Body Systems L20 Flashcards by Jade Benita McLaughlin

Describe what gases are transported from which systems / organs in the blood. (Major 2 paths)

• Transportation of Gas:
- O2 -> Alveoli to systemic tissues
- CO2 -> Systemic tissues to alveoli
Via Transportation -> Blood.

How well did you know this?

Not at all

Perfectly

Describe the features required for efficient gas exchange in the blood

•	Gas Transportation -> Blood:
-	Diffusion 
 Surface area 
    >> Large 
    >> Moist 
 Diffusion distance
    >> Short
 Conc. gradient / Diff. -> Partial pressure
    >> Alveolar air &amp; blood
 Solubility of gases
 Coordination -> Blood &amp; Air flow

How well did you know this?

Not at all

Perfectly

What are the partial pressures of N2 in the lungs alveoli & pulmonary veins?

-	Atmosphere
	N2 -> 78.6% -> 597mmHg
-	Alveoli
	N2 -> 75.4% -> 573mmHg
-	Pulmonary Veins
	N2  -> 12.5 ml/L

How well did you know this?

Not at all

Perfectly

What are the partial pressures of O2 in the lungs alveoli & pulmonary veins?

-	Atmosphere
	O2 -> 20.9% -> 159mmHg
-	Alveoli
	O2 -> 13.2% -> 100mmHg
-	Pulmonary Veins
	O2 -> 3 ml/L

How well did you know this?

Not at all

Perfectly

What are the partial pressures of CO2 in the lungs alveoli & pulmonary veins?

-	Atmosphere
		CO2 -> 0.04% -> 0.3mmHg
-	Alveoli
	CO2 -> 5.2% -> 40mmHg
-	Pulmonary Veins
	CO2 -> 26 ml/L

How well did you know this?

Not at all

Perfectly

What is the partial pressures of water in the atmoshpere vs. the alveoli of the lungs?

Atmoshpere
 H2O -> 0.46% -> 3.7mmHg
Alveoli
 H2O -> 6.2% -> 47mmHg

How well did you know this?

Not at all

Perfectly

What is Dalton’s Law?

• Dalton’s Law of Partial Pressure:

 Total pressure exerted by mixture of gases = Sum of pressures exerted independently by each gas in mixture.

How well did you know this?

Not at all

Perfectly

What is the partial pressure (Dalton’s Law)

 Partial pressure
 Pressure exerted by each gas
 Directly proportional to % in total gas mixture
Eg. Partial pressure of O2 -> Sea Level
&raquo_space; 20.9% of gases at sea level
&raquo_space; Atmospheric pressure = 760mmHg
-» 20.9 x 760 = 159mmHg (Partial Pressure)

How well did you know this?

Not at all

Perfectly

Describe the relationship between atmospheric pressure & altitude

• Atmospheric pressure decr. with incr. altitude above sea level.

How well did you know this?

Not at all

Perfectly

What are the partial pressures found in the capillaries & alveoli in the pulmonary circuit?

-	Pulmonary Circuit:
>> External Respiration 
	Capillary: 
P(O2) = 40
P(CO2) = 45 
	Alveolus:
P(O2) = 100
P(CO2) = 40
	Capillary :
P(O2) = 100
P(CO2) = 40

How well did you know this?

Not at all

Perfectly

What are the partial pressures found in the capillaries & alveoli in the systemic circuit?

-	Systemic Circuit:
>> Internal Respiration
	Capillary: 
P(O2) = 95
P(CO2) = 40
	Tissues:
P(O2) = 40
P(CO2) = 45
	Capillary :
P(O2) = 40
P(CO2) = 45

How well did you know this?

Not at all

Perfectly

What is Henry’s Law?

• Henry’s Law:
- The amount of gas that dissolves in water determined by
 Solubility in water
 Partial pressure in air

How well did you know this?

Not at all

Perfectly

Describe the conditions of equilibrium of Henry’s Law

At equilibrium:
 Vol. -> Dissolved gas in solution proportional to partial pressure of gas.
Eg. Incr. P(Gas) -> Incr. # gas molecules in solution
Incr. P(O2) -> Incr. amount of O2 in solution.

How well did you know this?

Not at all

Perfectly

Outline the gas diffusion requirements of the human body

•	Gas Diffusion Requirements:
-	At alveolar P(O2) -> (100mmHg)
	1L plasma dissolves 3ml O2
	Blood Flow -> Tissues = 5 L/min
                     >> 15 ml/min O2
-	Requires >200 ml/min (200-3000 ml/min)
-	1 L blood -> 195ml O2

How well did you know this?

