D6 gas transport

Question 1

identify pneumocytes, capillary endothelium cells and blood cells in this light micrograph

Answer 1

-

Question 2

identify a pneumocyte, capillary enodthelium cell and red blood cells in this electron micrograph

Answer 2

-

Question 3

oxygen dissociation curves show the relationship between… (hint: refer to the x and y axes)

Answer 3

the partial pressure of oxygen and haemoglobin’s affinity to oxygen

Question 4

at different partial pressures of oxygen, haemoglobin’s affinity to oxygen _________

Answer 4

changes

Question 5

what is partial pressure? (understanding)

Answer 5

the pressure exerted by a gas in a mixture of gases

Question 6

what’s the concept of cooperative binding (understanding)

Answer 6

the more oxygen bound to haemoglobin, the more higher the O2 affinity of haemoglobin

Question 7

where does the haemoglobin become saturated with O2?

Answer 7

at O2 rich areas

Question 8

at O2 rich areas, % O2 saturation of haemoglobin is [low/high]

Answer 8

high

Question 9

at O2 deficient areas, % O2 saturation of haemoglobin is [low/high]

Answer 9

low

Question 10

oxygen _____ from haemoglobin at O2 deficient areas

Answer 10

dissociates

Question 11

the shape of the oxygen dissociation curve is _____-shaped

Answer 11

S

Question 12

what are the factors that affect haemoglobin’s oxygen affinity?

Answer 12

1. partial pressures
2. temp
3. pH

Question 13

adult haemoglobin has [higher/lower] oxygen affinity than fetal haemoglobin at the same partial pressure

Answer 13

lower

Question 14

why does fetal haemoglobin have higher oxygen affinity than adult haemoglobin at the same partial pressure

Answer 14

to ensure that maternal oxyhaemoglobin dissociates to release O2 for binding to fetal haemoglobin

Question 15

where is myoglobin formed

Answer 15

muscle cells

Question 16

what protein in the muscle cells stores oxygen?

Answer 16

myoglobin

Question 17

what is the function of myoglobin?

Answer 17

it stores oxygen

Question 18

myoglobin has [lower/higher] oxygen affinity than haemoglobin at the same partial pressure

Answer 18

higher

Question 19

how does myoglobin function as an oxygen-storing molecule?

Answer 19

• it has a high affinity for O2
• it is saturated with oxygen at low partial pressures of O2
• it only releases oxygen rapidly at very low partial pressures of O2

Question 20

what type of curve is the oxygen dissociation curve for myoglobin?

Answer 20

logarithmic

Question 21

what is the function of myoglobin in intense exercise?

Answer 21

• during intense exercise, when O2 levels drop
• it releases O2 stores
• the slow release delays anaerobic respiration in muscles and lactic acid formation

Question 22

how is CO2 transported in blood? (3)

Answer 22

• as dissolved CO2 in plasma
• as hydrogen carbonate ions in plasma
• bound to haemoglobin as carbaminohaemoglobin

Question 23

when CO2 binds to haemoglobin it forms…

Answer 23

carboaminohaemoglobin

Question 24

what is the enzyme involved in converting CO2 to HCO3-?

Answer 24

carbonic anhydrase

Question 25

CO2 is converted by carbonic anhydrase into...

Answer 25

H+ and HCO3- (aka carbonic acid)

Question 26

where is carbonic anhydrase found in?

Answer 26

RBC

Question 27

where is HCO3- found in?

Answer 27

blood plasma

Question 28

what ion causes blood to become more acidic?

Answer 28

H+

Question 29

HCO3- ions are transported [out/into] the RBC at respiring tissues

Answer 29

out

Question 30

HCO3- ions are transported out of RBC by... (process)

Answer 30

facilitated diffusion

Question 31

___ is taken in when HCO3- exits RBC

Answer 31

Cl-

Question 32

a [incr/decr] in pH causes haemoglobin to release O2

Answer 32

decr

Question 33

what is another function of haemoglobin other than transporting O2?

Answer 33

- it functions as a pH buffer protein by absorbing H+ - this prevents a drop in pH

Question 34

H+ in plasma comes from the ________ of carbonic acid

Answer 34

H+

Question 35

what does carbonic acid dissociate to form?

