Sense Organs

Sense Organs

The General Function To detect ________ in the environment They receive_________ and send them as nervous _________along _______nerves to the________ The brain______ the impulses and sends the __________along motor nerves to the muscles or glands for action.Nervous Pathwahy

Specific Stimulus and FunctionSense organsSpecific stimulusSpecific Function

Skin

ChemicalsSmelling

Tongue

Hearing and balancing

Eye

The Sense of Sight

Part of eyeFunction

Sclera

Choroid

Retina

Yellow Spot

Blind Spot

Optic Nerve

Suspensory Ligament

Ciliary Muscle

Aqueous humour

Cornea

Pupil

Iris

Lens

Vitreous humour

Pathway of SeeingRetinaPupilLight

Properties of LightReflection

Light travels in _________ lines Light travels at a speed of ____________km per second through air Light can travel through a ____________ Parallel light rays which fall on a ___________surface (e.g mirror) are ________as parallel rays. This is called __________ reflection. Parallel rays which fall on an irregular surface (e.g the ground) are reflected in __________directions. This is called __________reflection.Refraction

When a ray of light passes from one medium into another ___________, the ray of light passes through without bent or _________. When the ray of light passes from one medium into another obliquely, the ray is bent or refracted. The bending of light is called ___________of light. The ray is refracted_________ the normal when it passes from a less dense medium into a denser medium e.g air to glass. The ray of light is reflected __________from the normal when it passes from a dense medium into a less dense medium.

Defects of vision and their correction

A short-sighted eye can see a ______object clearly; the image falls on the _______. A short-sighted eye cannot see a ______object clearly; the image falls in ________of the retina. Eye lens maybe too _______ Eyeball maybe too ________ A _________lens is used to correct short-sightedness. The concave lens ________the rays of light onto the retina.

A long-sighted eye can see a ______object clearly; the image falls on the _______. A long-sighted eye cannot see a ______object clearly; the image falls ______ of the retina. Eye lens maybe too _______ Eyeball maybe too ________ A _________lens is used to correct short-sightedness. The convex lens ________the rays of light onto the retina.

Responses in Plants1. The movement of plants are affected by external stimuli such as_________,__________, __________and ____________.2. The responses of plants to external stimuli are called ________movement or________.3. A response by a plant in the direction of the stimulus is called ____________4. A response in the opposite direction of the stimulus is called___________.5. Tropisms help plants to _______ because they help plants to obtain their needs such as _______and ___________.Plant responseStimulus

Phototropism

Gravity

Hydrotropism

TigmotropismIn contact with a solid

Touch, temperature, light

Phototropism1. Phototropism is the response of plants to ________2. Plant shoots always grow _______ light. They show _______phototropism.3. Root always grow ________from light. They show _________phototropism.4. Phototropism helps shoots and leaves to get sunlight to make food by _______________.

Geotropism1. Geotropism is the response of plants to __________2. Roots always grow ________gravity. They show _________geotropism.3. Positive geotropism helps the plants to get _________for survival and the roots to hold the plants firmly in the ground.4. Shoots grow ________against gravity. They show ________geotropism.5. Negative geotropism helps the shoots and leaves to get sunlight for ____________.

Hydrotropism1. A plant growth response to ___________is known as __________________.2. Roots tend to grow __________water. They show _________hydrotropism.3. The response of roots to water is __________than their response to gravity. They can grow upwards or sideways, ignoring the pull of gravity.

Thigmotropism1. ________________is a tropic response in which the stimulus is ___________or _____________.2. ___________ grow away from solid objects such as stones but _________ tend to grow ___________the objects that they come into contact with.

Nastic Movement1. Nastic movement are the responses of a plant towards __________,___________ and __________.2. In nastic movements, the direction of response of the plant does not depend on the ______________of the stimulus. The movement is reversible.