15.1 Irritability
Irritability
15.1 Irritability
Irritability
Ability
senses oursurroundings
responds tosurroundings
Body
Lion is coming
Part A
Part B
Running
Part C
15.1 Irritability
Body
Lion is coming
Part A
Stimulus
Receptor
Part B
CentralNervousSystem(CNS)
Running
Response
Nerveimpulse
Nerve
Nerve
Nerveimpulse
Part C
Effector
15.1 Irritability
15.1 Irritability
Stimuli
Receptor
CNS
Effector
Response
15.1 Irritability
Receptor
CNS
Effector
Nerve
Nerve
Response
Stimuli
15.1 Irritability
Stimuli
Pressure, touch, pain,movement of air, heat,cold, light, sound,chemicals substances
Pressure, touch, pain,movement of air, heat,cold, light, sound,chemicals substances
Blood pressure,water potential andCO2 conc. in blood,tension in muscles
Blood pressure,water potential andCO2 conc. in blood,tension in muscles
A change in
Externalenvironment
Internalenvironment
15.1 Irritability
Stimuli
Receptor
CNS
Effector
Nerve
Nerve
Response
produces
Receptor
CentralNervousSystem(CNS)
Stimulus
Nerve
nerve impulses
1
2
Interpret assensation
stimulates
Receptors
Receptors
15.1 Irritability
Receptors
Receptors
Detect stimuli
Detect stimuli
produce nerveimpulses
produce nerveimpulses
1
2
15.1 Irritability
Stimulus
15.1 Irritability
Stimulus
Sensation
Light
Sight
Sound
Hearing
Chemicals in air
Smell
Chemicals in food
Taste
Change in temp.
Touch
Pressure
Pain
Heat or cold
Texture
Pressure
Pain
15.1 Irritability
Stimuli
Receptor
CNS
Effector
Nerve
Nerve
Response
15.1 Irritability
Effector
Response
Muscle
1
Gland
2
Musclecontraction
Secretion
Innate
15.1 Irritability
Behaviour
Lower animals
Same stimulus
with different responses
Modified by learning
Higher animals
15.2 The five senses
Five senses
15.2 The five senses
Hearing
Smell
Sight
Touch
Taste
Touch
15.2 The five senses
Touch
Skin
What kinds of receptor arefound in the skin?
Painreceptor
Touchreceptor
Coldreceptor
Heatreceptor
Pressurereceptor
1
2
3
4
5
Touch
Skin
15.2 The five senses
Distributionof receptors
Uneven
Even
15.2 The five senses
Hearing
Smell
Sight
Touch
Taste
Taste
15.2 The five senses
Taste
Tongue
Taste bud
Taste bud
Taste
Epithelium
Solublechemicalsin food
Gives thesensation oftaste
15.2 The five senses
Brain
15.2 The five senses
Four basic tastesensations
Sourness
Saltiness
Sweetness
Bitterness
Taste
15.2 The five senses
Hearing
Smell
Sight
Touch
Taste
Smell
15.2 The five senses
Smell
Nose
Nasal cavity
Upperepithelium
15.2 The five senses
Nasal cavity
Upperepithelium
Mucus
Smell
15.2 The five senses
Smell
Air
Soluble chemicalsin gas
Smellreceptor
Gives sensation of smell
Brain
Mucus
15.2 The five senses
Detectssolublechemicals
Nose
Tongue
Stimulatesappetite
1
Detectsharmfulsubstances
2
Initiates secretion ofdigestive juices
3
Sense
Smell
Taste
Flavour of food
15.2 The five senses
Hearing
Smell
Sight
Touch
Taste
Hearing
15.2 The five senses
Ear
Hearing
OuterEar
MiddleEar
InnerEar
15.2 The five senses
Pinna
Auditorycanal
Eardrum
Air vibration
Pinna collectsthe sound wave
Passes alongauditory canal
Strikes on theeardrum
Result
Eardrumvibrates
Hearing
15.2 The five senses
Eardrum
Earbones
Oval window
Vibration ofear bones
Transmittionof vibration
Ovalwindow
Hearing
15.2 The five senses
Oval window
Cochlea
Auditorynerve
Vibration of fluidin cochlea
Sensory hair cellsare stimulated
Nerve impulsesare produced
Auditory nervetransmits impulses
Hearing
15.3 The eye
The Eye
15.3 The eye
Eye muscles
Skull
Opticnerve
Tear gland
