Brain And Five Senses

1. THE BRAIN AND FIVE THE BRAIN AND FIVE
SENSESSENSES
BRAIN- responsible for overseeing the daily BRAIN- responsible for overseeing the daily
operations of the human body and for interpreting operations of the human body and for interpreting
the vast amount of information recieves.the adult the vast amount of information recieves.the adult
human body brain weighs an average of 1.4 kg or human body brain weighs an average of 1.4 kg or
about 2% of the total body weight.about 2% of the total body weight.

2. The Brain is the main switching unit of the The Brain is the main switching unit of the
central nervous system;it is place to which central nervous system;it is place to which
impulses flow and from which impulses impulses flow and from which impulses
originate.originate.
Spinal Cord provides the link between the Spinal Cord provides the link between the
brain and the rest of the bodybrain and the rest of the body

3. THE BRAIN HAS THREE MAIN PARTSTHE BRAIN HAS THREE MAIN PARTS
CerebrumCerebrum
CerebellumCerebellum
-Brain stem-Brain stem
-the brain is protected by bony covering called -the brain is protected by bony covering called
the SKULLthe SKULL
-Wrapped in three layers of connective tissue Wrapped in three layers of connective tissue
called the MENINGES.called the MENINGES.

4. The innermost layer which covers surface of The innermost layer which covers surface of
the brain is the PIA MATER.the brain is the PIA MATER.
The ARACHNOID is thin,elastic,weblike The ARACHNOID is thin,elastic,weblike
layer between the PIA MATER and DURA layer between the PIA MATER and DURA
MATER.MATER.
The outer layer called the DURA MATER The outer layer called the DURA MATER
composed of thick connective tissue.composed of thick connective tissue.

5. CEREBROSPINAL FLUID –space CEREBROSPINAL FLUID –space
filled between the pia mater and the filled between the pia mater and the
arachnoid .arachnoid .
CSF –is a clear liquid that protects the brain CSF –is a clear liquid that protects the brain
from mechanical injury by acting as schock from mechanical injury by acting as schock
absorber.absorber.
VENTRICLES –Cerebrospinal fluid that VENTRICLES –Cerebrospinal fluid that
separates the middle and inner meninges and separates the middle and inner meninges and
fills four interconnected or cavities in the fills four interconnected or cavities in the
brain.brain.
In order that brain perform its functions must In order that brain perform its functions must
have constant supply of food and oxygen.have constant supply of food and oxygen.

6. PARTS OF THE BRAINPARTS OF THE BRAIN
THE CEREBRUM – control center of the brainTHE CEREBRUM – control center of the brain
Largest and most prominent part of the human Largest and most prominent part of the human
brain.Brain is the cerebrum 85% OF THE WEIGHT brain.Brain is the cerebrum 85% OF THE WEIGHT
OF HUMAN BRAIN.OF HUMAN BRAIN.
Responsible for all voluntary activities of the body,site Responsible for all voluntary activities of the body,site
of INTELLIGENCE,LEARNING AND of INTELLIGENCE,LEARNING AND
JUDGEMENT.JUDGEMENT.
It functions in It functions in
language,conscious,thought,memory,personality language,conscious,thought,memory,personality
development,vision and other sensations.development,vision and other sensations.

7. TWO HEMISPHERETWO HEMISPHERE
-The left and the right cerebral hemispheres.-The left and the right cerebral hemispheres.
-There is a DEEP GROOVE that separates the -There is a DEEP GROOVE that separates the
two hemisphere- this are connected in the two hemisphere- this are connected in the
region known as CORPUS CALLOSUMregion known as CORPUS CALLOSUM
-The right and left cerebral hemispheres are -The right and left cerebral hemispheres are
linked by a bundle of neurons called a linked by a bundle of neurons called a
TRACT.TRACT.
-It contains thick layers of unmyelinated neurons -It contains thick layers of unmyelinated neurons
which look gray(GRAY MATER)which look gray(GRAY MATER)

8. FOUR REGIONSFOUR REGIONS
LOBES –These lobes are named for the skull LOBES –These lobes are named for the skull
bones-FRONTAL,PARIETAL,TEMPORAL bones-FRONTAL,PARIETAL,TEMPORAL
AND OCCIPITAL LOBES.AND OCCIPITAL LOBES.
Scientist have discovered that the left side of Scientist have discovered that the left side of
the body SENDS sensations to the right the body SENDS sensations to the right
hemisphere of the cerebrum and the right side hemisphere of the cerebrum and the right side
of the body send its sensations to the left of the body send its sensations to the left
hemisphere.hemisphere.

