Lecture 12 Flashcards
Oxygen Transport:
- ______% bound to hemoglobin
- _____% is gas dissolved in plasma (low solubility compared to CO2)
- arterial blood carries about ______ mL of O2 per liter, so about ___ L of O2 in our body
- 98.5%
- 1.5%
- 200; 1
Hemoglobin
- Four protein (globin) portions
- each has a heme group, binds one O2 to an ____ atom
- ____________________ (____): O2 bound to hemoglobin
- ____________________ (HHb): hemoglobin with no O2
-serves as a _______ for H+
- iron
- oxyhemoglobin (HbO2)
- Deoxyhemoglobin (HHb)
- buffer
One hemoglobin can carry up to ___ O2
- _____% saturation Hb with ___ O2 molecules per Hb
- _____ % saturation Hb with ___ O2 molecules per Hb
- 100%; 4
- 50%; 2
Carbon Dioxide is _________ in the blood in three forms:
1. _________________ (___% of CO2)
2. ________________ (___% of CO2)
3. ________________ (___% of CO2)
transported
1. Gas; 5%
2. Carbonic acid; 90%
3. Carbamino compounds; 5%
Carbon Dioxide transportation
- Gas: dissolved in _______
- Carbonic acid: __________ –> _______–> __________
-this reaction occurs _______ in the blood plasma
-occurs _______ in RBC, catalyzed by enzyme _____________
- Carbamino compounds: CO2 + ________–> carbamino compounds (mostly _____________)
- blood plasma
- CO2+ H2O –> H2CO3–> HCO3- + H+
-slowly
-rapidly; carbonic anhydrase - plasma protein; carbaminohemoglobin (HbCO2)
Relative amounts of CO2 _________ from the blood to the alveolar air from these 3 reservoirs are __________ from the relative amounts transported in the blood
- while most exchanged CO2 comes from carbonic acid, it is not the full percentage present in blood; ____ % CO2
- more exchanged CO2 comes from ___________ than is present in blood; ____% CO2
- slight more gaseous CO2 is delivered to the alveoli than is present in blood; ___% CO2
exchange; DIFFERENT
- 70%
- carbamino compounds; 23%
- 7%
Blood gives up the ____________ and CO2 from the ____________ more easily than CO2 from __________________________
dissolved CO2 gas; carbamino compounds; bicarbonate-carbonic acid
Systemic Gas Exchange (in ________)
- ______ O2 from hemoglobin released into tissue
- ______ dissolved O2 gas released into tissue
- ______ CO2 + H2O into RBC, converted into H2CO3 —> HCO3- + (H+) by _____________
- ______ dissolved CO2 gas into blood
- ______ CO2+ plasma protein—> ______________
- _________ ______: uses HCO3- & Cl- ______ to put Cl- ____ and HCO3- _______ of RBC
-this helps keep concentration gradient going
Tissues
- 98.5%
- 1.5%
- 70%; carbonic anhydrase
- 7%
- 23%; carbamino compounds
- Chloride shift; antiport; IN; OUT
Alveolar Gas Exchange
- ______ O2 released into RBC to bind to HHb–> _____ + (H+)
- ______ O2 dissolved gas into plasma
- HCO3- + (H+)—> H2CO3—> CO2+H2O (70%) converted by ____________ and released into alveoli
- _____ dissolved CO2 gas into alveoli
- carbamino compounds—> CO2 + plasma protein (___%) into alveoli
- __________ __________ _______: uses HCO3- & Cl- antiport to put Cl- ______ and HCO3- _____ RBC
- 98.5%; HbO2
- 1.5%
- carbonic anhydrase
- 7%
- 23%
- Reverse Chloride shift; OUT; IN
hemoglobin unloads O2 to match ___________ needs of different states of activity of the tissues
FOUR factors adjust the _____ of oxygen unloading to match need:
1.
2.
3.
4.
metabolic; rate
1. Ambient PO2
2. Ambient pH (Bohr effect)
3. Temperature
4. Bisphophoglycerate (BPG)
- Ambient PO2
- active tissue has ______ PO2
- O2 is ________ from Hb - Ambient pH (Bohr effect)
- Active tissue has _____ CO2
- _______ pH of blood
- __________ O2 unloading
- decreased
- released
- increased
- lowers
- promotes
Acidosis= blood pH ______ than _____
Alkalosis= blood pH ______ than _____
lower; 7.35
higher; 7.45
- Temperature
- active tissue has ______ temp; _______ O2 unloading - Bisphophogylcerate (BPG)
- RBCs produce BPG which binds to ____; O2 is _________
- ______ body temp (fever), _________, ___________, __________, and ____________ all raise BPG and _______ O2 unloading
- increased; promotes
4.
