Respiration Physiology Pt 2

Question 1

During mammalian inhalation, ____ ____ stimulates inspiratory muscles

Answer 1

MOTOR NEURONS

Question 2

during inhalation, ____ intercostals and diaphrahm _____

Answer 2

EXTERNAL intercostals and diaphragm CONTRACTS.

Question 3

During mammalian inhalation, the diaphragm moves

Answer 3

downward

Question 4

During mammalian inhalation, the volume of thorax ____, and intrathoraic pressure ___

Answer 4

volume increases, and intrahthoracic pressure DECREASES, this creates a transpulmonary pressure gradient INCREASE.

Question 5

During mammalian exhalation, the volume of the thorax _____ and the intrathoracic pressure ____

Answer 5

thoracic volume DECREASES and intrathoracic Pressure INCREASES.

Question 6

forced exhalation is by the contraction of ____ intercostal muscles

Answer 6

INTERNAL

Question 7

surface tension inside the alveoli ___ expansion. how does this help? what can it cause?

Answer 7

OPPOSES. helps ensure elastic recoil along with elastic fibers in pulmonary connective tissue. BUT SURFACE TENSION reduces distensibility or compliance of the tissue and can potentially cause ALVEOLAR COLLAPSE Pulmonary surfactant’s role in reducing the alveoli’s tendency to recoil, thereby discouraging alveolar collapse, is important in helping maintain lung stability.

Question 8

LaPlace’s law and explain its significance. How can surfactant help with this?

Answer 8

magnitude of the inward-directed collapsing pressure is directly proportional to the surface tension and inversely proportional to the radius of the alveoli : Pressure = 2T/R P= inward pressure T= tension (surface tension) R= radius of alveolus water molecules in alveoli have surface tension which pull inward. the holes between alveoli connect them to create a risk that larger alveolus may absorb smaller ones (causing collapse). Accordingly, if two alveoli of unequal size but the same T are connected by the same terminal airway, the smaller alveolus—because it generates a larger collapsing pressure has a tendency to collapse and empty its air into the larger alveolus. The surfactant-induced lower T of small alveoli offsets the effect of their smaller radii in deter- mining the inward-directed pressure. Therefore, the presence of surfactant causes the collapsing pressure of small alveoli to become comparable to that of larger alveoli

Question 9

the holes that connect avleoli together to create a large alveoli sac are known as

Answer 9

pores of KAHN

Question 10

two ways that we mitigate distensibility (recoil) in alveoli

Answer 10

1) elasticity due to elastin fibers
2) surfactant. more surfactant is secreted in smaller alveoli and less in larger to EQUALIZE PRESSURE BETWEEN ALVEOLI in the sac

Question 12

What is spirometry

Answer 12

the tehcnique use to quantify volumes and capcities.

Question 13

what is the tidal volume

Answer 13

the difference between end-expiratory and end-inspiratory volume= tidal volume. The volume of air moved in one ventilatory cycle

ex/ volume of lungs at end of inspiration (2700ml) and volume of lungs at end of expiration (2200 ml) therefore tidal volume is 500ml.

Question 14

What is dead space? Two components of dead space

Answer 14

air that does not paricipate in gas exchange.

2 components: 1) anatomical dead space= volume of air of trachea and bronchi

2) alveolar dead space= volume of alveoli that are not perfused.

Question 15

During expiration, 500 ml of “old” avleolar air is expired: ___ml expired to atmosphere, while ___mL remain in the dead space.

Answer 15

350 ml expired to atmosphere, 150 ml remain in dead space

Question 16

what is alveolar ventilation volume (Va)? What is alvolar minute ventilation?

Answer 16

volume of fresh air that enters alveoi with each respiratory cycle.

Va= Vt- Vd= 500ml- 150 ml = 350ml

Va= alvolar ventilation volume

Vt= tidal vol

Vd= dead space

Alveolar munite ventilation is the volume of fresh air that enters the alveoli each minute :

VaDOT= f(Vt-vd)

f= brathing rate in breaths per minute.

Question 17

how do you maintain alveolar minute ventilation (VdotA) with a large dead space?

