Lec 19- Gas Exchange Mechanisms

Question 1

Partial Pressure

Answer 1

is pressure that a particular gas in a mixture exerts independently.

Question 2

Nitrogen narcosis

Answer 2

Under hyperbaric conditions takes more than hour for dangerous amounts to accumulate.
Resembles alcohol intoxication.

Question 3

Decompression sickness

Answer 3

Occurs as bubbles of nitrogen gas form in tissues and enter blood, blocking small blood vessel and producing “bends”.

Question 4

Hb - hemoglobin

Answer 4

Transports O2

Question 5

Heme groups

Answer 5

4 in Hb. Carries 4 O2.

Question 6

Fe - iron

Answer 6

The portion of a heme group that attracts the O2.

Question 7

Oxyhemoglobin

Answer 7

When oxygen in bound to Hemoblobin

Question 8

Methemoglobin

Answer 8

Contains ferric iron (Fe3+) - the oxidized form.
Lacks electron to bind with O2.
Blood normally contains a small amount.

Question 9

Carboxyhemoglobin

Answer 9

Heme combined with carbon monoxide.

Question 10

Carbon Monoxide

Answer 10

CO.

Hb has a higher affinity for CO than O2.

Question 11

Oxyhemoglobin dissociation curve

Answer 11

Shows a graph of how affinity decreases when pH decreases.

Question 12

BPG/D-2,3-biphosphoglycerate AKA DPG/2,3-diphosphoglycerate

Answer 12

Affect the ability of Hb to bind to O2.

Question 13

Fetal hemoglobin

Answer 13

has 2 y-chains in place of B-chains of HbA.

Question 14

Sickle-cell anemia

Answer 14

HbS has valine subsituted for glutamic acid at 1 site on B chains. At low PO2, HbS crosslinks to form a “paracrystalline gel” inside RBC’s. Makes RBC’s less flexible and more fragile.

Question 15

Myoglobin

Answer 15

Red pigment found exclusively in striated muscle.

Slow-twitch skeletal and cardiac muscle fibers are rich in myoglobin.

Question 16

Carbaminohemoglobin

Answer 16

20% of CO2 transported in blood.

Question 17

Carbonic Acid

Answer 17

…

Question 18

Bicarbonate ion

Answer 18

70% of CO2 transported in blood.

Question 19

CA - carbonic anhydrase

Answer 19

In RBC’s this catalyzes formation of H2CO3 from CO2 and H2O

Question 20

Chloride shift

Answer 20

In tissues.

Cl- enters the RBC; HCO3- leaves. Plays role in CO2 coming into RBC.

Question 21

Reverse chloride shift

Answer 21

In lungs.

Cl- leaves the RBC; HCO3- enters. Plays role in CO2 entering alveoli.

Question 22

Most important buffer in blood?

Answer 22

Bicarbonate

Question 23

Volatile acid

Answer 23

One of the 2 major classes of acids in body.

Can be converted to a gas.

Question 24

Non-volatile acid

Answer 24

All other acids are nonvolatile and cannot leave the blood.

e.g. lactic acid, fatty acids, ketone bodies.

Question 25

Respiratory acidosis

Answer 25

Acidosis resulting from abnormal retention of CO2 arising from hypoventilation

Question 26

Respiratory alkalosis

Answer 26

Alkalosis caused by excessive loss of CO2 from the body as a result of hyperventilation

Question 27

Metabolic acidosis

Answer 27

Acidosis resulting from any cause other than excess accumulation of carbonic acid in the body.

Question 28

Metabolic alkalosis

Answer 28

Alkalosis caused by a relative deficiency of noncarbonic acid.

Question 29

Rhythmicity center

Answer 29

FIND

Question 30

Chemoreceptors

Answer 30

Receptors that respond to a specific chemical

Question 31

Central chemoreceptor

Answer 31

Sensituve to changes of PCO2.

Located in the medulla.

Question 32

Peripheral chemoreceptor

Answer 32

Monitors atrial PO2.

Includes the carotid bodies and aortic acids.

Question 33

Aortic bodies

Answer 33

Peripheral chemorecptor located on the aorta.

Question 34

Carotid bodies

Answer 34

Peripheral chemorecptor located on the carotid artery.

Question 35

Hypocapnia

Answer 35

Caused by hyperventialtion.

Below normal CO2 in the arterial blood.

Question 36

Hypercapnia

Answer 36

Cause by hypoventilation.

Excess CO2 in the aterial blood.

Question 37

Hypoxemia

Answer 37

Abnormally low levels of O2 in the blood.