12. The right hemisphere associated with The right hemisphere associated with
creativity and artistic ability while the left creativity and artistic ability while the left
hemisphere with analytical and mathematical hemisphere with analytical and mathematical
ability.ability.
Sometimes blood vessels in the brain blocked Sometimes blood vessels in the brain blocked
by blood clots causing disorder called stroke.by blood clots causing disorder called stroke.

13. Two surfaces of cerebrumTwo surfaces of cerebrum
FOLDED OUTER SURFACE-CEREBRAL FOLDED OUTER SURFACE-CEREBRAL
CORTEX and consists of GRAY CORTEX and consists of GRAY
MATER(unmyelinated neuron)MATER(unmyelinated neuron)
INNER SURFACE –CEREBRAL MEDULLA INNER SURFACE –CEREBRAL MEDULLA
–made up of bundles of MYELINATED –made up of bundles of MYELINATED
AXONS . THE WHITE MATTER-MYLIN AXONS . THE WHITE MATTER-MYLIN
GIVES WHITE MATER COLOR.GIVES WHITE MATER COLOR.

14. CEREBELLUMCEREBELLUM
Second largest part of the brain and is locate at the Second largest part of the brain and is locate at the
back of the skull.back of the skull.
COORDINATES MUSCLE MOVEMENTCOORDINATES MUSCLE MOVEMENT
CONTROLS BALANCE,POSTURE AND CONTROLS BALANCE,POSTURE AND
COORDINATIONCOORDINATION
Receives sensory impulses from Receives sensory impulses from
muscles,tendons,joints,eyes and ears.muscles,tendons,joints,eyes and ears.
Processes information about position and controls Processes information about position and controls
posture by keeping skeletal muscles in a constan state posture by keeping skeletal muscles in a constan state
of partial contraction.of partial contraction.

15. This is a small CAULIFLOWER SHAPED This is a small CAULIFLOWER SHAPED
STRUCTURE.STRUCTURE.
Function of the cerebellum is Function of the cerebellum is
involuntary(NOT UNDER CONSCIOUS involuntary(NOT UNDER CONSCIOUS
CONDITION).CONDITION).

16. BRAIN STEMBRAIN STEM
CONNECTS THE BRAIN AND SPINAL CONNECTS THE BRAIN AND SPINAL
CORDCORD
Maintains life support,systems,consist of Maintains life support,systems,consist of
diencephalon,medulla oblongata,pons,and the diencephalon,medulla oblongata,pons,and the
midbrain.midbrain.
CONTROLS VITAL BODY PROCESSESS.CONTROLS VITAL BODY PROCESSESS.
UPPER BRAIN STEM- DIECENPHALONUPPER BRAIN STEM- DIECENPHALON
LOWER BRAIN STEM – MEDULLA LOWER BRAIN STEM – MEDULLA
OBLONGATA OBLONGATA

17. MEDULLA contains WHITE MATER-conducts MEDULLA contains WHITE MATER-conducts
impulses between the spinal cord and brain.-also impulses between the spinal cord and brain.-also
controls involuntary functions that include controls involuntary functions that include
breathing,blood pressure,heart breathing,blood pressure,heart
rate,digestion,swallowing and coughing.rate,digestion,swallowing and coughing.
Reticular activating system or reticular Reticular activating system or reticular
formation(RAS) –other important part of the medulla- formation(RAS) –other important part of the medulla-
RAS- HELP to allert or awakens the upper parts of the RAS- HELP to allert or awakens the upper parts of the
brain,including the cerebral cortex.-also helps to brain,including the cerebral cortex.-also helps to
control respiration and circulationcontrol respiration and circulation

18. PONSPONS
 just above the medulla,the brainstem enlarges just above the medulla,the brainstem enlarges
to form pons and it MEANS BRIDGE,mostly to form pons and it MEANS BRIDGE,mostly
white mater that link bet the cerebral cortex white mater that link bet the cerebral cortex
and the cerebellum.and the cerebellum.
Midbrain- above the pons and the smallest Midbrain- above the pons and the smallest
division of the lower stem-areas involved division of the lower stem-areas involved
hearing and vision.hearing and vision.