Eye ball
Skull
Forprotection
15.3 The eye
the eye can berotated
Contract or relax
15.3 The eye
Eye muscles
15.3 The eye
Transmitsimpulses to thebrain
Opticnerve
15.3 The eye
Tear gland
Keep theeyes moist
Kill germs
Tears
15.4 Structure and functions of the eye
Structure &functions of
15.4 Structure and functions of the eye
Wall ofeyeball
15.4 Structure and functions of the eye
Sclera
Choroid
Retina
1
2
3
Three layersin the wall of eyeball
15.4 Structure and functions of the eye
Sclera
For muscleattachment
3
Tough
Tough
Protection
Keeping theshape of eyeball
1
2
15.4 Structure and functions of the eye
Choroid
Internalreflectionof light
15.4 Structure and functions of the eye
Internalreflectionof light
Black pigment
Absorbs light
Choroid
15.4 Structure and functions of the eye
Containsblood vessels
Choroid
Supply nutrients and oxygen to the eyeball
15.4 Structure and functions of the eye
Walls ofeyeball
15.4 Structure and functions of the eye
Cornea
Conjunctiva
protects
15.4 Structure and functions of the eye
Light
Cornea
Allows light to pass
transparent
1
Refraction of light
curved
2
15.4 Structure and functions of the eye
15.4 Structure and functions of the eye
Cornea
is continuous with
Sclera
15.4 Structure and functions of the eye
Lens
Suspensoryligament
Ciliarymuscle
15.4 Structure and functions of the eye
Lens
For focusing
15.4 Structure and functions of the eye
Ciliary muscle
Contracts
Or
Relaxes
Change the tension ofsuspensory ligaments
Change the thickness of the lens
Forfocusing
15.4 Structure and functions of the eye
Controls the size of pupil
Controls the amount oflight entering the eye
Pupil
Iris
15.4 Structure and functions of the eye
Aqueoushumour
Vitreoushumour
Help in refracting light
1
Maintain the shapeof the eyeball
2
Diffusion of foodand oxygen to thelens and the cornea
3
15.4 Structure and functions of the eye
Retina
15.4 Structure andfunctions of the eye
Sclera
Choroid
Retina
15.4 Structure andfunctions of the eye
Light-sensitivecells
Sclera
Light
Cone
Rod
Optic nerve
Retina
Choroid
15.4 Structure andfunctions of the eye
Cone
How do you perceivethe colours?
Three types of cones:
blue cones
red cones
green cones
15.4 Structure andfunctions of the eye
Cone
How do you perceivethe colours?
blue cones
If blue light strikeson ,blue colour can beperceived.
It is the same for redcones and green cones
15.4 Structure and functions of the eye
How do you perceive the colours?
Red cone
Blue cone
Green cone
-
+
-
Blue
-
-
+
Green
+
-
-
Red
+
+
+
White
-
-
-
Black
All colours in between are produced by stimulation ofvarious combinations of the different types of cones
15.4 Structure andfunctions of the eye
Rod
It is sensitive to lightof low intensity
for dim light vision
15.4 Structure and functions of the eye
Yellowspot
Blind spot
15.4 Structure and functions of the eye
Clearest imagedetection withgreatest colourdiscrimination
No rodspresent
The density ofcones is the highestin the yellow spot
Yellowspot
15.4 Structure and functions of the eye
No image can bedetected
A point that opticnerve leaves theeyeball
Nophotoreceptors
Blind spot
15.4 Structure andfunctions of the eye
Rod
contains visual purple
for dim light vision
Nightblindness
Difficult tosee in thedark
No visualpurpleformation
Not enough vitamin A in diet
15.4 Structure and functions of the eye
Light rays reflected from anobject pass through cornea,aqueous humour, lens andvitreous humour
