Lacrimal System and Conjunctiva part 2 Flashcards Preview

Ocular Physiology > Lacrimal System and Conjunctiva part 2 > Flashcards

Flashcards in Lacrimal System and Conjunctiva part 2 Deck (64)
Loading flashcards...
1

what is a way to quantitatively test the tears produced

a Schirmer's test

2

what is the tear meniscus height at the lower lid margin

0.75mm

3

what is a noninvasive way to test the tear film stability

with a keratometer (watching the mires to see if they stay stable and clear) about 10 sec

4

what is an invasive way to measure the tear film stability

TBUT (tear break up time) with flourescein (10 sec)

5

how can you test the ocular surface integrity

tissue sampling (impression cytology-counting goblet cells in conjunctiva) or staining techniques

6

when would you give a Schirmer's test

dry eye or excessive tearing

7

what are the steps of the Schirmer's test

instill anesthesia and wait a min, wipe excessive tears, place strip on temporal side, wait 5 min, record results

8

why does the eye need to be numb for a Schirmer's test

otherwise you are testing the reflex tearing, no the basic secretion

9

why do you place the strip on the temporal side during a Schirmer's test

because the tears drain medially and it will give a false measurement

10

what is a normal outcome for the Schirmer's test

greater than or equal to 15mm

11

what is a variation of a normal result of a Schirmer's test

an older individual (over 60) may only have 10mm but not complain of dryness or epiphora

12

what can affect the outcome of a Schirmer's test

placement of the strip in the eye, age, effect of anesthesia, reflex tearing, and subjective measurement

13

what is a mild dry eye test result for Schirmer's

9-14 mm

14

what is a moderate dry eye result for Schirmer's

4-8 mm

15

what is a severe dry eye result for Schirmer's

less than 4 mm

16

what is the first stage of secretion of lacrimal gland electrolytes and water

the acini cells secrete a fluid that has an electrolyte composition similar to that of plasma

17

what is the second stage of secretion of lacrimal gland electrolytes and water

as the fluid passes through the duct system, the ductal cells modify the fluid by secreting a fluid rich in potassium chloride (KCl)

18

what drives acinar cell electrolyte secretion

a sodium potassium ATPase pumping sodium out of the cell and potassium into the cell

19

what is the solution called at low fluid rates

hypertonic

20

what is the solution called as the flow rate increases

isotonic

21

how do the ductal cells modify the fluid as it passes through the duct system

by secreting a fluid rich in potassium chloride

22

what ions does the lacrimal gland contain

Na+, K+, Cl-, HCO3, Ca2+ and trace amounts of other ions in the same concentration as plasma (except K+ and Cl- which are higher concentrations)

23

what stimulates the cells to secrete

nerves, peptide and steroid hormones present in the blood

24

what type of nerves innervate the lacrimal gland

parasympathetic nerves, sympathetic nerves, and sensory nerves

25

what specifically do the nerves and peptide hormones stimulate secretion of

electrolytes, water and the regulated proteins

26

what specifically do the steroid hormones stimulate

the secretion of the constitutive proteins

27

does stimulation of the sympathetic nervous system result in change in tear secretion

no

28

what parasympathetic nerves are responsible for the secretion of tears

CN 7 facial nerve

29

what are 5 stimulants that can cause secretion of the lacrimal gland

sensory nerves at optic surface, a bright light hitting the optic nerve, acetylcholine and vasoactive intestinal peptide (VIP) and norepinephrine

30

what is the conjunctiva

a mucous producing tissue lining the ocular surface (sero-mucous secreting tissue)