Ch. 13 Regulation of Gas Transfer Flashcards Preview

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

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

the requirements of the tissues for gas transfer

2

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

the amount taken away from the blood

3

the ventilation to perfusion ratio in humans is

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

4

the ventilation to perfusion ratio in fish is

10:1 to 20:1

water over gills:blood over gills

5

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

ventilation increases

and vice versa

6

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

maintain equal blood and inhalent flow over the respiratory surface

7

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

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

8

neuronal regulatuion of breathing 2 types

pattern generator

rhythm generator

9

pattern generator

sets depth and amplitude of each breath

10

rhythm generator

controls breathing frequency

pre-Botzinger complex in brain stem

11

medullary respiratory center

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

12

Hering-Breuer reflex

reflex to prevent overinflation of the lungs

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

13

phrenic nerve

affects diaphragm via inspiratory neuronal activity

14

inspiratory neuronal activity

controls muscles of inspiration

15

amphibian and reptile episodic breathing

intrinsic property of brainstem

16

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

reflex

17

two types of receptors that affect rate and depth of breathing

carotid bodies

aortic bodies

18

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

chemoreceptors, O2, CO2, and pH

19

"central" chemoreceptors CSF

in medulla

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

accurate b/c no buffer system in CSF

20

peipheral chemoreceptors monitor

arterial blood

21

do peripheral chemoreceptors react to high CO2 or low pH

they think low pH, not the actual CO2 level

22

carotid body chemoreceptors respond greater to...

pH/CO2 changes

leads to inc ventilation via medullary resp center

23

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

temperature, osmolarity, ADH

24

in mammals does CO2 or O2 dominate breathing rate

CO2

25

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

O2

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

26

fish exposed to high O2...

reduce breathing until there is a high PCO2 in blood

27

CO2 effect on mammal pulmonary stretch receptors

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

28

lung irritant receptors

stimulation by mucous or dust causes bronchioconstriction and coughing

29

type J receptors in the lungs

stimulation causes a feeling of breathlessness

responds to increased interstitial fluid (pulmonary edema)

30

hypoxia definition

reduced oxygen levels

31

fish exposed to hypoxia do what

stop feeding and inhibit protein metabolism (growth is impaired)

stop breeding

swim less

move to cooler water (lower temp reduces metabolism)

32

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

energy, anaerobic

33

what 2 systems do animals adjust to survive hypoxia

respiratory

cardiovascular

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

34

high altitudes are associated with lower...

temperatures and pressures

35

acute altitude sickness symptoms

fatigue

headache

dizziness, nausea

insomnia

36

chronic altitue sickness

memory loss

confusion

37

mountain sickness is common in _________ populations but not _________

Andean, Tibetans

38

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

reduces it

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

39

cardiovascular effects of high altitude

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

vasodilation

40

humans living at altitude usually have ______ bodies and _______ lungs

small, normal

41

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

increased (improve O2 carrying capacity)

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

42

Andean adaptations

inc RBC + Hb

many unsaturated RBC --> viscous blood

More O2 attached to Hb

43

Tibetan adaptations

Breathe more air and faster (larger lung volume)

low O2 saturation

240x NO levels --> vasodilation (more flow)

44

Kenyan adaptations

increased O2 transfer from alveoli to blood

45

HIF-1

stimulate EPO

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

46

what 3 places do diving animals store O2

blood

lungs

tissues

47

diving animals have high levels of

Hb and myoglobin

48

during a dive, where is O2 preferentially delivered

brain

heart

49

during a prolonged dive what happens to heart rate and CO

heart rate slows (bradycardia)

lower CO

50

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

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

51

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

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

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

near the glottis

near the mouth or nose

53

mammals during birth

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

what is symmorphosis

we are designed so function doesn't exceed our requirements

ex. gas transfer systems

55

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

swimming and using fins --> costs energy

solution: buoyancy device

56

3 ways aquatic animals maintain neutral buoyancy

swimbladder

large lipid bilayers

ammonium chloide

57

what does it mean that a swim bladder is compressible

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

58

hydrostatic pressure increases by _atm for every depth of __m

1atm, 10m

59

when a fish on the surface dives to 10m...

pressure in swim bladder goes from 1atm to 2atm

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

60

problem with swim bladder instability

volume changes is potentially dangerous

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

61

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

water is incompressible

62

what kind of gas is in a swim bladder

usually O2 but sometimes N2

63

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

added

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

64

structure of a swim bladder

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

easily expanded if pressure inside > pressure outside

65

rete mirabile

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

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

blood passes through arterial capillaries of rete

goes to secretory epithelium in swim bladder wall

then back through venous capillaries to liver

67

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

very small... 1.5micrometers

68

what does rete structure allow

blood to flow into the swimbladder wall without loss of gas

69

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

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

what molecule transfers drop in pH in rete to RBC

CO2 b/c RBC impermeable to H+

blood leaving gas gland to venous capillaries high in CO2

71

arterial (afferent) rete to venous rete steps

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

EPAS1 gene of Tibetans

Prevents overproduction of RBC