Not at all

Perfectly

Describe the structure of Haemoglobin

•	Haemoglobin:
-	4 globular protein subunits
>> 2 alpha 
>> 2 Beta
-	Each subunit 
>> Protein -> Globin
>> Non-protein group -> Haem
                                             --> Fe2+ -> Porphyrin ring

How well did you know this?

Not at all

Perfectly

State the reaction which occurs at haemoglobin & 2 properties of this reaction

Hb + O2 HbO2
Hb -> Deoxy-haemoglobin ; HbO2 -> Oxyhaemoglobin
&raquo_space; Rapid & reversible

How well did you know this?

Not at all

Perfectly

How many oxygen molecules does each Hb molecule bind with?

Each haem portion -> Haemoglobin

 Binds -> 4 molecules -> O2

How well did you know this?

Not at all

Perfectly

Describe the different ways in which oxygen is transported in the blood & the proportions of oxygen transported by these methods.

• Transportation of O2:

Approx. 97% O2 transported in Blood -> Using Hb
Remaining 3% O2 transported in Blood -> Plasma

How well did you know this?

Not at all

Perfectly

Describe the uptake of O2 by haemoglobin and what this causes.

 Hb changes shape upon binding with O2
&raquo_space; Enables further uptake of O2 -> Positive Feedback
&raquo_space; Binding of O2 mol. to Hb cause change in shape of Hb
> Enables easier successive binding of O2 to Hb.
&raquo_space; As max. limit of O2 binding approaches, affinity decreases.

How well did you know this?

Not at all

Perfectly

What is Hb saturation?

 Hb Saturation:

 % of haem units per Hb mol containing bound O2

How well did you know this?

Not at all

Perfectly

What is Hb saturation affected by?

 Affected by:
>> Partial pressure O2  - > P(O2) -> Blood
>> Blood pH
>> Temperature
>> No. of O2 mol. already bound -> haem 
      ---> O2 dissociation Curve

How well did you know this?

Not at all

Perfectly

What is the oxygen dissociation curve?

 O2 Dissociation (Saturation) Curve

 Graph illustrating Saturation of Hb in relation to P(O2) in blood

Describe the shape of the oxygen dissociation curve?

Steep portion of curve
    >> Range ->  % saturation within systemic capillaries. 
       > 75 – 100% saturation
         -->> P(O2) ~ 40mmHg 
    >> 100% sat. of Hb within alveoli

Steep rise followed by plateau

List the factors which influence the affinity of Hb for O2?

 Factors influencing affinity for O2:
% saturation & affinity of Hb for O2:
&raquo_space; Increases with each successive binding of O2 to Hb
&raquo_space; Increases with incr. P(O2)
» Partial pressure O2 - > P(O2) -> Blood
» Blood pH
» Temperature
» No. of O2 mol. already bound -> haem

Describe the affinity of Hb for O2 in relation to pH

>> Decr. with incr. pH > Incr. pH (incr. H+ conc.) alters ionic bonds -> protein structure of Hb > Changes shape of Hb -> Less able to bind -> O2

Describe the affinity of Hb for O2 in relation to CO2

>> Decr. with incr. p(CO2) > Incr. CO2 causes incr. acidity of blood -> Incr. pH -> change in shape -> proteins of Hb -> Less able to bind -> O2

Describe the affinity of Hb for O2 in relation to temperature

>> Decr. affinity with incr. temperature > Incr. temperature denatures bonds within Hb > Changes shape of Hb -> Less able to bind -> O2

Describe the Bohr shift in relation to pH & CO2 (unloading of O2 to tissues)

``` Unloading of O2 -> Tissues >> Incr. pH & Incr. CO2 o Curve shifts --> >> Bohr Shift >> Incr. efficiency of unloading >> Higher % saturation at lower P(O2) ```

Describe the Bohr shift in relation to the temperature(unloading of (O2 to tissues)

>> Incr. temperature - Higher -> Active tissues - Incr. 2,3 diphosphoglycerate (2,3-DPG) -> Anaerobic conditions o Curve shifts --> >> Bohr Shift >> Incr. efficiency of unloading >> Higher % saturation at lower P(O2)

Describe the effect of altitude on breathing / o2 as altitude increases

