STI

MULI

Done By: Mint + ThonIB Biology HL Y2

SENSORY cells: send messages to the part of the brain that controls emotion and memory

Music or food reminds our childhood times

Sense organ: Mouth, Eye, Tongue, Nose, SkinFilled with sensory neurons

Send messages to CNS

We see, smell, taste, feel with our BRAIN! (not sense organ)

Mechanoreceptors: respond to mechanical force/pressure

Pressure: Touching (Skin)Change in blood pressure (Arteries)Auditory and Equibrioception* (Ears)

(sense of balance)

Proprioreceptors: maintain posture and balance

Proprioreceptors: maintain posture and balance

Chemoreceptors: respond to chemical substances

Chemical: Taste and Smell (Tongue + Nose)Monitor pH changes (blood vessels)Adjust breathing rate according to

change in pH (Ears)

Painreceptors: respond to chemicals from damaged tissuese.g. reflex protects us from danger

Thermoreceptors: respond to change in temperature

Warmthreceptors: respond when temperature rises

Coldreceptors: respond when temperature drops

REGULATING body temperature (related to HOMEOSTASIS!)

Photoreceptors: respond to light energy

Light: Sensitive to light & give us vision (eye)

Rod Cell: Respond to dim lightGive black and white vision

Cone Cell: Respond to bright lightGive us color vision

Outer ear catches sound waves

Sound waves: successive vibrations of air molecules

1. EARDRUM2. BONES of the MIDDLE EAR3. OVAL WINDOW4. HAIR CELLS in the COCHLEA

Sound waves entered VIBRATE the eardrum

ROLE: Pick up sound vibrations from the air Transmit them to the middle ear

There’s a risk of breaking the ear drum (perforation)

Although this is commonly done…it’s recommend against using cotton tipped applicators, hair pins, and similar devices to clean the ear.

Series of small bones --- Ossicles

Ossicles: All of them are touchedTouched with eardrum and oval windowA lever to reduce the amplitude of waves

Muscles:Attached to ossicles to protect ear from loud sounds --- by contracting to damp down vibrations in ossicles

Membranous structure --- like eardrum

Oval Window: Transmitting sound waves to fluid

Round Window: Allows movement of fluid in cochlea(by moving away)

Oval window move towards cochlea |

Round window moves away

Fluid in cochlea can vibrate freely -- volume remaining constant

Cochlea --- a tube wound to form spiral shapehair receptors (hair cells) on membrane

Sound waves pass through fluid in cochlea

Each hair bundle resonates with particular frequencies

Hair cells: have hair bundlessend messages across synapse on to brain through

auditory nerve

http://www.youtube.com/watch?v=dCyz8-eAs1I&feature=related

On the Outside

• Iris: Regulation• Pupil: Admittance• Lens + Cornea: Focus• Sclera: Protect & Serve• Conjunctiva: Cover & Moisture

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From the Inside

• Aqueous Humor: Transmission & Support• Vitreous Humor: Transmission & Support

In the Back

• Retina: Receptors• Rods: Black, white, dim• Cones: Colorful, bright• Fovea: Dense with cones, acute vision• Choroid: Absorb strays• Optic Nerve: Transmission• Blind Spot: No vision perceived

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• Light focused on retina’s photoreceptor cells• Rods• Cones

• Vision: Light → Photoreceptor cell → Bipolar neurone → Ganglion cells → Optic Nerve

• D & C• Rods: Very sensitive to light, better in dim light• Cones: Less sensitive to light, better in bright light• Bipolar Neurone: Sends message of rods and cones to ganglion cells• Ganglion cells: Cell bodies of optic nerve, transmission to brain.

• Sensitivity & Function• Rods: High sensitivity, prefers dim lights• Cones: Low sensistivity, prefers bright lights

• Types of cells• Rods: One type• Cones: 3 types, (Red – Blue – Green)

• Attachment to Bipolar Neurones• Rods: Group of rod cells• Cones: Single cone cell

• Light stimulates rods and cones

• Impulses sent to Bipolar Neurones & Ganglion cells

• Brain corrects image orientation

• Study of vision• Optical Illusions• Effects of brain injuries

• Ganglion cells stimulated when light falls in receptive field

• 2 types of Ganglion cells• A: Light on receptive field = Stimulation, Light on periphery = reduced stimulation• B: Light on periphery = Stimulation, Light on receptive field = reduced stimulation

• Both Most Stimulated = Edge between contrasts in the receptive field

• Body has a knack for seeing edges

• Optic Chiasma: Intersection of L & R optic nerves

• Sharing of information: • L to R, R to L• ½ + ½ = 1

• Brain able to deduce distance, sizes, and identity.

• R Lesions: Identification problems• L Lesions: Naming problems