Respiratory Flashcards
In blood circulation what direction is the pressure gradient
gasses move down their pressure graident
describe the pulmonary circuit
O2 enters bloood CO2 leaves
Describe the sysemic circuit
O2 leaves blood CO2 enters
How does gas move throughout the respiratory system
diffusion
describe different anatomical and physiological properties to facilitate gas diffusion
Large surface area for gas exchange.
Large partial pressure gradients.
3) Gases with advantageous diffusion properties.
4) Specialised mechanisms for transporting O2 and CO2 between lungs and tissues.
what is partial pressure?
Sum of the partial pressures (mmHg) or tensions (torr) of a gas must be equal to total pressure
what are the two forms O2 is carried in the blood?
Dissolved
Bound to Heamaglobin
Is it a large or small amount of blood dissolved?
Only a small percentage of O2 in blood is in the dissolved form.
Amount of dissolved O2 in blood is proportional to its partial pressure
How is dissolved O2 measured clinically?
in arterial blood sample PaO2- piercing of artery (very invasive)
what is the amount of O2 dissolved in blood proportional too?
it’s partial pressure
Transport of O2 in dissolved form is not adequate for what?
Body’s requirement at rest.
How many heme groups are attached to the globin protein?
4 heam groups
What is the binding site for oxygen?
Each heme group contains
iron in the reduced ferrous
form (Fe+++), which is the
site of O2 binding.
how much oxygen does HB molecules in red blood cells
280 million Hb molecules
why does binding and dissociation of O2 with Hb occur in milliseconds?
because red blood cells in capillaries for one second only
Does the acidity of the blood affect the binding of Haemoglobin?
Yes so does temperature
Is O2 binding to Hb reversable?
Yes
What does oxygen saturation refer to?
to the amount of O2 bound to Hb relative to maximal amount that can bind.
When is Haemoglobin almost 100% saturated?
100 mmHg PO2
At what point does a drop in partial pressure have an effect?
<60 mmHg
How would you measure O2 saturation (SaO2)?
Pulse oximeter- measures ration of absorption and infrared waves
Healthy Individuals should have what percentage if oxygen saturation?
96-100% saturation
total oxygen capacity- 211 mlsO2/1L
How much more efficent is Haemoglobin at carrying oxygen around the blood?
hemoglobin 208 in 1L
dissolved 3 mls/ 1L
What is the respiratory exchange ratio?
Ratio of expired CO2 to O2 uptake
What are the 3 forms is CO2 carried in?
i)7% dissolved.
ii)23% bound to
haemoglobin (Hb).
iii) 70% converted to
bicarbonate.
In a bicarbonate reaction what effects does the concentration gradient have?
Speed and direction of the reaction
What has an effect in maintaining the acid-base balance in the body?
The CO2 to HCO3- pathway plays a critical role in regulation of H+ ions and in maintaining acid- base balance in body
What enzyme converts CO2 to HCO3
H2CO3
What organ/organs help to regulate bicarbonate concentration?
the kidneys
What shape is the O2 dissociation curve?
S-shaped Curve
Name some factors that affect Breathing
sleep, phonation, emotion, cardiovascular, temperature, exercise, mechanoreception, and chemoreception.