Ch. 13 Regulation of Gas Transfer Flashcards Preview

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Flashcards in Ch. 13 Regulation of Gas Transfer Deck (72)
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1
Q

the rate of blood perfusion of the respiratory surface is related to ….

A

the requirements of the tissues for gas transfer

2
Q

the amount of O2 delivered to the respiratory surface must equal …

A

the amount taken away from the blood

3
Q

the ventilation to perfusion ratio in humans is

A

1 b/c the O2 contnet of blood is approximately that of air

4
Q

the ventilation to perfusion ratio in fish is

A

10:1 to 20:1

water over gills:blood over gills

5
Q

to compensate for a decrease in PO2 in air or water…

A

ventilation increases

and vice versa

6
Q

why can the pattern of capillary blood flow change in gills and lungs

A

maintain equal blood and inhalent flow over the respiratory surface

7
Q

how does hypoxic vasoconstriction of blood vessels in the lung help to maintain an ideal ventilation to perfusion ratio?

A

low alveolar O2 level causes vasoconstriction so blood doesnt flow to this area of the respiratory surface

8
Q

neuronal regulatuion of breathing 2 types

A

pattern generator

rhythm generator

9
Q

pattern generator

A

sets depth and amplitude of each breath

10
Q

rhythm generator

A

controls breathing frequency

pre-Botzinger complex in brain stem

11
Q

medullary respiratory center

A

sends signals to spinal motor neurons that control the diaphragm and intercostal muscles

12
Q

Hering-Breuer reflex

A

reflex to prevent overinflation of the lungs

pulmonary stretch receptors sense over-stretching during large breaths and inhibit the vagus nerve

13
Q

phrenic nerve

A

affects diaphragm via inspiratory neuronal activity

14
Q

inspiratory neuronal activity

A

controls muscles of inspiration

15
Q

amphibian and reptile episodic breathing

A

intrinsic property of brainstem

16
Q

fluxes in O2 and CO2 levels in animals lead to ______ changes in ventilation

A

reflex

17
Q

two types of receptors that affect rate and depth of breathing

A

carotid bodies

aortic bodies

18
Q

carotid bodies and aortic bodies are ____________ that measure changes in __ and ____

A

chemoreceptors, O2, CO2, and pH

19
Q

“central” chemoreceptors CSF

A

in medulla

respond to decreases in pH of CSF (high CO2) detect H+

accurate b/c no buffer system in CSF

20
Q

peipheral chemoreceptors monitor

A

arterial blood

21
Q

do peripheral chemoreceptors react to high CO2 or low pH

A

they think low pH, not the actual CO2 level

22
Q

carotid body chemoreceptors respond greater to…

A

pH/CO2 changes

leads to inc ventilation via medullary resp center

23
Q

increases in _____________ and _______ can also stimulate carotid chemoreceptors, and stimulation of the carotid nerve causes release of _____

A

temperature, osmolarity, ADH

24
Q

in mammals does CO2 or O2 dominate breathing rate

A

CO2

25
Q

in aquatic vertebrates does CO2 or O2 dominate breathing rate and why

A

O2

O2 is limiting in water b/c less soluble and concentration fluctuates a lot more

26
Q

fish exposed to high O2…

A

reduce breathing until there is a high PCO2 in blood

27
Q

CO2 effect on mammal pulmonary stretch receptors

A

reduces their inhibitory effect to increase depth of breathing and lung ventilation

28
Q

lung irritant receptors

A

stimulation by mucous or dust causes bronchioconstriction and coughing

29
Q

type J receptors in the lungs

A

stimulation causes a feeling of breathlessness

responds to increased interstitial fluid (pulmonary edema)

30
Q

hypoxia definition

A

reduced oxygen levels

31
Q

fish exposed to hypoxia do what

A

stop feeding and inhibit protein metabolism (growth is impaired)

stop breeding

swim less

move to cooler water (lower temp reduces metabolism)

32
Q

in general, animals reduce ______ expenditure and use _________ metabolic pathways to survive hypoxia

A

energy, anaerobic

33
Q

what 2 systems do animals adjust to survive hypoxia

A

respiratory

cardiovascular

ex. fish increase gill ventilation and ram-ventilated fish open mouth gap wider

34
Q

high altitudes are associated with lower…

A

temperatures and pressures

35
Q

acute altitude sickness symptoms

A

fatigue

headache

dizziness, nausea

insomnia

36
Q

chronic altitue sickness

A

memory loss

confusion

37
Q

mountain sickness is common in _________ populations but not _________

A

Andean, Tibetans

38
Q

decrease in blood PCO2 and resultant increase in CSF pH does what to ventilation, and what happens at high altitude

A

reduces it

blood and CSF pH returned to normal after days-1wk by excretion of bicarbonate…gradual increase in ventilation