Answer 17

you can increase tidal volume and increase respiratory rate. Recall: VDOTa= f(Vt-Vd)

Question 18

T/F: during high demand exercise, increasing respiratory rate is sufficient to maintaining alveolar minute ventilation

Answer 18

false. you need to increase breathing rate, yes, but you also need to bood tidal volume to overcome dead space.

Question 19

How do ice fish survive with no Hb or RBCs?

Answer 19

they have an enlarge heart and large stroke volume. extremely cold water allows higher O2 solubility and leads to low MR of the fish. therefore, diffusion and dissolved O2 in the blood is enough. Most gas exchange still occurs across the gills, some is cutaneous.

Question 20

T/F: we can change the amount of dissolved O2 in the blood

Answer 20

false. BUT we can use respiratory pigments

Question 21

Blood can’t dissolve O2 much, instead we use ___ ___ typically made of metalloproteins

Answer 21

respiratory pigments.

Question 22

What are metalloproteins. Three major types?

Answer 22

metalloproteins are proteins containing metal ions which reversibly bind to O2. They increase o2 carrying capacity by 50 fold.

3 major types:

1) hemocyanin
2) hemoglobin
3) hemoerythrins

Question 23

hemoglobin contains a ____ molecule in the center of a ___ ____ (heme)

Answer 23

Fe2+ in the center of a porphyrin ring (heme)

Question 24

How many O2’s does one heme bind

Answer 24

1. but there are 4 hemes in a hemoglobin, thus one hemoglobin can bind 4

Question 26

hemoglobin is a ____ with 2 alpha and 2 beta chains. They are held together by ___ bonds and ____ \_\_\_\_. What structure changes during loading and offloading of O2?

Answer 26

hemoglobin is a tetramer. the dimers are held together by H bonds and salt bridges. It's quarternary structure of protein changes on loading and offloading

Question 27

IN addition to hemoglobin, what are the 2 primary enzymes that RBC's contain?

Answer 27

1) carbonic anhydrase: for Co2 tansport, pH regulation 2) methmemoglobin reductase. reduces Fe3+ to Fe2+ in RBC

Question 28

the binding of O2 to Hb is driven by \_\_\_\_.

Answer 28

PO2. Po2 decreases as Hb binds more O2 and becomes saturated

Question 29

law of mass action

Answer 29

an increase of mas on one set of reactants then the reaction is driven to the opposite side. Hb + O2 \<--\> HbO2.

Question 30

T/F: only dissolved O2 contributes to PO2.

Answer 30

true. Hb removes O2 from solution

Question 31

Why is a signmoidal relationship between O2 binding and PO2 so important?

Answer 31

it ensures consistant supply of O2 to tissue and indicates cooperativity. as partial pressure of O2 increases, the saturation of Hb also increases, and pO2 decreases(deoxy blood), Hb saturation decreases (offloading to tissues)

Question 32

R state vs T state in terms of affinity

Answer 32

R state: relaxed, high affinity. T state: tense, low affinity.

Question 33

what is p50

Answer 33

the Po2 level when Hb is 50% saturated

Question 34

How can you change P50 value?

Answer 34

by different hemoglobin O2 affinities.

Question 35

T/F: the AMOUNT of Hb can determine P50 values.

Answer 35

false. Low and high Hb content in blood does not define the P50. affinity does. therefore, if the blood with low and high Hb still have the same Hb isoform, they will s**till have the same P50 value**, but the body with high Hb content will just have more O2ml on average in the blood (because of the sheer volume of respiratory pigment)

Question 36

why is does myoglobin display a hyperbolic binding curve?

Answer 36

because it doesn't exhibit cooperativity.

Question 37

Bohr effect. What direction does it shift the Hb binding curve?

Answer 37

a decrease in pH (increase pCO2) REDUCES O2 affinity. Shifts it RIGHT, p50 is increased. Facilitates O2 transport to active tissues and O2 binding at respiratory surfaces

Question 38

Bohr effect vs root effect

Answer 38

bohr effect can be mitigated by incresing O2 concentration to achieve 100% saturation again. in the root effect, the saturation will always be alower because of the pH change.