19. DIENCEPHALON(UPPER BRAIN DIENCEPHALON(UPPER BRAIN
STEM)STEM)
Thalamus and hypothalamus-bet. Brain stem Thalamus and hypothalamus-bet. Brain stem
and cerebrumand cerebrum
Thalamus- gray matter serves as switching Thalamus- gray matter serves as switching
station for sensory input with the exception of station for sensory input with the exception of
smell.smell.
It is the relay station of the brain stem where It is the relay station of the brain stem where
sensory pathways in the spinal cord and brain sensory pathways in the spinal cord and brain
stem form synapses on their way to cerebral stem form synapses on their way to cerebral
cortex.cortex.

20. Hypothalamus-below the thalamus – control Hypothalamus-below the thalamus – control
center for hunger,thirst,fatique,anger and body center for hunger,thirst,fatique,anger and body
temperaturetemperature

21. Limbic systemLimbic system
Includes the thalamus and the hypothalamus Includes the thalamus and the hypothalamus
some deeper parts are the cerebral cortex and some deeper parts are the cerebral cortex and
the temporal lobes- an plays an important role the temporal lobes- an plays an important role
in emotions,memory and motivation in emotions,memory and motivation
 The seat of emotional interpretation.The seat of emotional interpretation.

22. SENSORY SYSTEMSENSORY SYSTEM
Sensory receptors react directly to stimulation Sensory receptors react directly to stimulation
from the environment.from the environment.
Sense organs-receive information from the Sense organs-receive information from the
environment.environment.
Examples of stimulation are ( LIGHT, Examples of stimulation are ( LIGHT,
SOUND,MOTION,CHEMICAL PRESSURE, SOUND,MOTION,CHEMICAL PRESSURE,
PAIN OF CHANGES IN THE PAIN OF CHANGES IN THE
TEMPERATURE.TEMPERATURE.

23. SENSORY RECEPTORSSENSORY RECEPTORS
ARE NEURON THAT IS SPECIALIZED TO DETECT ARE NEURON THAT IS SPECIALIZED TO DETECT
STIMULUS THEY RESPOND TO:STIMULUS THEY RESPOND TO:
Mechanoreceptors- respond to movement,pressure and Mechanoreceptors- respond to movement,pressure and
tensiontension
Photoreceptors (RODS AND CONES)-respond to Photoreceptors (RODS AND CONES)-respond to
variations to light.variations to light.
Chemoreceptors-respond to chemicalsChemoreceptors-respond to chemicals
Thermorecptors-respond to changes in temperatureThermorecptors-respond to changes in temperature
Pain receptors-respond to tissue damage-PAINPain receptors-respond to tissue damage-PAIN

24. FIVE SENSESFIVE SENSES
SIGHT-HEARING-SMELL-TASTE-TOUCHSIGHT-HEARING-SMELL-TASTE-TOUCH
MOST FAMILIAR SENSE ORGANS ARE THE MOST FAMILIAR SENSE ORGANS ARE THE
EYES,EARS,NOSE,SKIN AND TASTE BUDSEYES,EARS,NOSE,SKIN AND TASTE BUDS
THE RECEPTORS CONVERT THE ENERGY of a THE RECEPTORS CONVERT THE ENERGY of a
stimulus into an electrical energy that can travel in the stimulus into an electrical energy that can travel in the
NERVOUS SYSTEMSNERVOUS SYSTEMS
Messages from sense organs to CNS are in the form of Messages from sense organs to CNS are in the form of
Nerve impulses.Nerve impulses.

