Ch. 14- The Senses

Question 1

 what are the sensory receptors?

Answer 1

They are ends of sensory neurons Aktivated by specific stimuli!
ex.
Chemoreceptors - Taste buds
Osmoreceptors - hypothalamus
Mechanoreceptors - Touch, sound ( mechanical waves )
Photoreceptors -  eyes
Thermoreceptors - temperature


Question 2

Label the structure of an eye!

Answer 2

Cornea, lens, pupil, aqueous humor, Iris, clinary muscle, Vitreous humour, Retine, Choroid layer, arteries and veins, Foeva centralls, Optic nerve, Blindspot, sciera 

Question 3

What is the sclera?

Answer 3

-Outermost layer
-protects eye and maintains the shape
-White of Eye

Question 4

What is the cornea?

Answer 4

-clear part at front of eye
-is part of the sclera
-bulges at the front of the eye
-bends light toward the pupil
-no blood vessels, so nutrients come from the aqueous humor

Question 5

What is the Choroid layer?

Answer 5

-middle layer of the eye
-contains pigments to prevent light scatter within the eve

Question 6

What is the iris?

Answer 6

-the colored part of the eye (blue, green, hazel, brown, etc.)
-sphincter that acts as a pupil diaphragm

Question 7

What is the lens?

Answer 7

-focuses image on the retina
-ciliary muscles alter the shape of the lens to focus image

Question 8

What is the vitreous humour?

Answer 8

-large chamber containing jelly-like fluid that maintains the shape of the eye
-allows light to be transmitted to the retina

Question 9

What is the Pupil?

Answer 9

-not actually a structure
-a hole (space) in the center of the iris that allows light in

Question 10

What is the retina?

Answer 10

-contains 3 layers of cells
-light sensitive cells
-rods:low light intensity
responsible for night vision, black and white
not very detailed vision
-cones: color vision (detect red, green, and blue)
detailed vision
-bipolar cells, ganglion cells, the centre of the retina is the fovea centralis

Question 11

What is the chemistry of vision? How is it possible for us to see?

Answer 11

rods in the retina contain a light - sensitive pigment called rhodopsin
a single photon of light hits rhodopsin and breaks it into two components:
-retinene (a pigment)
-opsin (a protein)
rhodopsin› retinene + opsin
this causes an action potential in the rod cell
the action potential is conducted to bipolar cells, ganglion cells, then to the optic nerve

Question 12

Colour vision?

Answer 12

there are 3 different opsins (proteins) in cones: red, blue, and green
blended colors or shades are seen as the result of stimulating different combos of the 3 types of cones

Question 13

How does colour blindness occur?

Answer 13

red-green color blindness - occurs when the red cones don’t work
- mostly passed from mothers to sons

Question 14

What is a bipolar cell?

Answer 14

-carry info from rods to cones to ganglion cells
-one cone to one bipolar cells
-many rods to one bipolar cell

Question 15

What is a ganglion cell?

Answer 15

-clusters of neuron cell bodies
-receive inputs from bipolar cells
-transmit action potentials (nerve impulses) to optic nerve in the brain

Question 16

What is the fovea centralis?

Answer 16

-contains the highest density of cones in the eye - about 1 million
-there are cones, but no rods here
-this is where the image focuses

Question 17

Conducting the message

Question 18

Primary visual cortex

Question 19

Visual association area

Question 20

Focusing the image ?

Question 21

Visual Disorders?

Question 22

What is glaucoma?

Answer 22

• build-up of aqueous humour
  drainage ducts that normally allow this fluid to drain and re-circulate get blocked up
  fluid pressure builds up
  permanent damage (i.e. blindness) will occur in some cases if the pressure destroys the optic nerve

Question 23

What is a cataract?

Answer 23

• lens becomes opaque (clouded over)

Question 24

What is a astigmatism?

Answer 24

• irregularly shaped cornea or lens which causes blurred vision
  Solution: astigmatic lens

Question 25

What is a myopia (nearsightedness)?

Answer 25

-eyeball is longer than normal
-can see near objects but not far objects
-image focused in front of retina
-Solution: concave lens

Question 26

What is hyperopia (farsightedness) ?

Answer 26

-eyeball is shorter than normal
-can see far away objects but not near ones
-image is focused behind the retina
-Solution: convex lens

Question 27

What are the three parts of the ear?

Answer 27

outer
middle
inner

Question 28

What structures does the outer ear contain?

Answer 28

Pinna and auditory canal

Question 29

What is the pinna?

Answer 29

Fleshy part of the ear!
- funnels sound into the ear

Question 30

What is the auditory canal?

Answer 30

-carries sound into the eardrum
-contains wax glands

Question 31

What structures are contained in the middle ear?

Answer 31

Air filled chamber contains the tympanic (eardrum), ossicles, oval window and Eustachian tube

Question 32

What is the Tympanic membrane ?

Answer 32

tympanic membrane - eardrum
-vibrates in response to sound waves
-concentrates vibrations to the middle ear
-amplifies

Question 33

What is the ossicles?

Answer 33

Ossicles - middle ear bones (transmit vibrations to the oval window)
- tiniest cones in the body
1.hammer - malleus
2. incus - anvil
3. stapes - stirrup

Question 34

What is the Oval window ?

Answer 34

oval window
transmits the amplified sound to the round window of the inner ear

Question 35

What is the Eustachian tube?

Answer 35

Eustachian tube - helps maintain pressure in the middle ear
-ex) flying in an airplane - chewing gum or swallowing will equalize pressure
-connects the middle ear to the throat

Question 36

What structures are in the inner ear?

Answer 36

Vestibule, semicircular canals, cochlea and fluid

Question 37

What is vestibule ?

Answer 37

-vestibule - houses 2 sacs (utricle and saccule) which establish head position
-responsible for static equilibrium

Question 38

What is a semicircular canals?

Answer 38

semicircular canals (3)
-fluid-filled canals determined body position
-dynamic equilibrium

Question 39

What is the cochlea?

Answer 39

-snail shaped
-spiral canal that contains hair cells
-identifies sound frequency and intensity