Question 39

3 methods to reduce affinity for O2 by Hb

Answer 39

1) reduce pH 2) increase temperature 3) organic phosphates

Question 40

how does an increase in temperature result in a change in Hb O2 affinity? Why is this important for ectotherms

Answer 40

causes a reduced affinity (stabilization of T state). it causes the curve to shift left. body temp increase allows warmer tissues to receive more O2 because Hb will readily unload them due to lack of affinity. this is good for ectotherms because as temp increases, their Mr increases and thus they need more O2. more O2 can be delivered to them because of the increased unloading of Hb.

Question 41

How do organic phosphates change Hb binding affinity? How are they produed?

Answer 41

they reduce affinty (right shift). They stabilize T state by reforming salt bridges. allows for O2 offloading at tissues. 2-3 DPG is produced INSIDE red blood cells.

Question 42

explain cold weather adaptations in the muskox in terms of Hb

Answer 42

they have a difference in Hb sensitivity. the human p50 is wayyyy lower compared to musox. muskox has low Hb affinity and is **less sensitive to cold**, allowing for adiquate O2 tissue release. If they were sensitive to cold, the Hb would hold onto their O2 even more. recall (high temp= reduced affinity)

Question 43

explain cold weather adaptation in the wooley mammoth

Answer 43

- nucleotide difference coding for adequate O2 release in cold temp. therefore, they had a right shifted Hb curve.

Question 44

the ____ effect effects the CAPACITY of Hb to reach saturation, where as the ___ effect effects the AFFINITY of Hb, but still allows it to reach saturation.

Answer 44

the ROOT effect effects the CAPACITY of Hb to reach saturation, where as the BOHR effect effects the AFFINITY of Hb, but still allows it to reach saturation.

Question 46

Which organ in fish allows them to remain neutrally buyant?

Answer 46

swim bladders. bag og air to adjust buoyancy and regulate depth in water column.

Question 47

evolutionarily before the swim bladder in teleosts, were the physostomous fish. What did they have instead?

Answer 47

they had a sort of mouth bladder where they gulped air to float and burped the excess to sink. the problem is that they needed to physically swim to the top of the surface to get the guld of air to begin wiht.

Question 48

inaddition to a swim bladder, what do physoclistous fish have?

Answer 48

they have a gas gland and a rete mirabile counter current exchange system. No gas/water moving past blood- venous blood supply travels to gas gland and travels adjacently to arterial capillaries.

Question 49

what adverse effects happen when you reel up a deep water physoclistous fish too fast?

Answer 49

the rapid decrease in pressure causes their gas gland to expand. this gas gland expansion drags the stomach and intestines up through the mouth of the fish and it causes everted digestive trace.

Question 50

How is the gas gland in a physoclistous fish filled? ( 3 ways)

Answer 50

1) **secretion** of gas from blood to the gas gland: must go against a huge PO2 gradient. slow 2) **retention** of gass in swim bladder from the rete mirabile. 3) **reabsoprtion** of gas from the bladder: oval or oval window.

Question 51

structure of the swim bladder. what are its components?

Answer 51

1) gas gland 2) rete mirabile 3) oval 4) bladder wall.

Question 52

how does the swim bladder fill with air

Answer 52

there is a release of O2 from Hb in the blood stream near the organ, causing pO2 increase in plasma. This gradient causes air/gas to go INTO the swim bladder.

Question 53

the ___ \_\_\_ facilitates pO2 increase via O2 removal from Hb.

Answer 53

the gas gland (by secreting lactic acid and CO2 in order to decrease Hb affinity and make it release O2). Rete mirabile miantains the incremental pO2 increaes in the blood by a counter current exchange system

Question 54

purpose of the oval in a swim bladder system

Answer 54

its a muscular valve to release O2 back to the blood when the fish needs to sink

Question 55

what's salting out?

Answer 55

occurs when ionic content of venous blood in the rete mirabile increases, (ex/ by lactic acid), resultin gin the reduced solubility of Co2 and N2. Co2 comes out of the solution into the gas gland.

Question 56

what drives the diffusion of gas from the gland into the bladder

Answer 56

the PO2 in gas gland is higher than in the bladder. O2 diffuses into the bladder.