25. Hearing and BalanceHearing and Balance
EAR is really two sense organ in one.not only EAR is really two sense organ in one.not only
detect sound waves also senses the position of detect sound waves also senses the position of
the head whether it is still moving in a straight the head whether it is still moving in a straight
line or rotating.line or rotating.
Low-pitched-slow variationsLow-pitched-slow variations
High –pitched-faster variationHigh –pitched-faster variation

26. EXTERNAL EAREXTERNAL EAR
Consists of the visible fleshly part helps to collect Consists of the visible fleshly part helps to collect
sound and funnel into the AUDITORY sound and funnel into the AUDITORY
CANAL(CONNECTS THE EXTERNAL EAR) with CANAL(CONNECTS THE EXTERNAL EAR) with
the tympanic membrane also called eardrum.the tympanic membrane also called eardrum.
The AUDITORY CANAL- contains small hair and The AUDITORY CANAL- contains small hair and
wax producing glands that prevent foreign objects wax producing glands that prevent foreign objects
from entering the ear.from entering the ear.
Extends into the bone of the head and stops at the Extends into the bone of the head and stops at the
eardrumeardrum

27. Sound variations strike the eardrum and Sound variations strike the eardrum and
transmitted into three tiny bones.the transmitted into three tiny bones.the
malleaus(HAMMER) incus (ANVIL) and malleaus(HAMMER) incus (ANVIL) and
STAPES(stirrup)STAPES(stirrup)
 THE STIRRUP TRANSFERS THE THE STIRRUP TRANSFERS THE
VIBRATIONS TO A THIN MEMBRANE VIBRATIONS TO A THIN MEMBRANE
CALLED OVAL WINDOW.CALLED OVAL WINDOW.
This membrane transmits the vibrations to the This membrane transmits the vibrations to the
cochlea which begins the INNER EAR.cochlea which begins the INNER EAR.

28. The COCHLEA IS snail shaped consisting of The COCHLEA IS snail shaped consisting of
fluid filled chambers that are separated by fluid filled chambers that are separated by
membranes.membranes.
Organ of corti- middle chamberOrgan of corti- middle chamber
These nerve impulses are carried to the brain These nerve impulses are carried to the brain
by the AUDITORY OR ACOUSTIC NERVEby the AUDITORY OR ACOUSTIC NERVE
The ears also contain structures for detecting The ears also contain structures for detecting
stimulus that make us aware of our movement stimulus that make us aware of our movement
and allow us to maintain our BALANCE.and allow us to maintain our BALANCE.

29. LOCATED WITHIN THE INNER EAR JUST LOCATED WITHIN THE INNER EAR JUST
ABOVE THE COCHLEA ARE THREE ABOVE THE COCHLEA ARE THREE
TINY CANALS THAT LIE AT THE RIGHT TINY CANALS THAT LIE AT THE RIGHT
ANGLES TO EACH OTHER –semicicular ANGLES TO EACH OTHER –semicicular
canals because they each make half a circle.canals because they each make half a circle.
The semicircular canals and two tiny sacs The semicircular canals and two tiny sacs
located behing them helf us to sense balance or located behing them helf us to sense balance or
equilibirum.equilibirum.

30. OtolithsOtoliths
ARE TINY RAINS OF CALCIUM ARE TINY RAINS OF CALCIUM
CARBONATE AND PROTEIN.CARBONATE AND PROTEIN.

31. EYE- VISIONEYE- VISION
-The sense organ we use to sense light is the -The sense organ we use to sense light is the
eyes.eyes.
Composed of three layers- outer layer-consists Composed of three layers- outer layer-consists
of the sclera and cornea-middle choroid,ciliary of the sclera and cornea-middle choroid,ciliary
body and iris-inner layer retinabody and iris-inner layer retina
SCLERA ( white of the eye)-MAINTAIN SCLERA ( white of the eye)-MAINTAIN
SHAPE OF THE EYE AND PROVIDES SHAPE OF THE EYE AND PROVIDES
ATTACHEMENT FOR THE MUSCLES ATTACHEMENT FOR THE MUSCLES
THAT MOVE THE EYE.THAT MOVE THE EYE.

32. Cornea- front of the eye and forms a Cornea- front of the eye and forms a
transparent layers and the part of the eye that transparent layers and the part of the eye that
enters light.enters light.
AQUEOUS HUMOR- JUST INSIDE THE AQUEOUS HUMOR- JUST INSIDE THE
CORNEA AND A SMALL CHAMBER CORNEA AND A SMALL CHAMBER
FILLED WITH FLUID.FILLED WITH FLUID.
Choroid – back of the chamber ,contains blood Choroid – back of the chamber ,contains blood
vessels of the eye,becomes a disk-liske vessels of the eye,becomes a disk-liske
structure-IRISstructure-IRIS

33. DIAPHRAGM(iris)portion of the eye that DIAPHRAGM(iris)portion of the eye that
gives your eye its color and control the amount gives your eye its color and control the amount
of light entering the eye by altering the of light entering the eye by altering the
diameter of the pupildiameter of the pupil
PUPIL – middle of the iris ,a small opening PUPIL – middle of the iris ,a small opening
through which light enters the eye.-black disk through which light enters the eye.-black disk
in the center of the eye-regulate the size of the in the center of the eye-regulate the size of the
pupil controlling the amount of light to enter pupil controlling the amount of light to enter
the eye.the eye.