39
Q

cardiovascular effects of high altitude

A

increase in CO, then 1/3 increase in blood volume

vasodilation

40
Q

humans living at altitude usually have ______ bodies and _______ lungs

A

small, normal

41
Q

most vertebrates respond to altitude with ________ RBC, and blood hemoglobin

A

increased (improve O2 carrying capacity)

triggered by reduced blood O2 –> EPO from kidney/liver

42
Q

Andean adaptations

A

inc RBC + Hb

many unsaturated RBC –> viscous blood

More O2 attached to Hb

43
Q

Tibetan adaptations

A

Breathe more air and faster (larger lung volume)

low O2 saturation

240x NO levels –> vasodilation (more flow)

44
Q

Kenyan adaptations

A

increased O2 transfer from alveoli to blood

45
Q

HIF-1

A

stimulate EPO

stim vascular endothelial growth factor (VEGF) –> capillary growth for inc flow

46
Q

what 3 places do diving animals store O2

A

blood

lungs

tissues

47
Q

diving animals have high levels of

A

Hb and myoglobin

48
Q

during a dive, where is O2 preferentially delivered

A

brain

heart

49
Q

during a prolonged dive what happens to heart rate and CO

A

heart rate slows (bradycardia)

lower CO

50
Q

why must air-breathing animals have enough O2 stores during a dive and metabolism reduced

A

support aerobic metabolism b/c they can’t handle the lactic acid production from anaerobic metabolism

51
Q

why do some animals exhale before diving to reduce O2 stores in lungs and compress the lungs

A

air stored in trachea and bronchi which are more rigid than alveoli

this is so rapid ascent doesn’t cause formation of bubbles in the blood (which would happen if air was in alveoli cause they would be compressed on ascent)

52
Q

where are receptors that detect presence of water and inhibit inspiration during a dive

A

near the glottis

near the mouth or nose

53
Q

mammals during birth

A

move from an aqueous environment to air

short period of anoxia from stopping of placental circulation and 1st breath of air

behaves like a diving animal during this time

54
Q

what is symmorphosis

A

we are designed so function doesn’t exceed our requirements

ex. gas transfer systems

55
Q

fish are denser than surrounding water and must do what to maintain position

A

swimming and using fins –> costs energy

solution: buoyancy device

56
Q

3 ways aquatic animals maintain neutral buoyancy

A

swimbladder

large lipid bilayers

ammonium chloide

57
Q

what does it mean that a swim bladder is compressible

A

volume changes with depth and therefore so does the buoyancy of the animal

58
Q

hydrostatic pressure increases by _atm for every depth of __m

A

1atm, 10m

59
Q

when a fish on the surface dives to 10m…

A

pressure in swim bladder goes from 1atm to 2atm

volume reduced by 1/2 and density of the fish increases –> sinking

60
Q

problem with swim bladder instability

A

volume changes is potentially dangerous

solution: adding or removing gas into the bladder during descent or ascent to maintain volume

61
Q

why doesnt gas partial pressure or gas in water vary with depth

A

water is incompressible

62
Q

what kind of gas is in a swim bladder

A

usually O2 but sometimes N2

63
Q

if a fish dives to a depth of 100m, does O2 need to be added or removed to maintain buoyancy

A

added

supplied from environment against a pressure difference (bladder 10atm, water 0.228 atm)

64
Q

structure of a swim bladder

A

tough wall impermeable to gas but slow leak out at inc depth

easily expanded if pressure inside > pressure outside

65
Q

rete mirabile

A

present in fish that can move O2 into the bladder vs. a high pressure gradient

bundles of capillaries arranged for countercurrent flow btw arterial and venous blood

66
Q

what happens btw a rete and gas gland (secretory epithelium in swim bladder)

A

blood passes through arterial capillaries of rete

goes to secretory epithelium in swim bladder wall

then back through venous capillaries to liver

67
Q

in the rete, arterial and venous blood are separated by a large or small distance

A

very small… 1.5micrometers

68
Q

what does rete structure allow

A

blood to flow into the swimbladder wall without loss of gas

69
Q

how is O2 secreted into the swim bladder (low mitochondria is gas gland cells so glycolysis)

A

gas-gland cells make CO2 and H+ that lower pH so O2 is released by Hg (root-off effect)

also causes increase in ionic concentration –> reduce O2 solubility

therefore PO2 in gas gland > than swim badder so O2 diffuses from blood into the bladder

70
Q

what molecule transfers drop in pH in rete to RBC

A

CO2 b/c RBC impermeable to H+

blood leaving gas gland to venous capillaries high in CO2

71
Q

arterial (afferent) rete to venous rete steps

A

H+ produced by gas gland and CO2 diffuses from venous (efferent) rete

low pH from CO2 causes O2 release from Hb causing local high pO2 and O2 into swim bladder

when venous CO2 flows into afferent, pH raises and Hb picks up O2 again causing low pO2 (root-on)

72
Q

EPAS1 gene of Tibetans

A

Prevents overproduction of RBC