Chap 12

Question 1

Sensory receptors

Answer 1

The nerve endings in cells that detect sensory information
•initiate neural impulses
- Different forms of energy stimulate the receptors

Question 2

Sensation

Answer 2

Occurs when the neural impulses arrive at the cerebral cortex.
Ex) Face may detect warmth of a beam of sunlight and feel the warmth on at cheek

Question 3

Perception

Answer 3

Each person has a UNIQUE perception.

-cerebral cortex interprets the meaning of the sensory information

Question 4

Sensory adaptation

Answer 4

When the BRAIN filters out insignificant or REDUNDANT info.

• ex) sensory adaptation has occurred when you gone out clock ticking

Question 5

Sensory receptors

Answer 5

Are specialized cells or neuron endings that detect specific stimulus.
Humans have 4 categories of receptors
•transduce, convert a form of NRG into electrochemical NRG

Question 6

1) photoreceptors

Answer 6

Light stimulates this receptor.
•Eyes contains rods and cones in order to see and absorb light
-colours and shades
[damage: loss of associated sense]

Question 7

2) Chemoreceptors

Answer 7

Stimulated by certain chemicals

-tongue: contains TASTEBUDS that detect various particles in food

Question 8

3) Mechanoreceptors

Answer 8

Respond to mechanical forces from same form of pressure
•ex) hair cells in inner ear are activated by vibration of sound waves
•SKIN =pain, pressure and light touch

Question 9

4) Thermoreceptors

Answer 9

In SKIN: detects heat and cold

Question 10

Human eye: 3 layers

Answer 10

• external
• intermediate
• internal

Question 11

External eye layer

Answer 11

Sclera and cornea

Question 12

Sclera

Answer 12

External

•white of the eye/ touch and fibrous protective layer

Question 13

cornea

Answer 13

LIGHT enters the eye

•clear/transparent dome of the eye

Question 14

Intermediate layer of eye

Answer 14

Choroid
Iris
Pupil

Question 15

Choroid

Answer 15

Intermediate
•ABSORBS stray light rays that ARENT detected by photoreceptors
•blood vessels= nourish eye

Question 16

Iris

Answer 16

Front
Choroid forms DONUT shaped coloured iris
•allows light to enter via pupil

Question 17

Pupil

Answer 17

Iris contains dark pupil

•dilated/expands

Question 18

Adaptation

Answer 18

Light conditions

Ex) turning off lights, eyes adjust

Question 19

Internal layer of eye

Answer 19

Ciliary muscles
Retina
Rods
Cones
Optic nerve
fovea centralis

Question 20

Ciliary muscle

Answer 20

Thickened choroid extending

•attaches to lens, focusing images on retina

Question 21

Retina

Answer 21

Internal

•thin layer of tissue that contains photoreceptors (rod/cone)

Question 22

Rods

Answer 22

Sensitive to light intensity
(Black and white)
-more than cones
Peripheral

Question 23

Cones

Answer 23

Are sensitive to different colours
•pack most densely at back of eye
(FOVEA)

Question 24

Optic nerve

Answer 24

Connects to brain and sends impulses from cones and rods

Question 25

Suspensory ligaments

Answer 25

Attached to ciliary muscle and lens 1) anterior chamber 2) posterior chamber

Question 26

1) aqueous humour

Answer 26

Clear fluid in antechamber | •maintains SHAPE of cornea and provides o2+nutrients

Question 27

Glaucoma

Answer 27

Excess liquid builds up, ducts become plugged •delicate blood vessels rupture •cells of eye deteriorate due to lack of oxygen and nutrient *BLINDNESS

Question 28

2) vitreous humour

Answer 28

Clear jelly fluid in posterior chamber | •maintains shape of eyeball and supports surrounding cells

Question 29

Focussing

Answer 29

Lens focussed light in particular direction -rounded lens: ciliary contract suspensory relax NEAR -flattened lens: ciliary relax suspensory taut FAR

Question 30

Accommodation

Answer 30

Ability for lens to change shape in order to focus images clearly on retina •reflex •muscle fatigue~excess contraction or eye strain

Question 31

Cataracts

Answer 31

Lens ages/protein structure degenerate •grey/white spots form on lens -surgically treated

Question 32

Astigmatism

Answer 32

Inheritable condition impacting eyes FOCUS ability | •due to uneven curvature in cornea (blurry)

Question 33

Myopia

Answer 33

Nearsighted people •no trouble seeing CLOSE but not far •elongated eyeball -light in front of retina and not on

Question 34

Hypermyopia

Answer 34

Common FARSIGHTED •no trouble seeing FAR but not close •shortened eyeball •light doesn’t meet retina, focuses behind

Question 35

Fovea centralis

Answer 35

Back of eye | -cones densely packed

Question 36

Colour blindness

Answer 36

Deficiency in cones (Red, green and blue) More male

Question 37

Blind spot

Answer 37

Ganglion cells merge to form optic nerve. •areas do not contain photoreceptors ~incapable of detecting light

Question 38

Binocular vision

Answer 38

3D