Forensic 2

Question 1

alcohol is a CNS _____

Answer 1

depressant

Question 2

sources of alcohol

Answer 2

wine, beer, liquor, cooking wine, mouthwash, after-shave lotion

Question 3

what is the legal limit for driving?

Answer 3

80mg% BAC

Question 4

what can we test for alcohol?

Answer 4

• blood or urine (living or dead)
• vitreous humour, CSF, bile (dead only)
• breath (living only)

Question 5

Advantages of alcohol breath analysis?

Answer 5

• noninvasive

- convenient

Question 6

Breath test equipment relies on _____ law

Answer 6

henry’s

Question 7

What is Henry’s Law

Answer 7

The concentration of a gas dissolved in a liquid phase is directly proportional to the partial pressure of that gas in a gaseous phase that is in equilibrium with the liquid

Question 8

What does henry’s law mean?

Answer 8

concentration of ethanol in blood / concentration of ethanol in alveolar air = r

r = constant = 2100

Question 9

Describe pass, alert and fail results of the screening device

Answer 9

pass: between 0-49mg%
alert: 50-99mg%
fail: above 100mg%

Question 10

Consumption = ?

Answer 10

absorption + elimination

Question 11

Where does absorption of alcohol happen?

Answer 11

30% stomach

70% small intestine (more absorbed here due to increased surface area)

Question 12

how is rate of absorption affected by food in the stomach

Answer 12

-get more absorption of alcohol on an empty stomach (15-20 mins on empty stomach, 2-3 hours on full stomach)

**also fats/carbs delay absorption more so than protein

Question 13

how does drinking alcohol with carbonated beverages affect absorption?

Answer 13

carbonated beverages open pyloric sphincter longer which allows alcohol to go more quickly into the small intestine which increases absorption

Question 14

how does speed of consumption affect rate of absorption?

Answer 14

speed increases rate of absorption

Question 15

rate of absorption is also affected by _____ of alcohol

Answer 15

concentration

Question 16

What are the approximate concentrations of alcohol in wine, liquor and beer?

Answer 16

beer: 5%
wine: 10%
liquor: 40%

Question 17

what can rate of absorption also be affected by?

Answer 17

• drugs (nicotine and caffeine slow rate of absorption of alcohol)
• disease (trauma affects it)
• emotional state (get best absorption in a relaxed state)

Question 18

what is the widmark hypothesis

Answer 18

alcohol is distributed in the body in proportion to the water content of the tissues

• i.e. liver and brain will have higher concentration bc they have higher water content
• bone and fat have less alcohol distribution bc of lower water content

Question 19

what is the widmark factor (r)

Answer 19

r = conc of body alcohol / conc of blood alcohol

Question 20

what is R for males and females

Answer 20

males: 0.7
females: 0.6

Question 21

what does BAC depend on?

Answer 21

• body size (weight)
• body fat (body type)
• gender

Question 22

would a person weighing 160lbs or 240lbs have higher BAC if they drank the same

Answer 22

the smaller one (160 lbs)

Question 23

if 2 people weighed the same (but one had higher fat content), and had the same number of drinks, who would have higher BAC?

Answer 23

fat guy

Question 24

if a man and woman weighing the same had the same drinks, who has higher BAC

Answer 24

woman bc they tend to have higher fat content

Question 25

What is the formula for absorption?

Answer 25

Absorption = BAC x weight x 0.022

x 6/7 for females

Question 26

describe the metabolism of alcohol

Answer 26

90-98% occurs in the liver

alcohol -> acetaldehyde -> acetate -> cO2 and H2O

Question 27

how is metabolism of alcohol affected if you are an alcoholic

Answer 27

if you are an alcoholic, you will eliminate it a little bit faster

Question 28

describe excretion of alcohol

Answer 28

2-10% is eliminated unchanged (breath, urine, faces, sweat, tears, saliva)

Question 29

What does elimination = ?

Answer 29

elimination = metabolism + excretion

Question 30

Formula for elimination?

Answer 30

elimination = weight/70 x 25 x T

T = hours since first drink

Question 31

if wine or beer are involved, how do you account for this?

Answer 31

if it’s beer, you do 40/5

mL beverage = 40 / conc of alcohol in beverage x mL liquor

Question 32

What is the rate of elimination in mg%/hour?

Answer 32

15mg%/hour
(average 10-20mg%/hour)

• regardless of height, weight, gender or amount of fatty tissue
• alcoholics can have 25mg%/hour

Question 33

how can we use 1 BAC to calculate another BAC

Answer 33

BAC1 = BAC2 = (T x 15)

T = elapsed time from measured BAC