The Sensory Receptors
• Write the black• Read the blue
What do you know about sensory receptors?
A bit of review
sensory receptors = cells that capture information
Ear
Hearing
Eye
sight
Skin
touch
Tongue
taste
Nos
e
smell
Path
Sensory receptor captures information (stimulus)
A “transformer “ changes info into a nervous impulse
Sensory neurons send info. to the brain for analysis
The Eyesight
Picks up light rays from light sources or reflected off objects
Use pg. 213 of textbook to fill in pg. 129 of workbook
Parts of the eye
sclera
choroid
retina
iris
Aqueous humor
lens
Vitreous humor
Optic nerve
cornea
Use pg. 213 of textbook to fill in the handout on the eye
Structure Description
Sclera the white of the eye, protects eye from shock and gives it shape
Choroid layer of blood vessels that nourish the eye
Retina layer at the back covered with millions of photoreceptors that transform incoming data to nerve impulses
Cornea clear and rigid membrane at the front of the eye
Lens
Aqueous Humour
Vitreous Humour
Structure Description
Sclera
Choriod
Retina
Structure Description Iris pigmented membrane with an
opening (pupil)= regulate amount of light entering the eye
Lens flattened sphere that focuses light onto the retina
Aqueous Humour transparent liquid that fills space between cornea and lens
Vitreous Humour transparent liquid that fills spaces between lens and retina
a
cornea
Aqueous humor
lensVitreous humor
How we see• Light waves pass through the CORNEA and the
AQUEOUS HUMOUR and are controlled by the PUPIL.
• The light is then focused by the LENS and continues through the VITREOUS HUMOUR to the part of the RETINA called the MACULA.
• Photoreceptors change the light waves to nerve impluses.
The Retina specialized nerve cells called photoreceptors
sensitive to light = 2 types of photoreceptors
1. Cones Very few = concentrated in center of retina
called the macula.
Responsible for seeing colour
The retina
The macula
2. Rods
Rods detect contrast (not colour)= important for night vision
Rods cover the retina except in the macula and the “blind spot”.
The blind spot = where optic nerve leaves eye
The “blind spot” where optic nerve leaves the eye
Optional lab65- Adjusting the eye to light
This is weird, but interesting! fi yuo cna raed tihs, yuo hvae a sgtrane mnid too Cna yuo raed tihs? Olny 55 plepoe out of 100 can. i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt!
Lets play find the lioness
The Ear
hearing
Ear has sensory receptors:
• For hearing in the cochlea
• For balance in the semicircular canals and the vestibule.
Use pg. 215 of the textbook to fill in pg. 129 of the workbook
Check your answers
ear drum
ossicles
eustachian tube
cochlea
vestibule
Semicircular canals
pinna
Auditory canal
Use pg. 215 of the textbook to fill in the handout on the ear
Structure Description
Pinna funnels sound vibrations into ear
Auditory Canal carries vibrations to eardrum
Tympanic Membrane (ear drum)
thin membrane that moves with sound vibrations
Ossicles (bones)
miniature bones that move with sound vibrations
Eustachian tube
links ear to throat to equalize pressure around ear drum
Semi-circular canals
regulate balance when body = in motion
Vestibule regulate balance when body = in static position
Cochlea walls covered in auditory receptors linked to the auditory nerve
hammer
anvil
stirrup
vestibuleSemi-circular canals
cochlea
How we hear• Sound vibrations enter the PINNA and travel down
the AUDITORY CANAL. • The waves start the EAR DRUM vibrating. As the
OSSICLES are connected at one end to the ear drum, they move at the same speed.
• The ossicles are connected at the other end to the VESTIBULE, which is filled with liquid. The sound wave continues to the liquid-filled CHOCLEA where AUDITORY RECEPTORS pick up individual frequencies and change them to nerve impulses
How we Balance
• 3 x SEMICIRCULAR CANALS let body know location on the X, Y and Z axis (3D) while the body moves.
• The VESTIBULE helps with posture
Homework: pg. 130 of workbook
The Skin
Touch
• Touch sensory receptors are found in the dermis layer
• Skin= body’s largest organ, but only about 7% of our body mass.
• It is made of 3 layers:– Epidermis– Dermis– Hypodermis
Use pg. 217 of textbook to fill in pg. 131 of workbook (top)
Hypodermis
Use pg. 217 of textbook to fill in the handout on the skin
Structures of the Skin
Layer Structures Description
Epidermis Dead Layer Outer layer of skin. protects against elements
Living layer Constantly dividing cells push up old ones
Dermis Sensory Receptor
Pick up stimuli like temperature, pain, gentle and heavy pressure, and touch
Blood Vessels Nourish cells
Sebaceous Glands
Secrete sebum to waterproof skin
Sweat Glands Secrete sweat to cool the body
Hair Starts in dermis and continue through epidermis. Muscles can contract to raise hairs
Hypodermis Fat cells Energy reserve and thermal insulator
• Melanin =brown pigment that protects us from the sun’s harmful radiation
• The more sun exposure the more melanin is produced, “tanning”
• Over exposure to these harmful rays can cause mutations in the melanocytes causing melanoma (a deadly form of skin cancer) or basal cell carcinoma
Skin Physiology• Free nerve endings detect temperature,
tactile (touch) and pain
• touch receptors =not spread out evenly over the body - more touch receptors in the fingers and face, especially the lips, than in any of the other areas or the body
• why babies put everything into their mouths
• If human body drawn proportionally according to the number of touch receptors = looks like this
How we feel
• Various items may come in contact with the skin• Depending on the number of touch receptors,
you may or may not feel the touch• The pressure, temperature or touch is picked up
by different nerves and changed to a chemical impulse
Lab 66- skin’s receptors
• Bill Nye- skin
The Nose
smell
• The sensory receptor for smell = the olfactory epithelium
Use pg. 219 of textbook to fill in pg. 131 (middle) of workbook
Olfactory nerve
Olfactory bulb
Olfactory epithelium
Nasal Cavity
Nostrils
How we smell • The molecules that have odour travel up the nostril
to the nasal cavity.• The turbinates cause the air to swirl around• The mucus makes the molecules to stick and dissolve
into it. • The molecules come in contact with the olfactory
cilia in the epithelium.• They change the smell into a chemical impulse
• Bill Nye-smell
The Tongue
taste
• The sensory receptors are located in the taste buds
• has receptors to capture flavour molecules• tongue =muscle = covered with epithelial cells
(moist) that form rough bumps called papillae
Use pg. 220 of textbook to fill in pg. 131 (bottom) of workbook
Flavour detection• The tongue can only detect flavourful
molecules of the following 4 basic flavours:• Bitter• Sour• Salty• Sweet
• Taste and smell are interrelated. • Ever tried eating with a blocked nose = food has
very little flavour?• Other receptors on the tongue = temperature,
discomfort, and texture of food
How we taste• The molecules that have flavour cover the tongue.• The papillae increase the surface area in contact
with the flavour molecules• The saliva moistens the food and helps flavour
molecules to stick and dissolve into it. • The molecules come in contact with the taste buds • They change the flavour into a chemical impulse
Lab 67- Relationship taste and smell
Did You Know?
• Gene Simmons from KISS has his tongue insured for 1 million dollars
Homework: pg. 132 of workbook
Discuss pg. 230 q 9-13 in textbook