34. LENSLENS
Behind the iris-light is focused by the lens Behind the iris-light is focused by the lens
which cahnges shape when pulled by muscles which cahnges shape when pulled by muscles
around its edges.around its edges.
Crystalin-cells that form the lens contain Crystalin-cells that form the lens contain
special protein and is almost transparent and special protein and is almost transparent and
allows light to pass through.allows light to pass through.
VITREAL CHAMBER-behind lensVITREAL CHAMBER-behind lens
VITREOUS HUMOR-Transparent jelly-like VITREOUS HUMOR-Transparent jelly-like
fluidfluid

35. PHOTORECEPTORSPHOTORECEPTORS
CONVERT light energy into impulses that are carried CONVERT light energy into impulses that are carried
to the CNS.to the CNS.
CONTAIN PIGMENT CALLED rhodopsin-respond to CONTAIN PIGMENT CALLED rhodopsin-respond to
wavelenghts of light.wavelenghts of light.
TWO TYPES OF PHOTORECEPTORSTWO TYPES OF PHOTORECEPTORS
1.RODS –sensitive to all colors of light do not 1.RODS –sensitive to all colors of light do not
distinquish different colors.distinquish different colors.
2. CONES –sensitive than rods,do not respond 2. CONES –sensitive than rods,do not respond
differently to llight of different colors,producing color differently to llight of different colors,producing color
visionvision

36. Optic nerveOptic nerve
Impulses leave the eye by way of optic nerve Impulses leave the eye by way of optic nerve
and carried part of the brain known as the and carried part of the brain known as the
optic lobe or occipital lobe-which interprets optic lobe or occipital lobe-which interprets
the visual images and provides information the visual images and provides information
about the external world.about the external world.

37. SMELLSMELL
The sense of smell is a chemical sense responsible of The sense of smell is a chemical sense responsible of
smell called the olfactory receptors.smell called the olfactory receptors.
Located in the upper part of the nasal cavityLocated in the upper part of the nasal cavity
Chemorecptors contain cilia that extend into the air Chemorecptors contain cilia that extend into the air
passages of the nose and react to chemicals in tha passages of the nose and react to chemicals in tha
air.chemicals that come into contact with the air.chemicals that come into contact with the
chemoreceptors stimulate them causing impulses to be chemoreceptors stimulate them causing impulses to be
sent to the brain by the OLFACTORY NERVEsent to the brain by the OLFACTORY NERVE

38. TASTETASTE
The sense of taste is a chemical senseThe sense of taste is a chemical sense
Stimulated by the chemicals called Stimulated by the chemicals called
chemoreceptorschemoreceptors
The sense organ detects taste.taste are the taste The sense organ detects taste.taste are the taste
buds not the tonque.buds not the tonque.
Most 10,000 taste buds are embedded between Most 10,000 taste buds are embedded between
bumps called PAPILLAE on the tonque but bumps called PAPILLAE on the tonque but
can also found on the rrrof of the mouth,on the can also found on the rrrof of the mouth,on the
lips and in the throat.lips and in the throat.

39. TOUCHTOUCH
All regions of the body are sensitive to touchAll regions of the body are sensitive to touch
SKIN - largest sense organs of the skinSKIN - largest sense organs of the skin
 mechanoreceptors – located throughout the mechanoreceptors – located throughout the
skin make it posible to sense of touch,pressure skin make it posible to sense of touch,pressure
and tension.and tension.
TWO TYPES OF OF RESPOND;TWO TYPES OF OF RESPOND;
THERMORECEPTORS –respond to touchTHERMORECEPTORS –respond to touch
MECHANORECEPTORS –respond to tissue MECHANORECEPTORS –respond to tissue
damage which causes pain receptors.damage which causes pain receptors.