15.4 Structure and functions of the eye
Image
Image formed is real, upside downand smaller than the object
15.4 Structure and functions of the eye
Nerve impulsesare produced
Image is detectedby rods & coneson retina
Image
15.4 Structure and functions of the eye
Image
cerebrum
Vision isproduced
Impulses pass alongthe optic nerve tothe cerebrum forinterpretation
Experiment 15.1
To dissect and examine an ox’s eye
1. Obtain an ox’s eye from abutcher.
2. Examine the eye musclesand the optic nerve.
3. Remove the fat from theback of the eye.
15.4 Structure and functions of the eye
4. Cut through the cornea at right angles. Pick upthe flaps of the cornea and examine the iris.
15.4 Structure and functions of the eye
Experiment 15.1
To dissect and examine an ox’s eye
5. Cut through the iris andinto the sclera to abouthalf-way around the wallsof the eye. Examine theinner parts of the eye.
15.4 Structure and functions of the eye
Experiment 15.1
To dissect and examine an ox’s eye
6. Remove the lens. Place it on a piece of paper. Observethe words underneath. Then press the lens to feel itselasticity and observe the words through the lens again.What changes do you observe?
15.4 Structure and functions of the eye
Experiment 15.1
To dissect and examine an ox’s eye
7. Remove the vitreoushumour. Identify theblind spot.
15.5 The control of the amount of light enteringthe eye
15.5 The control of the amount of light enteringthe eye
Iris
Pupil
Radialmuscles
Circularmuscles
15.5 The control of the amount of light enteringthe eye
Prevents photoreceptors on retinafrom being over-stimulated
Under bright light
The size of pupil becomes smaller
Circular muscles contractand radial muscles relax
15.5 The control of the amount of light enteringthe eye
Allows more light to pass throughthe lens to form a clearer image
Under dim light
The size of pupil becomes larger
Circular muscles relaxand radial muscles contract
15.6 The accommodation of the eye
15.6 The accommodation of the eye
A
B
Lens
Focallength
Compare thetwo figures
In figure A,
* Thicker lens
* Shorter focal length
15.6 The accommodation of the eye
The ability of the eye
to adjust the thickness of the lensfor viewing near & distant objects
is called accommodation
15.6 The accommodation of the eye
Near object
1. Ciliary muscles contract
2. The tension of suspensoryligament is reduced
3. Lens becomes thicker
15.6 The accommodation of the eye
Distant object
1. Ciliary muscles relax
2. The tension of suspensoryligament is increased
3. Lens becomes thinner
15.6 The accommodation of the eye
Summary
Near object
Distant object
Ciliarymuscles
Contract
Relax
Suspensoryligaments
Tensiondecreases
Tension
increases
Lens
Thicker
Thinner
15.6 The accommodation of the eye
Near or Farobject ?
Distantobject
because the image cannot befocused onto the retina
but notclear
Short sight
15.6 The accommodation of the eye
Wearingconcave lens
Correction
Short sight
15.6 The accommodation of the eye
cannot see the near object clearly
Wearingconvex lens
Correction
Nearobject
Long Sight
15.6 The accommodation of the eye
It is a hereditary disease
Common type is red-green colourblindness
certain colours may not be distinguished
If a certain type of cone is missing,
15.6 The accommodation of the eye
Mind Map
Detecting ofenvironmental conditions
is called
change in external orinternal environmentis called
detected by
nerveimpulsessent to
to
produce
mainly by
include
sense organ
sense organ
sense organ
sense organ
sense organ
structures include
for
consists of
commoneye defects
irritability
stimulus
receptors
brain orspinal cord
effectorsinclude musclesand glands
response
five senses
hearing
taste
sight
smell
touch
ear
tongue
eye
nose
skin
1. aqueoushumour
2. vitreoushumour
3. retina
4. opticnerve
5. sclera
6. cornea
7. choroid
8. lens
9. iris
10. pupil
1. circularmuscles
2. radialmuscles
controlling thesize of pupil
1. long sight
2. short sight
3. colourblindness
examples
