Slide 1

THE WORLD THROUGH OUR SENSES

Receptor Our body have different types of receptors. These are:pain receptortouch receptorheat receptorcold receptorpressure receptor

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Human skin

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12345678ABCDThe degree of sensitivity of the skin depends on the:

1.Thickness of the epidermisThe thinner the epidermis, the more sensitive the skin is to the stimulus2. Number of receptors present PMR 05The more receptors found on the skin the more sensitive is that part of the skin.

Other functions of the human skin.Water proofprevent water loss from skin.Prevents entry of microorganisms that cause illnesses.Remove waste productsexcess water, urea and mineral salts.Produces Vitamin D in the presence of the sunlight.Stabilise body temperature

Fill in the blank with the suitable terms given in the box.

Receptors thickness thinner sense of touch touch more number The skin is an organ of __________________ There are five types of __ ___ in the skin sensitive to various stimuli.The sensitivity of the skin depends on the ___________ of the epidermis and the ____________ receptors on the skin.The ____________ the epidermis, the more sensitive it is to stimulus.The ________ receptors there are on the skin, the more sensitive it is to stimulus.Blind people use their ____ to help them read Braille

Human Tongue

Try these123456PMR 2012

Human nose

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ABCDEFGHIJKLSense of smellWhen we have a cold or flu, a lot of mucus is produce. The smell receptors are surrounded by this thick layer of mucus and vary little of chemical vapor gets to the smell receptors. Therefore, the smell receptors do not get stimulated enough to effectively function as a sensory organ of smell.

The sensitivity of the nose towards stimuli is influenced by the following factors: PMR 05

The strength of the smell. A stronger smell will be detected by the nose easily compared with a weaker smell.The presence of mucus in the nose. A lot of mucus will reduce the sensitivity of the nose.

Human ear

A human ear has three main part.the outer ear, filled with air.The middle ear, filled with air.The inner ear, filled with liquid

Human ear

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Test

FUNCTIONS OF DIFFERENT PARTS OF THE HUMAN EAR

PartfunctionOUTER EARPinnacollects and directs sound waves into the ear canal.ear canal / auditory canaltransmits sound waves to the eardrum.Eardrumvibrates and transmits sound waves to the ossicles.MIDDLE EAROssiclesintensify the vibrations of the sound waves by 22 times before transmitting to the oval window.Eustachian tubebalances the air pressure at both side of the eardrum.oval windowtransmits sound vibrations from the middle ear to the inner ear.INNER EARCochleatransforms sound vibrations into impulses.semicircular canalsbalance the body position.auditory nervessend messages to the brain which interprets the messages as sound.Stereophonic hearingStereophonic hearing is hearing using both ears.The advantages of stereophonic hearing:enables the direction of the source of hearing to be detected more accurately.This is because the ear nearer the source of sound receives sound louder and earlier than the other ear.Animals that have stereophonic sound can detect the presence of preys and predators more quickly.

Properties of soundsound can transferred through;solidsliquidsgasescannot be transferred through in vacuum.(particles in solids and liquids are closer each other compared to the molecules in gases. Vacuum is space that does not have any particles.)

ANIMALFrekuansi snake100-800Hzfrog50-10 000Hzdog10-50 000Hzcat60-60 000Hzbat1000-120 000Hzgrasshopper100-15 000Hzwhale10-50HzHuman 20hz 20 000 hzThe range of frequencies of hearing in man is 20 Hz until 20 000 Hz. The following table shows the range of frequencies of hearing of several animals:

Different people have different limitations of hearing.Experiment

PKBS 1 2012 F2

Reflection and absorption of soundSound can be reflected or absorbed by the surface of an object.The sound reflected repeatedly from one surface is known as echo.Surfaces that are smooth, even and hard are good sound reflectors and produce loud echo. For examples, concrete, plank, metal and mirrorSurfaces that are rough, hollow and soft are good sound absorbers and produce weak echo. For examples cloth, sponge, cork, rubber, carpet and cushion.

To overcome the limitations of hearing, we use

the stethoscopeenables doctor to detect the soft heartbeats of patients.ii.hearing aidscollects sound signals before being sent to the middle ear.iii.amplifierboosts weak sound signals.

Human eye

choroid

Human eye

Human eye

33Human eye

FUNCTIONS OF DIFFERENT PARTS OF THE HUMAN EYEPart Structure / characteristicFunction ScleraMaintains the shape of the eyeball Protects the eyeballcornearybb

ChoroidsConjunctivairispupilLens PMR 04Transparent and elastic convex lensRefracts and focuses light onto the retina.ciliary musclesupportive ligamentvitreous humouraqueous humourRetina PMR 2011optic nerveHuman eye

Yellow spotDaily activities

pupilirisdark roombright roomDaily activities

Stereoscopic vision

- using both eyes.predatorAdvantagesSee three-dimensional pictures of objects.Enables more accurate estimation of distance and position.DisadvantagesA narrow vision field.

Monocular vision.using only one eye.preyAdvantageshaving a wide vision field.

Disadvantagescannot estimate distance accurately.

Experiment Textbook pages 20

Mechanism of Sight PMR 03, 07The eye lens focuses the image onto the retina by changing the thickness of the eye lens. The thickness of the lens is changed by the cilliarry muscles.i.Focusing near objectsTo focus near objects onto the retina, the cilliarry muscles contract. The eye lens become thicker.

ii.focusing distant object.To focus distant objects onto the retina, the cilliarry muscles relax. The eye lens becomes thinner.

Reflection of light

Rough surfaceFlat, shiny, smoothContoh, BOMBA, POLISBOMBA

Device used concept reflection

Kalaideskop tak guna concept reflectionReflection of light

Refraction of light

Refraction of light

Refraction of light

Smooth, shiny, flatABCDEFGHIJLess densedenser

Short sightednessCauses:Eye ball is too bigEye lens is to thick.Correction:

Wearing concave lens

Long sightedness

Causes:Eye ball is too smallEye lens is to thin.Correction:

Wearing convex lens

Comparison between SS and LS

Astigmatism Light is refracted to multiple areas of the retina.This defect can be overcome by wearing glasses with cylindrical lenses or contact lens or by surgery.

Astigmatism

Instructions

First, I want you to form groups of four. In your group, discuss why some people wear glassesNext, I want you to look at the first picture on the screenClick and drag the picture from left to right. Observe what happens to the imageThen, repeat the activity on the second and third picturesExperiment short sightedness & long sightednessQuestions

Why do some people wear glasses?

What is the cause of short sightedness?

Where does the image fall when a short sighted person look at a far object?

What kind of lens is used to correct short sightedness?

Types of DefectsAble to see close/near objects(clear/blur)Able to see distant object (clear/blur)Types of lens used to correct defects1) Short sightedness2) Long sightedness3) AstigmatismFormative Assessment Complete the diagramShort sightednessLong sightednessThe image falls _______ of the retinaThe image falls ______of the retinaShort sightedness & long sightedness

Optical illusion

Optical illusion

Blind spot

The blind spot is a spot on the retina of the eye that cannot detect light stimulus.The image of the object formed at the blind spot cannot be seen by the eye because there are no light-sensitive cells (photoreceptors) at the blind spot.

Tropism Plant response to external stimulusPlants grow towards stimulus called positive tropismPlants grow away from stimulus called negative tropism

AnhydrousCalciumchloridePhototropismResponse to light.

HydrotropismResponse to water

GeotropismResponse to gravityThigmotropismResponse to touchmove towards to obtain support

Nastic movementResponse to touchMove - run away

Penutup 2. Tasbih Kifarah.

1. Baca Surah Al-`Ashr

The end