L23: Special Senses

Question 1

what percentage of sensory receptors are found in the eyeball?

Answer 1

70%

Question 2

40% of the cerebral cortex is involved in?

Answer 2

visual processing

Question 3

What does the lacrimal gland produce and why?

Answer 3

• lacrimal fluid

- spread across eyeball during blinking

Question 4

where does lacrimal fluid drain?

Answer 4

• lacrimal puncta and lacrimal canaliculi to the lacrimal sac where the fluid passes to the nasal cavity via the nasolacrimal duct

Question 5

what diameter is the eyeball?

Answer 5

• 25mm diameter

- spherical shape

Question 6

is the eyeball positioned closer to the lateral orbital wall and roof or the medial?

Answer 6

lateral orbital wall and roof

Question 7

is the eyeball housed entirely within the orbit?

Answer 7

no, it projects from the orbit

Question 8

how much of the eyeball if visible in frontal views?

Answer 8

1/6th

Question 9

what kind of tunic is sclera?

Answer 9

fibrous

Question 10

what are the vascular tunic?

Answer 10

• iris
• ciliary bodies
• choroid

Question 11

what kind of tunic is retina?

Answer 11

neural

Question 12

what is the iris? contains what kind of muscle?

Answer 12

• pigmented diaphragm with central pupil

- contains circular and radiate smooth muscle

Question 13

focusing of light =

Answer 13

accommodation

Question 14

where is the most visual acuity found?

Answer 14

• fovea centralis of the macula lutea (contains all cones)

Question 15

what does the posterior eyeball contain?

Answer 15

• macula lutea

- optic disc (no photoreceptors)

Question 16

how many photoreceptors does the retina possess?

Answer 16

approx 130 mil

Question 17

what is the most numerous, most sensitive to light, does not provide high acuity or colour vision and is found outside fovea centralis?

Answer 17

rods

Question 18

what has increased density towards fovea centralis, operates best in bright light, and has three subtypes to red, blue, and green light respectively?

Answer 18

cones

Question 19

role of the cochlea?

Answer 19

hearing

Question 20

what controls linear acceleration?

Answer 20

vestibule

Question 21

what controls rotational acceleration

Answer 21

semicircular canals

Question 22

what does the vestibule house?

Answer 22

• utricle

- saccule