Gas Exchange 2 Flashcards
What are metalloproteins
Proteins, like hemoglobin, that bind O2 to their heme group
What increases O2 carrying capacity of blood
Metalloproteins
Where is hemoglobin located
Red blood cells
What is hemoglobin
Tetramer - 4 polypeptide chains each containing a heme group.
What is the molecule called after O2 binds to a heme group
Oxyhemoglobin
Each hemoglobin can carry how many O2
4 O2 molecules
When is hemoglobin in relaxed state (R)
When it is bound to O2
When is hemoglobin in tense state (T)
When it is not bound to O2
What affects O2 equilibrium of hemoglobin
pH (Bohr effect)
What are two ways to alter hemoglobin content of blood
- Physiological acclimatization
2. Developmental acclimatization
What decreases the affinity of hemoglobin for O2 and increases O2 availability to tissue cells
- Increased temperature
- Increased CO2
- Decreased pH
- Increased 2,3 diphosphoglycerate (2,3 DPG)
What does 2,3 DPG do
Allosterically regulator of hemoglobin (decreases affinity for O2)
What generates 2,3 DPG
Red blood cells
Increased CO2 in tissues =
Decreased pH (more protons, more acidic)
When Po2 is decreased, what do red blood cells do
Increase production of 2,3 DPG
What happens in metabolically active tissues
- Increased ATP–>Increased Temperature
- Increased CO2–>Decreased pH
- At decreased PO2–>RBC stimulates 2,3DPG
- O2 affinity decreased
- Hemoglobin in (T) state
- More O2 becomes available to the tissue and the dissociation curve shifts to the right
How many heme groups does myoglobin have?
Only 1
Does myoglobin have a high or low affinity for oxygen
High
What is a good molecule to store O2 in
Myoglobin
Where is myoglobin found
Muscle
What are the three forms that CO2 is transported by
- Dissolved Co2 (7%)
- Carbaminohemoglobin (23%)
- Bicarbonate ion (70%)
What is the Haldane effect
When deoxygenated blood can carry more CO2 than oxygenated blood.
What is more favorable in tissues: CO2 to bicarbonate or Bicarbonate to CO2
CO2 to Bicarbonate (HCO3-)
What is responsible for the conversion of CO2 to Bicarbonate and vice versa
Carbonic Anhydrase
What moves bicarbonate out of the cell
A Cl-/Bicarbonate exchanger moves bicarbonate out of the cell. This is called the chloride shift.
What is the reverse chloride shift
When bicarbonate moves into the cell by a Cl-/Bicarbonate exchanger. This promotes CO2 out of the cell
Where doe the reverse chloride shift take place
The lungs
Where is ventilation rhythm monitored and regulated
The brain stem, within the pons and medulla oblongata
How are changes in O2 and CO2 concetrations within the blood detected
Chemosensory neurons in the aorta and carotid arteries
What prevents overexpansion of the lungs through negative feedback
Stretch receptors
What factors increase respiratory rate
- Increased body temperature
- Adrenal gland secretes epinephrine
- Reflexes originating from body movement (proprioceptors) send signals to cerebral cortex
- Signals from the cerebral cortex
What are bronchioles wrapped in
Smooth muscle
What role does the bronchiole smooth muscle play
Can dilate or constrict to increase or decrease gas exchange
What regulates the amount of inflow of gas
Sympathetic & parasympathetic systems
What does the sympathetic system do to regulate inflow of gas
Dilates bronchioles (works through the thoracic spinal cord)
What does the parasympathetic system do to regulate inflow of gas
Constricts bronchioles (works through Cranial Nerve X)
What signals vasoconstriction in the lungs
Low O2