Answer 35

HCO3- and H+

Question 36

why must the pH of blood be regulated?

Answer 36

for optimal enzymatic activity!

Question 37

____________ detect changes in blood pH

Answer 37

chemoreceptors

Question 38

what is the function of chemoreceptors?

Answer 38

they detect changes in blood pH

Question 39

chemoreceptors send _____________ to the ________

Answer 39

nerve impulses, medulla oblongata

Question 40

which part of the brain controls ventilation?

Answer 40

the respiratory control centre in the medulla oblongata

Question 41

where are chemoreceptors found?

Answer 41

- in the medulla oblongata - in the aorta and carotid arteries

Question 42

how is CO2 released from blood into the lungs for exhalation? (3)

Answer 42

- dissolved CO2 in blood plasma directly enters alveoli - carbaminohaemoglobin dissociates to release CO2 from haemoglobin - HCO3- from plasma is exchanged for Cl- ions in RBC –> forms carbonic acid with H+ in RBC - carbonic acid is converted to H2O and CO2 by carbonic anhydrase to be released into plasma

Question 43

carbonic acid catalyses a ________ reaction (think about the rxn it catalyses!)

Answer 43

reversible

Question 44

give a possible scenario that would cause pH in blood to drop

Answer 44

exercise

Question 45

how can one improve lung vital capacity?

Answer 45

regular exercise

Question 46

how does the body react to a drop in blood pH

Answer 46

- ventilation rate incr + heart rate incr - for quicker removal of CO2 - and for increased O2 uptake to support cell resp

Question 47

what muscles are involved in ventilation? (recap of core)

Answer 47

intercostal muscles, diaphragm and abdominal muscles

Question 48

to increase ventilation rate, where nerve impulses will be sent to?

Answer 48

intercostal muscles, diaphragm and abdominal muscles

Question 49

what is the regulated range of blood pH?

Answer 49

pH 7.35-7.45

Question 50

blood pH is regulated by...

Answer 50

homeostatic control

Question 51

when blood pH <7.35, __________ occurs

Answer 51

acidosis

Question 52

at what pH does alkalosis occur?

Answer 52

pH >7.45

Question 53

what components in blood act as pH buffers?

Answer 53

plasma proteins and RBC

Question 54

what is the Bohr shift? (defin.)

Answer 54

it is when the oxygen dissocation curve **shifts right** reflecting a **decr oxygen affinity** as a result of **incr acidity**

Question 56

a decr in pH causes oxygen affinity in haemoglobin to [incr/decr]

Answer 56

decr

Question 57

what causes the oxygen dissociation curve to shift right?

Answer 57

- when cells actively respire –> release more CO2 into blood - CO2 converted into carbonic acid by carbonic anhydrase - lowers the pH of blood - causes O2 affinity of RBC to decr –> haemoglobin releases O2 at same partial pressures

Question 58

when the oxygen dissociation curve shifts right, haemoglobin releases [more/less] O2 at ________ partial pressures

Answer 58

more, the same

Question 59

how do RBCs know when to release more oxygen?

Answer 59

- at O2 deficient regions, CO2 conc is high –> pH decr - haemoglobin's affinity to O2 decr –> releasing O2

Question 60

why is the Bohr shift important?

Answer 60

it ensures that respiring tissues get enough oxygen

Question 61

at higher altitudes, there is [more/less] O2 in atmosphere

Answer 61

less

Question 62

the partial pressure of O2 in atmosphere in the mountains is ________

Answer 62

lower

Question 63

under what conditions is haemoglobin not fully saturated?

Answer 63

at high altitudes

Question 64

how does the respiratory system respond in high altitudes?

Answer 64

- incr ventilation rate - incr heart rate

Question 65

if you climb a mountain and you haven't climbed any mountain before what kind of illness will you get

Answer 65

mountain sickness

Question 66

what are some symptoms of mountain sickness

Answer 66

nausea, dizziness, headache, fatigue

Question 67

how does the body acclimatise to high altitudes? (apply) (5)

Answer 67

- incr production of RBC - incr haemoglobin in RBC - muscles produce more myoglobin - vital capacity of lungs incr - incr in capillaries in muscles and lungs