Question 57

other than buoyancy and locomotion, what else can a swim bladder be used for?

Answer 57

can be used as a auditory center or a resonating chamber. social contact calls can be distriubted from gas released out of the swim bladder. It can also help with sound detection because it allows for the detection to feel vibration. ex/ gulf toadfish (midshipman)use the rapid contractions of the swim bladder to produce sounds.

Question 58

in high O2 supply situations, its advantageous to have ____ affinity Hb

Answer 58

LOW affinity. Allows them to release O2 to tissues.

Question 59

What adaptations do the bar headed geese have in order for them to fly over high altitudes?

Answer 59

1) VERY LOW P50s. Low p50= high affinity for O2. 2) but: they are very sensitive to the bohr effect. therefore, their acidic tissues drop pH and reduce the affinity at the site of the tissue for adequate O2 release to muscles.

Question 60

T/F: high altitude mammales have more RBCS

Answer 60

false. high altitude mammales don't have high RBXs. In short term, delivery at tissues seems to take precedence over loading at the lungs (higher p50 lower Hb affinity), but evolutionary solution is higher affinity for Hb (low p50, but sensitive to Bohr effect)

Question 61

3 ACCLIMATIZATIONS to high altitudes

Answer 61

1) hyperventilation 2) mechanisms to reduce tissue requirements (appetite) 3) pathological responses\*\*?

Question 62

3 ADAPTATIONS to high altitudes

Answer 62

1) higher affinity Hb 2) higher respiration rate and tolerance of alkalosis 3) reduced tissure requirements

Question 63

Compare fetal and afult Hb

Answer 63

fetal Hb is not as sensitive to 2,3 BPG. They have a higher affinity for O2 then adult. this is because the Hb of the fetus has to bind O2 after blood is already partially deoxygenated from mom. therefore, fetal Hb curve is shifted RIGHT. has a lower p50.

Question 64

compare tadpole and frog hemoglobin

Answer 64

adults have lower affinity for Hb because they liver in a higher O2 environment. therefore, their P50 is higher in tadpoles.

Question 65

primary respiratory pigment in the muscle

Answer 65

myoglobin

Question 66

how many oxygens can myoglobin bind? what shape is the curve?

Answer 66

it can bind only 1. this is because it is a single polypeptide protein. it does not have 4 subunits like hemoglobin does. it is a hyperbolic curve like all other enzymatic curves. it is made of 1 subunit and thus there is no inter-subunit cooperativity.

Question 67

the darker the meat the more:

Answer 67

myoglobin

Question 68

does myoglobin or hemoglobin have higher affinities for O2. significance?

Answer 68

myoglobin. the P50 is MUCH LOWER than that of Hb. this allows O2 to move from Hb to Mb, enhancing the rate of O2 diffusion through cells

Question 69

How does Mb interact with cytochrome oxidase? What is this important?

Answer 69

cyt oxidase is an enzyme in the ETC. its VMAX is at a PO2 of 4 or 5. V low. At very low PO2, Mb will release O2 to cytochrome oxiddase to keep mitochondria functioning. this is significant because Mb can thus act as an "O2 reserve" in periods of extreme PO2 reduction, such as in diving mammales.

Question 70

3 ways carbon dioxide is transported

Answer 70

1) dissolved CO2 in plasma and in cytoplasm of RBC 2) in the bicarbonate buffer system 3) **attached to Hb and as carbamino CO2**

Question 71

Draw the shape of the CO2 curve (CO2 concentration in blood vs PCO2). What other chemical does this curve dependent on? Is there any cooperativity going on?

Answer 71

Shape of CO2 curve depends on the kinetics of HCO3- formation - there is no sub unit cooperativity

Question 72

according to the Haldane effect, ____ blood can carry more CO2 than ____ blood

Answer 72

DEOXYGENATED blood can carry more CO2 than oxygenated blood.

Question 73

Co2 conversion into bicarbonate equation

Answer 73

CO2+ H2O ---\> H2CO3 --\> H+ + HCO3- via carbonic anhydrase

Question 74

What is the chloride shift? Where does it occur and what exchangers are present? What reaction is also occuring at the same time as chloride shift?

