routes of exposure

Question 1

Exposure to toxic substances occurs through the three major routes

Answer 1

o The skin (dermal absorption)
o The respiratory tract (inhalation)
o The digestive tract (ingestion)

Question 2

Contact with the skin is the most common path of toxic substance exposure

Answer 2

dermal absorption

Question 3

The skin is composed of three layers:

Answer 3

• epidermis (outer layer)
• dermis (inner)
• subcutaneous fatty tissue

Question 4

Factors affecting dermal absorption of toxic substances include

Answer 4

• the condition of the skin;
• chemical makeup of the substances;
• increasing concentration of toxic substance or exposure time

Question 5

easiest and fastest means of exposure to toxic substances because toxic substances are readily absorbed in the respiratory tract.

Answer 5

inhalation

Question 6

route of exposure that usually occurs accidentally or unknowingly

Answer 6

ingestion

Question 7

other routes of exposure

Answer 7

eye and injections

Question 8

common point of contact for toxic substances

Answer 8

eye and injections

Question 9

primary point of contact for toxic substances

Answer 9

cornea

Question 10

is affected because of the structure of the body and the length of time food containing the substance remains in the body.

Answer 10

absorption

Question 11

After being taken up in the blood, a chemical is be quickly distributed throughout the body; it may be moved from one organ or tissue to another (____________) or changed into a new compound (_______)

Answer 11

translocation, biotransformation

Question 12

outer layer of the eye is made up of connective tissue called

Answer 12

sclera

Question 13

middle layer of the eye is called

Answer 13

choroid

Question 14

Two compartments within the eye contain a fluid-like substance

Answer 14

aqueous humor

Question 15

a transparent jelly-like substance

Answer 15

vitreous humor

Question 16

are mainly used in laboratory studies on experimental animals.

Answer 16

injections

Question 17

different types of injections

Answer 17

• Intravenous injections (into a vein).
• Intramuscular injections (into the muscle).
• Intra peritoneal injections (into the abdominal cavity)
• Intradermal injections (into the skin)
• Subcutaneous injections (under the skin).

Question 18

occurs when a substance is changed from one form to another, which may also change the toxic properties of the substance.

Answer 18

biotransformation

Question 19

. It usually occurs in several steps, primarily in the liver, but it may also occur in other tissue like the kidneys, lungs, and digestive tract.

Answer 19

biotransformation

Question 20

The rate (speed) at which a toxic substance is removed from the body determines whether it will have a toxic effect on the body

Answer 20

excretion of toxins

Question 21

The longer a chemical is in the body, the greater the likelihood of damage.

Answer 21

excretion of toxins

Question 22

eliminates the greatest number of toxins than any other tissue/organ.

Answer 22

kidney

Question 23

eliminate substances that are in the gaseous phase, like carbon dioxide.

Answer 23

lung

Question 24

removes substances like lead or DDT (pesticide) by excreting them into bile, which is made by the liver and travels to the small intestine

Answer 24

liver