Chapter 15

Question 1

Levator palpebrae superioris muscle

Answer 1

Eyelid muscle

Question 2

Tarsal Glands

Answer 2

lubricating gland associated with the eyelids. Modified sebaceous glands. Oily secretion lubricates lid and eye.

Question 3

Ciliary glands

Answer 3

lubricating gland associated with eyelids. Between hair follicles. Modified sweat glands.

Question 4

Conjuctiva

Answer 4

produces a lubricating mucous secretion

Question 5

Lacrimal apparatus

Answer 5

a system of glands and ducts that drains into the nasal cavity.

Question 6

Lacrimal secretion

Answer 6

tears. Dilute saline solution containing mucus, antibodies and lysozyme. Blinking spreads tears toward medial commissure.

Question 7

Retina

Answer 7

Layer of tissue that is located as the out-pocketing of the brain. Delicate two-layered membrane.

Question 8

Outer pigmented Layer (retina)

Answer 8

single-cell-thick lining. Absorbs light and prevents its scattering. Phagocytize photoreceptors cell fragments. Stores Vitamin A.

Question 9

Inner Neural layer (retina)

Answer 9

Transparent. Composed of three main type of neurons (…..

Question 10

Optic Disc (retina)

Answer 10

Blind Spot. Site where optic nerve leaves the eye. Lacks photoreceptors.

Question 11

there is a 1/4 billion of these two types of cells in your eyes…

Answer 11

rods and cones

Question 12

Rods

Answer 12

Dim light, peripheral vision receptors. More numerous, more sensitive to light than cones. No color vision or sharp images. Number greatest at periphery.

Question 13

Cones

Answer 13

Vision receptors for bight light. High resolution color vision.

Question 14

Refraction

Answer 14

Bending of light rays. Due to change in speed when light passes from one transparent medium to another. Occurs when light meets surface of different medium at an oblique angle. Curved lend can refract light.

Question 15

Focal Point

Answer 15

image formed at focal point is upside-down and revered right to left.

Question 16

Light gets refracted three times along the pathway

Answer 16

1. Entering cornea
2. entering lens
3. Leaving lens

Question 17

Far point of vision

Answer 17

Distance beyond which no change in lens shaped needed for focusing.

Question 18

Focusing for close vision

Answer 18

Light from close objects (contracts the ciliary muscle, loosening the ciliary zonule->allowing the lens to bulge

Question 19

Focusing for close vision

Answer 19

Requires eye to make active adjustments using 3 simultaneous processes; Accommodation, constriction and convergence

Question 20

Accomodation

Answer 20

changing lens shape to increase refraction. Near point of vision (closest point on which the eye can focus). Presbyopia (loss of accommodation older age 50)

Question 21

Constriciton

Answer 21

accommodation pupillary reflex constricts pupils to prevent most divergent light rays from entering eye

Question 22

convergence

Answer 22

medial rotation of eyeballs toward object being viewed

Question 23

Myopia (nearsightedness) problems with refraction

Answer 23

focal point in front of retina, e.g., eyeball too long. Corrected with a concave lens

Question 24

Hyperopia (farsightedness) problems of refratction

Answer 24

focal point behind retina, e.g., eyeball too short. Corrected with a convex lens

Question 25

Astigmatism (problems with refraction)

Answer 25

unequal curvatures in different parts of cornea or lens

Question 26

Vision

Answer 26

is the dominant sense. 70% of all sensory receptors in boy found in the eye. Cushioned by a layer of fat. visual processing carried out by half of the cerebral cortex.

Question 27

Rods

Answer 27

Very sensitive to light, best suited for night vision and peripheral vision. Contain single pigment (perceived input in gray tones only) pathways coverage, producing blurry images.

Question 28

Cones

Answer 28

need bright light for activation ,react more quickly, have one of three pigments for colored view, nonconverging….

Question 29

Retinal

Answer 29

light-absorbing molecule that combines with one of four proteins (opsins) to form visual pigments. Synthesized from vitamin A.

Question 30

Light Adaptation

Answer 30

Lights moves from darkness into bright light. Both rods and cones strongly stimulated and pupils costrict. Large amounts of pigments broken down instantaneously, producing glare. Visual acuity improves over 5-10 minutes as rod system turns off, retinal sensitivity decreases and cones and neurons rapidly adapt.

Question 31

Dark Adaptation

Answer 31

Move from bright light into darkness. Cones stop funcitoning in low-intensity light. Rod pigments bleached; system turned off. Rhodopin accumulates in dark. Transducin returns to outer segments.

Question 32

Nyctalopia

Answer 32

Night blindness. Rod degeneration, commonly caused by vitamin A deficiency.

Question 33

Olfaction

Answer 33

smell

Question 34

gustation

Answer 34

taste

Question 35

Taste buds and the sense of taste

Answer 35

receptor organs are the taste buds. Most of 10,000 taste buds on tongue papillae.

Question 36

Hearing only

Answer 36

external (outer) ear

Question 37

Hearing only

Answer 37

middle ear (tympanic cavity)

Question 38

Hearing and equilibrium

Answer 38

Internal (inner) ear. Receptors for hearing and balance respond to separate stimuli.

Question 39

Sound is…

Answer 39

pressure disturbance (alternating areas of high and low pressure) produced by vibrating object

Question 40

Sound wave is…

Answer 40

moves outward in all directions. Illustrated…..

Question 41

Frequency

Answer 41

number of wAVES that pass given point in given time. Pure tone has repeating crest and troughs

Question 42

Wavelength

Answer 42

distance between two consecutive crests. Shorter wavelength=higher frequency of sound.

Question 43

Pitch

Answer 43

perception of different frequency.

Question 44

Quality

Answer 44

richness and complexity of sounds

Question 45

amplitude

Answer 45

height of the crests, amplitude perceived as loudness.