- Hb; unloaded
- increased; thyroxine; growth hormone; testosterone; epinephrine; PROMOTE
Percentage saturation of Hb at normal systemic capillaries: ____%
78%
Oxyhemoglobin dissociation curve:
Left Shift:
- _______ O2 unloading to tissue
- _______ H+ (_____ pH)
- _______ PCO2
- _______ 2,3-BPG
- _______ temperature
Right Shift:
- ______ O2 unloading to tissue
- _______ H+ (_____ pH–> Acid)
- _______PCO2
- _____ 2,3-BPG
- ______ temperature
- ____________
- _________ altitude
Left shift:
- decrease
- decrease (increase)
- decrease
- decrease
- decrease
Right shift:
- increase
- increase (decrease)
- increase
- increase
- increase
- exercise
- high
Blood Gases and the Respiratory Rhythm:
Rate and depth of breathing adjust to maintain arterial blood levels of:
- pH _____ to ______
- PCO2 ___ mmHg
- PO2 ____ mmHg
Brainstem respiratory centers receive input from ______ and ______ _____________ that monitor composition of ______ and _______
- most POTENT stimulus for breathing is _____, followed by ______, and least significant is _______
- 7.35; 7.45
- 40
- 95
central; peripheral; chemoreceptors; CSF; blood
- pH; CO2; O2
Pulmonary ventilation adjusted to maintain pH of the _____
- ________ chemoreceptors in medulla produce about ___% of the change in respiration induced by pH shift
-CO2 crosses _________ and reacts with water in ____ to produce _______ ______
-the ____ from _________ strongly stimulates ________ chemoreceptors, since CSF does not contain much protein buffer
- Hydrogen ions also stimulate ____________________- which produce, _____% of the respiratory response to pH changes
Brain
- central; 75%
-BBB; CSF; carbonic acid
-H+ carbonic acid; central
- peripheral chemoreceptors; 25%
____________: PCO2 less than 37 mmHg
- most common cause of ____________
___________: PCO2 greater than 43 mmHg
- most common cause of ____________
hypocapnia
- alkalosis
hypercapnia
- acidosis
- __________ can be a corrective homeostatic response to _________ (gets rids of CO2)
- ___________ can be a corrective homeostatic response to _________ (not exhaling as much, retaining CO2)
- hyperventilation; acidosis
- hypoventilation; alkalosis
PO2 usually has little effect on respiration at low elevations except with ________ ______________
- only if arterial PO2 < ____ mmHg (_____ bodies sense this)
-stimulates _______ breathing
- Hypoxic drive
-respiration driven ________ by low PO2 than by CO2 or pH
-can occur in: _________, ____________ or at ________ elevations after several days
chronic hypoxemia
- 60 (carotid)
-heavy
- MORE
-emphysema; pneumonia; high
Respiration and Exercise:
Causes of increase respiration during exercise
- when the brain sends motor commands to the muscles, it also sends this information to the __________ _______
-they increase pulmonary ventilation in _________ of the needs of the exercising muscles
- Exercise stimulates ____________ of muscles and joints, they transmit excitatory signals to brainstem ___________ _______
-increase breathing because they are informed that muscles are moving- prior to body’s demand/need for more O2
-increase in pulmonary ventilation keeps blood gas values at their normal levels in spite of the elevated____ consumption and _____ generation by the muscles
- respiratory centers
-anticipation - proprioceptors; respiratory centers
- O2; CO2
____________: deficiency of oxygen or the inability to USE oxygen
- a consequence of respiratory diseases
____________ ___________: state of low arterial PO2
- usually due to inadequate pulmonary ____ _________
- many possible causes:
-oxygen deficiency at high elevations; ________ ventilation: drowning, aspiration of a foreign body, respiratory arrest, degenerative lung diseases
Hypoxia
hypoxemia hypoxia
- gas exchange
- impaired
- ___________: inadequate circulation of blood
-congestive ______ failure - _____________: due to inability of the blood to carry adequate oxygen
- _____________: metabolic poisons (for example, cyanide) prevents O2 use in tissue
- Hypoxia is often marked by __________ (blueness of skin)
- ischemic hypoxia
-heart - anemic hypoxia
- histotoxic hypoxia
- cyanosis
Oxygen imbalances: too much
- Although safe to breathe ____% oxygen at 1 atm for a few hours, ________ _________ develops when pure O2 breathed at _____ atm or greater
-generates _____ ______ and ________
-destroys ____________
-damages ____________ ______
-leads to seizures, coma, death
- 100%; oxygen toxicity; 2.5
-free radicals; H2O2 (hydrogen peroxide)
-enzymes
-nervous tissue