``` • Altitude & Oxygen Transportation:  High Altitude: Faster, deeper breathing  V. High Altitude: Hypoxia -> V. low blood O2 conc  Extreme: Foggy Brain, Weak muscles. ```

What factors change as altitude increase in relations to gas exchange?

```  Changes: >> Arterial Mean P(O2) >> O2 saturation >> Haemoglobin conc >> O2 content ```

Name the types of haemoglobin

Carboxyhaemoglobin Methaemoglobin Foetal haemoglobin

Describe carboxyhaemoglobin

- Carboxyhaemoglobin:  Stronger binding -> CO >> (200x greater)  Greatly reduces ability of O2 binding to Hb

Describe methaehaemoglobin

``` - Methaemoglobin:  Fe2+ oxidised -> Fe3+ >> Drugs  Unable to carry O2 >> Slow reconversion ```

Describe foetal haemoglobin

``` - Foetal haemoglobin:  2 alpha & 2 ץ  Higher affinity -> O2  Important -> O2 transfer across placenta  Higher % saturation at lower P(O2) ```

How and where is CO2 produced in the body?

- Generated -> Aerobic metabolism -> Peripheral tissues

Name the methods in which CO2 is transported in the blood & what proportion of CO2 is transported in each

70% -> bicarbonate ion -> plasma 23% -> bound ->Haemoglobin 7% dissolves -> plasma

Describe the most common transportation method of CO2 in the blood

1. 70% converted -> carbonic acid formation -> H2CO3- >> Carbonic anhydrase enzyme -> Transported in plasma -> Bicarbonate ion HCO3- >> CO2 + H2O -> H2CO3 H2CO3 -> H+ & HCO3- -> Chloride shift >> HCO3- moves out RBCs & replaced by Cl -

Describe the transportation of CO2 in the blood using Hb

. 23% Bound -> Haemoglobin ->> Carbahameoglobin >> Hb-(NH2) + CO2  Hb-(NHCOOH) -> Carbamino group

Describe the least common method of transportation of CO2 in the blood

. 7% dissolved -> Plasma

Describe the chloride shift

-> Chloride shift >> HCO3- moves out RBCs & replaced by Cl - -> Bicarbonate ion (formed as result of carbonic anhydrase reaction with carbonic acid)

Write the equation for formation of bicarbonate ions for transportation of CO2 in the blood

>> CO2 + H2O -> H2CO3 | H2CO3 -> H+ & HCO3-

What kind of ion is CO2 transported as in the blood?

Bicarbonate

What is the name of the complex formed when CO2 is transported using haemoglobin

->> Carbahameoglobin

What is the equation for the formation of a carbamino group involved in transportation of co2 in the blood/

>> Hb-(NH2) + CO2  Hb-(NHCOOH)

Describe buffering in RBCs

• Buffering in RBCs: - Every CO2 -> HCO3- reaction yields H+ >> Leads to acidic pH - Consumption / release of H+ minimises incr. pH >> Imidazole groups of histidine residues in haemoglobin -> Act as buffers. >> Hb-(N)-(NH) + H+  Hb-(N)-(NH2+) - Deoxygenated Hb -> Strongest affinity for H+

What is the purpose of releasing H+ in the buffering of RBCs?

- Consumption / release of H+ minimises incr. pH >> Imidazole groups of histidine residues in haemoglobin -> Act as buffers.

Write the equation for formation of Imidazole groups of histidine residues in haemoglobin

>> Hb-(N)-(NH) + H+  Hb-(N)-(NH2+)

What kind of Hb has the strongest affinity for H+?

- Deoxygenated Hb -> Strongest affinity for H+

Describe the Haldane effect in the lungs

``` • Haldane Effect: - Lungs:  Oxygenation of Hb >> Conformational change -> Hb  Lower affinity -> H+ >> Decr. buffering ability  H+ released >> Aids in unloading of O2 -> lungs ```

Describe the Haldane effect in the tissues.

``` - Tissues:  Deoxygenation of Hb >> Conformational change -> Hb  Higher affinity -> H+ >> Incr. buffering ability  Uptake of H+  Transportation of CO2 from tissues ```

What is the name of the molecule formed as a result of incr. temperature & active tissues?

. 2,3 diphosphoglycerate (2,3-DPG)

In what conditions does formation of 2.3 diphosphoglycerate occur?

>> Incr. temperature - Higher -> Active tissues - Incr. 2,3 diphosphoglycerate (2,3-DPG) -> Anaerobic conditions