Answer 74

the chloride shift occurs on the RBC membrane, where HCO3- is pushed out of the RBC into the plasma and CL- in the plasma enters the RBC. It involves BAND 3 PROTEIN as a shuttle system. At the same time, HbO2 in the RBC dissociates into Hb + O2. this is so Hb is free to bind to H+ that is left when HCO3- leaves. --\> this mitigates acidity levels. Hb "mops up" H+ ions, but is now stabilized in T state ( bohr effect)

Question 75

how is CO2 driven up into alveoli after being excreted into plasma in the form of bicarbonate?

Answer 75

there is a reverse PCO2 gradient compared to that of the tissues. Blood Co2 is HIGHER than lung CO2. - carbonic anhydrase in the lung endothelium produces CO2 from plasma HCO3-. Elevated PO2 reduces CO2 binding with hemoglobin at any PCO2.

Question 76

Outline the Haldane Effect. What are the two mechanisms

Answer 76

Increased PO2 displaces CO2 into solution. The **unloading of O2** from Hb in the tissue capillaries facilitates the picking up of CO2 and H+ by Hb (produced by metabolism). The **ability of deoxygenated Hb to pick up CO2** and CO2-generated H+ is known as the **Haldane effect.** The Haldane effect and Bohr effect work in **synchrony** to facilitate gas exchange: Increased CO2 and H+ cause increased O2 release from Hb by means of the Bohr effect; **increased O2 release from Hb, in turn, causes increased CO2 and H+ uptake by Hb through the Haldane effect**. 2 mechanisms: 1) reverse carbamino reactoin (HbCo2 --\> Hb + CO2) 2) oxyhemoglobin is acidic: drives CO2 production from bicarbonate. H+ HCO3- --\> Co2 + H2O

Question 77

Haldane effect at the tissues vs Haldane effect at the lungs.

Answer 77

**at tissues;** enhancement of CO2 pickup by O2 release. Works in synchrony with bohr effect. ## Footnote The Haldane effect and Bohr effect work in synchrony to facilitate gas exchange: Increased CO2 and H+ cause increased O2 release from Hb by means of the Bohr effect; increased O2 release from Hb, in turn, causes increased CO2 and H+ uptake by Hb through the Haldane effect. **at lungs;** enhancement of CO2 dissociation in the presence of **high** O2.

Question 78

in mammals, the major loss of acid is by

Answer 78

breathing out CO2.

Question 79

if acid production exceeds acid loss, ____ can occur. two causes of this condition

Answer 79

acidosis can occur. can be caused by: 1) hypoventilation 2) metabolism (lactic acid buildup)

Question 80

is loss of acid exceeds production ____ occurs. 2 causes?

Answer 80

alkalosis may occur. causes: 1) hyperventilation 2) metabolic alkalosis.

Question 81

functions that are able to be regulated in order to influence respiration

Answer 81

1) rate of breathing 2) depth of breathing 3) diameter of airways

Question 82

three components of neural control in regulation of respiration

Answer 82

1) neural pattern generator: alternating rate of inspiration and exhalation 2) factors influencing magnitude of ventilation: depth of breathing is controlled bc cortical structures innervate skeletal muscle 3) other functions: cortex and other higher brain centers.

Question 83

which nerves innervate the diaphgrahm and intercostal muscles

Answer 83

phrenic and itnercostal nerves (somatic motor neurons). there fore, the diaphragm and intercostal muscles are neurally regulated

Question 84

which brain structure is responsible for determining the rhythmicity of breathing?

Answer 84

medulla oblongota.

Question 85

name 2 regions in the pons and 2 regions in the medulla that are responsible for breathing regulation, and outline their functions

Answer 85

pons: 1) pneumotaxic center: Off switch. Controls the apneustic center. 2) apneustic center: prolongs the activity of inspiratory neurons Medulla 1) dorsal respiratory group: inspiratory neurons. firing of these neurons causes INHALATION. inhibition of these neurons associated with EXHALATION 2) ventral respiratory gorup: has inspiratory and expiratory neurons, but is INACTIVE during normal breathing. Active when "overdrive is needed"

Question 86

the dorsal respiratory group is infleunced by the ___ \_\_\_\_ medulla, also known as the \_\_\_-\_\_\_ complex.

