Lecture 10: Gas Exchange Flashcards
What are the 5 elements that make up terrestrial air?
Nitrogen, oxygen, argon, water, carbon dioxide
What is the concept of Dalton’s Law?
Each gas in a mixture exerts its own pressure, and the total pressure of gas is the sum of all partial pressure.
Describe Henry’s law.
Gas moves from high pressure to low pressure, solubility shit…
What are the three factors that influence the movement of O2/CO2 across a respiratory membrane?
- partial pressure
- alveolar ventilation –> pulmonary blood perfusion
- structural characteristics of respiratory membrane
What happens when O2 is low? CO2 high?
Arterioles constrict and blood is redirected to respiratory areas. When high, bronchioles dilate to allow CO2 to be eliminated from body rapidly.
What are some examples of things that can impede gas exchange by interrupting surface area of resp system?
pneumonia, tumors, inflammation, emphysema
Hemoglobin, or HbA, is composed of what? What happens when O2 is picked up?
4 subunits - 2 alpha polypeptides, 2 beta. Each sub-unit has a heme group w/ iron that can bind O2 and becomes oxyhemoglobin.
As acidity increases, what happens to affinity of hemoglobin?
O2’s ability to attach to hemoglobin DECREASES because oxygen wants to enter tissues.
What happens when temperature changes occur?
Temp increase, more O2 released from Hb. During hypothermia, less O2 needed, stays bound to Hb.
What molecule decreases the affinity of Hb? When is it formed?
2,3-biphosphoglycerate. Formed in cells during glycolysis.
What are the three ways that CO2 is transported in the blood?
- dissolved CO2 in plasma
- carbamino compounds
- bicarbonate ions
What two parts of the brain fall under the ‘respiratory center?’
Medullary respiratory, pontine respiratory
What does the dorsal group (medullary) innervate? Ventral?
Dorsal: diaphragm, external intercostals
Ventral: Pre-botzinger complex sets the rhythm of breathing during forceful breathing
The pontine respiratory group is active during both ____ and ____. It transmits pulses to the ______ and modifies basic rhythm in the ____.
Inhalation, exhalation. DRG, VRG
Where are central chemoreceptors and what do they do?
In CNS, medulla. Respond to changes in H+, CO2 levels in CSF.
Where are peripheral chemoreceptors located and what do they do?
Located in aortic/carotid bodies, respond to changes of O2, H+, CO2 in blood.
Where are baroreceptors located and what do they do?
Located in walls bronchi and bronchioles. When overinflated, activates the DRG to protect against bursting.
What is the DRG activation, when new inhalation begins, called?
Hering-Breuer reflex
What are 4 other influences on the respiratory system?
Limbic system, temp, pain, airway irritation
