERIPHERAL NERVOUSPERIPHERAL NERVOUSSYSTEMSYSTEM
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PNS
SNS ANS
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SOMATIC NERVOUS SYSTEMSOMATIC NERVOUS SYSTEM(SNS)(SNS)
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SNSSNS
controls voluntary activities
Includes both sensory andmotornerves
Sensory nerves convey nerve impulses
from the sense organs to the central
nervous system (CNS), whilemotor
nerves convey nerve impulses from theCNS to skeletal muscleeffectors
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The sensory division, also called the afferent division,
contains neurons that receive signals from the
tendons, joints, skin, skeletal muscles,eyes,nose,ears and tongue, andmany other tissues and organs.
These signals areconveyed to thecranial and spinal
nerves.Themotordivision, also called theefferent
division,contains pathways that go from the brain
stem and spinal cord to the lowermotorneurons ofthecranial and spinal nerves.When thesenerves are
stimulated, they cause the skeletal muscles to
contract.This is called voluntary contraction of the
skeletal muscles.
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NERVES OF THE SENSORYNERVES OF THE SENSORY--SOMATICSOMATIC
SYSTEM (CRANIAL NERVES )SYSTEM (CRANIAL NERVES )I. olfactory nerve, a sensory nerve for the sense ofsmell
II. opticnerve, a sensory nerve forvision
III. oculomotornerve, a motornerve foreyelid andeyeball musclecontrol
IV. trochlearnerve, a motornerve foreyeball musclecontrol
V. trigeminal nerve, a mixednerve, the sensory part for facial andmouth
sensation and themotor part forchewing
VI. abducens nerve, a motornerve foreyeball movement control
VII. facial nerve, a mixednerve, the sensory part fortaste and themotor
part for thecontrol of facial muscles and salivary glands
VIII.auditory nerve, a sensory nerve forhearing and balancecontrol
IX. glossopharyngeal, a mixednerve, the sensory part for taste and themotor part for thecontrol of swallowing
X. vagus, a mixednerve,mainPNS nerve that controls thegut, heart and
larynx
XI. accessory, a motornerve for swallowing andmoving thehead and
shoulders
XII. hypoglossal, a motornerve for thecontrol of tonguemuscles
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Autonomic Nervous SystemAutonomic Nervous System
(ANS)(ANS)
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ANSANS
The ANS is part of the peripheral
nervous system and it controls many
organs andmuscles within the body. Inmost situations, we are unaware of the
workings of the ANS because it
functions in an involuntary, reflexivemanner.
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ANS
Sympathetic Parasympathetic
involuntary system
often associated
with the flight orfight response.
responsible for
promoting internal
harmony such as
regular heartbeat
during normal activity.
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ComparisonComparisonFeatures Sympathetic division Parasympathetic
divisionLocation of pre
ganglioniccell body
Lateral horns of spinal
cordgray matter (T1-
L2)
Brainstem and lateral
parts of spinal gray
matter (S2- S4)
Outflow from the CNS Spinal nerves
Sympatheticnerves
Splanchnic nerves
Cranial nerves
Pelvic splanchnic nerves
Ganglia Sympatheticchain
ganglia along spinal
cord for spinal and
sympatheticnerves
Collateral ganglia for
splanchnicnerves
Terminal ganglia near or
oneffectors organ
Num of postganglionic
neurons foreach pre
ganglionicneuron
Many (much
divergence)
Few (less divergence)
Relative length of
neurons
Short preganglionic
Long postganglionic
Long preganglionic
Short postganglionic
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Effects of the sympathetic and parasympatheticEffects of the sympathetic and parasympathetic
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TQTQ