Answer 86

influenced by the rostral ventromedial medulla, aka pre-Botzinger complex

Question 87

what happens if you damage the pneumotaxic or the apneuristic regions of the pons?

Answer 87

results in irregular breathing because the pons dictates the duration of breath holding and such.

Question 88

Cerebral cortex methods of regulating respiration

Answer 88

voluntary regulation. but it has a limited capability; its important for vocalization in air brathers. It can also suppress breathing or reflex responses.

Question 89

What is the Hering-Beuer reflex?

Answer 89

an inflation reflex. triggered by stretch receptors in the airways, and limits inspiration. reflex triggered to prevent over-inflation of the lung. Pulmonary stretch receptors present in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations

Question 90

peripheral chemoreceptors in the heart that control respiration are:

Answer 90

1) carotid bodies 2) aortic bodies carotid body functions as a sensor: it responds to a stimulus, primarily O2 partial pressure, which is detected by the type I (glomus) cells, and triggers an action potential through the afferent fibers of the glossopharyngeal nerve, which relays the information to the central nervous system there are also **central chemoreceptors i**n the medulla

Question 91

why is it important that even just a small mmHg (detected by peripheral chemoreceptors) decrease in O2 triggers the increase in respiration and blood pressure

Answer 91

its important that a drop in pO2 is "caught early" and changes can be made because low O2 impairs respiratory centers in the brain stem and then you can't fix it if its "too late"

Question 92

T/F: peripheral chemoreceptors can detect a fall in HbO2 concentrations

Answer 92

FALSE. it can only detect PO2. Therefore, blood O2 can fall dangerously low without triggering the peripheral chemoreceptors. Because of the ideal gas law, PO2 remains the same regardless of the other components of the air. If CO is in the air, Hb will bind to CO instead because it has higher affinity, and so even though PO2 is the same, the Hb actually has no O2 bound, and the tissues are not being oxygenated

Question 93

T/F: peripheral chemoreceptors (carotid body and aortic arch) are sensitive to PCo2

Answer 93

false. they are barely sensitive to it. they mainly detect PO2.

Question 94

which chemoreceptors primarily detect changes in PCo2 and pH?

Answer 94

mainly the major detector mechanisms in the medulla. very sensitive to pH changes, can detect a 5mmHg increase in PCo2

Question 95

Why is the brain so sensitive to CO2 levels?

Answer 95

because brain CSF does not have much of a buffer system. CO2 from blood can easily cross into brain but it can't be buffered. Therefore, the brain is very sensitive in increasing PCO2. this allows the medulla to detect it at very low amounts.

Question 96

at PCo2 increases, the rate of ventilation\_\_\_\_

Answer 96

increases

Question 97

T/F: H+ ions can permeate throguh the blood brain barrier

Answer 97

false. therefore, pH changes due to lactic acid production can cause increased breathing rate if detected by PERIPHERAL chemoreceptors only.

Question 98

\_\_\_ and __ can be detected by medullary chemoreceptors and ___ and ___ can be deteced by peripheral chemoreceptors

Answer 98

CO2 and pH can be detected by medullary chemoreceptors and pH and O2 can be deteced by peripheral chemoreceptors pH can be detected by both: lactic acid/metabolic waste causes pH changes in peripheral CO2 acidosis can be detected by medullary

Question 99

When we exercise, there is actually a very little change in PCO2 or PO2 in our bodies to trigger our chemoreceptors to increase ventilation. Why do we increase our rate of resp during exercise then?

Answer 99

there are dif hypothesis: 1) input from joints might increase breathing rate: Joint and muscle receptors excited during muscle contraction re- flexly stimulate the respiratory center, abruptly increas- ing ventilation. 2) increase in Tb might increase breathing rate 3) epinephrine and fight or flight response: Epinephrine also stimulates ventilation as well as blood circulation, 4) anticipatory response. Espe- cially at the onset of activity, the motor areas of the ce- rebral cortex are believed to simultaneously stimulate both the medullary respiratory and cardiovascular centers at the same time it activates the motor neurons of the exercising muscles.