Part IX

Question 1

What happens when one experiences oxygen toxicity?

Answer 1

seizures followed by coma within 30-60minutes

Question 2

When the oxygen partial pressures are above 2 atmospheres, what happens?

Answer 2

free radical damage can form, which can damage cell membranes and cellular enzymes and the nervous tissue is highly susceptible, which results in brain dysfunction

Question 3

How is oxygen toxicity preventable?

Answer 3

if one never exceeds the established max depth of a given breathing gas
and for divers, use “hypoxic blends” containing a lower O2% than ATM air

Question 4

What is narcosis?

Answer 4

state of stupor, drowsiness or unconsciousness

Question 5

How does one develop narcosis?

Answer 5

being submerged for over an hour

Question 6

What happens at 120ft?

Answer 6

jovial, carefree

Question 7

What happens at 150-200ft?

Answer 7

drowsiness

Question 8

What happens from 200-250ft?

Answer 8

weakness

Question 9

What happens above 250ft?

Answer 9

unable to function

Question 10

What is the mechanism behind gas anesthetics?

Answer 10

dissolves in neuronal membranes altering ionic conductance

Question 11

When is high PCO2 a problem?

Answer 11

almost never because depth doesn’t increase alveolar PCO2

Question 12

When could PCO2 be increased?

Answer 12

in certain types of diving gear

Question 13

What problems occur when CO2 toxicity does occur?

Answer 13

depression of respiratory centers, respiratory acidosis, lethargy, narcosis, anesthesia

Question 14

What happens when a person breaths air under high pressure for an extended period of time?

Answer 14

the amount of N2 in the body fluids increases as higher N2 levels equilibrate with levels in tissues

Question 15

Is nitrogen metabolized in the body?

Answer 15

no

Question 16

When does the dissolved nitrogen come out of the tissues of the body?

Answer 16

when N2 pressure in the lungs decreases as the person ascend back to sea level

Question 17

How much time is required to bring someone back up from under the sea? Why?

Answer 17

hours, the blood doesn’t flow rapidly enoguh and nitrogen doesn’t diffuse rapidly enough to cause instantaneous equilibration

Question 18

When is nitrogen dissolved in the blood a problem?

Answer 18

when someone has been under water for hours

Question 19

What is the Bends?

Answer 19

when nitrogen bubbles out of fluids after sudden decompression

Question 20

What can happen if nitrogen bubbles out of the blood?

Answer 20

can block blood vessels, large or small

Question 21

What are the symptoms of the bends?

Answer 21

pain in joints, muscles of arms and legs (85-90%), nervous system symptoms (5-10%), pulmonary capillaries blocked “the chokes” (2%)

Question 22

How do you prevent decompression sickness?

Answer 22

a diver who has been breathing air and has been on the sea bottom at a depth of 190 feet for an hour needs to stay underwater at various depths for about 3 hours

Question 23

Where does the lung rank as far as metabolism goes?

Answer 23

second to liver

Question 24

What is an advantage the lung has over the liver?

Answer 24

all blood passes through the lungs with every complete cycle

Question 25

What are some examples of metabolism that occurs in the lungs?

Answer 25

angiotensin I converted to angiotensin II

prostaglandins inactivated in one pass through pulmonary circulation

Question 26

How much air does the average adult breath in a day?

Answer 26

10,000 L of air/day

Question 27

What is in the air we breath?

Answer 27

inert dust, particulate matter (plants and animals), gases (fossil fuel combusion), infectious agents (viruses and bacteria

Question 28

What is a major source of contact with the environment?

Answer 28

respiratory membrane

Question 29

How many microns are between the air and blood?

Answer 29

.5 microns

Question 30

What do our defense mechanisms do?

Answer 30

protect tracheobronchial tree and alveoli from injury, prevent accumulation of secreions, repair

Question 31

What depresses defense mechanisms?

Answer 31

chronic alcohol use, cigarette smoke, air pollutants, occupational irritants

Question 32

Chronic alcohol use is associated with an increase incidence of what?

Answer 32

bacterial infections

Question 33

Cigarette smoke and air pollutants are associated with an increase incidence of what?

Answer 33

chronic bronchitis and emphysema

Question 34

Occupational irritants are associated with increase incidence of what?

Answer 34

hyperactive airways or intersitial pulmonary fibrosis

Question 35

What do nasal passages protect?

Answer 35

airwys and alveolar structures from inhaled foreign material

Question 36

What things help the nasal passage protect the respiratory system?

Answer 36

long hairs in nose filters our large particles, mucous coating nasal mucous membranes, nasal turbinates

Question 37

What are nasal turbinates?

Answer 37

highly vascularized structures that act as radiators to warm air

Question 38

What cranial nerve is associated with coughing?

Answer 38

CN X

Question 39

What is the process of coughing?

Answer 39

2.5L of air are rapidly inspired, epiglottis closes and vocal cords close tightly
muscles of expiration contract forcefully which causes pressure in lungs to rise to 100 mmHg
epiglottis and vocal cord open widely, which results in explosive outpouring of air to clear larger airways

Question 40

What is a cough ineffective at doing?

Answer 40

clearing smaller airways due to the total cross sectional area, it just can’t generate enough velocity